Biological Monitoring of Water Quality

“the totality of features and characteristics of water that bear upon

its ability to support an appropriate natural fauna, and to sustain legitimate

uses.” (Pugh, 1997)

The 3 components of management of ecological quality in rivers

General Quality Assessment

GQA Scheme for Biology

• A = Very Good– Biology similar (or better than) that expected for an average and

unpolluted river of this size, type and location. High diversity of taxa, usually with several species in each. Rare to find dominance of any one taxon.

• B = Good C = Fairly Good, D = Fair, E = Poor

• F = Poor– Biology limited to a small number of very tolerant taxa such as worms,

midge larvae, leeches and water hoglouse, present in very high

numbers.

Water Framework Directive (2000)

WFD looks at the whole system; seeks to manage water proactively on a catchment basis, using reference systems

Aims:1. To achieve “Good Status” for all waters by set deadlines

(2015)2. To promote sustainable water consumption3. To protect & enhance the status of aquatic ecosystems &

associated wetlands

Water management to be based on natural units not natural ones

Aquatic Invertebrates

Sampling

Identification

Using aquatic inverts as indicators of biological water quality

What are Aquatic Macro-invertebrates?

Aquatic Invertebrates - Examples

Why Sample Aquatic Invertebrates?

1. Aquatic inverts are ecologically important within the food chain –

- abundance

- species and ecological diversity

Functional roles include:•Algal grazers

•Consumers of bacteria & fungi

•Detritivores

•Predators

•Prey

Why Sample Aquatic Invertebrates cont. ?

2. Aquatic Invertebrates vary in their sensitivity to water pollution i.e. they are good biological indicators

3. Aquatic invertebrate data provides longer term information than chemical data

4. Sampling aquatic invertebrates is more meaningful than chemical monitoring

5. Aquatic invertebrates are relatively easy to collect

Collecting Samples

Health and Safety first!

1. Prepare necessary methods statement and risk assessment

Collecting Samples

2. Check mobile phone, put on life jacket

3. Review bank features including slope, vegetation, conditions underfoot, obstacles or special hazards

4. Review waterbody features including depth, turbidity, flow, substrate, channel profile, vegetation, obstacles or special hazards

Collecting Samples

5. Together with co-worker, identify point(s) of entrance and exit

6. Use ranging pole to test substrate and provide support

7. Go slowly

8. Common Sense Rule: Don’t get in if there is any doubt over safety

Collecting Samples

4 – Minute Combined Kick-sweep Sample

– 30 seconds collection of surface activity insects– 3 minute kicking and sweeping– 30 seconds collection of benthic invertebrates adherent

to stones, logs, car tyres and shopping trolleys

Key Point:

Important to divide time between component habitats or microhabitats proportionallyE.g. Open water, submerged vegetation, emergent vegetation, exposed substrate, overhanging vegetation, submerged wood

Sample Storage

Either a three stage process:• Firstly: apply a fixative, usually 4%

aqueous solution of formaldehyde

• Secondly: sort sample, i.e. pick out inverts

• Thirdly: store sorted sample in a preservative, usually 70% alcohol

Or; simply use 90% alcohol (IMS)

Sorting a Sample

• Wash out fixative

• ‘Dilute’ sample across a white tray

• Carefully pick out the invertebrates

Review of Aquatic Invertebrate Groups

Crustacea – Water Fleas

Crustacea – Freshwater Shrimp

Platyhelminthes - Flatworms

Annelida – Hirudinea - Leeches

Mollusca – Gastropoda - Snails

Insecta – Hemiptera – Water Bugs

Insecta – Coleoptera – Water Beetles

Insecta – Diptera – True Flies

Insecta – Megaloptera - Alderflies

Insecta – Tricoptera – Caseless Caddis Flies

Insecta – Tricoptera – Cased Caddis Flies

Insecta – Tricoptera - Adult Caddis Fly

Insecta – Plecoptera – Stone-flies

Insecta –Ephemeroptera - Mayflies

Insecta – Ephemeroptera – Adult Mayfly

Insecta – Odonata – Dragonflies & Damselflies

Data Interpretation

Calculate the Biotic Scores

• Taxon or species richness; the easiest measure of biodiversity

• BMWP score; the Biological Monitoring Working Party score

• ASPT index value; the Average Score Per Taxon

BMWP score Category Interpretation

0-10 Very poor Heavily polluted

11-40 Poor Polluted or impacted

41-70 Moderate Moderately impacted

71-100 Good Clean but slightly impacted

>100 Very good Unpolluted, unimpacted

BMWP Scale

BWMP – Score dependent on sample size, sampling efficiency and seasons

Different unpolluted rivers often generate very different BMWP scores due to natural variation in ecological communities eg.

silted lowland rivers with turbulent upland streams.

