典型城郊土地利用格局对水体抗生素的影响研究

阐明城郊地区土地利用格局对水环境中抗生素的影响，对维持城乡共生体水土安全和保障人居环境健康有重要意义.本研究基于典型城郊流域的定位监测，比较了不同等级子流域水体抗生素的组成、浓度和分布特征，探讨了土地利用格局对水体抗生素的影响.结果表明，研究区水体中抗生素浓度为1.126~54.236 ng·L^-1，不同等级子流域水体抗生素的种类和浓度有较大的差异.子流域土地利用结构与水体抗生素的种类和浓度密切相关，由主坐标分析（PCoA）可知，具有相似土地利用结构的子流域水体抗生素组成和浓度具有相似性.相关分析表明，子流域中城镇、农田和林地的面积比例与水体中四环素类抗生素（TCs）的浓度密切相关，而园地面积比例与水体中磺胺类抗生素（SAs）的浓度关系密切.耦合景观格局分析表明，水体抗生素总浓度与香农多样性指数（SHDI）和蔓延度指数（CONTAG）呈显著相关性（p<0.05）；四环素类抗生素与边界密度（ED）、香农多样性指数、均匀度指数（SHEI）、蔓延度指数和聚集度指数（AI）呈显著相关性（p<0.05）.通过构建逐步回归模型进一步表明，水体抗生素的浓度与园地、林地面积和香农多样性指数关系密切.研究结果表明受人类活动干扰程度大、景观破碎化较为严重的区域水体抗生素的浓度较高.

Effect of land use pattern on antibiotics in surface water in typical peri-urban area

Identifying the effects of land use patterns on antibiotics in surface water is an important issue in sustaining water security and guaranteeing human health in urban and rural systems. A typical peri-urban watershed located in Ningbo City was selected as study area. Based on surface water monitoring and laboratory analysis, types and concentrations of antibiotics in surface water were identified and compared between 16 different sub-watersheds, and the effects of land use patterns on antibiotics in surface water were explored. Results of this study showed that total concentrations of antibiotics in surface water ranged from 1.126 ng·L^-1 to 53.739 ng·L^-1. Considerable differences in types and concentrations of antibiotics in surface water were found in different sub-watersheds. Correlation analysis showed that area proportion of urban, cropland and forestland were closely related to concentration of tetracyclines (TCs) in surface water, and the area proportion of garden had a close correlation with concentration of sulfonamides (SAs). In considering land use patterns in different sub-watersheds, it was found that the total concentration of antibiotics in surface water was substantially correlated with Shannon''s Diversity Index (SHDI) and Contagion (CONTAG). Furthermore, concentrations of tetracyclines in surface water were found to have close correlations with Edge Density (ED), Shannon''s Diversity Index, Shannon''s Evenness Index (SHEI), Contagion, and Aggregation Index (AI). Results of regression analysis in considering land use and landscape indices indicated that antibiotic pollution in surface water was substantially affected by the area of garden, forestland and Shannon''s Diversity Index. In addition, the results indicated that area with relatively high human activities and landscape fragmentation usually has relatively higher concentration of antibiotics in surface water.