In August 2015, 11.3 million L of heavy metal–contaminated water spilled into the Animas River from the Gold King Mine (Colorado, USA). National attention focused on water quality and agricultural production in areas affected by the spill. In response to local concerns, surface soil elemental concentrations were analyzed in three New Mexico agricultural fields to determine potential threats to agronomic production. Irrigated fields in the Animas watershed were scanned using portable X-ray fluorescence (PXRF) spectrometry to monitor the spatiotemporal variability of Pb, As, Cu, and Cr. A total of 175 locations were scanned using PXRF before and after the growing season for 3 yr. The geostatistical model with the lowest RMSE was chosen as the optimal model. The lowest RMSE for the elements ranged from to 0.10 to 0.44 m for As, from 0.50 to 0.98 m for Cr, from 0.15 to 0.91 m for Cu, and from 0.14 to 0.44 m for Pb across the models selected. The spatial dependence between the measured values exhibited strong to moderate autocorrelation for all metals except for As, for which spatial dependence was strong to weak. Some areas in each field exceeded the New Mexico Environment Department soil screening limit of 7.07 mg As kg^–1. All sampling locations were below the screening limit at last sampling time in 2019. Mixed models used for temporal analysis showed a significant decrease only in As below the screening value at the end of the study. Results indicate that the agricultural soils were below the soil screening guideline values.

中文翻译：

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金王矿泄漏后阿尼马斯河流域的农业土壤：通过便携式 X 射线荧光光谱进行元素时空分析

2015 年 8 月，1130 万升受重金属污染的水从金王矿（美国科罗拉多州）流入阿尼马斯河。国家的注意力集中在受泄漏影响地区的水质和农业生产上。为响应当地关注，对新墨西哥州三个农田的表层土壤元素浓度进行了分析，以确定对农艺生产的潜在威胁。使用便携式 X 射线荧光 (PXRF) 光谱仪扫描 Animas 流域的灌溉田，以监测 Pb、As、Cu 和 Cr 的时空变异性。在 3 年的生长季节前后使用 PXRF 扫描了总共 175 个位置。选择具有最低 RMSE 的地统计模型作为最佳模型。元素的最低 RMSE 范围从 0.10 到 0.44 m，对于 As，从 0.50 到 0。在所选模型中，Cr为98 m，Cu为0.15至0.91 m，Pb为0.14至0.44 m。对于所有金属，测量值之间的空间依赖性表现出强到中等的自相关，除了 As，其空间依赖性从强到弱。每个田地中的某些区域超出了新墨西哥州环境部的土壤筛查极限，即7.07 mg As kg^–1 . 在 2019 年最后一次采样时，所有采样位置均低于筛选限值。用于时间分析的混合模型显示，在研究结束时，仅 As 低于筛选值有显着下降。结果表明，农业土壤低于土壤筛选准则值。