College of Environment and Public Health, Xiamen Huaxia University, Xianen, 361024, China; Key Laboratory of Fujian Universities for Environmental Monitoring, Xiamen, 361024, China.
College of Environment and Public Health, Xiamen Huaxia University, Xianen, 361024, China.
Environ Pollut. 2023 Jun 1;326:121489. doi: 10.1016/j.envpol.2023.121489. Epub 2023 Mar 21.
The source apportionment and transfer of Pb in a paddy soil-rice-human system within the Jiulong River Basin in southeast China was investigated by analyzing (1) the chemical fractionation of Pb in paddy soils using a modified BCR four-step sequential extraction procedure, and (2) the bioaccessibility of Pb in both paddy soils and rice grains using a Simple Bioaccessibility Extraction Test method. In addition, a qualitative Pb isotopic model was used in combination with IsoSource software to quantify the contribution of potential Pb sources. The results show the enrichment of Pb in agro-ecosystems in the Jiulong River Basin. Contaminant Pb in paddy soils was mainly present in the reducible (42.9%) and the residual fractions (27.1%). The average bioaccessibility of Pb in rice grains was significantly higher than that in paddy soil, with values of 77.85% and 37.44%, respectively. Lead in paddy soils was primarily derived from agricultural (35.3%), natural (25.5%), industrial (24.5%) and coal combustion sources (14.7%), while Pb in rice grains was primarily derived from coal combustion (54.1%), agricultural (35.1%), industrial (6.0%) and natural sources (4.8%). The bioaccessible Pb was mainly derived from anthropogenic sources [agricultural (42.3% for soil and 25.3% for grain) and coal combustion sources (25.3% for soil and 59.3% for grain)]. Lead isotopic ratios are an effective tracer of Pb transfer from potential sources to rice plants and within the rice plants. Rice plants absorb Pb from the soil and the atmosphere through the roots and leaves, respectively. Most of the Pb was accumulated in roots. The integrated use of chemical fractionation, bioaccessibility and Pb isotopic data provides an effective method to study the source apportionment and transfer characteristics of Pb in paddy soil-rice-human systems.
采用改进的 BCR 四步连续提取法分析了中国东南地区九龙江流域稻田土壤-水稻-人类系统中 Pb 的源解析和迁移，（1）利用改进的 BCR 四步连续提取法分析了土壤中 Pb 的化学形态，（2）利用简单生物可提取性提取试验法分析了土壤和水稻籽粒中 Pb 的生物可提取性。此外，还使用定性 Pb 同位素模型结合 IsoSource 软件定量量化了潜在 Pb 源的贡献。结果表明，九龙江流域农业生态系统中 Pb 含量丰富。土壤中 Pb 主要以可还原态（42.9%）和残渣态（27.1%）存在。水稻籽粒中 Pb 的平均生物可提取率明显高于土壤，分别为 77.85%和 37.44%。土壤中 Pb 主要来源于农业（35.3%）、自然（25.5%）、工业（24.5%）和煤炭燃烧源（14.7%），而水稻中 Pb 主要来源于煤炭燃烧源（54.1%）、农业（35.1%）、工业（6.0%）和自然源（4.8%）。可提取 Pb 主要来源于人为源[农业（土壤中为 42.3%，籽粒中为 25.3%）和煤炭燃烧源（土壤中为 25.3%，籽粒中为 59.3%）]。Pb 同位素比值是示踪 Pb 从潜在源向水稻植株及植株内迁移的有效示踪剂。水稻植株通过根和叶分别从土壤和大气中吸收 Pb。大部分 Pb 积累在根部。化学形态、生物可提取性和 Pb 同位素数据的综合应用为研究稻田土壤-水稻-人类系统中 Pb 的源解析和迁移特征提供了一种有效的方法。
