By Ayesha Baig.
Have we ever paid attention to the food we eat, let alone the air we breathe? Sparing us a moment in order to analyse the filth we ingest and breathe on regular basis is simply not among our priorities.
We turn our eyes away from filth. We try to block off the unpleasant odour of garbage. We, as humans, simply do not surround ourself with things that arouse our natural reactions of repulse or distaste. But it seems that visibility of germs has become the only standard of dispelling the same.
Second by second, invisible contaminants not known to our biological system are being added in our environment by the work of our own hands. Severer forms of diseases and weaker immunities: the invisibility of these contaminants make us prone to risks, the impacts of which are revealed years later.
Environmental pollution with xenobiotics such as pesticides, dioxins, petroleum compounds, polyaromatic hydrocarbons, polychlorinated biphenyls etc is a global problem. Soil is an essential part of our environment as it supports the growth of plants, purifies air and water and ultimately sustains life on Earth; its contamination by man-made chemicals is, therefore, of paramount importance.
Xenobiotics are those organic compounds which intimate those natural chemicals that are necessary for life but posses an inherent property of being strange in nature which makes them toxic to life. Such synthetic compounds are unrecognizable by chemical activities in microorganisms and plants and thus remains persistent in the environment. Mostly, xenobiotics are synthetic compounds that originate from various anthropogenic interruptions in the natural environment such as household, industrial, medical, and intensive agricultural activities.
Xenobiotics are considered as one of the most dangerous group of environmental contaminants consisting of both inorganic elements like heavy metals, metalloids and synthetic organic compounds like man-made pesticides, industrial solvents, drugs, food additives, pharmaceuticals and endocrine disruptors. It has been reported that over 70,000 xenobiotics may have the potential of causing high risk to the health status of human beings.
Research work on xenobiotics indicates that once in soil, their recalcitrant nature there can lead to several other problems. Plants growing on such contaminated soils are able to take them up and incorporate them in their various palatable parts. From plants, such persistent organic compounds can enter the natural food cycle leading to their accumulation in the organisms which are a part of ecological food chain, thus disrupting the natural balance of food chain. Long residence time of xenobiotics in the soil can also lead to their transfer from soil to other locations by various processes such as erosion, runoff, windblown soil particles, thus they are not restrained to one particular location but are able to distribute them in the entire ecosystem. Xenobiotics are known to cause many harmful diseases in humans. They are mutagenic and carcinogenic in behavior and are responsible for causing various developmental abnormalities in humans.
The dreadful thing about xenobiotics is that, their presence is everywhere in the environment including the air in which we breathe, the water which we drink, the food that we eat, the things that we touch. So, one cannot avoid its exposure and dealing with them is one of the greatest challenge we are facing today. There is a dire need to work on such recalcitrant synthetic chemicals in order to control them at their source point, ultimately reducing their exposure to humans and protecting the society as a whole as it is rightly said that:
We won’t have a society if
We destroy the environment. (Margaret Mead)
Potential pathways for toxic elements to become concentrated in plants, soil, animals and ultimately humans.
Environmentalist, MPHIL research scholar in Environmental Sciences at Punjab University. Areas of interest are: Environmental Toxicology and Food Safety. She is also pursuing Masters in History.