POLLUTION FROM THE TOLUKUMA

POLLUTION FROM THE TOLUKUMA GOLD MINE

IN THE AUGA-ANGABANGA RIVER SYSTEM

PAPUA NEW GUINEA

A. & S.R. TINGAY PTY LTD

2006 Cover: Children swimming in the unpolluted Yeme River in foreground with the Auga River in the background. The very high levels of sediment that are evident in the Auga are due to the disposal of tailings into the river from the Tolukuma Gold Mine. (Photo: Brendan Ross/Oxfam Australia)

ACKNOWLEDGEMENTS This study of pollution in the Auga-Angabanga River system would not have been possible without the help of many people both in Papua New Guinea and Australia. We especially thank Oxfam Australia for sponsoring the study and the following for their assistance, support and advice: Shanta Martin (Mining Ombudsman), Ingrid Macdonald (former Mining Ombudsman), Brendan Ross, Katy Southall and Sara Bice of Oxfam Australia. Matilda Koma, Augustine Hala, Seymour Pok and Philip Ugu of the Centre for Environmental Research and Development in Papua New Guinea. Associate Professor Jack Ng and his colleagues at the National Research Centre for Environmental Toxicology at the University of Queensland. The Fuyuge people of Fane and in particular the communities of Tula, Dubuilenga, and Hala on the Auga River and the Mekeo communities of Veifa’a, Rarai and Inauauni on the Angabanga River.

A. & S.R. Tingay Pty. Ltd. A. & S.R. Tingay Pty. Ltd. is an environmental consultancy based in Perth, Western Australia. It was formed in 1975 and since that time has specialised in the preparation of environmental impact assessments and other major multi-disciplinary studies. Its principal, Dr Alan Tingay, has managed many such studies for industrial and marine projects, mining and mineral processing plants (gold, vanadium, uranium, mineral sands, off-shore oil and gas), road and pipeline corridors, urban development, and waste management and disposal (municipal, and hazardous and intractable materials). He also has been responsible for the preparation of management plans for conservation and community reserves, design of research studies, investigation and rehabilitation of contaminated sites, environmental audits and management systems, wildlife studies, and the design and implementation of environmental monitoring studies.

TABLE OF CONTENTS SUMMARY ................................................................................................................................... 1 1. INTRODUCTION..................................................................................................................... 4 2. METHODS ................................................................................................................................ 7 3. RESULTS ................................................................................................................................ 10

3.1 Village Water Supplies..................................................................................................... 10 3.2 Physical Description of the Rivers .................................................................................. 11 3.3 Temperature ..................................................................................................................... 11 3.4 Dissolved Oxygen.............................................................................................................. 12 3.5 pH....................................................................................................................................... 13 3.6 Turbidity ........................................................................................................................... 13 3.7 Total Arsenic and Metal Levels in the Tailings............................................................. 16 3.8 Total Arsenic and Metal Levels in the River System.................................................... 16 3.9 Dissolved Arsenic and Metal Levels in the River System............................................. 19 3.10 Arsenic and Metal Levels in Sediments........................................................................ 21 3.11 Statutory Compliance .................................................................................................... 26

4. DISCUSSION .......................................................................................................................... 27

4.1 Village Water Supplies..................................................................................................... 27 4.2 Pollution of the River System.......................................................................................... 27 4.3 Statutory Compliance ...................................................................................................... 30

5. CONCLUSION ...................................................................................................................... 35 6. REFERENCES........................................................................................................................ 36 APPENDIX 1 - RESULTS OF ANALYSES ............................................................................ 38

Pollution from the Tolukuma Gold Mine 1

SUMMARY The Tolukuma Gold Mine is located about 100km north of Port Moresby at an altitude of about 1700m. It has been in operation since 1994. Waste (tailings) resulting from the gold extraction process at the mine has been discharged since then into the nearby Auga River. The Auga connects with the Angabanga River, which in turn flows to the sea about 110 kilometres downstream from the discharge point. According to the owners of the mine, 141,900 tonnes of tailings were discharged into the rivers during 2003. This report describes the results of a study carried out in August 2004 of the extent and nature of pollution that is caused by the tailings discharge. In this study we assessed standard indicators of water quality (pH or acidity/alkalinity, dissolved oxygen and turbidity) and collected total (unfiltered) water, filtered water and streambed sediment samples at a number of locations along both the Auga and Angabanga Rivers. Samples were also collected from a tributary of the Auga River and another coastal river for comparison, and from two village water supplies that appeared to be independent of the rivers. One of the village water supply samples had an elevated level of arsenic and the other of mercury. These results need to be confirmed by further sampling. The tailings have very high levels of suspended solids. As a consequence, turbidity levels are extremely high in the Auga River and are elevated in the Angabanga River about 90km downstream of the mine. Comparison of the levels with Australian Water Quality Guidelines indicates that the turbidity in the Auga River is sufficient to probably have eliminated all aquatic life. Changes in species composition and populations are also probable in the Angabanga River further downstream. The tailings also contain high levels of arsenic, copper, lead, mercury and zinc and elevated levels of these were present in water and streambed sediment samples collected downstream. The rivers were a primary source of domestic water for many villages prior to the waste discharge from the Tolukuma gold mine. It is not known how many villages continue to use the water but there are at least two that depend on the Angabanga River for their water supply. Therefore, the degree of the pollution can be illustrated by comparing the levels of arsenic and metals in the samples with guidelines for drinking water. These are based on unfiltered or total water samples. In this study we compare the results with the Australian Drinking Water Guideline (ADWG) levels as these are based on an extensive review of the toxicological literature. The total arsenic and lead levels in all unfiltered water samples from both rivers exceeded the ADWG levels and total mercury in the Auga River and at one location on the Angabanga River also exceeded the guideline level. The degree of pollution in the river system can also be considered by comparing the results of the analyses with water quality guidelines for the protection of aquatic species of plants and animals. These guidelines are based on filtered water samples that indicate the levels of dissolved toxicants, and derive from laboratory studies of acute toxicity, i.e. the amount of a dissolved toxicant that will kill test organisms. It is important to remember that long-term exposure to lower levels of toxicants than are specified in the guidelines may also have an impact on aquatic plants and animals. The results from the samples were evaluated by comparison with the Australian Water Quality Guidelines. These guidelines are based on extensive literature reviews. They specify Trigger Values (TV), which are estimates that are considered to provide protection to a defined percentage of aquatic species. The Auga and Angabanga Rivers are now highly disturbed ecosystems according to the definitions of levels of disturbance in the Australian guidelines, although they were relatively undisturbed prior to the commencement of mining operations. The suggested TV for highly disturbed ecosystems depends on management objectives and range from high (95%) to low (80%) levels of protection. The results indicate that there are levels of dissolved copper in the Auga River and of dissolved mercury


in the Angabanga River that exceed the AWQ TV for the protection of 80% of aquatic organisms. There also are elevated levels of zinc and lead in a few samples from the Auga River that exceed the AWQ TV for the protection of 95% of aquatic organisms. The levels of toxicants in streambed sediments also indicate the degree of pollution in a river system. It was apparent from visual inspection during the field work that sediment in the tailings discharge had been deposited on the beds and margins of the Auga and Angabanga Rivers as layers of light grey-brown silt. This material contains a reservoir of toxicants that are a source of contaminants for organisms that live on or in the streambed and therefore may be introduced into food chains. The sediments also are likely to contribute to the levels of dissolved toxicants in the water column. Streambed sediment samples were collected in the present study from the margins of the rivers and were analysed to provide an indication of the levels of toxicants that are in this reservoir. The results are compared with the US National Oceanic and Atmospheric Administration (NOAA) reference levels for freshwater sediments. These levels are the Threshold Effects Level (TEL) and the Probable Effects Level (PEL). The TEL represents the concentration below which negative effects on the health of aquatic organisms are expected to occur only rarely. The PEL is the level above which effects are expected frequently. The data indicate that there are very high levels of arsenic, lead, mercury and zinc in streambed sediments from the upper Auga River and high levels of the first three of these in streambed sediments from the Angabanga River, relative both to the PEL values and the levels at the reference sites. There also are elevated levels of cadmium in the streambed sediments from the Auga River but these are less than the PEL for cadmium. In summary, the present study clearly indicates that the discharge of tailings from the Tolukuma Gold Mine is causing ongoing pollution of the Auga-Angabanga River system by suspended sediment and toxicants including arsenic and various metals. This pollution has occurred continuously over a period of more than 10 years. The suspended sediment plume from the tailings discharge and streambed sediment deposits are visible along the entire length of both rivers and elevated levels of toxicants are detectable in both the water and in the streambed sediments. It is probable that this pollution has caused major impacts on the ecology of the river system. Potential effects include obliteration of most aquatic life in the Auga River and changes in species composition, populations and behaviour further downstream in the Angabanga River as far as the coast. These changes may have adversely affected nutrition and health in communities near the rivers as an important source of protein, namely fish, is no longer available or has been considerably reduced in abundance. The pollution also has deprived the people who live close to the rivers of a traditional source of drinking and domestic water or has put those that continue to drink water from the rivers at risk. The Government of Papua New Guinea approved the Tolukuma Gold Mine subject to certain environmental conditions. These include a requirement that cyanide, ammonia and the filtered or dissolved levels of arsenic and a range of metals in the Auga River must not exceed specified levels in water samples collected at a monitoring site located approximately 7km downstream of the mine. The criteria do not include any requirement regarding suspended solids or turbidity levels. A series of filtered samples were collected at the compliance point in the present study. The levels of arsenic and most of the metals in these samples were less than the criteria but the level of mercury in some samples exceeded the criteria. There also is clear evidence in the Annual Environmental Reports produced by Tolukuma Gold Mines that the compliance levels for various metals are often exceeded. In its annual environmental reports the company refers to the fact that the annual mean (average) concentrations of all filterable metals assessed usually are less than the compliance criteria. It is apparent in these reports however, that the licence criteria do not refer to average values but rather to absolute values that should not be exceeded in any samples. Reference to average values is questionable as it may conceal the fact that many recorded levels may exceed the criteria.


