This study investigated the contamination levels and sources of As and Cd vicinity area from Nui Phao mine that is one of the largest tungsten (W) open pit mines in the world. Soil and plant samples were collected from the study area to identify the concentrations of As and Cd using aqua-regia or HNO₃ digestion. According to the Vietnamese agricultural soil criteria, all soil samples were contaminated with As and Cd. The distribution of As concentration is related to the distance from the Nui Phao mine. The higher As concentrations were measured in the area close to the mine. However, the Cd distribution in the soil showed a different pattern from As. Enrichment factor and Geoaccumulation Index (Igeo) indicated that As in the soil is derived from the mining activities, while Cd could have other geogenic or anthropogenic sources. The ranges of As and Cd concentration in polished rice grains in the Nui Phao mine area exceeded the CODEX criteria (0.2 mg/kg), which indicated extreme contamination. The arsenic concentration between soil and plant samples was determined to be a positive correlation, while the Cd concentration showed a negative correlation, implying that As and Cd have different geochemical behavior based on their sources.

这项研究调查了Nui Phao矿的As和Cd附近地区的污染水平和来源，Nui Phao矿是世界上最大的钨（W）露天矿之一。从研究区域收集土壤和植物样品，以使用王水域或HNO ₃识别As和Cd的浓度消化。根据越南农业土壤标准，所有土壤样品均被砷和镉污染。砷的分布与距Nui Phao矿的距离有关。在靠近矿区的地方测得较高的砷浓度。但是，土壤中的镉分布与砷呈现出不同的模式。富集因子和地质累积指数（Igeo）表明，土壤中的砷源自采矿活动，而镉可能具有其他地质或人为来源。Nui Phao矿区的精制米粒中As和Cd的浓度范围超出了CODEX标准（0.2 mg / kg），表明存在严重污染。土壤和植物样品之间的砷浓度被确定为正相关，