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，茶树种植过程中农药与重金属的施用使其食用安全性面临隐患。本研究旨在评估天然茶园来源茶叶及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）、Lambda chalothrin、吡虫啉（Imadachloroprid）、敌敌畏（Dichlorovas）、草甘膦（Glyphosate）及甲氨基阿维菌素苯甲酸盐（Emamectin）共6种农药残留；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）及钴（Cobalt）共6种重金属含量。针对部分超标样品，本研究还计算了健康风险指数（Health Risk Index, HRI）与靶标危害商（Target Hazard Quotient, THQ）的数值。研究结果显示，部分茶叶样品的钴、锰等重金属及敌敌畏、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（Difenaconazole）及Lambda chalothrin等农药残留含量超出了限量标准。评估结果表明，消费者存在潜在健康风险。本研究结果建议，应在茶叶生产与加工源头开展风险评估与监测工作，以避免有毒有害物质流向消费者或进入环境。