of these by an adult and on the basis of basic radiation dose limits (ICRP), the maximum permissible concentrat ion of radionuclides in the bay waters was derived. The operations were guided by these values for waste releases into the bay.

Extensive laboratory investigations were conducted on the bay sediments to reveal their absorption characteristics, the extent of labile consti tuents and the release of radionuclides from sorbed sediments. Radiation surveillance in the area is carried out routinely. Monitoring results over the last decade have shown that even in areas close to the discharge locations, the concentrations of 9o Sr and 13 ~ Cs in sea waters are much below the permissible limits. Seepage of 106 Ru through soil into well waters observed during survey indicated possibilities of its movement into the nearby bay.

Coastal bay waters normally contain heas'y loads of silt which has high sorption capacity, for radionuclides. The bot tom sediments also showed high pick-up of t37Cs, 144 Ce and 106 Ru. Most accumulation was in the discharge area. Transport of radionuclides through movement of sediments is an important parameter and is under ob- servation. The shore-line acts as an external radiation source for organisms living in it and for the fishing population.

The fish tissues and salt showed pick up of 137 Cs and 9°Sr but the levels were very. low compared to derived permissible limits. An interesting observation made was that benthic organisms like the crab Sevlla serrata showed high pick-up of 13~Cs, l ° 6 R u and 144Ce but non-benthic organisms like catfish (Arius sp.) showed only 13~Cs pickup thereby showing the transfer of radionuclides through sedentary benthic material. The radiation exposure from consumption of fish and salt harvested from the bay waters was below 1 per cent of the dose limits prescribed for human populations. Tarapur The. power station is located in a promontary ju t t ing about 250 m into the sea. Radioactive effluents from the station are discharged daily into the condenser outflow of about 1000 cusecs in about 4 h. The dilution of effluents readily available is thus about 4x10 ~ . The releases are made near shore.

Water movement experiments were carried out in the near shore ~-aters with dyes and bottle floats. It was

observed that near the shore there exists an oscillatory current closely in phase with the tidal current but much reduced in speed. The water involved in dilution of effluents is that lying between high water line and the S fathom line.

The shore-line is heavily populated by fishermen and there is considerable fishing activity. There are salt pans in the area for product ion of solar sait. The silt load in the waters varies seasonally. Laboratory studies were done to obtain estimates of the equilibrium concentrations of radionuclides in the silt and these levels were used in estimating the maximum exposure possible in the Tarapur a r e a .

The control of contaminat ion in sea water has been exercised normally by fixing a discharge limit which will not affect its utilization. The pe,i~,fissible limits for radionuclides were derived, as for Trombay, on the basis of intake of fish in the region.

Experience at Tarapur over one year of operation has shown that the highest concentrat ion of activity presen~ in the effluents is due to 131 I and this becomes the most critical radionuclide. Monitoring showed that radioiodine was taken up intensively along the beaches and among other specific biota including sea weed. The sea weed, sargassum, concentrated radioiodine by a factor of 103 and served as a good indicator. At the Tarapur Power Station, there is a possibility of thermal discharges resulting in heat circulation in the condenser waters. The extent of this problem and the possible ecological changes in the area are being studied.

A large Power Reactor Fuel Reprocessing plant is being set up at Tarapur which will also discharge low-level liquid effluents containing long-lived radionuclides. Water move- ment studies are underway to locate the discharge point so as to keep the shoreline free from radioactive contaminat ion and offshore fishing free from radiation hazard.

Health Physics Division, Bhabha Atomic Research Centre, Bombay 85, India.

K.C. Pillai .

P.R. Karnath

The Effect of Marine Pollutants on Laminarea Hyperboria Investigations by BeUamy and co-workers (Bellamy et al, 1967) suggested that the flora and fauna of the north east coast of Britain were being affected by pollution. As a resuiL of this work, a number of projects were set up as part of the Productivity Marine section of the International Biological Programme, to examine the problem in greater detail. This report concerns laboratory, experiments with Laminaria hyperborea (Gunn.) Fosl. which is ecologically the most important plant in the sublittoral region around much of the coast of Britain. The surxdval of the early stages, zoospores, gametophytes and young sporophytes is clearly vital to this community .

