Gala Lake is an internationally important lake due to its location on one of the world's most important bird migration routes. For this reason, water quality of the lake is of great concern. However, the lake surrounded by paddy fields may face eutrophication and toxic metal contamination due to excessive use of fertilizers and pesticides. In this study, impact of paddy fields on water quality of the Gala Lake was investigated. The concentrations of metal(loid)s and physico-chemical parameters in surface water samples taken from the lake were measured and compared with water quality guidelines. Also, human health risks and contamination status of metal(loid)s were assessed. The mean NO, SRP and BOD concentrations in the lake exceeded the permissible levels for both salmonid and cyprinid waters. The mean BOD value indicated contaminated water quality in the lake, while mean COD and SRP values indicated lightly contaminated water quality. The mean As, Cr and Pb values in the winter exceeded the drinking water limits set by WHO and EC, while the mean Cr and Zn values exceeded the limit values for the protection of freshwater aquatic organisms set by USEPA. Similarly, heavy metal pollution index and the degree of contamination values in the winter indicated that the lake water is moderately polluted. Health risk assessment results revealed that As and Cr in the lake water via ingestion exposure pathway may pose both non-carcinogenic and carcinogenic health risks to the residents. The results of this study indicated that paddy fields are a major source of nutrients, organic matter and toxic metal(loid)s to the Gala Lake. To improve the water quality of the lake, we suggest that excessive use of fertilizers and pesticides should be controlled to reduce metal(loid) and nutrient loads from the paddy fields.

中文翻译：

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稻田对加拉湖（土耳其）水质的影响：重要的候鸟中转栖息地

加拉湖是一个国际重要的湖泊，因为它位于世界上最重要的鸟类迁徙路线之一。因此，该湖的水质备受关注。然而，由于化肥和农药的过度使用，被稻田包围的湖泊可能面临富营养化和有毒金属污染的问题。本研究调查了稻田对嘎拉湖水质的影响。对从湖泊中采集的地表水样品中的金属（类）浓度和理化参数进行了测量，并与水质指南进行了比较。此外，还评估了人类健康风险和金属（类）污染状况。湖中 NO、SRP 和 BOD 的平均浓度超出了鲑鱼和鲤鱼水域的允许水平。 BOD平均值表示湖泊水质受到污染，COD和SRP平均值表示湖泊水质受到轻度污染。冬季As、Cr、Pb平均值超过WHO和EC规定的饮用水限值，Cr、Zn平均值超过USEPA规定的淡水水生生物保护限值。同样，重金属污染指数和冬季污染程度值表明湖水为中度污染。健康风险评估结果显示，湖水中的砷和铬通过摄入暴露途径可能对居民造成非致癌和致癌的健康风险。研究结果表明，稻田是嘎拉湖养分、有机物和有毒金属的主要来源。为了改善湖泊水质，我们建议控制化肥和农药的过量使用，减少稻田的金属和养分负荷。