In practice, Tolukuma Gold Mines also may meet the compliance criteria but still have a significant adverse impact on water quality as shown in this study. This is because of the differences between the environmental licence criteria and contemporary water quality guidelines. For example, the compliance criteria for cadmium, chromium, copper, nickel and zinc are higher than the Australian Water Quality 80% Threshold Values. In addition, some of the compliance criteria (chromium, copper and zinc) approximate more the Australian Drinking Water Guidelines rather than guidelines designed to protect aquatic life, and the criterion for cadmium is higher than both of the guidelines. This means that the objectives of the criteria are unclear and they are not adequate for minimising the risks of environmental impact or protecting human health. If compliance monitoring is to have any meaning, the rationale and objectives of the criteria must be specified, the criteria must be based on contemporary internationally recognised guidelines, and their scope and the type of samples must be appropriate. Monitoring sites also should be established throughout the river system and selected on the basis of a logical sampling rationale rather than the single arbitrarily located monitoring point that is used at present.


1. INTRODUCTION The Tolukuma gold mine is located approximately 100km north of Port Moresby in the Central Province of Papua-New Guinea. It is at an altitude of 1700m and is close to the Auga River. The Auga River joins the Angabanga River 30km downstream of the mine and the Angabanga flows to the sea near Bereina about 80km further on. The river system and the area around Tolukuma are shown in Figure 1 and 2 respectively.

Figure 1: Regional Location Dome Resources NL, an Australian company, commenced gold mining at Tolukuma in 1995. DRDGold (formerly known as Durban Roodeport Deep Ltd), a South African company, acquired the mine in March 2000. At the time of writing this report it appeared that an Australian company Emperor Gold would acquire the mine in the near future. Mine operations are conducted by its subsidiary Tolukuma Gold Mines Ltd. Gold is extracted using the carbon-in-leach process. This involves milling the ore then passing it through a series of leach tanks containing sodium cyanide in an alkaline solution. The cyanide dissolves gold from the ore and forms a stable gold-cyanide complex. Highly activated carbon is introduced into the leach tanks and this adsorbs the gold-cyanide. The carbon is then separated from the slurry by screening, the


gold-cyanide complexes are separated from the carbon by washing and finally the gold is separated by electrolysis. After the gold is extracted, the slurry or tailings are discharged directly into the Auga River through a 90mm poly pipe at a rate of about 140,000 tonnes each year (Tolukuma Gold Mines Limited, 2004). Other waste material also enters the river system due to erosion and drainage from waste dumps at the mine.

Figure 2: The Auga-Angabanga River System

It was predicted in the Tolukuma Gold Project Environment Plan, that significant quantities of sediment in the tailings would be deposited in the river system over time particularly during periods of low flow (Natural Systems Research and David Ballach and Associates, 1993). This was expected to obliterate fish habitats and food resources in parts of the system with moderate to minor impacts as far downstream as the floodplain of the Angabanga River. The tailings and waste rock also were expected to contain high levels of arsenic, lead, mercury, nickel, copper, iron, zinc, antimony, bismuth, selenium, sulphur, thallium, and cadmium throughout a mixing zone extending for 35km downstream of the mine to the village of Yaifu. Despite these predictions, the Government of Papua New Guinea approved the mine subject to certain conditions. These include a requirement that cyanide, ammonia and a range of metals in the Auga River must not exceed specified levels in water samples collected at a monitoring site located approximately 7km downstream of the mine.


A number of village-based communities live in the Auga River valley and close to the Angabanga River. Many of these communities have complained to Government authorities and the mining companies since the start of mining operations, that significant environmental, social and health impacts have occurred as a result of the waste discharge into the river system. In particular, they can no longer use the river as a source of drinking water due to the pollution, and food resources such as fish and prawns have either disappeared, are reduced in abundance or are potentially contaminated with heavy metals. There are also reports of increased incidences of unexplained sickness and death in some communities. These communities have found it difficult to obtain information from Tolukuma Gold Mines Ltd and the Annual Environment Reports and other studies commissioned by the company have generally not been made public. As a result, people living along the river are not able to independently assess the implications of water quality in the river system or to verify that the compliance levels are being met. The communities therefore have sought assistance from non-government organisations. In response, in July 2002 Oxfam Community Aid Abroad (OCAA) funded an initial assessment of water quality by the NGO Environmental Watch Group (NEWG) and the Centre for Environmental Law and Community Rights (CELCOR). Both of these organisations are based in Port Moresby. Assistance also was provided for a second more detailed assessment by NEWG in August 2003. In this report we describe the results of a further study of water quality in the Auga-Angabanga River system carried out in August 2004. This study also was funded by Oxfam Australia (formerly OCAA). The objectives of this study were to: • Assess water quality and sediments in a section of the Auga River downstream of the Tolukuma gold

mine to the compliance monitoring point and in a section of the Angabanga River. • Compare the recorded levels of parameters with Australian and other international standards for

environmental protection and for drinking water, and • Review other available data on water quality and compliance.


2. METHODS The fieldwork for the present study occurred in the period 21 to 30 August 2004 inclusive. The weather during this period was fine and there was no significant rainfall. The average rainfall at the Tolukuma mine site is about 3500mm. The lowest monthly rainfalls typically occur from May to August. Data and samples were collected at various locations along the upper section of the Auga River and the lower section of the Angabanga River. Samples also were collected from two tributaries of the Auga, the Guguma and Yeme Rivers and from the Aroa River between Port Moresby and the Angabanga River. The Guguma River receives run-off from waste dumps at the mine and is close to the tailings discharge point. The Yeme and Aroa Rivers provided data from sources that are unaffected by discharges from the Tolukuma gold mine. Two single samples also were taken from village water supplies, one from Dubuilenga on the Auga River about 5.5km from the tailings discharge point and the other from Veifa’a on the lower Angabanga River. The Dubuilenga supply runs down the slope of the valley probably from a spring and is delivered into the village through a short section of pipe. The pipe was salvaged from the river after it was washed down from the mine where it may have been part of the pipeline used to discharge tailings. The Veifa’a supply is groundwater from a shallow bore fitted with a hand pump. The locations of all of the samples are shown in Figure 2 and are listed in Table 1.

Table 1: Location of Sample Sites

Site Name Labels Coordinates

Discharge K 8°33.311S,147°07.741E

Guguma H 8°33.380S,147°07.541E

Auga/Yeme T 8°32.518S,147°06.600E

Yeme Y 8°32.500S,147°06.608E

Dubuilenga D 8°32.389S,147°06.336E

Dubuilenga Village 8°32.383S,147°06.346E

Compliance G 8°32.217S,147°05.855E

Inauauni E 8°30.076S,146°40.005E

Veifa'a Village 8°32.416S,146°33.870E

Oriropetana O 8°33.102S,146°34.580E

Inawae N 8°37.687S,146°32.633E

Aroa B 9°01.061S,146°49.293E


The data and samples collected at each of the river sites comprised:

• A photograph or photographs to provide a record of the physical appearance, • Notes describing the appearance of the river, nearby land uses, proximity of houses, information

supplied by residents and other matters, • The position as determined by a hand held GPS instrument, • Elevation at river level, • Estimates of the width, depth and rate of flow of the river. The flow was measured by placing a

object on the water and measuring the distance that this floated downstream during a set period of time,

• On-site measurement of pH, dissolved oxygen, water and air temperatures and turbidity, and • Water and sediment samples.

The pH, dissolved oxygen level, water temperature and turbidity were recorded directly from the rivers using the following equipment:

• DO, pH and temperature – Wissenschaftlich-Technische Werkstatten MultiLine F/SET-3 • Turbidity – McVan Instruments Analite NEP 160 Turbidity Meter

The air temperature also was measured using the WTW meter. The meters were calibrated each morning prior to sampling and the probes were cleaned in distilled water after each measurement. We waded into the river to a depth of approximately 0.5m to collect water samples, faced upstream and immersed a plastic jug approximately 20cm below the surface. The jug was filled and emptied three times before the sample was collected by inverting the jug and turning it towards the flow of the river, again at a depth of 20cm. A 50mL syringe was filled twice with water from the sample jug and the water was ejected to the ground before the actual sample was collected. Three types of water samples were collected. Most of the samples were filtered directly into a plastic sampling bottle through a new 0.45µm membrane filter fitted to a sampling syringe, a series of unfiltered samples also was collected and a few samples were passed through a special arsenic speciation cartridge to enable the analysis of arsenite [As (III)] levels. The sampling procedure for As (III) was as follows: 100mL of sample water was extracted by syringe from the jug and filtered into a sample bottle. 50mL was then extracted from the sample bottle with a clean syringe, the speciation cartridge was fitted to the syringe and the sample was ejected through the cartridge into a clean storage bottle. The village water supply samples were collected after rinsing the collection jug and syringe three times from the water supply. These samples were not filtered. 0.5mL of nitric acid (1%) was extracted from a storage bottle using a new pipette and added to each water sample. The National Research Centre for Environmental Toxicology at the University of Queensland specified the sample preservation procedures and also supplied all of the sampling equipment comprising syringes, membrane filters, arsenic speciation cartridges, pipettes and storage bottles. A series of sediment samples also was collected at the edge of the rivers using a short length of 40mm PVC pipe forced into the soil. The pipe was cleaned with distilled water before each sample was collected and the sample was placed directly into a plastic storage bottle. All of the samples were sealed, labelled and placed in an esky for storage immediately after collection. Sample numbers were written on the bottles and all descriptive information from each site was entered into a field notebook with the sample numbers.


