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Title: Biological effects of coastal oil refinery effluents
Author: Petpiroon, S.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1982
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This thesis was initiated to study the ecological effects of refinery effluent discharges by field study and comparison with their toxicity in the laboratory. The study comprises two parts which were complementary to each other: (a) field studies on ecological effects of effluent discharges in various estuarine environments including saltmarshes and rocky shores; and (b) the development of a rapid laboratory toxicity test using behavioural responses of a periwinkle as a criterion to determine whole effluent toxicity and to compare the toxicities of some important effluent components (ammonia, sulphide and phenol). An additional study was also carried out on the rhythmic behaviour of the periwinkle both in the field and in the laboratory in order to determine whether natural rhythms (i.e. tidal and circadian) could affect toxicity test results. Studies of three contrasting refinery effluents (a large water-cooled refinery effluent discharged to a Spartina marsh in Southampton Water, and two modern air-cooled refineries discharging small effluents to rocky shore areas in Milford Haven) show that effluent effects depend on the biological and physical nature of the receiving environment, effluent volume and quality, and the location of the discharge point. Information from the studies reported here and elsewhere can be used in predicting effects of future developments and in locating discharges to ensure minimum damage. To study effluent effects of individual effluent components and whole effluents, a behavioural test was developed using the periwinkle, Littorina nigrolinesta. Activity was used as the test criterion. The test proved simple, reliable, repeatable and could be carried out very rapidly. Natural activity rhythms (tidal and circadian) were investigated in the field and laboratory, and were shown not to interfere with test results. Observed rhythms appeared to be largely controlled by physical factors (tidal cycles and day/night cycles) but further experimental work would be required to determine their persistence, control and adaptive significance. Using the test to compare toxicity of whole effluents, ammonia, sulphide and phenol showed that toxicity of effluents varied from sample to sample, and that toxicities increased in the order of magnitude from ammonia -4 phenol-2), sulphide. Concentrations which depress periwinkle activity to 50% of the controls over a two-hour test period were 95, 39 and 9.6 ppm respectively. Various combinations of ammonia, sulphide and phenol resulted in an additive effect, but neither synergistic nor antagonistic reactions. Effects of effluents on whole communities could not be predicted from toxicity tests. Actual field studies of whole communities at present provide the only means of assessing whether standards of effluent quality are effective in producing acceptable levels of environmental impact. Toxicity testing and field studies may be used in a complementary manner - the former as a means of identifying toxicities of industrial components and that effluent quality is maintained, and the latter in ensuring that environmental quality is acceptable. Where unacceptable effects are observed, toxicity test data can be valuable for identifying the most toxic constituents for remedial action. Treatment of effluent streams to high standards is very costly. Ultimately a balance has to be achieved between economic considerations and acceptable environmental standards in the discharge area. Sensible decisions can only be made with suitable biological data being available.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available