Effects of atmospheric deposition on heavy metal contamination in paddy field systems under different functional areas in ChangZhuTan, Hunan Province, China

• Published in: The Science of the total environment 2024-07, Vol.933, p.172953-172953, Article 172953
• Main Authors: Yu, Pengyue, Shao, Xingyuan, Wang, Maodi, Zhu, Zhen, Tong, Zhenglong, Peng, Jianwei, Deng, Yaocheng, Huang, Ying
• Format: Article
• Language: English
• Subjects: atmospheric deposition; Cadmium; China; environment; Foliar uptake; health effects assessments; heavy metals; human health; paddies; paddy soils; pollution; Potential health risk assessment; Rice; risk; roadsides; Translocation
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.172953

In recent decades, the problem of heavy metal contamination in rice paddies has attracted widespread attention. However, most studies on heavy metal contamination in paddy fields are biased towards soil and/or rice plants, without taking atmospheric deposition into account. In this study, atmospheric deposition, paddy soil, and rice samples were collected from three functional areas (area proximity to factories, along the roadside, and suburban) in ChangZhuTan, Hunan Province. The pollution characterization, translocation, and health risk of heavy metals were reassessed. The findings revealed that Cd and As contamination in the study area's soils was more severe, with point exceedance rates reaching 70 % and 35.9 %, respectively. The highest concentrations of As, Ni, Cd, and Pb in atmospheric deposition were found along the roadside, with 1.42 μg/m2/day, 3.21 μg/m2/day, 0.34 μg/m2/day, and 8.28 μg/m2/day, respectively. In area proximity to factories, As and Ni in atmospheric deposition showed to be lowest, whereas Cd and Pb concentrations showed lowest in suburban areas. Furthermore, the accumulation of Cd and Pb in rice grains in regions proximity to factories was significantly higher than in other regions. The human health risk assessment indicated the health risk caused by rice intake in areas proximity to factories was the highest and requires attention, which was mainly due to Cd accumulation, with HQ value reached 3.19. Correlation tests indicate that atmospheric deposition has a positive effect on heavy metal enrichment in rice grains. Further Random Forest analysis revealed that the transport of heavy metals from atmospheric deposition to leaves and shells were important influencing factors for As, Cd, Ni and Mg accumulation in rice grain. Therefore, more attention should be paid to the effects of atmospheric deposition on the accumulation of heavy metals in paddy fields in order to maintain the production safety of crops. [Display omitted] •The contamination characteristics of heavy metals in paddy fields (atmospheric deposition, soils and rice) were analyzed•Soil Pb contents were all lower than standard (100 mg/kg), while 71.8% rice samples exceeded food safety standard (0.2mg/kg)•Atmospheric deposition was an important contributor to Cd and Pb accumulation in rice grain•As, Cd, and Pb had the largest impacts on human health risks