Source apportionment of cadmium pollution in agricultural soil based on cadmium isotope ratio analysis

• Published in: Applied geochemistry Vol. 123; p. 104776
• Main Authors: Zhang, Xiaowen, Yan, Ying, Wadood, Syed Abdul, Sun, Qianqian, Guo, Boli
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2020
• Subjects: agricultural soils; anthropogenic activities; atomic absorption spectrometry; automobiles; cadmium; Cd isotope ratios; cement; China; computer software; Contribution rate; dust; environmental quality; fertilizers; food security; geochemistry; heavy metals; Identification; isotope labeling; isotopes; pollution; Pollution sources; topsoil; China; Identification; Pollution sources; Contribution rate; Cd isotope ratios
• ISSN: 0883-2927; 1872-9134
• DOI: 10.1016/j.apgeochem.2020.104776

Anthropogenic activities, especially industrial production and agricultural practices have led to Cd accumulation in the agricultural soil locating near to the industrial areas of China threatening soil environmental quality and food security. In this study, the sources of Cd pollution were accurately analyzed, which may lead to efficiently control the Cd content in the soil. The samples of agricultural topsoil, four possible pollution sources such as smelter dust, automobile exhaust, cement factory dust and agricultural fertilizer were collected, and the Cd concentrations and Cd isotope ratios were analyzed using the instrument of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Multi-collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The results indicated that the Cd concentration of agricultural topsoil (11.72 ± 0.30 mg kg−1) was much higher than the recommended value (0.6 mg kg−1). The highest δ114/110CdNIST3108 value (−0.15 ± 0.14‰) was observed for smelter dust and the lowest δ114/110CdNIST3108 value (−0.64‰) was found in cement factory dust. Similarly, the highest Cd concentration was found in smelter dust and it was clearly distinguishable from the other samples based on δ114/110CdNIST108 values. Cd isotope analysis suggested that smelter along with agricultural fertilizer were the major sources of Cd accumulation in agricultural topsoil. In addition, based on the IsoSource software, the relative Cd contribution rates due to automobile exhaust, cement factory, agricultural fertilizer, and smelter dust were 14%, 7%, 20%, and 59%, respectively, demonstrating that smelter dust is the main pollution source of Cd in the study area. Cd isotope analysis is a promising tool to accurately identify the heavy metal pollution sources. •The highest Cd concentration was observed in smelter dust followed by automobile exhaust and cement factory dust.•The highest δ114/110Cd value was found in the smelter dust samples whereas other three pollution sources showed lower δ114/110Cd values.•Based on IsoSource software, the relative Cd contribution rates of automobile exhaust, cement factory, agricultural fertilizer and smelter dust were 14%, 7%, 20%, and 59%, respectively.