Industrialisation, urbanisation and mining are generating large quantities of solid wastes with copious quantities of heavy metals in it. In Odisha alone for instance, chromite mining accounts for 98% of India’s chromites mining reserves. The heavy metal pollution in drinking water is a result of mining activities accounts for 60% of the hexavalent chromium. Although 0.05 mg/l is the maximal tolerance limit for hexavalent Chromium in potable water, ten to hundred fold higher levels were detected in drinking water during routine check up.
Hexavalent chromium is a potent mutagenic agent and is connected to physiological disorders, organ failures, respiratory problems and a potential carcinogen too. It is widely known that the chrome plating and leather industries including tanneries make use of hexavalent chromium thus leading to voluminous amounts of hexavalent chromium finding its way in surface waste water discharges which ultimately find their way into water bodies, rivers, lakes, surface and ground water as well as the marine environment. The bio-accumulation of this hazardous heavy metal into water bodies and well waters in rural areas, lead to the bio-magnification of the toxic metals up the food chain, leading to slow but steady rise of morbidity and mortality of the flora and fauna through the adverse impacts of heavy metal across the food chain through variety of consumption patterns at different trophic levels and biodiversity utilisation.
Although the case study of Chromium poisoning has been placed in focus, it must be abundantly clear, localised deleterious effects of arsenic, antimony, cadmium, mercury, lead, nickel and also copper poisonings have been reported by scientists and environmental activists, specially around backward and developing rural areas, where mining is prevalent and heavy metal industries and paint manufacture units are installed. The inhabitants residing close to these areas are often illiterate, poor and docile, unaware of their rights towards protection of their lives and the need for clean, green and healthy basic needs of clean air, pure water and uncontaminated soil capable of producing uncontaminated food supply for basic needs.
Since it is known now that plants, animals, microbes have the capacity to bio-accumulate heavy metals, scientists around the globe are now directing their energies to use trees, microbes and animals to absorb and adsorb heavy metals from soils, water and air from commercially important sites in urban areas, agricultural fields, horticultural farms, agriculture and animal husbandry hot spots, so that those species used by man as food, and feed remains unaffected and bio-remediation practices are used to allow human kind to be shielded against the adverse effects of heavy metal pollution.
There are various trees used extensively today to restore soils contaminated with heavy metals by selective adsorption and accumulation of the toxic metals, amongst them are as under – Pithecellobiumdulce, Taramindusindicus, Pongamiaglabra, and Azadirachtaindica.
Goa in particular, the scientists at the Goa State Pollution Control Board are working on a project with the association of a bio-technological enterprise in Gujarat trying to bio-remediate soils around Cuncolim Industrial Estate where in the rejects of industrial processing done by Sunrise Zinc are dumped through the use of vermi-composting technology in which the earthworms are used to bio-accumulate nickel, arsenic etc in the discarded sludge.
It is hoped that by the bio-remediation process envisaged the heavy metals from the dumped wastes around Cuncolim Industrial Estate would not find their way into the surrounding soils, wherein agriculture, farming and horticulture is extensively practised. Also it is perceived that during heavy monsoons, the rain waters do not leach and drain away these heavy metals into water bodies leading into River Sal and adversely affecting the marine resources in shell fish, prawns, crabs and fish and finally affecting man down the food chain and recovered if necessary through biohdyro metallurgical processes.
Besides plants and animals the most preferred method to remove heavy metals from soils contaminated with heavy metals is by the use of single celled micro-organisms, which not only grow fast, occupy large surface area for both oxidative and reductive capabilities of metal transformation and can with stand wide variations of temperature, nutrient limitation and other physical, chemical and biological changes. Among the common algae species are the blue green algae and the green algae species.
Goa in particular is a tourist destination relying heavily on the quality of its water bodies, soil, air and ecosystems in general. We have to ensure pollution free environment and thus research in Institutes, Universities and college must be relevant and directed towards the challenges of growing pollutants and pollution due to challenges of industrialisation, commercialisation and even growing tourism, through which large quantities of solid wastes generated from both municipalities as well as industries. The copious amounts of heavy metals through paints, dyes used in packaging, cosmetics, and the mushrooming residential and commercial complexes etc have deleterious effects on phytoplankton, zoo planktons and retard their action working “as sinks” for containing global warming as effluents from waste treatment plants are released in the seas thus harming them. Goa’s meteorological department has rightly sounded “alarm bells” that average temperatures in Goa are rising sharply leading to warming and sea water rise in Goa. We have to keep our rivers free from casino sewage discharges and Goa environment has to have scientifically treated garbage systems in place. Or else Goa and Goans would be victims of their wayward habits.
