Dr Mahmood A. Khwaja
khwaja@sdpi.org
Chemicals, such as dioxins, furans, polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB), are highly toxic substances that can seriously harm human health and the environment. They are members of a group of chemicals called persistent organic pollutants (POPs), also known as the “dirty dozen.”
To protect human health and environment, the chemicals have been targeted for reduction and elimination by a global legally binding treaty - the Stockholm Convention, 2001. The convention entered into force last year, and the first Conference of the Parties (COP1) was held on May 2, 2005 in Montevideo, Uruguay.
POPs are long lasting, and can travel great distances on the air or water currents. Wildlife and humans can come in contact with POPs through breathing contaminated air, by eating contaminated foods or by drinking or washing in contaminated water.
Unborn babies in the womb are dangerously affected through absorption of these accumulated chemicals in the fats of their parent bodies. Traces of POPs contaminations have been found to be present in the food web, in animal products - meat, fish and milk in particular, with significant hazard to people who consume these foods.
A recent study of free-range chicken eggs from 20 localities in 17 countries (including Pakistan) in the five continents has indicated high levels of contamination with dioxins and PCBs. The study was carried out, published and distributed among the delegates of Uruguay COP1 by International POPs Elimination Network (IPEN), a global network of more than 350 public interest organizations in 65 countries working to eliminate POPs, in support of the Stockholm Convention.
Chicken eggs were chosen for the global study because they are a common food item and their fat content makes them appropriate for monitoring fat-soluble chemical pollutants like POPs. Eggs are also a powerful symbol of new life. The study focused on backyard and free-range hens because they eat worms, insects and other small organisms, making their eggs a useful bio-indicator of food contamination and environmental pollution.
In Pakistan, the study was jointly carried out by IPEN participating organizations, ARNIKA, a Czech NGO, and the Sustainable Development Policy Institute (SDPI), in collaboration with Pakistan Environmental Protection Agency (Pak-EPA), to support the “POPs Enabling Activity Project” for the National Implementation Plan (NIP), which would lead to ratification of the Stockholm Convention 2001 by the government of Pakistan.
The free-range chicken egg samples were collected from the households near an old abandoned municipal and hospital waste dumpsite along Charsada Road on the outskirts of Peshawar City. Open burning of all sorts of wastes was carried out at the site from time to time. The site was in use for over ten years before being abandoned in 2004.
All kinds of municipal and hospital wastes, including ash/residue from local hospitals incinerators, were dumped in the open at the site without any pre-treatment, ground insulation or cover on the site. The chemical analyses of the sampled eggs were done in the Axys Varilab Laboratory, Czech Republic.
The analytical data obtained from the study indicated presence of dioxins/furans (PCDD/Fs), PCBs, HCB and DDT chemicals in the egg samples collected from the dumpsite. The level of PCDD/Fs (2.85- 2.91 World Health Organization (WHO) Toxic Equivalent, pictogram per gram egg fat, WHO-TEQ pg/g) was found to be close to the limit (3.0 WHO-TEQ pg/g) set by the European Union (EU).
However, these observed levels are much higher compared to samples from Australia, North America and some European countries. Egg samples from similar sites in Kenya and Senegal showed much higher levels, 22.92 and 35.10 WHO-TEQ pg/g, respectively.
PCBs and HCB pollutants levels (0.80 WHO-TEQ pg/g and 1.1 nanogram per gm egg fat, respectively) in egg samples from the dumpsite in Peshawar were found to be lower than Czech Republic (5.0 WHO-TEQ pg/g) and EU (200 nanogram per gram) limits. However, high levels of DDT were found in the egg samples, with measured sum equal to 2329.30 nanogram per gram of egg fat. The DDT level in the Peshawar dumpsite sampled eggs is four and a half times higher than the EU limit for the sum of DDT in eggs (EU limit = 500 nanogram per gram of egg fat).
The study is the first report of dioxins/furans in chicken eggs or any other food item in general in Pakistan. The results, indicating presence of toxic chemicals, especially high level of PCDD/Fs and DDT, are alarming.
The persistent chemicals, even in very small doses, are known to cause serious health problems such as cancer, reduced immunity, nervous system disorder, miscarriages, birth deformity, and negatively affect child development. There is no “threshold dose.” The tiniest amount of these chemicals can cause damage, and our bodies have no defense against it. The effects are not limited to one generation. Women, children and infants are especially vulnerable to certain effects of these chemicals.
We are exposed to these deadly chemicals due to their presence in our environment, because of their use as pesticides (DDT), as industrial chemicals (PCBs, HCB), or as unwanted byproducts (PCDD/Fs) of combustion or chemical processes.
The Stockholm Convention on POPs is the first global, legally binding instrument to protect human health and the environment by controlling production, use and disposal of toxic chemicals, including PCDD/Fs, PCBs, HCB and DDT.
So far 172 countries have signed the convention, and 98 of them have ratified it by or before April 25, 2005. Pakistan signed the convention on December 6, 2001 but has still to ratify. Pakistan also did not attend the COPI.
An early ratification of the convention would enable Pakistan to participate in international decision- making (financial mechanism, adding new POPs to the list of “dirty dozen”). Pakistan would also become eligible for financial support and technical assistance towards identification, safe collection, transportation and disposal of the existing obsolete POPs stockpiles in the country.
Very little data on environmental health impacts due to exposure to chemicals, especially POPs, is available in Pakistan. There is a dire need to initiate monitoring projects focused on addressing POPs sources as well as their levels in all segments of the environment.
Stringent limits for POPs releases and levels in wastes should be introduced both in the international and national legislations.
A comprehensive waste management strategy should be implemented for Peshawar to help prevent further threats to public health and environment by the dumpsites, open burning and medical waste incinerators.
Non-combustion alternatives should be applied to medical and other hazardous wastes incineration to avoid releases of toxic dioxins and other POPs into environment. One such facility is already being installed at Tabba Heart Institute, Karachi.
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