Table_1_Potential ecological risk from heavy metals in surface sediment of lotic systems in central region Peru.DOCX

High Andean rivers are fragile ecosystems in the face of various threats, including heavy metal contamination. The objective of this study was to evaluate the potential ecological risk of heavy metals in surface sediment of lotic systems in the central region of Peru. Composite samples of surface sediments were collected from the Chía and Miraflores rivers and the concentrations of heavy metals were determined. The ecological risk analysis was carried out based on the contamination indexes and confirmed by the modified degree of contamination (mCd). The concentration of heavy metals in the sediment of the Chía river was in the following descending order: Fe > Mn > Zn > V > Pb > Cr > Ni > Cu > Mo > Hg, y en el río Miraflores fue: Fe > Mn > Zn > Ni > V > Cr > Cu > Pb > Hg > Mo. The mean concentration of Cu, Cr, Fe, Mn, Mo, Ni, Pb, and V in the sediment samples in both rivers did not exceed the threshold values of the continental crust concentration, nor the interim sediment quality guidelines of the Canadian Council of Ministers of the Environment. However, the mean concentration of Hg exceeded the guideline values in the Miraflores river and the likely effect (0.7 mg.kg−1) adverse effects. The values of the enrichment factor (EF), contamination factor (CF), geoaccumulation index (Igeo), and pollution load index (PLI) indicated low contamination in the sediments of the rivers studied, being confirmed by the modified degree of contamination (mCd). Finally, the risk assessment showed that heavy metals in the sediments presented a low potential ecological risk.

高海拔安第斯河流属于脆弱生态系统，面临包括重金属污染在内的多种威胁。本研究旨在评估秘鲁中部地区流水生态系统表层沉积物中重金属的潜在生态风险。研究人员从奇亚河（Chía）与米拉弗洛雷斯河采集表层沉积物混合样本，并测定其中重金属浓度。本研究基于污染指数开展生态风险分析，并通过修正污染指数（modified degree of contamination, mCd）进行验证。奇亚河沉积物中重金属浓度按降序排列依次为：Fe > Mn > Zn > V > Pb > Cr > Ni > Cu > Mo > Hg；米拉弗洛雷斯河沉积物中重金属浓度则为：Fe > Mn > Zn > Ni > V > Cr > Cu > Pb > Hg > Mo。两条河流沉积物样本中Cu、Cr、Fe、Mn、Mo、Ni、Pb及V的平均浓度均未超过大陆地壳浓度阈值，也未超出加拿大环境部长理事会（Canadian Council of Ministers of the Environment）制定的临时沉积物质量指南限值。但米拉弗洛雷斯河沉积物中Hg的平均浓度超出了该指南限值，达到了可能产生不良影响的阈值（0.7 mg·kg⁻¹）。富集因子（EF）、污染因子（CF）、地质累积指数（Igeo）及污染负荷指数（PLI）的计算结果显示，本次研究涉及的两条河流沉积物整体污染程度较低，该结论得到了修正污染指数（mCd）的验证。最终风险评估结果表明，沉积物中的重金属仅存在较低的潜在生态风险。