Biological indicators in relation to coastal pollution along Karnataka coast, India

• Published in: Water research (Oxford) Vol. 40; no. 17; pp. 3304 - 3312
• Main Authors: Verlecar, Xivanand N., Desai, Somshekhar R., Sarkar, Anupam, Dalal, S.G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-10-2006; Elsevier Science
• Subjects: Applied sciences; Benthic organisms; Bio-indicators; Cadmium; Chaetoceros; Coastal environments; Coastal pollution; Coscinodiscus; Crude oil; Diatoms - classification; Diatoms - isolation & purification; Dinoflagellates; Dispersing; Effluents; Environmental Monitoring - methods; Exact sciences and technology; Hydrocarbons; India; Marine; Nutrients; Other industrial wastes. Sewage sludge; Oxidizing agents; Petroleum hydrocarbon; Phytoplankton; Plankton; Pollutants; Pollution; Pollution abatement; Rhizosolenia; Seasons; Sewage; Sewage effluents; Species Specificity; Stress concentration; Stresses; Thalassiosira; Trace metals; Wastes; Water Pollutants - analysis; Water pollution; Water treatment and pollution; Water wells; Asia; Karnataka; India; India, Karnataka; ISW, India, Karnataka; Petroleum hydrocarbon; Bio-indicators; Plankton; Benthic organisms; Trace metals; Nutrients; Coastal pollution; Chemical plant; Nitrates; Biomass; Oxidant; Coastal zone; Waste water; Heterokontophyta; Pollution; Bacillariophyta; Water well; Ecosystem; Lead; Phytoplankton; Agriculture; Organic compounds; Thallophyta; Chemical industry; Atmospheric condition; Benthic organism; Fertilization; Hydrocarbon; Village; Algae; Biological indicator; Regression analysis; Sediments; Petroleum; Multiple regression; Fertilizers; Trace element; Dinophyta; Industrial waste water; Zooplankton
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2006.06.022

Marine pollutants in relation to planktonic and benthic organisms were examined at two locations along Karnataka coast, one at Kulai (74°47.74′′E and 12°55.16′′N) receiving huge amount of industrial effluents from fertilizer, petroleum and chemical plants along with the sewage discharges. The other site Padubidri (74°45′′E and 13°10′′N) is located 20
km away, which is a typically agricultural and fishing village having no stress of industrial discharges. Although the concentrations of dissolved oxygen (DO), nutrients and trace metals in water and sediment showed marginal differences at these two locations, the concentration of petroleum hydrocarbon (PHC) remained exceptionally high with a maximum of 1523
μg/l at Kulai which is 10 times higher than that at Padubidri (144
μg/l). Biomass and population of phytoplankton and zooplankton showed that the seasonal differences were more conspicuous rather than the regional changes. Macro and meiobenthic population remained high at both the locations during the two seasons. Phytoplankton species indicated that centric diatoms such as
Rhizosolenia, Leptocylindricus,
Chaetoceros,
Thalassiosira and
Coscinodiscus contributed to >90% of population in May and >70% in January at Kulai. While mixed population of centric, pennate, cyanophycean and dinoflagellates prevailed at Padubidri in January. Lower species diversity and richness accompanied with dominance of fast growing centric diatoms over pennates observed at Kulai act as an index for detection of organic pollution and nutrient enrichment. Similarly, proliferation of benthic bivalves >54% at Kulai relative to Padubidri suggests that these organisms could sustain organic and industrial pollutants. The results suggest that although Kulai receives large quantities of industrial and sewage effluents responsible for alteration of the ecosystem structure, the excellent wind-driven mixing and tidal flushing keep the waters well aerated thus reducing the severe pollution stress by dispersing the organic and other pollutants. Direct relationship of PHC with Cd and Pb as contaminants, NO
3 and PO
4 as oxidants of excess PHC and species diversity as promoters of phytoplankton (centric diatoms) and benthic bivalves shown by multiple regression analysis further suggest that these biological parameters could serve as indicators for detecting moderately high environmental stress at Kulai, compared to Padubidri.