The National Research Centre for Environmental Toxicology analysed all of the samples. The parameters determined were magnesium, calcium, arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc. We did not collect samples or analyse for other potential contaminants such as cyanide and ammonia. The sediment samples are total levels of arsenic and metals in sediment including pore water. All of the samples were analysed by ICP-MS (inductively coupled plasma mass spectroscopy).


3. RESULTS 3.1 Village Water Supplies The main focus of the present study was the condition of the Auga-Angabanga River system. We also however, collected two samples from village water sources at Dubuilenga on the Auga River and Veifa’a on the Angabanga River. The results of the analyses of these samples are shown in Table 2 together with the PNG and Australian Drinking Water Guidelines for each parameter.

Table 2

Drinking Water Quality

Dubuilenga and Veifa’a Villages (µg/L)

PNG ADWG DB VFA

Arsenic 50 7 3.67 28.73 Cadmium 10 2 0.26 0.7 Chromium - 50 0.1 0

Copper 1500* 2000 0.23 3.79 Lead 100 10 0.26 0.98

Mercury 1 1 1.37 0.2 Nickel - 20 0.78 1.31 Zinc 15000* 3000 2.72 210.25

Notes: PNG – Public Health (Drinking Water) Regulation 1984

ADWG – Australian Drinking Water Guidelines (ANZECC, 2000) DB – Dubuilenga Village VFA – Veifa’a Village

*Highest Permissible Level The levels of all parameters in the sample from Dubuilenga were less than the guidelines except for the level of mercury, which was 0.37µg/L higher than both the PNG standard and the Australian guideline. The levels of all parameters in the sample from Veifa’a were less than the guidelines except for the level of arsenic, which was four times higher than the Australian guideline. However, the level was less than the PNG standard of 50µg/L. The Australian Government through AusAID have provided a discussion of guidelines for arsenic in drinking water (AusAID, 2004). They note that the World Health Organisation acceptable maximum level of arsenic in drinking water is 10µg/L but that national standards range from 7µg/L in Australia to 50µg/L in Vietnam, Cambodia, Laos and Bangladesh. They advise that AusAID recipients in such countries should “advocate progressive application of the WHO guidelines”. Long-term exposure (5 to 15 years) to arsenic at levels less than 50µg/L may cause skin lesions and internal cancers (World Health Organisation, 2001). The data from the present study indicate that further assessment should be made of the water supplies of villages near to both rivers and especially along the lower Angabanga River as the arsenic level at Veifa’a is of particular concern.


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3.2 Physical Description of the Rivers The elevation, width, depth and rate of flow of the rivers were determined at each sample site. The data which are shown in Figure 3 provide a basic description of the physical features at each location.

Figure 3: Physical Features at Each Sample Site

The upper section of the Auga River and its tributaries, the Guguma and Yeme Rivers, are represented by Sites H to G. These rivers are located in steeply incised valleys at relatively high altitudes of 800+m. They were narrow in width and shallow at the time of sampling with moderate rates of flow. Sites E to N represent the lower section of the Angabanga River and Site B the Aroa River. These rivers are located on a coastal plain at low altitudes and are relatively wide. The Angabanga was shallow and was flowing at a moderate rate at the time of sampling while the Aroa River was relatively deep with a slow flow rate. 3.3 Temperature The temperature of the water at the sample sites is shown in Figure 4. The range in the Auga River was 16.8° to 19.8°C and the water temperature in the Guguma and Yeme Rivers were within this range. The water temperature in the Angabanga River on the coastal plain was between 23.7º and 25.7ºC and in the Aroa River was slightly higher at 26.6ºC. The water temperature was related to and less than the ambient air temperature as shown in Figure 4 except for one of the G samples in the early morning and for the Aroa River when the water temperature was higher than the air temperature. The temperature in the Aroa River may have been due to its depth and slow flow rate.


Figure 5: Dissolved Oxygen Levels

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H = Guguma River, K = Tailings discharge point, T = near junction with Yeme River, Y = Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae, B = Aroa River 3.4 Dissolved Oxygen Dissolved oxygen (DO) occurs as microscopic bubbles in the water. Concentrations vary with temperature, salinity, biological activity and rate of transfer from the atmosphere and are generally higher in cold water than warm water. DO is an important indicator of the ability of the water to support aquatic life. H = Guguma River, K = Tailings discharge point, T = near junction with Yeme River, Y = Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae, B = Aroa River The levels of Dissolved Oxygen (DO) in the water samples in terms of mg/L and % saturation are shown in Figure 5. DO levels of 5 to 6mg/L are required by most fish species, levels below 3mg/L are stressful to most aquatic animals and levels less than 2mg/L are fatal. The USEPA DO criteria for warm water systems are – Early life stages 7-day average 6.0mg/L, 1 day minimum 5.0mg/L; Other life stages 7-day minimum 4.0mg/L, 1 day minimum 3.0mg/L. All of the samples in the present study were above 7mg/L.


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The lower and upper limits of dissolved oxygen for slightly disturbed upland rivers in tropical Australia are 90 and 120% saturation (ANZECC, 2000). The saturation levels in the Auga River and the Guguma and Yeme Rivers were between 87 and 94%. The lower and upper limits of dissolved oxygen for slightly disturbed lowland rivers in tropical Australia are 85 and 120% saturation. The saturation levels in the Angabanga and Aroa Rivers were within this range. 3.5 pH H = Guguma River, K = Tailings discharge point, T = near junction with Yeme River, Y = Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae, B = Aroa River pH is a measure of how acid or basic the river water is. The pH scale ranges from 0 to 14, the central value 7.0 being neutral, levels less than 7 increasingly acid, and levels greater than 7 increasingly basic. The scale is logarithmic which means that a pH value of 6 is 10 times more acid than a pH value of 7, pH 5 is 100 times more acidic than pH 7, and pH 4 is 1,000 times more acidic than pH 7 and so on. All of the measurements of pH in the present study were in the range 7.0 to 7.9, which indicates neutral to slightly alkaline conditions at all locations. 3.6 Turbidity The amount of suspended solids in the Auga and Angabanga Rivers was assessed in the present study in terms of turbidity levels in the water. The turbidity level at the tailings discharge point (Location K) on the Auga River was more than 2500 NTU (nephelometric turbidity units) (Figure 7a) and at the compliance monitoring point 7km downstream (Location G) was generally above 1000 NTU. These levels contrast with that in the Yeme River (Location Y) that does not receive tailings which was 4.3 NTU. This low value corresponds with turbidity levels in upland rivers in tropical Australia which generally are in the range 2 to 25 NTU with the high levels only during short-term high flow events (ANZECC, 2000). The upper limit of this range is shown as blue columns in Figure 7a.


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Figure 7a: Turbidity in the Auga River

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H = Guguma River, Y = Yeme River (Control), K = Tailings discharge point, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point The difference in turbidity in the Auga River and the Yeme River is illustrated in the cover photo. Turbidity in the river approximately 8 kilometres downstream from the tailings discharge pipe is shown in Figure 8 and sediment deposits on the margin of the Auga River are shown in Figure 9. Elevated turbidity levels also were evident in the Angabanga River where the range was 52.4 to 71.7 NTU (Figure 7b). By comparison, in the Aroa River (Location AR) the level was 11.1 NTU. Turbidity levels in lowland rivers in tropical Australia generally are in the range 6 to 50 NTU with the high levels only during high flow following significant rainfall events. The turbidity levels recorded in the Angabanga River are higher than the upper limit of the Australian range even though there had been a long period with low rainfall before we collected the samples. The middle of the Australian range is shown by the blue columns in Figure 7b.

INAU = Inauauni, ORA & ORB = Oriropetana, INAW = Inawae, AR = Aroa River (Control)


Figure 8: Extreme turbidity in the Auga River at a crossing used regularly by villagers. (Photo: Brendan Ross/ Oxfam Australia)

Figure 9: Sediment deposits on the margin of the Auga River (Photo: Brendan Ross/ Oxfam Australia)


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Figure 10: Analysis of Tailings

3.7 Total Arsenic and Metal Levels in the Tailings

As = Arsenic, Cd = Cadmium, Cr = Chromium, Cu = Copper, Hg = Mercury, Ni = Nickel, Pb = Lead, Zn = Zinc One unfiltered sample of the tailings was collected directly from the outlet of the discharge pipe. The results of the analysis of this sample are shown in Figure 10. They indicate that the tailings at the time of sampling contained very high total levels of lead, arsenic, zinc, mercury and copper. There also were relatively high total levels of chromium and cadmium but these are not apparent on the graph due to the scale required for the other parameters. High levels of total arsenic and metals in the tailings are documented also in the Annual Environmental Reports of the mine operators. In 2003 the maximum levels recorded were arsenic 80,700µg/L on 7/11/03: cadmium 130µg/L on 7/11/03: chromium 17,600µg/L on 7/11/03: copper 25,300µg/L on 6/11/03: lead 169,000µg/L on 7/11/03: mercury 110µg/L on 25/4/03: and zinc 79,000µg/L on 7/11/03 (DY Environmental Consultants (PNG) Limited, 2003 – Table A2). The average arsenic level in 89 samples collected in 2003 was 2,208µg/L, lead (87 samples) was 3,068µg/L and mercury (81 samples) was 17.9µg/L. 3.8 Total Arsenic and Metal Levels in the River System The analytical data for the unfiltered or total water samples collected from the Auga and Angabanga Rivers in the present study are shown in Figure 11. A consistent pattern is evident in all of the graphs with elevated levels of toxicants in the upper section of the Auga River from the tailings discharge point to at least 7km downstream (the compliance point) and lower levels in the lower section of the Angabanga River. The relative level of each of the toxicants is similar to those in the tailings with very high levels of lead, zinc, arsenic and mercury, moderate levels of copper and chromium and low levels of nickel and cadmium. The significance of these levels can be illustrated by comparison with guidelines for drinking water. The comparison is relevant as at least two villages on the Angabanga River (Gaigafua, also known as Angaifu, and Oriropetana) depend on the river as their primary source of drinking water. Whether other villages get drinking water from the rivers on a regular or occasional basis is not known but both rivers were a major source of domestic water for most villages in their vicinity prior to the waste discharge from the Tolukuma gold mine.


