March 08, 2009

Backyard trash burning and medical waste incineration are of particular health concern in Pakistan since these give rise to a group of potent compounds called dioxins. ‘Dioxin’ is a term loosely used for persistent, bioaccumulative, and toxic pollutants (PBTs) including Dioxins and Furans (two potent chemical families).

‘Persistent’ means that they remain in the environment for extended periods of time while ‘bioaccumulative’ means their concentration levels increase as they move up the food chain. As a result, animals at the top of the food chain (such as humans) tend to have the highest dioxin concentrations in their bodies. Dioxins are a global health threat because even at low levels they have been associated with immune system suppression, reproductive disorders such as endometriosis, a variety of cancers and disruption of hormonal systems.

According to a report by WWF, the waste generation growth rate of Pakistan is 2.4% per year, which is almost the same as the population growth in the country and this municipal solid waste is infrequently collected by the municipal corporation. Around 40% of the generated waste remains either in roadside dumpsters or loose on the streets. It is common practice to burn this waste in open. Residential waste is usually collected and transported directly to a landfill site. However, these landfills are not designed properly causing problems like incomplete combustion and methane production from the decomposition of organic matter, and leachate contamination of groundwater.

Unregulated trash burning and medical waste incineration involve incomplete combustion of waste containing high amounts of chlorine, such as PVC (a chemical used in packaging). Burning these and other household waste containing trace amounts of chlorine, or PCB (also a PBT) based industrial solvents and household cleaning products, gives rise to dioxins which can build up in the food chain to levels that are harmful to human and ecosystem health.

Much of the dioxins created and released into the air through backyard burning settle on plants. These plants are, in turn, eaten by animals that are our source of meat and dairy products, who then store the dioxins in their fatty tissue. People are exposed to dioxins primarily by eating meat, fish, and dairy products, especially those high in fat content. Similarly backyard burning also occurs frequently in rural farming areas where dioxin emissions can more easily be deposited on animal feed, crops and grazing lands. These dioxins then accumulate in the fat of cattle and poultry, making human consumption of these harmful chemicals difficult to avoid.

Local government must provide alternatives to backyard trash burning. Solid waste should be collected in large scale incinerators or in well designed landfills by the municipality. Different types of waste should be collected separately through proper waste collection systems and recycled where possible. Medical waste disposal should be strictly regulated while making sure that incinerators are functioning properly and are not a source of dioxins themselves. Food contamination monitoring systems must be in place to ensure that tolerance levels of dioxins are not exceeded. Moreover people responsible for cleaning our houses and taking the trash out should be stopped from igniting the dumps as that is where it all begins!

Consumers can reduce the risk to exposure to dioxin compounds by trimming fat from meat and consuming low fat dairy products. Moreover, a balanced diet that includes adequate amounts of fruits, vegetables and cereals can help to avoid excessive exposure from a single source. People with gardens and backyards can significantly reduce the amount of household solid waste generated by composting the kitchen and garden wastes, such as food scrapes, used tea, grass trimmings and shredded paper. Composting is an activity that apes the natural decomposition of organic matter when given the right mix of oxygen, water and nutrients. The finished compost can then be used as an organic fertilizer in gardens and household planters.

We, as a society, have not only become immune to road side trash spewing garbage dumps and back yard trash fires but also seriously oblivious of what we breathe and eat as a result of this immunity. Next time a bag of trash leaves our house, we should take a moment to think about where it will end up and how we as individuals can change that.