Perchlorate is a chemical that is extensively used in the arms and ammunition industry. It acts as a potential thyroid disrupter and affects the uptake of iodide causing hypothyroidism and associated health effects in foetuses, infants and pregnant women. A number of animal studies have reported perchlorate-induced toxicities including delayed metamorphosis, haemolytic anaemia, and thyroid tumor development.
The paper titled 'Surveillance of perchlorate in ground water, surface water and bottled water in Kerala, India' published in the Journal of Environmental Health Science & Engineering, informs that a number of recent studies in Tamil Nadu, Karnataka, Bihar, Maharashtra, West Bengal and Pondicherry have found water samples in these states to be contaminated with perchlorate. The World Health Organisation (WHO) has established a provisional maximum tolerable daily intake (PMTDI) of 0.01 mg/kg body weight for perchlorate. However, in many countries such as India, drinking water/wastewater standards for perchlorate is yet to be defined.
Earlier studies in India have found high perchlorate concentrations in groundwater samples collected near cracker manufacturing industrial areas (Sivakashi) in Tamil Nadu. Kerala also has two known major inventories of perchlorate--the ammonium perchlorate experimental plant (APEP) at Aluva in Ernakulam district where this chemical is produced in bulk, and Vikram Sarabhai Space Research Centre (VSSC) at Thumba, Trivandrum district.
Studies in coastal areas of central Kerala have found that a considerable section of the population suffers from thyroid disorders as well as a high incidence of thyroid cancer compared to other states.
Assessment of perchlorate concentrations in water samples in Kerala
However, there are no studies that have shown evidence of the presence of perchlorate contamination in the water and its connection to health disorders. This paper presents the findings of a study that aimed at assessing the perchlorate concentrations in ground and surface water samples in locations in Kerala where the chemical is handled in bulk quantities.
Four sites in Kerala were selected in this study, and that included water samples found near Ammonium Perchlorate Experimental Plant (APEP) at Aluwa in Ernakulam district, Thumba near Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram district. The other two locations were in Kannur and in Palakkad districts.
Findings of the study
The study revealed high levels of perchlorate contamination in ground and surface water samples around places where perchlorate was handled in bulk. The contamination was more severe in groundwater samples as compared to surface water samples. The highest level of contamination was found in Ernakulam district, Kerala. The paper ends by arguing that there needs to be frequent monitoring of groundwater samples around places where perchlorate is handled in bulk. Also, detailed epidemiological studies need to be carried out in the contaminated areas to assess the connections between the presence of the contaminant and its impact on the health of the population in the area.
This study also underlines the need to definine water quality standards for perchlorate in India and also to control the environmental release of perchlorate especially from point sources like manufacturing and using sites.
Please download a copy of the paper below.