Two different techniques have been used. i . Culture experiments were carried out lasting 28 days in which zoospores developed into garnetophytes which were followed by sporophytes. The young plants were grown on cover slips in seawater with added nutrients (tCNO~, K~HPO4, Fe(C1)3 and vitamins (Kain, 1964), under opt imum light for maximum growth, at 10 deg.C. The medium was changed weekly and sampling was usually carried out daily by making a permanent preparation of one cover slip per experimental series. The time taken for sporophytcs to appear was observed and the growth of sporophytes was measured by counting the cell number in

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the largest in a given area. All zoospores for a series of po l lu tan t concentrat ions came from the same parent . 2. The Respiration rate of tissue discs from adul t plants was measured in a Gilson differential respirometer for up to 26 h, in the dark. Individual pol lutants were tested with both techniques using a logari thmic series of concentrat ions in order to cover a sufficiently wide range of concentrat ions. For the main series of culture experiments the pol lu tant was added at the beginning and remained throughout the durat i6n of the experiment . In the respirat ion exper iments the pol lu tant was added after 90 rain and respirat ion fol lowed for up to 24 h with readings taken at not more than 50 min intervals. By one or both of these methods the toxic concentra t ion was found for 15 chemical pol lutants including examples of heavy metals, detergents and herbicides.

A further series of culture experiments has involved the growth of young stages in water collected from the estuary of the river Tyne.

Results and conclusiom Table 1 lists the toxic Concentrations found in bo th the

culture and respirometer experiments . The toxic concentra t ion was taken as the lowest concentra t ion in the logari thmic series in which growth of the plants differed from the control . For culture experiments the metals tested

(mercury, copper and zinc) along with Atrazine (a herbicide) were the most toxic chemicals tested. Other herbicides (MCPA and 2,4D) were less toxic and the detergents were the least toxic of all. Because of the large concentration steps in the logarithmic series, growth was usually either normal or completely inhibited. More recent cu l tu re experiments have determined the toxic concentra t ion with greater accuracy (these results have been incorpora ted into Table 1). These recent experiments have given some interesting informat ion with regard to sublethal effects.

Zinc at concentrat ions of 0.25 and 0.5 ppm resulted in the product ion of sporophytes at the usual t ime (8-10 days in culture) but they grew at a considerably slower rate than the sporophytes cul tured in control medium and 0.1 ppm zinc (see Fig 1). Fur thermore , at a concentra t ion of 1.0 ppm zinc the product ion of sporophytes was delayed by approximate ly 9 days (i.e. sporophvtes formed after 18 days). The growth rote of the sporophytes was also reduced at this zinc concentrat ion. The reduct ion of growth of sporophytes in 0.25 and 0.5 ppm zinc, although they were p roduced after the normal matura t ion time for gametophytes , suggests that the gametophytes may be bet te r able to wi ths tand these condit ions than sporophytes . To test the sensitivity of the la ter stages in the life history, the zoospores must be allowed to settle and germinate

TABLE I

Pollunumt

Metals

The toxic concentra t ion of the pol lutants in the two types of experiment .

Culture Respriometer Experiments Experiments

Remarks

Mercury 0.01 ppm 10 ppm* Copper 0.05 100 Zinc 0.25 1000

Herbicides

Added as HgCI 2 Added as CuSO4 Added as ZnSO 4

Ammine 0.01 Non toxic (1000) Dalnpon 100 D~tpon 100 1000 (Probable toxicity) MCPA 1.0 Not tested 24D 1.0 Not tested

Mixed Detergents

Fairy liquid 1.0 Not tested Blusyl 10 Non toxic (1000)

Anionic Dete~ents

Sodium lauryl 10 100 (Possible toxicity) ether sulphate Sodium dodecyl 1.0 Non toxic (1000) benzene sulphonate

Non-Ionic Detergents

Coconut fatty acid 10 1000 (probable toxicity) dieth~olamide Pluronics Non toxic (100) Non toxic ( 1000 )

Phenol 50 100

2 chloro, 4 ethylamino 6 isopropylamino, 1,3,5 triazine Sodium 2, 2 dichloropropionate

Propylene oxide/ethylene oxide condensate

Insecticides

Endosuiphan 10 "Not tested

*A later experiment showed the toxic concentration to be 2.5 ppm.

