The ever-magnifying peril of Biomagnification and Bioremediation as its salvation.by Ajaya Poudel | 29-04-2020 12:59 |
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     The ever-magnifying peril of Biomagnification and Bioremediation as its salvation. In this so called modern world, due to the ever-increasing use of synthetic and unwanted substances and introduction of hazardous environmental pollutants to the ecosystem, our mother Earth is tending towards inhabitability slowly but surely. The pollutants or the contaminants of the environment generally include Persistent Organic Pollutants (POPs) such as DDT, Polychlorinated Biphenyls (PCBs), Furans, Dioxins, Aldrin, Chlordane, etc. and heavy metals like mercury, lead, arsenic, cadmium, etc. Due to their low water soluble and lipophilic nature, low digestibility and degradability and their ability to travel long distances, the POPs concentrate in the fat tissues of organisms that consume them i.e. in the food chain which is called Bioaccumulation. These contaminants not only accumulate in a single lower trophic level of organisms but also get transferred across the food chain with increased concentration from lower to higher trophic level. This phenomenon is known as Biomagnification. The ability of such pollutants to bioaccumulate and biomagnify to cause toxicity in the biological systems(i.e. humans, animals, microorganisms and plants) is a serious and important issue of concern that needs immediate addressing for environmental health and safety in the modern world. These pollutants donot emerge themselves from nowhere but are produced in our day to day household and industrial activities. How does Biomagnification occur? The initial concentration of these pollutants during their release into the seas, land and air may seem to be very low but eventually when they are consumed and absorbed by lower organisms in the food chains such as fish, earthworms, and plants, they bioaccumulate in their fat tissues and when they are eaten by other organisms of higher trophic levels over the periods of time, they accumulate and Biomagnification occurs. Let me explain with an example: Very low concentrations of the toxic chemicals and pollutants are released to the seas. Phytoplanktons - the small plants that float in the seas absorb the toxins and as the toxins donot get broken down or excreted, stay in their tissues. With time, those toxins increase in concentration in the cells. When more and more of these phytoplanktons are eaten by the zooplanktons, the concentrations of these toxins increase in them at a higher rate than the phytoplanktons. Still the toxic effects of the pollutants may not be seen in them. But when they are eaten by the small fishes and the small fishes by the Big fishes, the build up rate of the toxins increases even more. Consequently, when the organisms of the top level like Dolphins, sea birds, and humans consume the large fish, the levels of the concentrations of the toxins are at the highest levels. The toxins may have some serious impacts specially to the top level consumers due to the highest concentration. They can be affected in various ways such as animal's fertility, make them vulnerable to diseases interfering their normal functioning of vital organs, etc. Causes of Biomagnificatiion: Obviously all the causes are directly or indirectly related to activities of humans in the environment. Some of the major causes are: Plastic Pollution: Research shows that plastic contains a harmful chemical called Bisphenol A which is regarded as one of the major contaminant released to water bodies. It not only directly affects the aquatic organisms but also the other terrestrial organisms of the higher trophic levels that consume them. What they say about Karma is indeed true. What we throw into the sea comes to us and harm us through the fishes we eat ultimately. As it is directly related to the ecosystem and every living beings being connected to the ecosystem one or the other way, there is no plant or animal Biomagnification does not have an impact on. The impact however may be major or minor depending upon the concentration of the toxins and even the species of the organisms. The major effects of Biomagnification can be discussed under the following headings: Another effect may be the destruction of coral reefs compromising the survival of several other aquatic creatures due to use of cyanide in leaching gold and in fishing. -Industries should work on innovative strategies to eliminate mercury and other heavy metal emissions and prohibition and ban policies should be strictly applied to the emission of the toxic substances -Proper treatment and decontamination of identified polluted areas must be carried out. -Usage of lead paints and PVC must be reduced or completely avoided if possible to prevent contamination of drinking water. -Cooking oils, grease, household chemicals, medications, etc. must be disposed properly. -Arsenic containing chemicals like CCA and ACZA additives to prepare furnitures. Bioremediation, besides all these remedial measures, is found to be more reliable and sustainable to solve the problem of Biomagnification. Bioremediation is the process of using biotechnology to degrade hazardous environmental pollutants into non-toxic or less toxic substances especially by utilizing microorganisms like bacteria, fungi, and yeast. Microorganisms contain enzymes that can degrade the environmental pollutants by using them as food and degrade them into less or non toxic forms. As bioremediation can be effective only where environmental conditions permit microbial growth and activity, its application often involves the manipulation of environmental parameters to allow microbial growth and degradation to proceed at a faster rate.(Kumar et al., 2011). The technology is principally based on biodegradation and refers to complete removal of organic toxic pollutants in it to harmless or naturally occuring compounds like carbon dioxide, water, inorganic compounds which are safe for human, animal, plant and aquatic life.(Jain and Bajpai, 2015) Some of the microorganisms used in bioremediation are Penicillium chrysogenum, other species of Penicillium, Aspergillus niger, Gleophyllum striatum, Cyanobacteria, Corynebacterium propinquum, etc. Bioremediation is of two types namely Insitu and exsitu. Insitu bioremediation involves introduction of MO to the area of contamination itself whereas exsitu involves excavation of the pollutants from the area of pollution. Why go too deep or far to understand the basic concept of bioremediation when the compost which we prepare at our homes, homegarden or agricultural field is also a perfect example of it. The impacts of most of the newer man made chemicals are still unknown. God knows what extreme consequences they may bring in the future to the biological systems. Its not enough to discuss the impacts human activities on the environment, what's lacking the understanding how deeply we are connected to the nature. Only when we come to love and respect nature will the planet have any hope of the surviving the current 6th mass extinction i.e. The Holocene/Anthropocene extinction.
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