KARACHI, May 1: Human contact with the ocean has often resulted in fairly grave consequences for the aquatic ecosystem. Environmentalists have expressed alarm and concern over the manner in which highly toxic heavy metals, such as chromium, cadmium, lead and mercury, have found their way into different seafood varieties that are not only local favourites but also popular exports.
“These deadly substances have penetrated marine creatures mainly due to criminal irresponsibility on the part of human beings,” they said.
Environmentalist groups have also blamed an overwhelming majority of industrialists who, in their bid to skimp on a few bucks, flout the laws of both land and nature by not treating their industrial effluents.
“They just release these into either municipal or storm water drains, which eventually end up in the sea which is lethal,” said the former chief of IUCN’s aquatic ecosystem programme, Dr Najam Khursheed.
The presence of these trace metals was recently discovered in a study conducted by scientists of the country’s premier research institution, the Pakistan Council for Scientific and Industrial Research (PCSIR).
Ecologists believe that the results of this research were so astonishing that the government is said to have issued verbal instructions restricting the execution of all such studies in future. Authorities have stressed that if such studies are carried out, then institutions must ensure that their outcome is not made public.
The PCSIR study was conducted by three scientists: Dr S. Farid Sibtain, senior scientific officer of Fuel Research Centre of PCSIR, Dr S.S. Tahir of the federal environment ministry and M. Zahid Raza of the Fuel Research Centre at PCSIR.
“Government officials, particularly those working in the Sindh Environmental Protection Agency (Sepa) are either inefficient or corrupt and turn a blind eye to industrialists contaminating the food chain,” declared conservationists who are up in arms over the extent of damage.
“When toxic effluents enter the sea, they contaminate the water, sediments and marine flora and then the plankton which is the lowest organism,” said Dr Khursheed.
Plankton is eaten by smaller fish, which are consumed by the higher category of marine creatures such as larger varieties of fish, shrimps, crabs, lobsters and many others which are part of the human food chain. “Some fish are consumed by aquatic birds which are eaten by humans and as one species is eaten by the higher category of predators, the load of pollutants multiplies and since humans sit at the top of the food chain, they end up with the maximum concentration of hazardous materials,” explained Dr Khursheed.
Environmentalists also emphasized that these heavy metals have varied effects on vital human organs. Chromium, for example, has carcinogenic qualities and harms the lungs, causing cancer and ulcers. Cadmium, also a carcinogen, damages the liver, kidneys, lungs and causes anemia. Lead causes neurological problems, particularly in children and mercury can cause low-level chronic poisoning associated with confusion, headaches, fatigue and tremors.
They also maintained that the situation has worsened since the PCSIR study was conducted as more industries have entered the market. Sadly, an overwhelming majority of these industries do not have secondary treatment facilities, resulting in an even greater quantity of deadly chemicals and trace metals in the sea.
The study found that cadmium, a heavy metal, was present in extremely high concentration in food species. While relatively safer limits of 2 ppm (parts per million) to 73ppm were found in crabs, up to 22ppm in shrimps, 3.2ppm in lobsters and 2.1ppm in fish.
Similarly, chromium was present in high concentrations in almost all marine food species. Crabs topped the list with 29ppm, shrimps had 17ppm, fish had accumulated 10ppm and lobsters were at the bottom of the list with 2.9ppm.
Only 6ppm of lead is permissible but crabs contained 8ppm, fish and shrimp had 7ppm.
Objectionable levels of mercury were found in crabs at 0.62ppm against the permissible level of 0.5ppm.
However, PCSIR officials continue to feign criminal ignorance towards the issue.
“The centre has not carried out such studies recently and was now focusing on fuel research,” declared Ishaque Qaimkhani, director PCSIR Fuel Research Centre.
However, World Wide Fund for Nature was vehement about its concern for the slow destruction of our marine ecosystem. “It is high time some steps were taken to control growing marine pollution before the food chain contamination becomes uncontrollable and human beings suffer,” said Dr Ejaz Ahmad, deputy director general, World Wildlife Fund for Nature.
A top Sepa official agreed and said that it was a pity that such a large number of industries did not treat their wastes and contaminated the sea in the process.
He said that Sepa was short-staffed and even the existing staff was not fully trained. “As soon as more technically qualified staff is recruited, action would be taken against the polluting industrial units,” said the official.