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Figure 11:

Total (Unfiltered) Water Samples Levels of Toxicants (µg/L)

T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae.


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Figure 12a: Dubuilenga Total Water & ADWG

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Figure 12b: Inauauni Total Water & ADWG

The Australian and Papua New Guinea Drinking Water guidelines and the levels found in the present study are listed in Table 3. The guidelines are based on total water samples.

Table 3

Total Water Toxicant Levels and Drinking Water Guidelines (µg/L) Bold Levels Exceed the Australian Guidelines

ADWG PNG T5 D1 G1 E3 O2 O3 N3

Arsenic 7 50 224.79 150.73 176.48 13.96 9.96 13.97 8.14 Cadmium 2 10 1.25 1.04 1.37 0.02 0.06 0.1 0.12 Chromium 50 50 21.44 17.4 22.24 0.4 0.92 1.85 0.49

Copper 2000 1500* 71.6 80.4 64.4 0.6 0.65 3.97 1.31 Lead 10 100 494.64 457.89 446.14 23.59 16.33 16.18 13.31

Mercury 1 1 40.26 38.21 26.48 1.33 0.64 0.42 0.09 Nickel 20 - 4.1 2.02 5.68 0 0 0 0 Zinc 3000 15000* 280.57 294.63 310.94 0 1.27 17.03 14.68

Notes: ADWG – Australian Drinking Water Guidelines 1996; PNG – Public Health (Drinking Water) Regulation 1984

T5, D1, G1 = Auga River Samples. E3, O2, O3, N3 = Angabanga River Samples *Highest Permissible Level

The above data show that the arsenic levels in the Auga River exceed both Australian and PNG guidelines. The levels in the 4 samples from the lower section of the Angabanga River (E3 to N3) also exceed the Australian guidelines and 2 exceed the WHO guidelines of 10µg/L. These guidelines are discussed in Section 3.1 of this report. Similarly, the lead levels exceed both guidelines for all of the samples from the Auga River while those from the Angabanga River are higher than the Australian guidelines. The levels of mercury in the Auga River samples and in the sample collected from the Angabanga River near Inauauni also exceed the both guidelines. The results for total water levels of arsenic, lead and mercury are also illustrated in Figure 12a to 12d for various locations on the rivers together with the respective Australian Drinking Water Guidelines (purple columns). The results for Oriropetana in Figure 12c are the average for the 2 samples. The data indicate that the discharge of tailings has made the water throughout the Auga and Angabanga Rivers unsuitable for human consumption.

As = Arsenic, Hg = Mercury, Pb = Lead. Purple columns indicate Australian Drinking Water Guideline values.


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Figure 12c: Oriropetana Total Water & ADWG

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Figure 12d: Inawae Total Water & ADWG

As = Arsenic, Hg = Mercury, Pb = Lead

Purple columns indicate Australian Drinking Water Guideline values.

3.9 Dissolved Arsenic and Metal Levels in the River System The filtered water samples provide data on the levels of dissolved toxicants in the river system and the other rivers sampled for reference purposes. These may be compared with water quality guidelines for the protection of aquatic species of plants and animals as such guidelines are generally derived from laboratory analyses of toxicity using dissolved toxicants. In the present study, the data were compared with Australian Water Quality Trigger Values (ANZECC, 2000). These guidelines are based on extensive reviews of scientific research findings on the toxicity and metals and other parameters on aquatic organisms. The findings generally relate to acute toxicity and it should be noted that long-term exposure to lower levels of toxicants than are specified in the guidelines might also cause impacts. The TVs for certain metals have to be adjusted if the water is hard as this affects toxicity. Hard water contains dissolved salts especially of calcium and magnesium. The level of hardness can be estimated in terms of mg/L of equivalent calcium carbonate (CaCO3) (Geoscience Australia, undated) using the formula: Hardness = 2.5 (mg/L Ca) + 4.1 (mg/L Mg). The categories of hardness are 0-75 mg CaCO3/L = soft; 75-150 mg CaCO3/L = moderately hard; >150 mg CaCO3/L = hard. Calcium and magnesium levels were determined for all of the water samples collected in the present study, in order to determine hardness. The data, which are provided in Appendix 1, show that the water in the Auga and Angabanga Rivers and in the Guguma, Yeme and Aroa Rivers is soft. Therefore, the AWQ TVs do not need to be adjusted for hardness. The Australian Guideline Trigger Values (TV) are considered to provide protection to a defined percentage of aquatic species. The guideline selected in general should aim to achieve a high level of protection. The Auga and Angabanga Rivers are now highly disturbed ecosystems according to the definitions of levels of disturbance in the Australian guidelines, although they were relatively undisturbed prior to the commencement of mining operations. The suggested TVs for highly disturbed ecosystems range from 95% (high degree of protection) to 80% (low degree of protection) depending on management objectives. The results of the present study indicate that there are very high levels of dissolved copper in the Auga River. High levels of dissolved mercury also were recorded in samples from both rivers.


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Figure 13a: Auga River Dissolved Copper Levels & AWQ 80%TV

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Figure 13b: Dissolved Mercury LevelsGuguma,Yeme and Auga - AWQ95%; Angabanga and Aroa - AWQ80%

Copper

Y = Yeme River, K = Tailings discharge point, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point The dissolved copper levels in the Auga River are shown in Figure 13a (green columns). These are all considerably higher than the AWQ 80%TV of 2.5ug/L (purple columns). The levels in the samples from the unpolluted Yeme River (Y1 and Y2) were less than the AWQ 80%TV and the AWQ-95% TV. The levels of dissolved copper in the samples from the Angabanga River and also from the Aroa River which are not shown in the graph were approximately equal to the AWQ-95% TV. Mercury The levels of dissolved mercury in two samples from the Angabanga River at Inauauni (E2) and Inawae (N2) exceeded the AWQ-80% TV (5.4ug/L) as shown in Figure 13b. The levels of dissolved mercury in 5 samples from the Auga River exceeded the AWQ-95% TV (0.6ug/L). The levels in the Auga River also are elevated relative to those from the Yeme River. Y = Yeme River, K = Tailings discharge point, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae, B = Aroa River


Other Toxicants There also are elevated levels of dissolved arsenic and lead in both rivers relative to the Yeme and Aroa Rivers and of dissolved nickel and zinc in the Auga River. The levels of lead and zinc in the Auga River exceeded the AWQ95% TV down to the confluence with the Yeme River. The most important forms of arsenic in terms of water quality are arsenate [As (V)] and arsenite [As (III)]. The Australian Water Quality Guidelines differ for these two species with more stringent guidelines for arsenate. Three samples were collected in the present study with procedures that enabled analysis for dissolved As (III). The levels are compared with the total dissolved arsenic results for samples from the same locations in Table 4.

Table 4 Total Dissolved Arsenic and As (III) Levels

The levels of dissolved cadmium and chromium in the Auga and Angabanga Rivers were equivalent to or higher than the samples from the Yeme and Aroa Rivers. 3.10 Arsenic and Metal Levels in Sediments It was apparent from visual inspection during the field work that a considerable amount of sediment had been deposited on the beds and margins of the Auga and Angabanga Rivers as layers of light grey-brown silt as shown in Figure 9. Some of this was suspected to have originated from the tailings discharge. Such deposits could contain a reservoir of toxicants that are a source of contaminants for organisms that live on or in the streambed and therefore may be introduced into food chains (ANZECC, 2000). The sediments also are likely to contribute to the levels of dissolved toxicants in the water column. Sediment samples were collected and analysed in the present study to provide an indication of the levels of toxicants that are in this reservoir. The significance of the levels was evaluated by comparing them with the U.S. National Oceanic and Atmospheric Administration (NOAA) reference levels for freshwater sediments (Buchman, 1999). These are the Threshold Effects Level (TEL) and the Probable Effects Level (PEL). The TEL represents the concentration below which negative effects on the health of aquatic organisms are expected to occur only rarely. The PEL is the level above which effects are expected frequently. The data indicate that there are very high levels of arsenic, lead, mercury and zinc in sediments from the upper Auga River and high levels of the first three of these in the Angabanga River, relative both to the PEL values and the levels at the reference sites. There also are elevated levels of cadmium in the sediments from the Auga River but these are less than the PEL for cadmium. Arsenic The levels of arsenic in the samples of surface sediments from the Auga River (Samples T1 to GW) were between 15 and 29 times higher than the PEL of 17mg/kg and a sample taken from approximately 10cm below the surface (D4) was about 8 times higher (Figure 14a). The arsenic level in the sediment of the Guguma River (Sample H2), which receives runoff from waste dumps, was approximately six times higher.

Sample Site Total As As(III) T 8.35 2.04 G 6.63 1.34 O 5.94 0.51


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Figure 14b: Sediment Cadmium and TEL (Threshold Effects Level)

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Figure 14a: Sediment Arsenic & PEL (Probable Effects Level)

The levels in the Auga River samples may be compared to those in the sediment sample from the Yeme River (Y3) and Site G8, which were the reference or control sites. G8 was near the compliance point but on the slope of the valley, above the flood level of the river. The levels in both of these samples were between the TEL (5.9mg/kg) and PEL (17mg/kg) at 6.9 and 11.1mg/kg respectively. Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae The arsenic levels in sediment samples from the lower Angabanga River also were higher than the PEL with values from approximately 135 mg/kg for E4 (Inauauni) to 17.1mg/kg for O6 which was collected from a sandbar in the river near Oriropetana. Cadmium Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae The cadmium levels in all of the surface sediment samples from the upper Auga River and from the Guguma River (H) were above the TEL of 0.596mg/kg (Figure 14b) but were less than the PEL of 3.53mg/kg. The samples from the Yeme River (Y3), the control site (G8), and the sample from a depth of 10cm (D4) all had cadmium levels less than the TEL.


