Evaluation of toxicity of some industrial wastes to fish by bioassay

EVALUATION OF TOXICITY OF SOME INDUSTRIAL W A S T E S T O F I S H BY B I O A S S A Y

R. C, TRIVEDIt & P. S. DU~E~'

School of Studies in Botany, Vikram University, Ujjain (MP) India

ABSTRACT

Toxicities of eJfluentsJrom caustic and rayon industries to fish (Barbus stigma) were determined by bioassay. Wastes dilutedJbrty times were stillJbund to be lethal. Zinc, mercury, sulphuric acid and organic matter were the main pollutants. The receiving river was Jound to be unfit jbr fish growth up to 35 km downstream. Some treatments ,/or such wastes are suggested, and the TLm l,alues discussed. INTRODUCTION

Determination of the minimum concentration of industrial effluents which kill fish in a particular period is necessary when setting up standards for the safe disposal of such wastes. Although the minimum concentration depends on the quality, volume and flow of the water and the nature of the soil in the river bed, experimental standards are still useful in the conservation offish populations in rivers. Only with the help of bioassay experiments can toxicity limits of any pollutant substance in an effluent be established, by evaluating the median tolerance limit (TLm) for particular substances. The present paper refers to bioassay experiments conducted with wastes from Gwalior rayon and caustic industries at Birlagram Nagda (MP) India. The industrial complex is one of the biggest rayon plants in India, producing nearly 200 tonnes a day of staple rayon fibre by a viscose rayon process. Along with this, it produces nearly 125 tonnes of sodium sulphate and 200 tonnes of sulphuric acid a day by a contact process, nearly 50 tonnes of carbon disulphide by the electric furnace process and nearly 150 tonnes of caustic soda, 50 tonnes of chlorine and 100 tonnes t Present address: Central Board for the Prevention and Control of Water Pollution, Dr Rajendra, Prasad Rd, New Delhi 110001. India.

75 Environ. Pollut. (17) (1978)--~c) Applied Science Publishers Ltd, England, 1978 Printed in Great Britain

76

R.C.

TRIVEDI, P. S. D U B E Y

of hydrochloric acid by electric dissociation of common salt. With this considerable production it also discharges huge amounts of chemicals and organic matter. Of the total waste (nearly 1300ma/h) the spin bath (including viscose + sulphuric acid + carbon disulphide sections) contributes nearly 700 m3/h, the water treatment plant 100 m3/h, the power house 300 m3/h, floor washing 125 m3/h and the caustic soda plant 50 m3/h. The remainder is sewage from Nagda town. (This was only about 25 ma/h.) The wastes from the power house and water treatment plant contain negligible amounts of pollutant and act as diluents for other discharges. These combined wastes, without any treatment, are discharged into the Chambal river, an important Indian river. Before discharge of such wastes the river has a rich freshwater flora and fauna, but just after discharge it completely disappears. In the summer season when the flow of upstream water nearly stopped, the flow in the downstream part of the river was only due to the discharge and thus there was no question of dilution of.the wastes. This problem attracted our attention to start a study of the ~effluent monitoring test' with an important species of fish (Barbus stigma) in the river. This fish is easily available throughout the year and was dominant in unpolluted zones of the river.

MATERIALS AND METHODS

The experiments were conducted in a 5 litre aquarium. The diluent used was ordinary tap water, chemically similar to the unpolluted river water. The dilutions of the effluents were made on a logarithmic scale soon after they were brought to the laboratory. The dissolved oxygen was maintained at 6 + 1 ppm by aerating with air when necessary and the temperature was maintained at 30 + 2 °C by wrapping the aquarium in a thick cloth kept constantly wet. The test fish (Barbus stigma) used in this experiment were collected from the same river. They were carefully transported to the laboratory and stored in a large aquarium to acclimatise for four days, feeding, which was on natural plankton and other food, being suspended for two days before the experiments. These test animals were removed one by one from the big aquarium with a hand net and, after careful examination (to ensure that they were free from disease and damage), were transferred to a small aquarium. Ten fish were used in each aquarium, with a control, seven dilutions being made of the original effluent. The pH of all the dilutions was determined. Observations continued for a period of 48 h. A fish was considered to be dead when it failed to respond to a slight prod with a rod. Such experiments were conducted in July, when the temperature range was 27 to 40 °C and the relative humidity 25 ~ to 80 %. The numbers offish deaths were recorded at intervals of 24 h and 48 h. The percentage of fish deaths was plotted against the dilution and TLm values for different effluents were determined as shown in Fig. 1.

