Godavari Residents at Risk of Cancer From Toxic Soils near Oil and Gas Drilling Sites

Hyderabad: A study conducted by the National Geophysical Research Institute (NGRI), Hyderabad, and Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, has raised safety concerns over toxic concentrations of heavy metals in soils affecting the health of the people living close to oil and gas drilling sites in East and West Godavari districts of Andhra Pradesh.

The study, “Spatial distribution, sources and health risk assessment of heavy metals in topsoil around oil and natural gas drilling sites, Andhra Pradesh, India, “ highlights carcinogenic as well as non-carcinogenic health risks due to high levels of heavy metals in the soil, attributed majorly to pollution caused by the backwater waste generated during drilling. Apart from oil drilling sites, the other probable source of contamination of soils by heavy metals can be attributed to agriculture, points out the study.

The study has revealed disconcerting levels of heavy metals – arsenic, chromium, copper, nickel, lead, and zinc -- in the soil near drilling sites. Some concentrations have been found to surpass safe limits significantly, with levels reaching as much as hundreds of times higher than recommended thresholds.

While the scientists found higher than permissible concentrations of all six heavy metals, they highlighted a persistent significant risk especially due to high concentrations of Arsenic, Lead, and Chromium.

These heavy metals, often dubbed silent killers, pose a dual threat to villagers. The study has highlighted the cancer risk among children and adults due to the high concentrations of Arsenic and Chromium in the soil as the Total Carcinogenic Risk (TCR) calculated for these heavy metals has been found to be above the threshold value set by the USEPA.

Also, the non-carcinogenic risks due to lead and chromium were found to be higher as the Hazard Index value calculated for these heavy metals was above the recommended limit of one.

Adding to the urgency of the situation, the study highlights the potential for heavy metals to leach into groundwater. The same water that sustains life could become a hidden danger, laden with toxic substances. Villagers, unknowingly, could find themselves consuming a deadly cocktail, further exacerbating the health risks.

While the ingestion of heavy metal-contaminated water might result in severe health hazards, it can also cause non-carcinogenic health problems such as malfunction of internal organs, gastrointestinal dysfunction, renal dysfunction, neurological diseases, skin lesions, vascular damage, immune system malfunction and birth abnormalities.

The NGRI scientists have recommended regular monitoring of the soil parameters by applying basic quality testing and monitoring of activities in the drilling sites.

To contain the backwater chemicals generated at the drilling sites that raise the heavy metal concentrations in soil, they recommend biological treatment methodologies like fixed-film treatment, membrane bioreactors, wetlands and ponds, activated sludge treatment, and anaerobic treatment. They also suggest bio-electrochemical treatment and bio-preparation for the bioremediation of oil-contaminated soils.

Other information

* Areas covered for the study: Konalapalli, Tallakodu, Prathallamaraka, Nagendrapuram, Arjunudupalem, Sitharamapuram, Elamanchili, Mandapeta, Kalvacherla, Yedurulanka, Challapalli, Bantumilli, Malleshwaram, and Mogallu.

* The hazard quotient (HQ) of chromium (Cr) and lead (Pb) was found to be significantly higher than that of other heavy metals in the study area due to their elevated concentrations in the soil.

* The study indicates Cr and Pb may adversely affect female adults residing in the study area.

* The study indicates the non-carcinogenic risk values in provinces surrounded by drilling rigs are comparatively higher than in various other areas.

( Source : Deccan Chronicle. )
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