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Figure 14c: Sediment Chromium and TEL (Threshold Effects Level)

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Figure 14d: Sediment Copper & TEL (Threshold Effects Level)

All but one of the samples from the lower Angabanga River had cadmium levels less than the TEL. The exception was E4 from near Inauauni that had a level of 0.865mg/kg. Chromium All of the chromium levels in the sediment samples from the upper Auga River were below the TEL of 37.3mg/kg (Figure 14c). The sample from the Yeme River however, had a higher level of chromium than the TEL. This may indicate that natural background levels of chromium in the Yeme River catchment are relatively elevated. The levels of chromium in all but one of the sediment samples from the lower Angabanga River (E4 to N1) also were below the TEL but were generally higher than those from the Auga River. The exception was E4 from near Inauauni that had a level of 40.337mg/kg. Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae Copper Y3 = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae


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Figure 14e: Sediment Lead & PEL (Probable Effects Level)

The levels of copper in most of the sediment samples from the Auga and Angabanga Rivers are elevated relative to the reference sample G8 (Figure 14d). All of the levels were approximately equivalent to or above the TEL (35.7mg/kg) but were considerably less than the PEL (197µg/L). Lead The lead levels in the sediment samples from the Guguma River and the Auga River were higher than those in the samples from the Yeme River (Y3) and the reference site G8 (Figure 14e). The levels also were mostly close to or considerably above the PEL (91mg/kg) whereas the levels for Y3 and G8 were less than the TEL (35mg/kg). The exception was the Auga River sample from a depth of 10cm (D4), which had a lead level above the TEL but less than the PEL. Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae The lead levels in two of the sediment samples (E4 and O5) from the sides of the Angabanga River also were above the PEL and a third (O4) was close to it. The level in the sample from the sand bank in the river (O6) was less than the TEL. The sample from the furthest location downstream (N1) from the western side of the river at Inawae also was less than the TEL. Mercury The mercury levels in all of the sediment samples were higher than the PEL of 0.486mg/kg (Figure 14f). This suggests that the natural background levels of mercury are higher than the PEL and that comparisons should be made with the reference samples Y3 and G8. The levels in these samples were 1.546mg/kg and 1.675mg/kg respectively. The Guguma River and all of the Auga River samples had mercury levels that were considerably higher than this. The range was between 16.7mg/kg in the sample from a depth of 10cm (D4), to 274.972mg/kg for D3. The levels of mercury in four of the sediment samples from the lower Angabanga River also were elevated with a range from 5.195mg/kg (N1) to 60.887mg/kg (E4). The sample from the sand bank in the river (O6) had a lower but still elevated mercury level of 3.469mg/kg.


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Figure 14f: Sediment Mercury & PEL (Probable Effects Level)

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Figure 14g: Sediment Nickel & TEL (Threshold Effects Level)

Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae Nickel The highest level of nickel recorded in the sediment samples was from the Yeme River (Figure 14g). This was the only sample that had a level higher than the PEL (46.037mg/kg compared to 35.9mg/kg). The levels in the samples from the Auga River and in the reference sample G8 were below or slightly higher than the TEL. The level in the sample from the Guguma River also was less than the TEL. The levels of nickel in the sediment samples from the lower Angabanga River were higher than those from the Auga River and were between the TEL and PEL guidelines. Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae Zinc The levels of zinc in the sediment samples from the Guguma River and the Auga River were elevated relative to those from the Yeme River and the G8 reference site. Five of the levels from the Auga River also were equal to or higher than the PEL of 315mg/kg and the other sample from this river had a level higher than the TEL (Figure 14h). The sample collected from 10cm depth at Dubuilenga on the Auga


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Figure 14h: Sediment Zinc & TEL (Threshold Effects Level)

River (D4) and the sample from the Guguma River (H2) also had sediment zinc levels higher than the TEL as did three samples from the Angabanga River. Y = Yeme River (Control), G8 = slope above compliance point (Control) , H2 = Guguma River, D4 = Dibuilenga sub-surface sample, T = near junction with Yeme River, D = Dibuilenga, G = Compliance Point, E = Inauauni, O = Oriropetana, N = Inawae 3.11 Statutory Compliance The compliance criteria for arsenic and metals that are set as part of the Environment (Waste Discharge) Permit for the Tolukuma Gold Mine are listed in Table 5. These criteria apply to filtered water samples for all of the toxicants. The samples are collected for monitoring purposes at the compliance point approximately 7km downstream from the tailings discharge. This is where the samples denoted with a G were collected in the present study. The data for the G samples are listed in Table 5.

Table 5 Permit Criteria and Levels in Present Study

(µg/L)

Criteria Present Study Arsenic 50 6.19-7.31

Cadmium 10 0.28-0.73 Chromium 50 0.06-0.56

Copper 1000 28.33-85.28 Lead 5 1.11-2.15

Mercury 0.2 0.02-1.75 Nickel 1000 2.07-3.44 Zinc 5000 2.06-9.19

All of the levels are less than the criteria except for the level of mercury in three of the eight samples collected.


4. DISCUSSION 4.1 Village Water Supplies The two samples of water from village supplies revealed elevated levels of mercury at Dubuilenga on the Auga River and arsenic at Veifa’a on the lower Angabanga River. These samples suggest that further analyses of the water supplies are advisable. Long-term exposure to mercury may cause a variety of health disorders including major effects on the central nervous system and kidneys (National Health and Medical Research Council/ Agriculture and Resource Management Council of Australia and New Zealand, 1996). Continuous exposure to arsenic levels for long periods (>5 years) may cause skin lesions, respiratory problems, damage to internal organs and cancers (AusAID, 2004). The USEPA guideline for arsenic in drinking water is 10µg/L but it also recommends that the ambient concentration should be zero for the maximum protection of human health from potential carcinogenic effects. 4.2 Pollution of the River System The main finding of the present study is that the Auga and Angabanga Rivers are polluted as a result of discharges from the Tolukuma Gold Mine. The findings of the present study mainly relate to the effects of the discharge of tailings, as run-off from waste dumps was relatively low due to low rainfall conditions. The Angabanga River is the primary source of drinking water for the villages of Gaigafua and Oriropetana and prior to the start of mining other villages used both rivers extensively. The water is now unfit for human consumption as a result of the pollution. It also is very likely that the pollution has had a major impact on aquatic and benthic organisms in the upper Auga River and probable impacts as far downstream as the lower Angabanga River, due to the levels of some dissolved toxicants and of toxicants in sediments on the stream bed and margins. The pollution detected was both physical and chemical in nature. The physical pollution was due to extreme levels of sediments in the tailings while the chemical pollution was due to very high amounts of arsenic, copper, lead, mercury and zinc. Physical Pollution The tailings that are discharged from the Tolukuma Gold Mine into the Auga River have very high levels of suspended solids. This is reflected in the high turbidity levels recorded along the length of the upper Auga River in the present study and the elevated levels recorded in the lower Angabanga River. These are considerably higher than the turbidity recorded in the Yeme and Aroa Rivers that are unaffected by mining. For example, the turbidity levels in the Auga River were at least 250 times higher than those in the Yeme River. Monitoring carried out by the mine owners also reveals the degree of physical pollution of the river. During 1998, 75,088 tonnes of tailings including about 16,000 tonnes of suspended solids (21.4%) were discharged to the Auga River (Dome Resources NL, 1999a), 109,850 tonnes including 42,900 tonnes of suspended solids (38.5%) in 2000 (Tolukuma Gold Mines Limited, 2001), 113,500 tonnes including 29,500 tonnes of suspended solids (26.1%) in 2002 (Tolukuma Gold Mines Limited, 2003) and 141,900 tonnes including 30,030 tonnes of suspended solids (21.1%) in 2003 (Tolukuma Gold Mines Limited, 2004). Other solids enter the river as a result of erosion from waste dumps at the mine. During 1997 and 1998 at the compliance point on the Auga River 7km downstream from the tailings discharge, average total suspended solids were estimated to have increased 1,400-fold over baseline levels