The solution ?

RIVPACSIn this system the different river types are taken into account

Mesolveliidae Hydrometridae Gerridae Nepidae NaucoridaeNotonectidae Pleidae CorixidaeHaliplidae Hygrobiidae Dytiscidae GyrinidaeHydrophilidae Clambidae Scirtidae Dryopidae EliminthidaeChrysomelidae CurculionidaeHydropsychidaeTipulidae SimuliidaePlanariidae Dendrocoelidae

BaetidaeSialidaePiscicolidae

Valvatidae Hydrobiidae Lymnaeidae Physidae PlanorbidaeSphaeriidaeGlossiphoniidae Hirudidae ErpobdellidaeAsellidae

Chironomidae

Oligochaeta (whole class) 1

3

2

4

5

Data Interpretation

• Compare sampling stations, e.g. up and downstream of potential pollution source

• Compare with historical data

• Compare with Environment Agency data

0102030405060708090

100

1 2 3 4 5 6

BM

WP

Sc

ore

Site

BMWP at sites along the Tory Brook & River Plym

River Plym

Tory Brook

0

1

2

3

4

5

6

7

8

9

10

1 2 3 4 5 6

Ave

rag

e S

core

per

Tax

on

Site

Average score per Taxon at sites along the Tory Brook & River Plym

River Plym

Tory Brook

Site two at the Tory Brook

Evidence of china clay in the water

Evidence that channel may have be altered

Site six at the Tory Brook

02.5

57.510

12.515

17.520

22.525

27.530

1 2 3 4 5 6Su

sp

en

de

d S

olid

s (m

g/l)

Site

Suspended Solids at sites along the Tory Brook & River Plym

River Plym

Tory Brook

Site one at the River Plym

Site two at the River

Plym

Site four at the River Plym

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1 2 3 4 5 6

Ph

os

ph

ate

(mg

/l)

Site

Phosphate at sites along the Tory Brook & River Plym

River Plym

Tory Brook

ReferencesBourne Stream. 2008. BMWP Scoring – measuring Freshwater Quality [online] Available at

http://www.bournestreampartnership.org.uk/bmwpscoring.htm [Accessed 23rd March 2008]

Centre for Ecology & Hydrology. 2008. RIVPACS (River Invertebrate Prediction and Classification System): an introduction. [Online] Available at: http://www.ceh.ac.uk/sections/re/RIVPACS.html [Accessed 2nd April 2008]

DEFRA. 2006. Key Facts about: Inland Water Quality and Use, Phosphate Concentrations in rivers: 1995-2005. [Online]. Available at: http://www.defra.gov.uk/environment/statistics/inlwater/kf/iwkf09.htm [Accessed 4th April 2008] 

Environmental Agency. ND. General Quality Assessment of rivers – biology, [Online] Available at: http://www.environment-agency.gov.uk/commondata/acrobat/bio_method_09_03_559881.pdf [Accessed 19th November 2007] 

EPA, 2007. Biological Indicators of Watershed Health. [Online] (Updated 30th November 2007) Available at: http://www.epa.gov/bioindicators/html/indicator.html [Accessed 20th March 2008]

Gainey P. 2007. Cornish mineral company fined for polluting salmon river. [Online] Available at: http://www.environment-agency.gov.uk/news/1901125 [Accessed 4th April 2008]  

Hawkes H. 1997. Technical Note, Origin and Development of the Biological Monitoring Working Party Score System, 32 (4) Pages 964-968

Martin R. 2004. Origin of the Biological Monitoring Working Party System, A brief summary, [Online] Available at http://www.cies.staffs.ac.uk/origbmwp.htm [Accessed 20th November 2007]