Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, China.
College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China.
Environ Sci Pollut Res Int. 2019 Aug;26(22):22596-22610. doi: 10.1007/s11356-019-04706-0. Epub 2019 Jun 4.
Comprehensive understanding of the influence of soil properties on the potential availability of heavy metals could facilitate soil environment management. This study investigated the distribution of heavy metals and their potential availability in paddy and vegetable fields around electroplating factory outlets and irrigated with its wastewater. The potential availability was assessed using secondary phase fraction (SPF) of heavy metals, including acid-soluble, reducible, and oxidizable fractions resulting from BCR sequential extraction procedure. In total, 94 of topsoil samples (0-20 cm) were collected. Total and SPF concentrations of heavy metals as well as soil physicochemical properties were determined. Multivariable statistical analyses (i.e., principal component analysis (PCA) and redundancy analysis (RDA)) were employed. Results showed that total and SPF concentrations of heavy metals in soil decreased (P<0.05) as sampling distance away from the electroplating factories increased, suggesting that sampling distance was the major parameter that affected gradient variations of both total and potential availability of soil heavy metals. According to PCA, soil samples distributed on the PCA axis representing anthropogenic effect, illustrating that the variation of soil properties resulted from irrigation with electroplating wastewater. RDA and stepwise regression indicated that soil Mn oxides, amorphous Fe oxides, silt content, and pH could explain 68.8% and 43.5% of the variation of SPF concentration in paddy and vegetable garden soil, respectively, suggesting they were the most important factors influencing the potential availability of heavy metals in soils. The potential availability of heavy metals in soil was positively correlated with soil Mn oxides but negatively associated with soil amorphous Fe oxides, indicating that Mn oxides enhanced the potential availability of heavy metals while amorphous Fe oxides reduced the potential availability.
全面了解土壤性质对重金属潜在可利用性的影响有助于土壤环境管理。本研究调查了电镀厂出水口周围稻田和菜地土壤中重金属的分布及其在受其废水灌溉条件下的潜在可利用性。采用重金属二次相态（SPF）评估潜在可利用性，包括 BCR 连续提取程序产生的酸可溶态、可还原态和可氧化态。共采集了 94 个表层土壤样品（0-20cm）。测定了重金属的总量和 SPF 浓度以及土壤理化性质。采用多元统计分析（即主成分分析（PCA）和冗余分析（RDA））。结果表明，随着距电镀厂采样距离的增加，土壤中重金属的总量和 SPF 浓度均降低（P<0.05），表明采样距离是影响土壤重金属总量和潜在可利用性梯度变化的主要参数。根据 PCA，土壤样品分布在代表人为影响的 PCA 轴上，表明土壤性质的变化是由电镀废水灌溉引起的。RDA 和逐步回归表明，土壤 Mn 氧化物、无定形 Fe 氧化物、粉粒含量和 pH 可以分别解释稻田和菜园土壤中 SPF 浓度变化的 68.8%和 43.5%，表明它们是影响土壤重金属潜在可利用性的最重要因素。土壤重金属的潜在可利用性与土壤 Mn 氧化物呈正相关，与土壤无定形 Fe 氧化物呈负相关，表明 Mn 氧化物增强了重金属的潜在可利用性，而无定形 Fe 氧化物降低了重金属的潜在可利用性。