(DY Environmental Consultants (PNG) Limited, 1999), in 2002 the average TSS was 80 times the baseline average and in 2003 it was about 90 times the baseline average (Tolukuma Gold Mines Limited, 2004). The natural level of suspended solids in the river system will vary depending on the rate of erosion of soil in the catchment area and may be quite high during periods of heavy rainfall. High sediment loads however, are likely to be short-term in natural conditions whereas the discharge of suspended solids in the tailings and the impact that it has on the river ecosystem, is effectively continuous. The suspended solids are transported downstream and much of the material probably is eventually transported to the lower reaches of the Angabanga River (DY Environmental Consultants (PNG) Limited, 1999) and the coastal marine environment near the river mouth. Some of the solids however, are deposited on the river beds and margins. The rate and amount deposited varies with the flow rate of the river and is highest during the dry season and in the Angabanga River which is located on the relatively flat coastal plain. High levels of suspended solids may have a severe impact on aquatic life and even small changes in suspended solids may cause large changes in primary production. The impacts include reduction in aquatic plants due to reduced penetration of light and covering with sediments, and direct and indirect impacts on aquatic animals due to clogging of the gills, impairment of feeding and other behaviour, changes in the availability of food items and physical changes to habitat. The United States and European Union water quality criteria recommend a permissible level of total suspended solids (TSS) of 25mg/L because of these potential effects (ANZECC, 2000). In comparison, the average TSS at the compliance point in 2002 and 2003 were 826 and 890mg/L or more than 30 times this recommended permissible level (Tolukuma Gold Mines Limited, 2004). Chemical Pollution Tailings - Samples of the tailings in the present study were found to contain very high total levels of arsenic, copper, lead, mercury and zinc. Even higher levels of some metals have been recorded in the more extensive monitoring carried out by the mine owners as summarised in Section 3.7 of the present report. Water Quality – Samples of water collected from the Auga and Angabanga Rivers in the present study were found to contain: • High levels of total arsenic, lead and mercury in the unfiltered water samples from both rivers that

exceed Australian Drinking Water Guidelines. • Dissolved copper levels in the Auga River that exceed the Australian Water Quality guidelines for the

protection of 80% of aquatic organisms and, • Dissolved mercury levels in both rivers that exceed the Australian Water Quality guidelines for the

protection of 95% of aquatic organisms. Some data on total and dissolved levels of arsenic and metals in the Auga and Angabanga Rivers are also available in the Annual Environmental Reports. Total arsenic and metal concentrations in samples collected in September 1998 and November 1999 from selected sites (Dome Resources NL, 1999a and b) are shown in Table 6 and dissolved concentrations in Table 7. The data differ from those of the present study probably as a result of different flow rates of the river and other factors. The results are similar however in that they include total levels of arsenic, lead and mercury that exceed the Australian Drinking Water Guidelines. In particular, the level of lead recorded at Inawi on the Angabanga River in November 1999 was 11.4µg/L. The level recorded in August 2004 in the present study at Oriropetana which is close to Inawi was 16µg/L. The levels of total mercury at Veifa’a and Inawi in September 1998 also exceeded the ADWG. These sites are close to villages that continue to depend on the Angabanga River for drinking water.


Table 6

Total Arsenic and Metal Concentrations in Water Samples Collected by Dome Resources NL (µg/L)

Sep-98 Arsenic Cadmium Chromium Copper Lead Mercury Zinc

Compliance Point 30 nd 6 22 36 11 23 Veifa'a 7 nd 2 4 5 2 10 Inawi 8 nd 4 6 8 6 13 Coast 19 nd 8 15 16 2 23

Nov-99 Compliance Point 17.2 0.1 2.2 16 13.8 3.2 19.4 Inawi 5.6 0.3 10.5 23.1 11.4 nd 29.8 ADWG 7 2 50 2000 10 1 3000

Values in bold type exceed the Australian Drinking Water Guidelines (ADWG), nd = not detected

The level of dissolved copper in the Angabanga River in September 1998 also exceeded the AWQ 80%TV as shown in Table 7.

Table 7 Dissolved Arsenic and Metal Concentrations in Water Samples Collected by Dome Resources NL

(µg/L)

Sep-98 Arsenic Cadmium Chromium Copper Lead Mercury Zinc Compliance Point 11 nd nd 9 nd nd 6 Veifa'a 4 nd nd 4 nd nd 8 Inawi 4 nd 1 5 1 nd 10 Coast 6 nd 2 6 nd nd 8

Nov-99 Compliance Point 3.8 0.6 0.2 3.5 1.9 nd 8.7 Inawi 2.1 0.5 0.4 0.3 0.2 nd 0.6 AWQ (95%) 13 0.2 1 1.4 3.4 0.6 8 AWQ (80%) 140 0.8 40 2.5 9.4 5.4 31

Values in bold type exceed the Australian Water Guidelines (AWG), nd = not detected

Sediments – In the present study levels of arsenic, lead, mercury and zinc that exceed the U.S. NOAA Sediment Quality reference levels were found in sediment samples in both the Auga and Angabanga Rivers. Data on concentrations in sediment samples are also provided in some of the Annual Environmental Reports (Dome Resources NL, 1999a; DY Environmental Consultants (PNG) Limited, 2000 and 2003). These are summarised in Table 8.


Table 8 Concentrations of Arsenic and Metals in Sediment Samples

DY Environmental Consultants (PNG) Limited, 2000 and 2003 (mg/kg in <63µm fraction)

Sep-98 Arsenic Cadmium Chromium Copper Lead Mercury Zinc

Inauauni 108 0.8 37 107 87 8.6 170 Veifa'a 131 1.1 30 66 117 21.9 206 Inawi 51 0.4 88 863 57 8.6 216

Apr-99

Compliance Point 348 3 27.5 371 104 78.6 400

Inauauni 54 0.5 23.5 60.5 28.5 1.75 103 Veifa'a 57.5 1.5 37.5 96.5 33.5 2.1 125 Inawi 43.5 0.5 25 108 23.5 1.45 106 Coast 30.5 nd 23 64 26 2.2 95.5

Nov-99

Compliance Point 181 nd 20 145 145 5.9 512

Inauauni 20 nd 23 35 14 0.2 70 Veifa'a 35 nd 36 49 22 0.5 91 Inawi 33 nd 36 48 19 0.5 88

Jun-03

Compliance Point 585 4.3 15 104 235 245 525

Inauauni 96.2 0.9 51.1 64.5 48.3 16.8 196 Inawi 90.9 0.7 37.5 59.4 38.9 15 167

NOAA TEL 5.9 0.6 37.3 35.7 35 0.2 123 NOAA PEL 17 3.5 90 197 91.3 0.5 315

ASQG Low 20 1.5 80 65 50 0.15 200 ASQG High 70 10 370 270 220 1 410

Figures in bold type exceed the NOAA PEL. Figures in italics exceed the ASQG High level. NOAA = U.S. National Oceanic and Atmospheric Administration, TEL = Threshold Effects Level, PEL = Probable Effects Level, ASQG = Australian Sediment Quality Guidelines. These data also include levels of arsenic and mercury in sediment samples in both the Auga and Angabanga Rivers that exceed the U.S. NOAA Sediment Quality reference levels and the Australian Sediment Quality Guidelines High values (ANZECC, 2000). The Australian guidelines are provided here as they are cited in the Annual Environment Reports produced by Tolukuma Gold Mines. These guidelines however, correspond to the effects range-low and median used by the NOAA in 1995 for marine sediments. We consider that comparison with the 1999 NOAA reference levels for freshwater sediments is more appropriate. The levels are generally considerably higher than those in samples from the Alabule River (a tributary of the Angabanga River that is not affected by mining) that also were collected as part of the monitoring program. In 2003, the levels in the Alabule River were: arsenic 14.7mg/kg and mercury 0.8mg/kg. 4.3 Statutory Compliance Monitoring Data The Environment (Waste Discharge) Permit for the Tolukuma Gold Mine specifies water quality criteria for the Auga River that are determined at the compliance point 7km downstream from the tailings discharge.


The levels of dissolved mercury in three filtered water samples collected from the compliance point in the present study exceeded the compliance criteria. The operators of the Tolukuma Gold Mine collect water samples from the compliance point over a period of several days each month. These are filtered and analysed for arsenic, various metals, ammonia and cyanide and the results are provided in Annual Environmental Reports. We have been able to obtain the annual environmental reports for the Tolukuma Gold Mine for 1998 and 1999 (Dome Resources NL, 1999a and b) and for 2000, 2002 and 2003 (Tolukuma Gold Mines Limited 2001, 2003 and 2004). The data from 1989 are unreliable as some samples were acidified prior to filtration and these are therefore not included in the review below. A summary of the available monitoring data is provided in Table 9.

Table 9 Summary of Monitoring Data from Compliance Point on the Auga River

Year Samples (n) Criterion (µg/L) Range (µg/L) Non-compliance

Arsenic 1999 191 50 <0.2 - 86 5 (3%) 2000 192 50 <0.2 - 22 0 2002 184 50 <0.2 - 150 22 (12%) 2003 176 50 <1 - 18 0

Cadmium 1999 191 10 <0.1 - 4.4 0 2000 192 10 <0.1 - 12.5 1 (0.5%) 2002 184 10 <0.1 - 5 0 2003 175 10 <1 - 1 0

Chromium 1999 191 50 <0.2 - 10 0 2000 192 50 <0.2 - 8.1 0 2002 184 50 <0.2 - 5 0 2003 175 50 1 - 2 0

Copper 1999 191 1000 <0.2 - 21 0 2000 191 1000 <0.2 - 18.9 0 2002 183 1000 <0.2 - 38 0 2003 175 1000 <1 - 156 0

Lead 1999 191 5 <0.2 - 4.3 0 2000 191 5 <0.2 - 23 8 (4%) 2002 184 5 <0.2 - 180 57 (31%) 2003 175 5 <0.8 - 4 0

Mercury 1999 191 0.2 <0.2 - 44 38 (20%) 2000 192 0.2 <0.2 - 2.5 9 (4.7%) 2002 183 0.2 0.2 - 4.1 31 (17%) 2003 139 0.2 0.1 - 0.5 1 (0.7%)

Zinc 1999 191 5000 <0.05 - 78 0 2000 192 5000 <0.05 - 120 0 2002 184 5000 <0.05 - 505 0 2003 174 5000 <1 - 430 0

Ammonia 1999 189 50 <0.5 - 490 95 (50%) 2000 192 50 <5 - 870 38 (20%) 2002 184 50 <5 - 460 51 (28%) 2003 173 50 <10 - 3000 114 (66%)

Free Cyanide 1999 173 5 <10 - 25 9 (5%) 2000 176 5 <10 - 16 2 (1%) 2002 185 5 5 - 13 6 (Note A) 2003 175 5 <1 - 80 21 (12%)

Note A: The lowest laboratory detection limit in this case was higher than the compliance criterion. This means that it is unknown whether the levels exceeded the criteria or not. Therefore, the number of non-compliant results cannot be determined.


