Poisoned Punjab: Study finds declining groundwater quality, southwestern Punjab most affected

Southwestern Punjab is suffering from high levels of groundwater pollution, gravely affecting the people living in the region, according to a new study. 

Previously, Down To Earth visited villages in southwestern Punjab and reported a host of health issues linked to water pollution.

The water quality index — a tool for evaluating surface water quality — has increased in 2020 relative to 2000, with higher values found in southwestern Punjab, the study published in journal Environmental Science and Pollution Research stated.

This could be due to intensive agriculture practices and over-exploitation of groundwater due to declining rainfall, according to the paper. 

Overuse of fertilisers 

Overexploitation of groundwater has resulted in contamination from geological sources, causing highly toxic elements such as uranium, arsenic, manganese, zinc, copper, lead and iron to leach from aquifer rock or sediment into the water, according to the paper. Because of the high toxicity in the drinking water, the state is frequently referred to as the cancer capital of the country.

The total accreage under rice crop has increased to 28,400 hectares in the years 2019–2020 from 5,000 hectares in the years 2001–2002, the study highlighted. 

“We aimed to assess how groundwater quality for drinking purposes changed to 2020 from 2000 at different places. It also sought to examine ten-year trends in health hazards associated with contaminants like nitrate and fluoride, along with identifying regions with notably subpar groundwater quality,” DP Shukla, Associate Professor, School of Civil and Environmental Engineering, IIT Mandi, said in a statement.

Shukla and colleagues used spatial tools to examine how groundwater quality has changed across more than 315 sites in Punjab between 2000 and 2020. 

They also collated and analysed data collected from the Central Groundwater Board on pH (a measure of how acidic or basic the water is), electric conductivity (a measure of a material's ability to carry an electrical current), bicarbonate, chloride, sulphate, nitrate, fluoride, calcium, magnesium, sodium and potassium.

The team also calculated the water quality index for 315 samples every four years during the period.

About 31.11 per cent of sampling sites were above the permissible limit for sodium in 2000, 25.71 per cent were above permissible limit in 2010 and 31.11 per cent in 2020, the results showed.

As for magnesium, 7.94 per cent, 4.76 per cent and 5.71 per cent of the sampling sites were above the permissible limit in 2000, 2010 and 2020, respectively. 

High levels of magnesium can trigger depression and nerve problems, while excessive sodium can cause nausea, muscle twitching and fatality in severe cases. 

Also, in 2000, 13.01 per cent of the locations were categorised as having very poor water quality and 20 per cent as unsuitable for drinking.

In 2020, 6.35 per cent of locations were in the very poor category and 12.38 per cent were classified as unsuitable for drinking.

“Our study shows that major areas in districts Ferozepur, Moga, Fazilka, Bathinda, Mansa, Barnala, Sangrur, Muktsar and Faridkot were observed as hotspots of declining water quality throughout the two decades,” the paper read.

But this is not limited to southwestern Punjab. A major area of the Ludhiana district was included in the list of hotspots in 2000, 2004 and 2008. SAS Nagar (Mohali) and Patiala districts have been hotspots since 2008 and since 2012, respectively. 

Amritsar district was considered a hotspot in 2008 and 2016, Gurdaspur in 2012 and 2016, Tarn Taran in 2008, 2016, as well as in 2020 and Pathankot in 2020. 

The paper recommended the need to regulate the use of fertilisers, deploy irrigation techniques to reduce agricultural runoffs and implement environmentally sustainable agricultural practices in regions where the water table is close to the surface. 

They also call for efforts to install diverse water treatment facilities to enable the use of groundwater for drinking purposes.

However, the study had some significant limitations. For starters, it failed to identify the source of various ions. It also did not look at seasonal changes in groundwater quality and level. The researchers explain that this was due to a lack of long-term historical data on seasonal changes in water quality.  

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