Eco-toxicity of hexavalent chromium and its adverse impact on environment and human health in Sukinda Valley of India: A review on pollution and prevention strategies

Sukinda Valley of Jajpur district, Odisha contributes about 98% of India's total chromite reserves with about 334 million tons annual production rate globally, which plays a colossal role to strengthen the economy of our country and leads to sustainable development. The consequences related to chromite mining and excessive production of chromium have entitled this valley a “Valley of Despair”. A far-reaching production of different forms of chromite ore has bowed this area into a contamination-prone region due to the deposition of an unacceptable amount of chromium in the soil, sediment, groundwater and air of Sukinda. Around 1.8 lakh mining workers and nearby village dwellers are getting affected due to the presence of the forbidden amount of chromium ions. The foremost roots of exposure by humans are inhalation of contaminated air, accidental ingestion and contact absorption by skin. In the environment, chromium occurs in different forms and its level of toxicity also varies in each state. Chromium in its hexavalent form is bio-leachable and water-soluble. Thereby easily contaminates the water body which in turn becomes accessible to human beings and reacts with the cellular components. Long-term exposure to the human body may result in initiating several serious diseases like microcytic anaemia, mitochondrial and DNA damage of blood cells which in turn induces carcinogenicity, occupational asthma, airway hypersensitivity, nose, eye and skin irritation etc. The repercussion of chromium contamination at the terrestrial level is not endemic but also invades other sectors of the natural environment via the food chain and other means of transportation. Numerous on-going studies are yet to be carried out for the reduction and remediation of chromium from the contaminated environment. Nevertheless, this issue is worsening at a rapid rate making it difficult to tackle. The chromite mining activities in Sukinda Valley are creating difficulties for the livelihood as well as for the natural environment due to the discharge of massive amount of contaminants. The issue related to the chromium contamination is gigantic and needs urgent management and control strategies. Therefore, the present review focuses on the present scenario to combat deleterious effects initiated as a result of long-term exposure to metallic pollutant, Hexavalent Chromium [Cr(VI)] on the natural environment as well as on human health specifically on the health of mining workers and villagers residing near the Sukinda Valley, Odisha.