These data reveal that the levels of arsenic, lead, mercury, ammonia and cyanide in some samples have exceeded the compliance criteria. For example, 22 out of 184 samples collected in 2002 (or 12%) had arsenic levels that exceeded the criteria (50µg/L). Similarly, 58 of 184 samples collected in 2002 (or 31.5%) had lead levels that exceeded the criteria (5µg/L). The levels of ammonia frequently exceed the criterion with 114 instances of non-compliance out of 173 samples collected in 2003 (66%). It is suggested in the Annual Environmental Reports that the Department of Environment found elevated levels of ammonia in all local rivers upstream of the compliance point and in tributaries of the Angabanga River downstream (Dome Resources NL, 2000). This suggestion cannot be evaluated as no data are provided in the reports. The results for ammonia are also interpreted in the reports in terms of Schedule 4 of the Regulations of the PNG Water Resources Act, 1982 or Schedule 1 of the Regulations of the Environment Act 2000. These provide tables that enable the calculation of the maximum permitted concentration of ammonia nitrogen at a range of temperatures and pH. The monitoring data are generally less than the maximum concentrations permitted in the Regulations when these calculations are made. However, there is no statement in the Environment (Waste Discharge) Permit that this treatment of the data is permitted. Adequacy of the Compliance Criteria Limitations - There are major deficiencies in the compliance criteria as follows: • They do not include emission standards that apply to the tailings discharge • The water quality criteria are limited to certain toxicants and do not include physical contaminants

such as suspended solids that may have an equal or greater impact on the aquatic ecosystem than the toxicants specified in the criteria.

• They do not include sediment quality criteria. • They do not require direct assessment of environmental impact. • The compliance point is a considerable distance downstream from the discharge point. • The criteria for cadmium, chromium, copper and zinc are higher than the Australian Water Quality

80% Threshold Values. • Tolukuma Gold Mines appears to determine its compliance on average values for a series of samples

collected over a year rather than absolute values that must not be exceeded at any time, and • There is no requirement for drinking water standards to be met in the Angabanga River where many

people regularly drink the water during the dry season. The best method of assessing the environmental impact of the discharge of pollutants into a river is by direct study of the receiving environment. This requires descriptive and quantitative assessment of the aquatic ecosystem and associated features such as human populations that are, or may be, exposed to the river either by direct or indirect contact. Preferably, an assessment of this nature is made prior to the start of discharge and is then repeated periodically to determine whether any significant changes have occurred from the baseline conditions. Comparisons should also be made between the river ecosystem and that of a similar river such as a tributary in the same local area. Reliance on a limited range of compliance criteria as indicators of environmental condition fails to acknowledge that compliance criteria do not guarantee environmental protection. They are guidelines that are designed to provide information that is useful in formulating management strategies. The limitations of the guidelines also need to be recognised when interpreting the significance of pollution. For example, the Australian Water Quality guidelines are based on information on the acute effects of the toxicants on specific organisms in laboratory studies. The effects of long-term exposure to lower levels of toxicants and the possibility of bio-accumulation also should be considered as should the potential effects of combinations of toxicants (synergistic effects).


Emission Standards – Emission standards that are designed to protect the receiving environment are usually applied to industrial discharges. These standards are in addition to water quality criteria that apply to the receiving environment. Such standards are an incentive to companies to adopt best available waste treatment and management practices prior to discharge. Mixing Zone - The location of the compliance point was established to provide a mixing zone for discharges from the mine prior to sampling of the river water. The term “mixing zone” generally applies to a defined area around an effluent discharge where the management goals of the ambient waters do not need to be achieved and environmental values may not be protected (ANZECC, 2000). The concept of a mixing zone however, should not be applied to a discharge of this type or to a receiving environment such as the Auga River. Mixing zones should be small in area and are not appropriate for the management of substances that bio-accumulate or of particulates, or to discharges that affect the whole width of a river (ANZECC, 2000). The emissions also should not cause toxicity or irreversible harm to fish or other aquatic vertebrates in the zone. It is probable that none of these conditions are met by the discharge into the Auga River. Average versus Absolute Criteria - The fact that the mine owners are not meeting the compliance criteria is reported in the earlier Annual Environmental Reports. In the more recent reports however, the average (or mean) concentrations of the metals and other pollutants are compared to the compliance criteria rather than the concentrations found in individual samples. These references to annual averages are questionable as they tend to obscure the fact that the levels of toxicants in many individual samples exceed the criteria. Drinking Water and Water Quality Guidelines - Guidelines based on dissolved levels of toxicants are used to assess water quality in ecosystems and relate to environmental impact. For example, the criteria that apply to TGM are the same as those specified for the protection of aquatic organisms in the PNG Environmental Act, 2000. It is evident therefore that the criteria are intended to protect aquatic life. Drinking water guidelines are based on the total levels of toxicants in unfiltered water samples (National Health and Medical Research Council/ Agriculture and Resource Management Council of Australia and New Zealand, 1996). The differences between the guidelines for various toxicants are illustrated in Table 10. The PNG drinking water standards are listed in the Public Health (Drinking Water) Regulation 1984 and are based on the WHO standards of 1971. It is apparent in this Table that some of the compliance criteria approximate the Australian Water Quality Guidelines (arsenic and lead) but others are considerably higher than those guidelines (cadmium, copper, nickel and zinc). Some of the criteria also approximate more the Australian Drinking Water Guidelines (chromium, copper and zinc), while the criterion for cadmium is higher than both of the Australian Water Quality and the Australian Drinking Water Guidelines. The Department of Environment and Conservation has recommended in the past that the compliance levels for free cyanide, copper and zinc should be made more stringent (Papua New Guinea Office of Environment and Conservation, 2000). The purpose of this presumably was to make the criteria equivalent to international water quality guidelines. It appears that no action has been taken to implement this recommendation. If compliance monitoring is to have any meaning, the rationale and objectives of the criteria must be specified and their scope and the type of samples must be appropriate. Monitoring sites also should be established throughout the river system and selected on the basis of a logical sampling rationale rather than the single arbitrarily located monitoring point that is used at present.


In the case of the Auga and Angabanga Rivers, the objectives should be to protect aquatic organisms and to achieve drinking water guideline levels on a continuous basis at those locations where the rivers were the primary source of water prior to the mine and adequate alternative supplies (in terms of quantity, reliability of supply and quality) are not available. A monitoring program for these objectives would require the regular (monthly) collection and analysis of series of both unfiltered and filtered water samples and sediment at a number of fixed locations along the Auga and Angabanga Rivers and reference rivers and interpretation of the results using internationally recognised guideline values.

Table 10 Comparison of Standards, Criteria and Guidelines

(µg/L)

TGM Compliance

Criteria¹

Australian Water Quality

Guidelines¹*

Australian Drinking Water

Guidelines²**

PNG Drinking Water

Standards² †

Arsenic 50 13-140 7 50

Cadmium 10 0.2-0.8 2 10

Chromium 50 1-40 50 50

Copper 1000 1.4-2.5 2000 1500#

Lead 5 3.4-9.4 10 100

Mercury 0.2 0.6-5.4 1 1

Nickel 1000 11-17 20 -

Zinc 5000 8-31 3000 15000#

1 – Dissolved levels. 2 – Total levels. # - Maximum Permissible Level

* ANZECC 2000, 95% and 80% protection values respectively; ** National Health and Medical Research Council/ Agriculture and Resource Management Council of Australia and New Zealand (1996); † PNG Public Health (Drinking Water) Regulation 1984.


5. CONCLUSION The discharge of tailings from the Tolukuma Gold Mine is causing ongoing pollution of the Auga-Angabanga River System by sediment and toxicants including arsenic and various metals. This pollution has occurred over a period of more than 10 years. The sediment plume from the tailings discharge and sediment deposits are visible along the entire length of the river and elevated levels of toxicants are detectable in both the water and in the sediments. It is probable that this pollution has caused major impacts on the ecology of the river system. Potential effects include obliteration of most aquatic life in the upper Auga River and changes in species composition, populations and behaviour downstream as far as the coast. . The pollution also has deprived the people who live close to the rivers of a traditional source of drinking water and food. This in turn has caused changes in lifestyle and may have affected nutrition in some villages as an important source of protein, namely fish, is no longer available or is not as abundant as before. In addition, there have been reports of undiagnosed illnesses that local people have attributed to the pollution levels in the rivers. Some people continue to drink water from the rivers and many come into contact with the water on a regular basis and live nearby. There also are reports of chemical odours coming from the upper Auga River. This raises the possibility of exposure to atmospheric pollution as a factor in community health. These reports should not be discounted in the absence of comprehensive and appropriately designed assessments of community health. The only investigations so far took place some time after the sickness and deaths were reported and were unable to reach a conclusion as to the cause (Central Province Administration Division of Health 2000; Taufu and Bomareo, 2003). Studies that should be implemented in addition to an improved monitoring program include: • An assessment of the nature and extent of the impact on the river ecosystems and the marine

environment close to the mouth of the Angabanga River. • Ongoing detailed surveys of community health particularly of people who live close to the river on a

continuous basis. • Continuous atmospheric monitoring of potential toxicant levels in the valley of the upper Auga River. • An assessment of the social impact of the pollution in terms of community lifestyles, diet, access to

water, etc. These studies would provide information about the actual impact of the waste discharges from the Tolukuma Gold Mine. Such information could be used to assist in the preparation of strategic plans to protect the local communities from potential health impacts and to replace resources that have been impaired or lost. Such studies however, would not enable better protection of the environment as the discharge of tailings would have to stop, or the contents of the tailings would have to be significantly improved, for there to be any possibility of this. Alternative methods of waste treatment and disposal therefore should be investigated.


