To better understand the environmental fate of pesticides in Sri Lankan soils, we studied the sorption behavior of two commonly used pesticides (carbofuran and diuron) in 43 surface soils representing a range of soil physicochemical properties from dry and wet zones of Sri Lanka. For carbofuran, the K(d) (L/kg) values varied from 0.11 to 4.1 (mean, 0.83; median, 0.62) and K(oc) ranged from 7.3 to 120.6 (mean, 41.65; median, 36.1), whereas for diuron K(d) values varied from 0.5 to 75 (mean, 9.6; median, 5.15) and K(oc) ranged from 55.3 to 962 (mean, 407; median, 328). A comparison of sorption data on these tropical soils with published studies (mostly European and north American soils) showed that the ranges of sorption coefficients from Sri Lankan soils were within the wide range of K(oc) values reported in the literature. However, these values for both pesticides in soils from dry zones of Sri Lanka were consistently higher (up to two times) than those from the wet zone. The wide range of K(oc) values in Sri Lankan soils may be due to the possible difference in the nature of soil organic carbon, which needs to be further investigated.
The introduction of elevated amounts of foreign ions into the blood may lead to impairment of the filtration membrane of kidneys and chronic kidney damage. In order to assess the risk of consumption of drinking water (dug well water) in chronic kidney disease of unknown etiology (CKDu), affected areas in Sri Lanka, trace metals, and other counterions in water samples obtained from dug wells were analyzed and compared with a reference area. Drinking water could be the major source that is responsible for entering nephrotoxic ion contaminants into the human body. To achieve the objective, drinking water samples were collected from dug wells in two CKDu endemic areas and a reference area where no CKDu patients were found in a dry season. In the Wewelketiya area (one of the endemic areas), Cd concentrations in 60% of water samples and Pb concentrations in 40% of water samples have exceeded the maximum limit given by Sri Lanka water quality standards. Fluoride concentrations also have exceeded the permissible limits of more than 80% of collected water samples in both CKDu endemic areas. However, none of the water samples in reference areas has reported that Cd, Pb, and fluoride are beyond their maximum permissible limits. Hence, people in the particular CKDu endemic areas are at risk of kidney tissue damage due to long-term exposure to drinking water with elevated levels of some metal ions and counterions.
Aquatic plants are known for uptake of heavy metals from water and sediments. This very feature qualifies these plants as wastewater treatment agents. Capacity to absorb, heavy metals however, varies among plants.Three aquatic plants, Pistia stratiotes (floating), Limnocharis jlava (rooted) and Ipomoea aqualica (rooted plant with floating runners) from lriyawetiya wetland at Kelaniya were tested for the presence of copper, zinc, lead, nickel, cadmium, manganese, tin and chromium in the plant tissues.
Chronic kidney disease of unknown etiology (CKDu) has become an alarming health issue in Sri Lanka. The disease is more notable among farming communities and people who consume groundwater as their main source of drinking water. To assess the possible links between drinking water chemistry and expansion of CKDu, the study was compared with hydrogeochemical data of drinking water sources in a CKDu prevalent area (Girandurukotte GND, Badulla District) and a reference area (Dambethalawa GND, Ampara District) in Sri Lanka. Based on the results, nephrotoxic heavy metal (Cd, Cr, Pb, and As) concentrations were significantly higher in the CKDu prevalent site than the reference area, compromised the harmful consequences to the people in the CKDu hotspot. Results of the inverse distance weighted (IDW) interpolation tool indicated the nephrotoxic heavy metals contents including Cd, Pb, As, and Cr in CKDu hotspot were changed in the ranges of 9.78–187.25 μg/L, 0.08–0.66 μg/L, 20.76–103.30 μg/L, and 0.03–0.34 μg/L. The random distribution patterns were shown by the result in Moran’s index values. Noteworthy, the results have emphasized a strong association between fluoride and water hardness. The frequency of occurrence above the threshold limit of fluoride was 28% in non-CKDu water samples, while 81% in CKDu prevalent sites. The hardness values in the CKDu prevalent site indicated “moderately hard water,” while the non-CKDu area indicated the “soft water.” Furthermore, this paper quantified overall water quality and heavy metal contamination and assessed the human health risks associated with drinking water. According to the results of the water quality index, 90% of the samples in the CKDu prevalent area were classified as “poor water” and “very poor water” for drinking purposes, while 73.33% of the samples in the non-CKDu area were “good” and “excellent” for drinking usage. Calculated chronic daily intake (CDIoral) and hazard quotient (HQoral) of nephrotoxicants were higher in CKDu hotspot than the non-CKDu site. Besides, the hazard index (HI) values obtained for the CKDu prevalent area exceeding the acceptable limit (HI = 1) indicated potential health risks to the people in those areas. This study suggests that long-term exposure to nephrotoxic heavy metals, water hardness, and fluoride present in drinking water may threaten human health and affect kidney functions. Therefore, regular monitoring and better management of water supplies in CKDu prevalent areas are essential to determine the contamination load and reduce the health impacts due to excessive and long-term exposure to the nephrotoxicants.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.