A large-scale field investigation revealing the distribution characteristics of arsenic in earthworm tissues

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发表日期：

2024年3月23日

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An Yang,
Dong Zhu,
Tingting Zhu,
Bowen Liu,
Hongtao Wang,
Yuanhu Shao,
Weixin Zhang,
Yulong Wang,
Shenglei Fu

摘要

Arsenic characteristics in earthworms and soils across 47 sites in China were studied.

Earthworm tissues showed lower arsenic levels than surrounding soils.

Higher arsenite to arsenate ratio was observed in earthworm tissues.

Positive correlation of arsenic levels in earthworm tissues with soil nitrate.

The total arsenic (As) and As species of earthworm body tissues and surrounding soils were investigated in 47 locations (16 forested lands and 31 agricultural lands) at a national scale across China using inductively coupled plasma-mass spectrometer (ICP-MS) and high-performance liquid chromatography-inductively coupled plasma-mass spectrometer (HPLC-ICP-MS). Earthworm body tissues had an average total As concentration of 6.21 mg kg⁻¹, significantly lower than the soil As concentration of 12.99 mg kg⁻¹. The ratio of arsenite to arsenate (As^III/As^V ratio) in earthworm body tissues (67%) was significantly higher compared to that in surrounding soils (19%). HPLC-ICP-MS analysis detected small amounts of organic As forms, such as arsenobetaine (2.9%), dimethylarsinic acid (1%), and monomethylarsonic acid (0.3%), mainly in earthworm tissues from certain locations. The total As content and As^III/As^V ratio in earthworm tissues exhibited a strong positive correlation with soil NO₃⁻ content. This field study enhances our understanding of As concentration and speciation in earthworm body tissues across China, contributing valuable insights into the biogeochemical cycle of As and its biological risks in diverse soil ecosystems. These findings provide crucial evidence for policymakers to formulate strategies addressing and mitigating soil As pollution and associated health risks.