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I 0 0 0 [ . " f ' " ~ O ' | p p m Zn

~ C o n t r o l i I

I O 0 ~- * ' ........ "0" 25 ppm Z n

-- ' " " . ,O.Sppm Zn

p / "• .st..- ..-'

,. - '" ~- ...... o I'O ppm Zn

/ . / s " /

! •

d 1 . . . . I

Io 20 30 JE)8 ¥ $

Fig. 1. The effect of different concentrations of zinc upon the formation and growth of sporophytcs of L. hyperborea.

before the addition of any pollutant . This has been done in a small number of experiments. In such an experiment with Zinc, added after 7 days at a concentrat ion of 5 ppm {that is just before the time a maturation of gametophytes), the gametophytes failed to mature in the normal way and the females developed into filaments. Under opt imum conditions the female remains unicellular and produces only one oogonium. The particular result could be of considerable ecological importance because it would provide the alga with a means of surviving certain adverse conditions.

in a small number ofexper iments , the young stages have been cultured in Tyne estuary water and in all cases, provided that the salinity had been adjusted to approximately 3.3 per cent, the algae grew at least as well as those in control seawater.

With regard to the respirometer results - concentrat ions ranging from an hundred to several thousand times greater than the toxic concentrat ion in the culture experiments was required to inhibit respiration. For phenol it was only double the culture toxic concentrat ion. Fig. 2 shows the respiration rate of tissue discs over a period of 17 h, starting five h after the addition of mercm'y. Each point on the

2-0

1'O

I I ~, I f ! 2 4 6 8 IO

ppm Mercury

¢¢ .&

Fig. 2. The effect of different concentrations of mercury upon the respiration rate 0ua 0 : at NTP per g.dry wt. per min) of tissue discs from adult fronds.

2°° F

.-. I O0

[--

1 I I

ppm M e r c u r 7

Fig. 5. The effect of different concenuations of mercu~, upon the time lapse between the addition of mercury and perceptible inhibition of respiration rate of tissue discs.

graph is the average of duplicate flasks. Mercury at a concentrat ion of 1.0 ppm had no noticeable effect upon the respiration rate whereas 2.5 ppm caused a small reduction and 5.0, 7.5 and 10 ppm a considerable reduction in the respiration rate. Fig. 3 shows results taken from the same experiment as shown in Fig 2, and gives the time of initial inhibi t ion of respiration after the addition of mercury. A progressive decrease in the time from addition of mercury to inh ib i t ion-of respiration rate can be seen with increase in concentrat ion.

The two methods used in this investigation differ in four important ways. The most important difference is that the culture technique measures whether or not all the metabolic systems are funct ioning normally, while the respirometer experiments measure only the respirator3" pathway. Secondly, culture experiments last 28 days, respirometer experiments, 1 day. Thirdly, these culture experiments involve only the early stages of the species while the respirometer experiments involve parts of mature plants. Fourthly, the uptake of ions may be decreased in the absence of light in the respirometer experiments.

The differences between the methods are reflected in the results and this was paticularly noticeable with Atrazine. This herbicide was toxic at 0.01 ppm in culture but not toxic at 1000 ppm in respirometry. In higher plants the site of action of this herbicide is in the chloroplast {Crafts, 1961) . . am effect on the photosynthet ic apparatus and therefore growth might be shown in culture but not in short term measurements of respiration. Experiments on photosynthesis in the presence of this compound will be carried out this summer. Phenol, on the other hand, showed a very similar toxicity in both types of experiment {50 ppm in culture, 100 ppm in Respirometry). Perhaps its site of action is in the respiratory pathway.

Marine Biological Station, Rick ard Hopkins_ Port Erin, Joanna M. lxai~ ~Jc,,.cs) Isle of Man, UK.

Bellamy DJ., Bellamy P.,., John D.M., Whittick A., (1967), Some effects of po/lution on rooted marine macrophytes on the north-east coast of England. 'Br. phycol. Bull. ' 3(2)409.

Crafts A.S. 1961. The Chemistry and mode of action of herbicides. 'Publ. lnterscience. '

Kain J.M. 1964. Aspects of the Biology. of Laminaria hyperborea~ llI Survival and growth of gametophytes. 'J. mar. biol. Ass. U.K.' 44, 415 - 33.

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