THIS is apropos of the news (Feb 6 and 14), regarding water pollution in the KB Feeder Canal and Keenjhar Lake.

The selection of variables for water quality monitoring is done in relation to pollutant sources. In the present case, it was desired to assess the impact of industrial effluents in KB Feeder Canal and Keenjhar Lake. The nature of culprit industries discharging effluents should have been assessed based on which the variables should have been selected.

Typically, for hazardous industrial effluents, the preferred variables requiring analysis are cadmium, chromium, copper, iron, lead, arsenic, mercury, nickel, zinc, organic solvents, phenols, oils, pesticides, chemical oxygen demand (COD), dissolved oxygen and solids (suspended and dissolved). In the present case, the bottom sediments need to be analysed, as well.

Hyderabad-based people are once again making a blunder by comparing apples with oranges. The water quality of the KB Feeder Canal at Al Manzar is being compared with the national environmental quality standards (NEQS). How can one compare water quality of a canal with NEQS? NEQS gives the maximum limits of various parameters in the effluents (both, municipal and industrial).

Although this is the job of the Sindh EPA, the Hyderabad administrator deserves praise for taking initiatives in curbing water pollution. It, however, needs to have a technical adviser to guide it technically on water pollution control.

Previously, people were fooled by the SITE management into believing that oxidation ponds are treating the SITE industrial effluents.

According the news, the Kotri-based industrialists are supplying their untreated industrial effluents to some rural areas where people use the industrial effluent for cultivation. This is dangerous and unethical. All newborns in that area will be mentally retarded and physically impaired. The horrific incident of Minimata in Japan is known to all the technical people.

According the news, KWSB chief Misbahuddin Farid has said that it is not the KWSB’s job to deal with contamination of water in the KB Feeder Canal and Keenjhar Lake. The water board’s jurisdiction began from post-Keenjhar, he said. This shows rather a childish outlook of the KWSB chief. Leaving aside the fact that the KWSB is the biggest beneficiary of water from the KB Feeder Canal since it takes nearly 555 mgd from the canal, out of a total supply of 655 mgd to Karachi, it is the job of service provider to protect water from catchment to the consumer.

Catchment protection is not only essential for safety of drinking water for Karachi from threats and hazards, the operational costs of the water treatment plant become prohibitive, if the source water is highly contaminated.

The type of water treatment plants that the KWSB has are rapid-sand filters. Stand-alone rapid-sand filters can only treat fecal contamination and turbidity. It cannot remove pesticides, heavy metals and agro-chemicals, unless tertiary or advanced water treatment is provided (activated carbon, ion exchange, ammonia stripping, membrane filtration, etc).

It is known that in the catchments areas, in rural Sindh, fertilisers and pesticides are used indiscriminately. In the long run, it would be cost-effective for the KWSB to control the catchment areas and protect their water sources. The KWSB must take control of the water bodies supplying water to their water treatment plants.

F.H. MUGHAL     Karachi