Nonpoint source pollution from agricultural runoff which contains hazardous agrochemicals like pesticides and fertilizers threatens water bodies, posing a serious danger to aquatic ecosystems and drinking water resources. Use of agrochemicals in rice cultivation has rapidly increased in the last few decades in Sri Lanka. It has been reported that many agrochemicals contain toxic trace elements like As, Cd, Pb, Zn, Cu, Ni, Cr, Al, etc. To reduce the harmful effect of heavy metal containing agrochemicals, the Government of Sri Lanka has banned the use of several toxic agrochemicals in recent years. In this context, this study was conducted after posing these restrictions to assess the occurrence of heavy metals in surface water bodies in rice cultivation areas in Trincomalee district, Sri Lanka. Ninety-three (n = 93) sample locations were randomly selected for collection of water, before and after applying agrochemicals to rice fields. This include areas from rural farming communities having endemic (Padavi Sripura DS) and non-endemic (Kanthala DS and Seruvila DS) Chronic Kidney Disease of unknown etiology (CKDu). Mean and standard error of mean of As, Cd, Pb, Cu and Zn concentrations (µg/L) before and after applying agrochemicals were as {0.048 ± 0.038 and 6.220 ± 0.912}, {0.014 ± 0.013 and 0.371 ± 0.192}, {not detected and 4.421 ± 0.712}, {1.583 ± 0.397 and 1.262 ± 0.165} and {not detected and 6.403 ± 0.366}, respectively. Findings revealed that concentrations of As, Cd, Pb and Zn were significantly different (p < 0.001) before and after the application of agrochemicals. However, the observed heavy metal concentrations were far below the permissible levels for irrigation water set by Food and Agriculture Organization and United States Environmental Protection Agency, ambient water quality set by Central Environmental Authority, and drinking water quality set by World Health Organization. In addition, analyzed heavy metal concentrations in surface water samples from CKDu endemic areas were not significantly different from those from non-endemic areas (p < 0.05). To our knowledge, this is the first report of heavy metal analysis after government ban of agrochemicals. Therefore, continuous detailed research is required to fully comprehend the behavior of agrochemicals in surface water bodies in Sri Lanka.

农业径流中含有农药、化肥等有害农用化学品的非点源污染威胁着水体，对水生生态系统和饮用水资源构成严重威胁。在过去的几十年里，斯里兰卡在水稻种植中使用农用化学品迅速增加。据报道，许多农用化学品含有砷、镉、铅、锌、铜、镍、铬、铝等有毒微量元素。为减少含重金属农用化学品的有害影响，斯里兰卡政府已禁止使用近年来的几种有毒农药。在此背景下，本研究是在提出这些限制后进行的，以评估斯里兰卡亭可马里地区水稻种植区地表水体中重金属的存在情况。九十三（n = 93) 在稻田施用农用化学品之前和之后，随机选择样本位置收集水。这包括来自农村农业社区的地方性（Padavi Sripura DS）和非地方性（Kanthala DS 和 Seruvila DS）不明病因慢性肾脏病（CKDu）的地区。施药前后 As、Cd、Pb、Cu 和 Zn 浓度（μg/L）的平均值和标准误差分别为{0.048 ± 0.038 和 6.220 ± 0.912}，{0.014 ± 0.013 和 0.371 ± 0.192}，{未检测到，分别为 4.421 ± 0.712}、{1.583 ± 0.397 和 1.262 ± 0.165} 和 {未检测到和 6.403 ± 0.366}。结果表明，As、Cd、Pb 和 Zn 的浓度存在显着差异（p < 0.001) 施用农用化学品之前和之后。然而，所观察到的重金属浓度远低于粮食及农业组织和美国环境保护署规定的灌溉水、中央环境局规定的环境水质和世界卫生组织规定的饮用水质量的允许​​水平。此外，CKD流行区地表水样中重金属含量分析结果与非流行区差异无统计学意义（p  < 0.05）。据我们所知，这是政府禁止农用化学品后的首份重金属分析报告。因此，需要持续进行详细的研究，以充分了解斯里兰卡地表水体中农用化学品的行为。