77

BIOASSAY OF INDUSTRIAL WASTES USING FISH

'ooI80

f

.J"

o • A •

701-

Spinbath waste Washing waste Caustic waste Combined waste

6O

_

O

-i

(/1 ~g 4 0

I0 -o-g--6"---------~" 1:2 I;4 I-'8

1:16

I

I

1::32

1:64

Dilutions Fig. 1.

Relationship between percentage survival of B. stigma for 48 h and dilutions of different wastes from a viscose rayon/caustic soda industrial complex together with their TLm values.

The effluent was analysed for various chemicals according to the standard methods for examination of water and waste water (American Public Health Association, 1955). The physicochemical nature of the effluent is given in Table 1.

RESULTS

Observedfish behaviour In caustic liquor with a high concentration of 1 : 0 dilution the fish showed quick, almost vibratory, gill movements and signs of distress; within 7 min two fish lost balance and overturned and within 15 min almost all ten fish had overturned. In spin bath wastes with a higher concentration of 1:0 asphyxiation-like symptoms appeared as rapid opercular movements and loss of the sense of balance. Later the fish remained swimming in a slanted manner at an angle of 45 °, head downwards. In washing waste quick jumping movements occurred but the fish did not lose their balance until the last movement before death. The percentage of deaths in 24 h and 48 h and T L m values are given in Table 2.

78

R . C . TRIVEDI, P. S. DUBEY

DISCUSSION

All industrial wastes are very complex and it is difficult to define which particular factor is actually operating (Ohio River Valley Sanitation Commission, 1955; Henderson & Tarzwell, 1957). In the present study acidity, BOD and heavy metals (zinc and mercury) are the main toxic factors. The toxicity of the waste decreased after combining, probably due to neutralisation of acidic waste with washing waste and to precipitation of zinc and mercury as sulphides (as thefr sulphides are insoluble at higher pH). The precipitate could be seen as a thick deposition on the river bed. The higher BOD of the waste caused anaerobic conditions in the river up TABLE 1 PHYSICO-CHEMICAL NATUREOF WASTE Characteristics

Colour Odour pH Temperature Total solids Dissolved solids Suspended solids Acidity as CaCo 3 DO BOD COD Zinc Mercury Sodium Calcium Sulphates Sulphites Sulphides Chlorides

Combined wastes

Spin bath wastes

Washing wastes

Caustic wastes

Whitish Odour of H2S 2.5 52 °C 5211 3950 1261 310 Nil 245 336 22 1.2 325 245 3099 23 48 635

Whitish Odour of HzS 1-9 65 °C 2635 2008 627 412 2 205 312 250 Nil 105 6 8735 45 210 24

Yellowish Odourless 10.5 57 °C 315 285 30 -Nil 225 415 Trace Nil 207 12 278 Nil Nil 25

Reddish Odour of chlorine 3.5 45 °C 8221 5625 2596 105 1-5 189 264 Trace 15 1235 332 Trace Nil Nil 2442

Note: All values except colour, odour, pH and temperature are given in mg/litre.

to 16 km downstream from the point of discharge and thus there was no organism in the river up to that point except bacterial activity (the well known sulphate-reducing bacterium Desulphovibrio desulphurican, the only possible organism in such acidic waters). The B. stigma reappeared after 35km downstream from the point of discharge where the conditions became normal and the BOD loads reduced from 250ppm to 10ppm, pH from 2.5 to 6.5, zinc from 22ppm to 1 ppm, and mercury from 1.2 to 0.001 ppm. The other pollutants were also considerably reduced and thus became tolerable to the fish. From a study of the results of the foregoing bioassay with caustic and rayon wastes it can now be safely assumed that three kinds of waste are harmless to fish provided there is at least a dilution of forty times. This did not occur in the summer

79

BIOASSAY OF INDUSTRIAL WASTES USING FISH

TABLE 2 PERCENTAGE SURVIVAL AND

Source

Spin bath wastes

W a s h i n g wastes

Caustic

Combined

TLm

VALUES OF DIFFERENT WASTES FOR

Dilution of liquid

pH

Survival ( % aJier 24 h)

1:0 1:2 1:4 1:8 1 : 16 1:32 1:64 Control 1:0 1:2 1:4 1:8 1 : 16 1 : 32 1:64 Control 1:0 1:2 1:4 1:8 1 : 16 1:32 1:64 Control 1:0 1:2 1:4 1:8 1 : 16 1:32 1:64 Control

