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Heavy Metal Contamination Threatens Vidarbha’s Lakes

Heavy Metal Contamination Threatens Vidarbha’s Lakes
Heavy Metal Contamination Threatens Vidarbha’s Lakes

Urban lakes in the Vidarbha region have long served as vital water bodies for local communities, offering not just ecological services but also recreation and aesthetic value.


Over the past two years, however, increasing scientific and environmental investigations have revealed a concerning reality. Heavy metal contamination has emerged as a serious issue affecting many of these lakes, with levels of dangerous substances often exceeding national and international safety standards.


Evidence collected between 2023 and 2025 confirms that lakes such as Futala, Ambazari, Gorewada, Khindsi, and Rishi are exhibiting elevated concentrations of heavy metals like nickel, cadmium, and manganese.


These findings highlight a growing environmental problem with potential consequences for aquatic ecosystems and public health across the region.



Contamination Levels and Findings


Recent studies, including detailed assessments by Shukla et al. (2025) and surveys conducted by NEERI, reveal widespread contamination of lake waters.


Measured concentrations of cadmium, nickel, and manganese often surpass the limits set by the Bureau of Indian Standards (BIS) and the World Health Organisation (WHO).


At Khindsi Lake near Ramtek, nickel levels have been recorded at approximately 0.4 mg/L, significantly above the BIS safe limit of 0.02 mg/L.

Rishi Lake, located within Nagpur city limits, displayed nickel concentrations around 0.2 mg/L and manganese levels nearing 0.7 mg/L.


The BIS permissible limit for manganese in drinking water is only 0.3 mg/L, making these findings particularly alarming.


Similarly, Kharpudi Lake showed cadmium levels of 0.3 mg/L, substantially exceeding the Indian drinking water standard of 0.01 mg/L.


While cadmium was detected at lower levels in other lakes like Rishi and Ambajhari, its presence above permissible thresholds remained consistent across most sampled sites.



Beyond heavy metals, ancillary parameters pointed towards extensive organic pollution. NEERI's report on Ambazari Lake recorded biological oxygen demand (BOD) values between 9 and 14 mg/L and chemical oxygen demand (COD) levels ranging from 29 to 47 mg/L.

Both indicators far exceed the limits typically prescribed for safe recreational or potable water. Dissolved oxygen levels, crucial for aquatic life, were dangerously low in several locations, correlating with observations of periodic fish mortality events.


Overall, the data paint a clear picture: Vidarbha’s lakes, especially those located in urban or semi-urban areas, are increasingly burdened by chemical contamination that threatens their ecological balance.


Sources of Lake Pollution

Sources of Lake Pollution
Sources of Lake Pollution

Investigations into the origins of heavy metal contamination point to a combination of sewage inflows, industrial discharges, and cultural practices associated with urban growth.


In many cases, untreated domestic wastewater continues to be the primary contributor.


Lakes such as Ambazari and Futala, positioned downstream of Nagpur’s older drainage systems, receive significant volumes of sewage carrying detergents, pathogens, and dissolved metals.


Industrial activity compounds the problem. Effluent from metalworking units and chemical industries in zones like Wadi and Hingna enters natural drainage channels, eventually making its way into water bodies.

Studies confirm that pollutants from the Nag River, heavily burdened by industrial waste, spill into lakes like Ambazari, increasing concentrations of chromium, nickel, and zinc.


Cultural practices also play a role. The immersion of painted idols during the Ganesh and Durga festivals introduces lead, chromium, cadmium, and other metals into the lakes. Investigations have shown post-festival spikes in heavy metals such as zinc, iron, and lead in the water column, indicating a clear seasonal pattern of additional contamination.



Urban runoff contributes further to the deterioration of water quality. With increasing vehicular activity and unplanned urbanisation, road runoff carries particles rich in heavy metals like cadmium, copper, and lead into stormwater drains and directly into lakes.


In rural areas, fertiliser and pesticide use around catchment zones of lakes like Khindsi and Kharpudi adds additional contaminants, including residues of arsenic and other trace metals.

Moreover, studies near thermal power plants like Koradi and Khaparkheda suggest that fly ash disposal impacts groundwater quality in nearby villages, introducing mercury and arsenic. While these findings primarily concern underground aquifers, contaminated subsurface flows could indirectly affect surface lakes over time.



Environmental and Health Implications


Heavy metal accumulation in water bodies brings a series of ecological and public health risks that extend beyond immediate visibility. Toxic metals such as cadmium, nickel, and lead have well-documented effects on aquatic ecosystems.


They interfere with the reproductive, neurological, and growth processes of fish and invertebrates, leading to biodiversity loss over time.


Low dissolved oxygen levels in lakes like Ambazari have already caused notable fish kills, affecting species such as tilapia.

Metals deposited in sediments can continue to leach into the water over the years, even if external pollutant sources are later controlled. This persistence ensures that contamination remains a long-term problem, requiring sustained monitoring.


Human exposure pathways are equally concerning. Although most urban lakes are not direct drinking water sources, they are used for agriculture, aquaculture, and recreation. Water from contaminated lakes irrigates crops, leading to bioaccumulation of metals in food products.


Consuming fish raised in polluted waters can introduce mercury, lead, and cadmium into human diets, posing risks of neurological disorders, cancers, and organ damage.


Evidence from areas around Nagpur, particularly in villages close to power plants, points towards chronic illnesses associated with long-term heavy metal exposure.



Elevated rates of liver, kidney, and bladder cancers have been linked to ingestion of contaminated water containing mercury and arsenic well above safety thresholds.

Even low-level chronic exposure to substances like lead is considered dangerous. International bodies such as the United States Environmental Protection Agency emphasise that no amount of lead exposure is considered safe, particularly for children.


In this context, recreational activities such as swimming, washing, and festival-related gatherings around contaminated lakes pose unquantified but significant health risks.


The findings regarding Vidarbha's lakes illustrate the broader need to view water quality issues not as isolated problems, but as part of larger urban and rural environmental management systems that require comprehensive attention.


Widening Gaps in Monitoring and Awareness


Despite the clear scientific evidence of contamination, consistent monitoring of lake water and sediments remains limited.


While recent research efforts have highlighted chemical pollution in surface water, very few studies have systematically assessed heavy metals in lakebed sediments, where long-term ecological threats often hide.

Sediment contamination plays a critical role in the persistence and re-release of heavy metals into aquatic environments. Without regular monitoring, there is a risk that pollution is underestimated, allowing invisible dangers to accumulate over decades.


Moreover, public awareness of the nature and scale of heavy metal contamination remains low. Festivals continue to see mass immersion of idols made with heavy-metal-based paints. Industries continue to discharge partially treated effluents into rivers and natural drains.



Urban planning continues without sufficient emphasis on runoff management and eco-sensitive zoning.


The environmental stress on lakes like Futala, Ambazari, and Khindsi today represents a warning signal.


Heavy metal contamination, once established, becomes exceedingly difficult to reverse, affecting not just aquatic life but entire ecosystems and human communities dependent on them.

Understanding and acknowledging the true scale of contamination is a critical first step toward securing the health of Vidarbha’s lakes for the future.


References




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