为加强中国与秘鲁两国地学合作,推广我国优势的地球化学调查与研究方法,中国地质调查局与秘鲁地质矿产冶金研究院(INGEMMET)以秘鲁中部曼塔罗(Mantaro)盆地为研究区共同开展了多目标地球化学调查,以我国现行相关行业规范为标准,采集样品并于我国实验室进行分析测试。调查和研究表明:研究区土壤总体呈弱碱性,Au元素强烈富集,I、C、C_org、Cd和N等指标较富集;土壤养分指标N和P较丰富,K则较缺乏,土壤养分综合等级以较丰富(二等)为主,面积占比为74.1%,土壤肥力较好;土壤环境评价指标中,Zn和Pb在少量地区存在轻微—重度污染,Cd和As则有较大面积的污染,土壤环境综合等级以轻微污染和轻度污染为主,污染地区主要分布于曼塔罗河两侧5 km范围内,重度污染区则主要分布于紧邻曼塔罗河地区和人口密度最大的万卡约市周边,重金属污染较严重,污染空间分布与曼塔罗河密切相关;土壤质量综合评价等级主要为中等—劣等,面积占比达83.18%,优质和良好级土壤面积仅占16.82%。综上所述,秘鲁曼塔罗盆地地区土壤养分较丰富,土壤重金属污染较严重,土壤综合质量为中等偏差,建议秘鲁有关部门加强对曼塔罗河及上游重金属污染源的环境管理与整治。

In order to enhance the geoscientific collaboration between China and Peru using China’s advanced geochemical investigation and research methods, the China Geological Survey (CGS) and Peru Instituto Geológico, Minero y Metalúrgico (INGEMMET) jointly conducted a multipurpose geochemical survey in the Mantaro Basin of central Peru. The samples were collected and analyzed in Chinese laboratory according to applicable Chinese national standards. According to the results, the soil of the study area was in general weakly alkaline, with strong enrichment of Au and relatively enriched indicators such as I, C, C_org, Cd, and N. The soil nutrient indicators N and P were relatively abundant, but K was lacking. The comprehensive nutrient grade was mainly “relatively rich” (Grade 2), accounting for 74.1% of the total area, indicating good soil fertility. In terms of soil environmental assessment, Zn and Pb showed slight to severe pollution in a small number of areas, while Cd and As contamination was widespread. The comprehensive grade of soil environment was predominantly “slightly to lightly polluted”, with the polluted areas mainly concentrated within 5 km from either side of the Mantaro River, while the heavily polluted areas were mainly distributed close to the Mantaro River and Huancayo City with large population density. The heavy metal pollution was serious, and the spatial distribution of pollution was closely related to the Mantaro River. The comprehensive geochemical grade of soil quality was mainly “moderate” to “severe”, constituting 83.18% of the area, with only 16.82% of the area graded “good to high quality”. In summary, the Mantaro Basin was found to have relatively rich soil nutrients, severe heavy metal pollution, and a moderate to poor overall soil quality. Recommendations to relevant agencies include strengthening environmental management and control of heavy metal pollution sources in the Mantaro River and its upstream areas.