Evaluation of the influence of various physico-chemical parameters on coastal water quality, around Orissa, by factor analysis

Physico-chemical parameters such as salinity, pH, DO, BOD, chlorophyll-a, n utrients (NO2-N, NO3-N, NO3-N, NH4N, PO4-P, total phosphorus) and major ion s (Ca2+, Mg2+, F-) were studied during February-March, 1994 in the coastal waters off Orissa. Data comprising 13 variables obtained from 38 water samp les have been subjected to R-mode factor analysis so as to understand the s ources, the processes occurring and the influence of various physico-chemic al parameters on coastal water quality. About 67.8 % of variance has accoun ted for three factors such as(i) river run-off or terrestrial input; high p ositive loading on nutrients with high negative loading on salinity implyin g that the nutrient economy in. the coastal waters off Orissa is primarily dependent on the magnitude of river run-off; (ii) estuarine discharges whic h include remineralisation of organically bound materials into its dissolve d inorganic form or oxidation product of ammonia; high positive: lending: o n nitrite and high negative loading of pH and ammonia in second factor sugg est the possibility of oxidation of ammonia to nitrite and (iii) land drain age (including waste discharged from domestic sewage, fertilizer plant and fresh water run-off) has significant influence an fluoride content in coast al water.