Aquatic Pollution and Coastal Management

Unit 11 : Monitoring and control of pollution

11.12.Status of Marine Pollution
As a result of the systematic monitoring of the coastal areas, health of our seas could be assessed and areas of low, medium and high concentration of pollutants are being monitored intensively. Details of these locations are:
i). Areas of Clean Sea Water Quality
The sea approximately beyond 2 km along the coastline of India except off Mumbai is clean and confirm to the quality of clean waters. In Mumbai the sea off 5 km is clean. This is primarily due to the fact that the levels of dissolved oxygen and other parameters fulfilling the requirements of clean sea water.
ii). Area of no Concern
In Vadinar and Kandla of Gujarat, Ratnagiri in Maharastra, Mandavi and Zuari in Goa, Mangalore port in Karnataka, kannur and kozhikode in Kerala, Cuddalore in Tamil Nadu and the West Bengal coast, the concentrations of dissolved oxygen was fairly good and other toxic elements like ammonia, and heavy metals in sediments and biota were slightly higher (about 15%) than the clean waters.
iii). Areas that need Intensive Monitoring
In Porbandar, Damanganga estuary, and Vapi industrial estate in Gujarat, Mangalore coast in Karnataka, Kochi backwaters, Kollam Paravur in Kerala and Thoothukkudy and Arumuganeri in Tamil Nadu, and Puri in Orissa the levels of dissolved oxygen were moderate to normal , however, some of the elements like ammonia, pathogenic bacteria in sea water and heavy metals in sediments showed higher concentration (about 25%) than the normal values. Due to the definite source of pollutants and chances of increase in concentration are likely to be high, these areas need intensive monitoring.
iv). Areas of Concern
In Veranal Port in Gujarat, Versova Creek, Mahim Bay and Thane Creek in Maharashtra, Veli in Kerala and Visakhapatnam harbour and Kakinada Bay (canal) in Andra Pradesh, the concentrations of dissolved oxygen were nil to low during low tide period and improved their levels only moderately (30-50%) during the high tide period. Further, the levels of toxic metals like Cadmium and lead were high in sediments in some locations (like Thane creek) and pH was very low (Veli). If no control measures are exercised now, the areas will become regions of high concentration of pollution in another 5 to 6 years.
Levels of organochlorine pesticides like HCH and DDT were analysed in 32 species of marine fish collected at various locations along the east coast of India. The levels of both the chemicals were very much lower than those observed in the terrestrial animals and other food items. These levels are well below the limits (5 parts/billion is the safety limit) set by the health authorities. This would indicate that the marine fish is not contaminated with the pesticide residues in the locations from which the samples were collected.
Several samples of fish species collected along the various locations along the west coast also indicated that the DDT levels ranged from 0 to 1.7 parts per billion and HCH levels from 0.045 to 1 part per billion well below the safety limits.
The results are being brought to the notice of the state pollution control boards and they are being evaluated by a steering committee chaired by the Chairman, Central Pollution Control Board and represented by all the coastal state pollution control boards. In these meetings actions to be taken by the concerned pollution control boards are discussed at length.