Persistent Organic Pollutants (POPs)
Polychlorinated Biphenyls (PCBs) belong to a group of pollutants known as "Persistent Organic Pollutants" or POPs. Often called "Dirty Dozen", POPs are twelve in number and are considered the most hazardous substances in nature. The two most important characteristics that make POPs so dangerous is the fact that these don't degrade readily and can travel thousands of miles. For the protection of human health and environment, the convention was adopted at Johannesburg during the 5th session of international negotiating committee (INC), in December, 2000.
Pakistan participated in all sessions of INC and all along strongly supported reduction of POPs (including PCBs) production and use, leading to its total elimination. Pakistan signed the Stockholm Convention on Persistent Organic Pollutants on December 6, 2001.
In Pakistan, Persistent Organic Pollutants (POPs) problem including PCBs, has not been a priority environmental issue. In the National Environmental Action Plan (NEAP) approved by Pakistan Environmental Protection Council (PEPC) in 2001, the given four areas of immediate concerns are clean air, clean water, disposal of solid wastes and eco-system management. Toxic and hazardous substances, including PCBs, are one of the additional areas of concerns of NEAP. However, as a result of signing of Stockholm Convention on POPs, in December 2001 by Pakistan, an "Enabling Activity Project", with support from GEF/UNDP, has been launched to strengthen capacity in the country for meeting its obligations under the convention.
The release of PCBs into the environment is generally expected to be due to (a) leakage from PCBs containing electrical equipment (transformers, capacitors, circuit breakers, voltage regulators etc. and (b) handling and processing of wastes containing PCBs.
In Pakistan little documented information is available in any form on PCBs containing electrical equipment, use and wastes. Of many uses/applications of PCBs in other parts of the world, in Pakistan the main use seems to be in different PCBs formulations, generally termed as "Transformer Oil", used in power and distribution transformers for cooling and insulation purposes. A survey carried out by the Sustainable Development Policy Institute (SDPI) has indicated that the oil content in 15, 100 and 200 KVA capacity transformers as declared on the transformer label was 48.5, 114 - 152 and 198.5 kg, respectively.
However, different volumes of oil are used in distribution transformers according to their voltage rating and range from 40 liters in 10 KVA to 270 liters in 200 KVA. Reported synthetic oils, which have been/are being used, include Silicon, Ester and Askarrel.