Abstract:

Antibiotics introduced into the soil undergo various environmental processes, leading to environmental pollution. This paper summarizes the source, pollution status, and environmental behavior of antibiotics in soil. It systematically outlines the functional groups and molecular structure of antibiotics, along with the fundamental principles and mechanisms that influence adsorption in soil, such as soil type, pH, coexisting ions, and organic matter. Antibiotics in soil primarily originate from animal husbandry and medical waste, with tetracyclines, sulfonamides, macrolides and quinolones being the main types. These antibiotics persist in the soil through processes such as bioaccumulation and adsorption, which can lead to the emergence of resistance genes or cross-contamination with other pollutants, posing ecological risks. Antibiotics containing ionizable groups, such as hydroxyl, carboxyl and amino groups, as well as diverse molecular structures, exhibit different acid dissociation constants. They are adsorbed by the soil through mechanisms such as H bond, π-π interaction, metal ion complexation, deprotonation and cation exchange. Soils with fine particles, fine texture, and larger specific surface area and pore volumes provide more adsorption sites, making it easier for antibiotics to be adsorbed. Soil charge also plays a crucial role; when the valence state of the soil charge matches that of antibiotics, it inhibits adsorption, while the opposite promotes it. Organic matter enhances antibiotic adsorption by competing for adsorption sites through functional groups such as hydroxyl and carboxyl. Acidic metal ions like Al³⁺ and Fe³⁺ act as a bridge and promote antibiotic adsorption, whereas alkaline metal ions (K⁺, Na⁺, Ca²⁺ and Mg²⁺) compete for sites and inhibit adsorption. In addition, microorganisms in the soil that produce extracellular enzymes such as β-lactamases and aminoglycoside hydrolases can decompose antibiotics. Plant roots can secrete organic acids and sugars to interact with antibiotics. Future efforts may focus on using humus soil with high organic matter and ion content can be used to develop contaminated soil amendments for in-situ remediation of contaminated soil, or making use of minerals to develop efficient and cost-effective adsorption materials. It is also recommended to conduct more research on multiple compound pollution systems and develop multi-mechanism prediction models.

Key words: antibiotics, soil, adsorption, influencing factor, action mechanism, antibiotic treatment

摘要：

抗生素进入土壤后会发生一系列环境行为，造成环境污染。该文梳理了土壤中抗生素的来源、污染现状和环境行为，系统总结抗生素的官能团和分子结构以及土壤的类型、pH、共存离子和有机质影响抗生素在土壤中吸附的基本规律以及作用机制。土壤中抗生素主要来源于畜牧和医疗产生的废弃物；主要有四环素类、磺胺类、大环内酯类和喹诺酮类；通过生物蓄积和吸附作用残留在土壤中，诱导抗性基因产生或与其他污染物交叉污染造成生态风险。具有羟基、羧基、胺基等可电离基团和不同分子结构的抗生素，存在不同酸解离常数，通过H键作用、π-π相互作用、金属离子络合作用、去质子化作用和阳离子交换等机制被土壤吸附；颗粒细小，质地细腻，具有较大比表面积和孔隙体积的土壤会暴露更多吸附位点，更容易吸附抗生素；土壤存在可变电荷，土壤电荷与抗生素的价态相同会抑制抗生素吸附，反之则促进；有机质通过羟基、羧基等官能团增强抗生素吸附，或与抗生素竞争土壤吸附位点抑制抗生素吸附；Al³⁺、Fe³⁺等酸性金属离子，作为抗生素与土壤颗粒联结的桥梁促进抗生素吸附；K⁺、Na⁺、Ca²⁺和Mg²⁺等碱性金属离子，竞争吸附位点抑制抗生素吸附。此外，土壤中能产生β-内酰胺酶、氨基糖苷类水解酶等胞外酶的微生物可以分解抗生素；植物根系可以分泌有机酸和糖类与抗生素相互作用。未来可利用有机质、离子含量较高的腐殖土研发污染土壤改良剂用于污染土壤原位修复，或利用矿物研发高效低成本的吸附材料；并加强多重复合污染体系与多机制预测模型研究。

关键词: 抗生素, 土壤, 吸附, 影响因素, 作用机制, 抗生素治理