6. REFERENCES ANZECC (2000) – Australian and New Zealand Guidelines for Fresh and Marine Water Quality. Australia and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand, October 2000. AS/NZS: 5667.1: 1998 – Australian and New Zealand Standard Water Quality Sampling, Part I: Guidance of the Design of Sampling Programs, Sampling Techniques and the Preservation and Handling of Samples. AusAID (2004) – Interim AusAID Guidelines and Operating Procedures for Managing Arsenic in Water Supplies. Australian Government Department of the Environment and Heritage (2003) – Cyanide Management. (Website) Buchman, M.F. (1999) – NOAA Screening Quick Reference Tables, NOAA HAZMAT Report 99-1, Seattle WA, Coastal Protection and Restoration Division, National Oceanic and Atmospheric Administration. Central Province Administration Division of Health (2000) - Report on the Environmental Health Investigations into the Allegations of Illness and Death Relating to Use of the Auga-Angabanga River System – Tolukuma Gold Mine Central Province, PNG”. Dome Resources NL (1999a) – Tolukuma Gold Mine 1998 Annual Environmental Report. Dome Resources NL (1999b) – Tolukuma Gold Mine 1999 Annual Environmental Report. Durban Roodeport Deep Ltd (2003) – Information presented on website ww.hoovers.com/free/co/secdoc DY Environmental Consultants (PNG) Limited (1999) – Tolukuma Gold Mine Hydrology and Transport Issues November 1999 Review. Report No. 4/99. DY Environmental Consultants (PNG) Limited (2000) – Tolukuma Gold Mine Water quality and Geochemical Incestigations along the Auga-Angabanga Rivers System and the Floodplain. Report No. 5/99. DY Environmental Consultants (PNG) Limited (2003) – Tolukuma Gold Mines Limited Environmental management and Monitoring: Sampling and Review of Downstream Physico-Chemical Issues: Auga-Angabanga Rivers System. Report No1/2003. Geoscience Australia (undated) – Water Hardness. www.ozestuaries.org/indicators/DEF_hardness.html (Accessed 8/2004) Koma, Matilda (in prep.) – An Assessment of Water Quality in the Auga River Downstream of the Tolukuma Gold Mine. NGO Environmental Watch Group Inc., Port Moresby. Minproc Limited (2000) – Tolukuma Gold Mine. Report prepared for Durban Roodeport Deep Limited. National Health and Medical Research Council/ Agriculture and Resource Management Council of Australia and New Zealand (1996) – Australian Drinking Water Guidelines. National Water Quality Management Strategy. NSR Environmental Consultants Pty Ltd and David Ballach and Associates (1993) - Tolukuma Gold Project: Environmental Plan Inception Report. Dome Resources (PNG) Pty Ltd CR 486/2.


Oxfam Community Aid Abroad (2003) – Mining Ombudsman Annual Report 2003. Oxfam Community Aid Abroad (2004) – Critique of the “Report on the Water Quality Investigations in the Allegations of Elevated Cyanide and Mercury Levels in the Auga-Angabanga River System – Tolukuma Gold Mine Central Province, PNG”. Papua New Guinea Office of Conservation and the Environment (2000) – Tolukuma Annual Water Quality Data 1999. Taufa, Tukutau and Bomareo, Kobby (2003) – The Investigation of Disease Outbreak in the Fane and Mekeo Areas of Central Province, Papua New Guinea. Report prepared for Tolukuma Gold Mines Limited. The Papua New Guinea Department of Conservation and the Environment (2003) – Report on the Water Quality Investigations into the Allegations of Elevated Cyanide and Mercury Levels in the Auga-Angabanga River System – Tolukuma Gold Mine Central Province, PNG”. Tolukuma Gold Mines Limited (2001) – 2000 Annual Environment Report. Tolukuma Gold Mines Limited (2003) – 2002 Annual Environment Report. Tolukuma Gold Mines Limited (2004) – 2003 Annual Environment Report. World Health Organisation (2001) – Arsenic in Drinking Water. World Health Organisation Geneva, Fact Sheet #210.


APPENDIX 1 - RESULTS OF ANALYSES

Pollution from the Tolukuma Gold Mine

39

Total (Unfiltered) Water Samples (µg/L)

Notes: K = Tailings sample; T5 to G1 = Auga River samples; E3 to N3 = Angabanga River samples

____________________________________________________________________________________________________________________________

K T5 D1 G1 E3 O2 O3 N3

Ca >250000 11,766 17,299 20,324 18,580 20,174 20,568 20,661

Mg 240079 8,621 9,467 11,392 4,039 4,133 4,452 4,326

As 24193.41 224.79 150.73 176.48 13.96 9.96 13.97 8.14

Cd 243.32 1.25 1.04 1.37 0.02 0.06 0.10 0.12

Cr 966.33 21.44 17.40 22.24 0.40 0.92 1.85 0.49

Cu 5469.81 71.60 80.40 64.40 0.60 0.65 3.97 1.31

Pb 29231.08 494.64 457.89 446.14 23.59 16.33 16.18 13.31

Hg 11844.66 40.26 38.21 26.48 1.33 0.64 0.42 0.09

Ni 393.34 4.10 2.02 5.68 0.00 0.00 0.00 0.00

Zn 17417.19 280.57 294.63 310.94 0.00 1.27 17.03 14.68


40

Filtered Water Samples (µg/L)

H1 = Guguma River; Y1, Y2 = Yeme River; B1 = Aroa River

_____________________________________________________________________________________________________________________________

Ca Mg As Cd Cr Cu Pb Hg Ni Zn

H1 11,280 2,716 0.83 0.41 0.19 0.33 0.57 0.91 2.40 26.15 Y1 11,115 3,780 0.74 0.69 0.32 0.76 0.10 0.12 0.55 2.76 Y2 11,270 3,837 0.84 0.69 0.32 0.66 0.18 0.20 0.59 0.24 K3 15,975 2,387 9.94 0.31 0.57 90.39 3.84 2.09 4.01 14.93 T3 15,945 2,610 8.40 0.31 0.24 67.61 4.69 3.19 3.00 9.85 T6 14,510 2,423 8.33 0.73 0.09 31.82 1.02 0.36 1.73 9.85 D6 14,325 2,890 6.30 0.30 0.23 52.48 1.80 2.46 2.79 3.85 D7 14,410 2,856 6.85 0.72 0.22 48.08 1.54 0.16 2.06 2.69 G1 15,165 2,962 7.31 0.71 0.17 28.33 1.74 0.02 3.44 3.16 G2 14,445 3,032 6.19 0.28 0.23 33.69 1.51 1.53 2.07 3.27 G3 14,285 2,933 6.62 0.73 0.16 50.08 1.52 0.07 2.52 2.58 G4 14,510 2,935 6.54 0.29 0.12 85.28 1.89 1.75 3.02 6.67 G5 14,865 2,936 7.21 0.71 0.49 46.88 1.18 0.09 2.36 2.37 G6 15,185 2,945 6.46 0.72 0.56 48.71 2.15 0.20 2.44 9.19 G7 15,395 2,947 6.37 0.72 0.19 53.76 1.16 0.23 2.35 2.45 G9 14,590 2,705 6.43 0.72 0.06 39.70 1.11 0.13 2.12 2.06 E1 18,290 3,574 4.88 0.26 0.26 1.09 1.17 0.73 0.84 0.54 E2 18,665 3,628 6.25 0.27 0.25 1.18 2.38 15.64 0.82 1.55 O1 19,690 3,748 5.37 0.26 0.23 1.12 1.16 1.53 0.92 2.82 O7 20,120 3,759 5.51 0.79 0.14 1.36 0.76 0.11 0.66 0.00 N2 20,230 3,878 5.23 0.27 0.20 1.05 1.21 5.57 0.96 1.79 B1 10,715 4,196 0.71 0.35 0.37 0.99 0.35 0.77 0.78 2.84


41

Sediment Samples (mg/kg)

H2 = Guguma River; Y1 = Yeme River; D4 = 10cm below surface; G8 = on slope above river; O6 = Sand bank in river.

_______________________________________________________________________________________________________________________

Y3 G8 H2 D4 T1 T2 D2 D3 GE GW E4 O4 O5 O6 N1

Ca 6107 3599 1551 2055 4692 4059 2616 3128 4311 2574 5529 6391 5812 6,146 6126

Mg 11592 5135 4634 5985 4231 3800 3790 3304 4275 4198 7687 6805 6837 7961 7122

As 6.941 11.134 126.217 138.700 493.524 488.375 414.797 400.711 410.625 263.405 134.987 44.067 17.102 51.937 27.637

Cd 0.202 0.111 0.796 0.504 1.683 1.788 1.417 1.479 1.337 0.938 0.865 0.425 0.433 0.184 0.28

Cr 54.412 14.262 26.296 30.975 20.119 17.267 17.362 13.829 19.374 19.140 40.337 34.836 32.975 27.625 32.662

Cu 49.381 37.919 36.492 36.112 58.939 68.175 50.389 47.326 54.781 34.795 58.587 48.214 52.237 36.175 44.550

Pb 9.625 23.175 81.446 65.512 233.235 230.844 185.684 170.489 206.544 94.697 232.850 85.789 100.187 15.663 31.297

Hg 1.546 1.675 32.372 16.701 138.794 67.762 89.207 274.972 70.400 24.942 60.887 15.878 67.037 3.469 5.195

Ni 46.037 19.000 10.668 17.172 20.727 20.840 18.457 14.250 17.737 13.499 24.124 29.119 26.325 30.762 29.500

Zn 70.650 96.262 189.857 145.437 359.907 521.625 315.815 318.282 344.000 236.289 255.875 124.995 131.775 85.937 97.612

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POLLUTION FROM THE TOLUKUMA