Rising heat stress poses grave occupational health risk for workers in Tamil Nadu: Study

New Delhi: Rising heat stress due to soaring global temperatures poses a grave occupational health risk to the salt pan workers in Tamil Nadu, according to a study.

The research, published in the journal Kidney International Reports, reveals the urgent need for adaptation strategies and improved health care access to protect vulnerable individuals. Between 2017 and 2020, 352 workers were studied in seven salt pans in Tamil Nadu.

The workload for different job roles and classified heat stress levels were evaluated. Key indicators such as pre- and post-shift heart rates, core body temperatures, urine characteristics, sweat rates, and kidney function parameters were measured.

The study led by researchers at Sri Ramchandra Institute of Higher Education and Research, Chennai, found that every participant had either a heavy or moderate workload, and an alarmingly close to 90 per cent of workers were found to be working above the recommended limits of heat exposure.

International regulations advise implementing regular break periods under such circumstances, but none of the salt pans examined had such breaks in place, the researchers said.

The wet-bulb globe temperature (WBGT), a composite measure of environmental factors affecting human thermal comfort, consistently surpassed safe levels in the saltpans, particularly during summer months, they said.

The workers reported symptoms of heat strain, dehydration, and urinary tract infection symptoms, likely due to excessive sweating, lack of toilet access and limited water consumption during their shifts. Of particular concern is the impact of heat stress on kidney health, according to the researchers.

The study revealed a prevalence of low estimated glomerular filtration rate (eGFR), a marker of kidney function, in 7 per cent of workers. Heat stress has been linked to various kidney-related issues, including acute kidney injury, kidney stones, chronic kidney disease, and urinary tract infections, the researchers said.

"We have compelling evidence that heat stress poses significant health risks for these workers," said Vidhya Venugopal of Sri Ramchandra Institute of Higher Education and Research.

"Urgent action is needed to implement adaptation strategies and improve health care, sanitation access and welfare facilities to protect the vulnerable individuals," Venugopal said.

The researchers said failure to address this issue will result in increased heat-related illnesses, particularly chronic kidney diseases, worsened by pre-existing medical conditions, and potentially devastating health consequences for workers around the world.

The study underscores the fact that these workers, experience prolonged exposure to high temperatures without sufficient access to adaptation strategies such as shade, rehydration, and rest breaks, they said.

Furthermore, many are hesitant to report symptoms of heat stress due to fear of job loss or retaliation. The risk is further magnified for undocumented workers who lack access to health care, according to the researchers.

Approximately 40 per cent of the global population is exposed to consistently high ambient temperatures above 30 degrees Celsius throughout the year, they said.

The researchers noted that India, in particular, faces significant risks, with the mean temperature having risen by 0.7 degrees Celsius between 1901 and 2018.

Projections indicate a staggering increase of 4.4 degrees Celsius by the end of the century, exacerbating the health impact on its population, they added.