Monitoring and risk assessment due to presence of heavy metals and pesticides in tea samples

Abstract Tea is one of the most consumed beverages after water, but unfortunately the application of pesticides and heavy metals in crops make it unsafe for use. This research was conducted to evaluate the risk of heavy metals and pesticides in samples of natural source tea (gardens) and different local market brands. High Performance Liquid Chromatography was used to detect pesticides, Bifenthrin, Lambda chalothrin, Imadachloroprid, Dichlorovas, Glyphosate and Emamectin. Heavy metals such as Zinc, Iron, Chromium, copper, manganese and cobalt were determined by atomic absorption spectroscopy. The value of HRI and THQ was still calculated for some exceeded samples. From results obtained some of the tea samples were contaminated from with heavy metals i.e., cobalt and manganese and pesticides as: dichlorovas, imacloroprid, bifenthrin, emamectin, glyphosate, difenaconazole and lambda above the allowed limits. The assessments revealed the potential for potential health risk for the consumers. The results of the study suggested that risk assessment and monitoring should be done at source that is at the production and processing area so that toxic effects are not passed on to the consumers or to the environment.摘要：茶是仅次于水的全球最常饮用的饮品之一，但遗憾的是，农作物种植过程中农药与重金属的施用使其饮用安全性受到挑战。本研究旨在评估茶园天然源茶叶样品与不同本地市售品牌茶叶样品中的重金属与农药残留风险。本研究采用高效液相色谱法（High Performance Liquid Chromatography, HPLC）检测联苯菊酯（Bifenthrin）、氯氟氰菊酯（Lambda chalothrin）、吡虫啉（Imadachloroprid）、敌敌畏（Dichlorovas）、草甘膦（Glyphosate）与甲氨基阿维菌素苯甲酸盐（Emamectin）等农药残留；采用原子吸收光谱法（Atomic Absorption Spectroscopy, AAS）测定锌（Zinc）、铁（Iron）、铬（Chromium）、铜（copper）、锰（manganese）与钴（cobalt）等重金属含量。针对部分超标样品，还计算了健康风险指数（Health Risk Index, HRI）与靶标危害商数（Target Hazard Quotient, THQ）数值。研究结果显示，部分茶叶样品的重金属（钴与锰）与农药残留（敌敌畏、吡虫啉、联苯菊酯、甲氨基阿维菌素苯甲酸盐、草甘膦、苯醚甲环唑与氯氟氰菊酯）超出了限量标准。评估结果表明，消费者面临潜在健康风险。本研究结果提示，应在茶叶生产与加工源头开展风险评估与监测工作，以避免有毒物质传递给消费者或污染环境。