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Preferring profit to pollution
AMONG numerous environmental issues facing Pakistan, efficient management of metallurgical solid and liquid wastes needs immediate attention. The problem is twofold, as it involves the protection of environment as well as the development of industries to sustain safe economic growth.
At the time of independence, there were only a few industrial units in the country. Unfortunately, during the initial stages of industrial development in the country, not enough attention was paid to environmental issues, as almost no measures were taken for the treatment of industrial effluents before disposal.
Several decades later, the Pakistani industrial units are still not equipped technically to cope with potential environmental problems. As a result, ever-increasing volumes of industrial effluents containing toxic metals continue to be dumped untreated in streams, rivers and the sea.
These effluents leach down into subsoil water, thus making wells unsafe. The toxic metals, when absorbed by the human body through drinking water or indirectly through the use of vegetation or marine organisms, attack vital organs, such as the kidney and liver and cause an overall failure of the biological functions of the body.
Water, with its dissolved toxic impurities, has become a major threat to human health in industrial cities as these have been witnessing a tremendous increase in life-threatening diseases. It is, therefore, about time that attention is drawn to this problem and efforts are made to launch remedial measures to save the population from hazards of untreated effluents.
Data on environmental degradation are not easily available in Pakistan. However, in the light of the sketchy data available, courtesy some scientific studies, the leather tanning, textile and electroplating industries may be considered as the sectors that produce more harmful toxic wastes than others.
Tanneries and textile units are the bulk users of metallurgical material. The electroplating industry also discharges metals, which are highly poisonous.
Leather tanning industry
The leather tanning industry has made rapid progress since independence and is very important in terms of export earnings. Over the decades, however, the industry has caused considerable damage to both groundwater and seawater.
The tanning industry presently comprises about 436 units, 50 of which enjoy large capacities. Almost no treatment facilities are available. And the industry is heavily concentrated in Karachi and Lahore.
In the tanning process, the total volume of effluents produced is 3,000 to 3,500litres per 100kg of hide and skin processed. During the tanning process, chromium emerges as a major pollutant, which is often discharged untreated in the nearby streams and rivers that take it to the sea, thereby affecting aquatic life, besides polluting groundwater.
Chromium compounds are particularly harmful and can cause irreversible damage to health. Most of the tanneries in Karachi are located either in the Site or Korangi industrial areas, which discharge untreated effluents into storm drains that ultimately lead to the Arabian Sea.
A trend towards increased chromium concentrations in discharges from the Korangi industrial area was highlighted in a study conducted by the Karachi laboratories of Pakistan Council of Scientific and Industrial Research (PCSIR) in the 80s. The study, titled “Impact on environment due to tannery effluents from the Korangi industrial area,” showed that the concentration of chromium in effluents had increased from between 0.25 and 0.5ppm to between 2.0 and 14ppm within a short period.
An IUCN study, carried out in 1987 in the same area, showed that the concentration of chromium had risen to 57ppm. The study concluded that 225tons of chromium were discharged every year from the industrial units in Korangi.
Another study carried out in 1993 by PCSIR in the same area revealed a nine-fold increase in chromium concentrations in tannery effluents. Yet another study showed a discharge of 60 to 200ppm of chromium en route to the Arabian Sea. It was found that along the way, trivalent chromium settled as sludge. Considerable quantities of chromium were detected in the sediment samples taken ten kilometres away from the source and near the sea. Presence of chromium at this point makes it clear that the sludge moves towards the sea.
Studies also revealed that water samples taken from wells situated within a 2km radius of the tanneries had high concentrations of chromium, rendering them unsafe for humans. The most recent study in this regard was made by the PCSIR’s Fuel Research Centre in which a detailed survey of tanneries in Karachi was undertaken. The exercise revealed that almost all of them had heavy concentrations of chromium in their effluents.
The textile industry
This industry is well developed in many places but Faisalabad acts as its nerve centre. There are about 67 textile units in Faisalabad, which during calendaring, printing and dyeing processes discharge nearly 1.43million cubic metres of untreated effluents into natural streams. These effluents contain hazardous metals, like zinc, nickel, manganese, copper, iron and lead.
In Faisalabad the units are situated near residential areas, consequently posing serious environmental problems to its residents. Insufficient capacity of the drainage system causes spilling over of heavily polluted effluents. This either evaporates or leaches down into groundwater.
A rather detailed study about the environmental impact of effluents was made in Faisalabad. The deposition rate of zinc, iron, copper, manganese and lead was found to be 136.87, 52.55, 66.26, 82.32 and 7.88tons per annum, respectively. These heavy metals are toxic and their presence in such high concentrations is a cause for alarm.
Lead causes damage to the brain, kidney and liver. Excessive amounts of copper and zinc cause renal damage and hypertension. The study indicated that iron, copper and manganese concentrations in groundwater had reached dangerous proportions. It may thus be concluded that subsoil and groundwater in Faisalabad will become hazardous, even dangerous, for humans if immediate remedial measures are not taken.
The electroplating industry
This is a small-scale industry with an estimated 1,150 units throughout the country. The industry discharges about 23,000cubic metres of effluents each day. Because of the high toxicity of its effluents, this industry should receive high priority vis-a-vis pollution control.
At the industrial units nickel, copper, chromium, lead, cadmium, zinc, silver and gold are electroplated to alter the surface properties of base metals, in order to achieve corrosion resistance, water resistance and improved and decorative appearance. All the constituents of the plating bath contain toxic heavy metals.
Many additives, which are introduced to improve grain refining, contain toxic metals like arsenic, cobalt and molybdenum, all of which aggravate the problem. These metals find their way into water streams through batch dumps or floor spills.
Waste material from the industry are low in volume, contain relatively high organic matter, but are highly toxic due to heavy metals. The problem posed by treatment and disposal of effluents from a large number of small-scale units is unique in nature.
Wide distribution of the industrial units, their small-scale operations and high recurring costs of treatment are some of the factors responsible for lack of controls. A few composite samples taken from electroplating shops contained excessive amounts of chromium (4.8ppm), copper (16.7ppm) and cadmium (21.5 ppm).
What should be done
Today, adequate environmental protection is a serious global issue. But in Pakistan, there is almost no recognition of the issues involved. The people are generally not aware of the effects of excessive exposure to hazardous chemicals.
Industrialized nations have developed cost-effective technologies for rectifying the situation. Import and implementation of these technologies in Pakistan may not be a cost-effective option. However, a feasible alternative for the country is to develop indigenous preventive technologies, based on locally available raw material.
The writer, currently based in the US, used to work for the Pakistan Council of Scientific and Industrial Research
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