1.9 2.5 3.7 4.2 6.5 6.8 6.9 7.5 10.5 9.8 9.3 8-6 8.2 7.9 7.6 7-5 3.5 4.2 4.9 5.2 5.8 6.3 6.9 7-5 2.5 3.2 4.0 5.7 6,2 6,7 7,0 7.5

0 0 0 10 50 100 100 100 0 0 10 40 50 70 100 100 0 0 0 0 10 50 100 100 0 0 20 50 100 100 100 100

Barbus stigma

Survival ( % after '48 h)

TLm

0 0 0 40 70 100 100 0 0 0 10 40 60 100 100 0 0 0 0 0 30 100 100 0 0 0 50 80 100 100 100

1:22

1 : 24

1:41

1:8

months, resulting in high fish mortality. However, in rainy and winter months there was no fish mortality in the river due to sufficient dilution. Accordingly, before discharging such effluent in the summer months the treatments described below should be followed to save fish resources. (1) (2)

Minimising discharge of contaminants into the streams by improving their recovery. Treating effluent suitably to bring the concentration of contaminants to an acceptable level in the following ways: (a) Removal of suspended impurities such as waste rayon fibres by filtration. (b) Reduction of colour caused by the pigments and sulphides by precipitation followed by filtration. (c) Neutralisation of whatever free acid is present in the final effluent by limestone, which can also remove zinc and mercury by precipitation at higher pH.

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R . C . TRIVEDI, P. S. DUBEY

(3)

Equalisation to even out fluctuations in the effluent quantity as sometimes a sudden increase in concentration of waste causes dangerous conditions in the river.

As Warren (1971) and Mount & Stephan (1967) have suggested, long exposure experiments for assessing the 'safe concentration' are more useful than acute toxicity results. They suggested that a study should be made over a period of years when the known dilution had been maintained and that the effects on growth, reproduction, physiology and behaviour should be studied. If concentrations apparently safe for the species concerned turned out to be some relatively constant fraction of the median tolerance limit of the species, this fraction would seem to be a reliable application factor. Henderson (1957) noted the possible usefulness of such an approach to the development of application factors. This approach is being followed with some success in Great Britain (Herbert et al., 1965; Edwards & Brown, 1967). It does, however, present many difficulties. Seasonal and annual changes in effluent characteristics and volume and in the quality and discharge of the receiving stream occur. Thus the TLm values are a quick and most useful method for assessing the harmful effect of an effluent.

ACKNOWLEDGEMENTS

We are indebted to Professor L. P. Mall, Head of the School of Studies in Botany, Vikram University, Ujjain, for providing the necessary facilities. The first author is also thankful to CSIR for sanctioning a scheme under which the work reported in this paper was conducted.

REFERENCES AMERICANPUBLICHEALTHASSOCIATION(1955). Standard methods for the examination of water and waste water including bottom sediments and sludges, 10th ed. New York, APHA. EDWARDS,R. W. & BROWN,V. M. (1967). Pollution and fisheries; A progress report. J. Inst. Wat. Pollut. Control, 66, 63-78. HENDERSON,C. (1957). Application factors to be applied to bioassays for the safe disposal of toxic wastes. In Biological problem in water pollution, ed. by E. M. Tarzwel[, Transactions of the 1956 Seminar R. A. Taft Sanitary Engineering Center, US Dept. of Health Education & Welfare, 35-7. HENDERSON, C. & TARZWELL, C. M. (1957). Bioassay for control of industrial effluents. Sewage ind. Wastes, 29(9), 1002-17. HERBERT, D. W. M., JOm3AN, D. H. M. & LLOYD, R. (1965). A study of s o m e fishless rivers in the industrial midlands. J. Proc. Inst. Sew. Purif., 6, 569-79. MOUNT, D. I. & STEPHAN, C. E. (1967). A method for establishing acceptable toxicant limits for fish M a l a t h i o n and butoxyethanol ester of 2,4-D. Trans. Am. Fish. Soc., 96, 185-93. OHIO RIVER VALLEY WATER SANITATIONCOMMISSION(1955). First Progress Report of Aquatic Life; Water quality criteria. Aquatic Life Quality Committee, Cincinnati, Ohio, USA. WARREN, C. W. (1971). Biology and water pollution control. Philadelphia, W. B. Saunders Company.