National Demonstration Center for Environmental and Planning, College of Environment and Planning, Henan University, Kaifeng, 475004, China.
Henan Engineering Research Centre for Control & Remediation of Soil Heavy Metal Pollution, Henan University, Kaifeng, 475004, China.
Environ Sci Pollut Res Int. 2023 Nov;30(54):115994-116003. doi: 10.1007/s11356-023-30640-3. Epub 2023 Oct 28.
Copper (Cu) and tetracyclines (TCs) often coexist in agricultural soils because of the use of manures on farmland; however, the influence of Cu on the bioavailability of TCs is still unclear, especially for cases with aging Cu. The freely dissolved concentrations (FDCs) of TCs are believed to be directly related to their bioavailability. In the present study, the FDCs of TCs were determined using organic-diffusive gradients in thin films (o-DGT), and the influence of Cu on the FDCs of TCs in soils was evaluated. The results showed that the FDCs of tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC) were 0.11-0.93, 0.28-1.02, and 0.24-0.53 μg/kg in the CK groups (no Cu added) and accounted for 0.09-0.58, 0.10-1.40, and 0.05-1.19‰ of their total concentrations which ranged from 0.2 to 10.0 mg/kg for TC, OTC, and CTC, respectively. The co-contamination of Cu reduced the FDCs of TCs in most cases, and aging increased the influence of Cu. The presence of Cu resulted in a decrease in the TC FDC by 35.48-95.04% in aged soils and 3.42-87.19% in newly prepared soils. FTIR analysis revealed that aging facilitated the bonding of Cu to soil particles via Cu-O, and Cu bonded to groups such as hydroxyl groups (-OH) in TCs. Our results suggested that the presence of Cu might reduce the bioavailability of TCs, and aging would enhance these effects. This is helpful for the bioavailability analysis of TCs under co-contamination of heavy metals.
铜（Cu）和四环素类（TCs）经常共存于农业土壤中，因为农田使用了粪便；然而，Cu 对 TCs 生物有效性的影响仍不清楚，特别是对于 Cu 老化的情况。TCs 的自由溶解浓度（FDCs）被认为与它们的生物有效性直接相关。在本研究中，使用有机扩散梯度薄膜（o-DGT）测定了 TCs 的 FDCs，并评估了 Cu 对土壤中 TCs 的 FDCs 的影响。结果表明，在 CK 组（未添加 Cu）中，四环素（TC）、土霉素（OTC）和金霉素（CTC）的 FDCs 分别为 0.11-0.93、0.28-1.02 和 0.24-0.53μg/kg，占其总浓度的 0.09-0.58、0.10-1.40 和 0.05-1.19‰，TC、OTC 和 CTC 的总浓度范围分别为 0.2-10.0mg/kg。Cu 的共污染在大多数情况下降低了 TCs 的 FDCs，而老化增加了 Cu 的影响。Cu 的存在导致老化土壤中 TC 的 FDC 降低了 35.48-95.04%，新制备的土壤中降低了 3.42-87.19%。FTIR 分析表明，老化通过 Cu-O 促进 Cu 与土壤颗粒的结合，Cu 与 TCs 中的羟基（-OH）等基团结合。我们的结果表明，Cu 的存在可能会降低 TCs 的生物有效性，而老化会增强这些效应。这有助于重金属共污染下 TCs 生物有效性的分析。
