Potentially toxic metals in lotic systems with aptitude for aquaculture at the watershed Mantaro River, Peru

Abstract The objective of the study was to analyze the concentration of Cu, Zn, Fe, Pb and As in river water suitable for aquaculture in the watershed of the Mantaro River using multivariate statistical methods, during the period 2011-2013. The determinations of total heavy metals in water collected during two different climatic periods were performed by atomic absorption spectrophotometry, according to the methodology recommended by FAO. The results obtained show that, in the seven rivers evaluated, the average concentration of Pb, Fe and Cu exceeded the quality standards of Peru's continental water for the extraction and cultivation of hydrobiological species and USEPA standards for the protection of fish and aquatic life. The average concentration of Zn only exceeded USEPA standards. While the concentrations of Pb and Cu also surpassed those of the WHO. The cluster analysis suggests that the evaluated rivers, in which fish farming activity is intensively developed, have similar characteristics in relation to the concentration of heavy metals. According to the analysis of main components, in Component 1, there are moderate loads for arsenic; in Component 2, there is a strong load for zinc and relatively low loads for iron; and, in Component 3, there is a moderate load for iron. The discriminant analysis revealed that two of the five variables were significant predictors of the season; in this case, copper and lead were sufficient to discriminate the variables between the rainy or dry season.

摘要 本研究旨在采用多元统计方法，分析2011-2013年间曼塔罗河（Mantaro River）流域适宜水产养殖的河水中铜(Cu)、锌(Zn)、铁(Fe)、铅(Pb)和砷(As)的含量。
本研究依据联合国粮食及农业组织（FAO）推荐的分析方法，采用原子吸收分光光度法对两个不同气候时段采集的水样中的总重金属浓度进行了测定。
研究结果显示，在评估的7条河流中，铅(Pb)、铁(Fe)和铜(Cu)的平均浓度超出了秘鲁用于水生生物物种捕捞与养殖的内陆水体水质标准，以及美国环境保护署（USEPA）制定的鱼类与水生生物保护标准。锌(Zn)的平均浓度仅超过美国环境保护署标准；此外，铅(Pb)和铜(Cu)的浓度还超出了世界卫生组织（WHO）的限值。
聚类分析结果表明，水产养殖活动集约化开展的参评河流，其重金属含量特征具有较高相似性。
基于主成分分析结果，主成分1中砷的载荷量处于中等水平；主成分2中锌具有强载荷量，铁的载荷量相对较低；主成分3中铁的载荷量为中等水平。
判别分析结果显示，5项监测变量中有2项可作为季节的显著预测因子：铜与铅足以区分雨季与旱季的水质变量差异。