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年期间曼塔罗河（Mantaro River）流域内适宜水产养殖的河水中铜（Cu）、锌（Zn）、铁（Fe）、铅（Pb）与砷（As）的浓度。本研究于两个不同气候时期采集水样，依照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水中总重金属进行测定。研究结果显示，在所评估的7条河流中，铅、铁与铜的平均浓度均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）为保护鱼类及水生生物所制定的水质标准。锌的平均浓度仅超过美国环境保护署（USEPA）标准；而铅与铜的浓度同时也高于世界卫生组织（WHO）的限值。聚类分析结果表明，水产养殖活动密集开展的受访河流，其重金属浓度特征具有相似性。基于主成分分析结果，主成分1中砷呈现中等载荷；主成分2中锌具有强载荷，铁则呈现相对较低的载荷；主成分3中铁呈现中等载荷。判别分析显示，5个变量中有2个可作为季节的显著预测因子：在此场景下，铜与铅足以区分雨季与旱季的水质变量。