Soils in the Lower Swansea Valley, (United Kingdom) contain elevated level of metals, enough to cause direct or indirect effects on human health. This study assesses the severity of soil pollution and bioavailability of Cu and other metals (Ni, Zn, Co, Pb and Cr) in soils with various distances from a Ni refinery. We compare Cu concentrations in operationally defined soil fractions (bioavailable, bound to Fe/Mn oxide and incorporated in organic matter) with other metals (Ni, Zn, Pb, Co, Cr) usually occurring in ores used in metallurgic processes and report their pollution and geoaccumulation indices (PI and I_geo). Further, we use Cu stable isotope ratios (δ⁶⁵Cu) to trace the fate and mobility of Cu in soils. Our data suggest a point source of contamination for some of the heavy metals including Ni (I_geo = 1.9), Zn (I_geo = 0.28) and Cu (I_geo = 3.6) near the Ni refinery. However, Co (I_geo = 0.15) and Pb (I_geo = 3.3) contaminations are likely to be linked to different sources. No elevated Cr levels (I_geo= -0.07) occur in any of the studied soils. All soil metals are predominantly associated with organic matter (>50%) which reduces their bioavailibility and thus their risk for ecological and human health. The Cu isotope data show that Cu in soil organic matter is enriched in ⁶⁵Cu, while the lighter isotopes (⁶³Cu) remain in the dissolved bioavailable Cu fraction (Δ⁶⁵Cu_{organic-bioavailable} is +0.12 ± 0.13‰). This suggests the preferential complexation of ⁶⁵Cu with soil organic matter after dissolution of Cu deposited to the soil. Thus, Cu isotope data can effectively indicate pathways of metal migration in polluted soils.

下斯旺西河谷（英国）的土壤中金属含量升高，足以对人类健康造成直接或间接影响。本研究评估了土壤污染的严重程度以及距离镍精炼厂不同距离的土壤中铜和其他金属（镍、锌、钴、铅和铬）的生物有效性。我们将操作定义的土壤组分（生物可利用性、与 Fe/Mn 氧化物结合并掺入有机质）中的 Cu 浓度与通常出现在冶金过程中使用的矿石中的其他金属（Ni、Zn、Pb、Co、Cr）进行比较，并报告它们的污染和_地理累积指数（PI 和I _geo）。此外，我们使用 Cu 稳定同位素比率 ( δ ⁶⁵Cu) 来追踪 Cu 在土壤中的命运和流动性。我们的数据表明 ，Ni 精炼厂附近的一些重金属包括 Ni（I _geo  = 1.9）、Zn（I _geo  = 0.28）和 Cu（I _geo = 3.6）存在点污染源。然而，Co ( I _geo  = 0.15) 和 Pb ( I _geo  = 3.3) 污染可能与不同的来源有关。没有升高的 Cr 水平 ( I _geo= -0.07) 发生在任何研究的土壤中。所有土壤金属主要与有机质 (>50%) 相关，这降低了它们的生物利用度，从而降低了它们对生态和人类健康的风险。Cu同位素数据表明，土壤有机质中的Cu富含⁶⁵ Cu，而较轻的同位素（⁶³ Cu）保留在溶解的生物可利用Cu组分中（Δ ⁶⁵ Cu_{有机-生物可利用}为+0.12±0.13‰）。这表明在沉积到土壤中的铜溶解后，⁶⁵铜与土壤有机质优先络合。因此，Cu同位素数据可以有效地指示污染土壤中金属迁移的途径。