Laboratoire Hydrologie et Environnement, EPHE, UMR Sisyphe 7619, UPMC-Paris 6, 4 place Jussieu, BC 105, 75252 Paris Cedex, France.
Sci Total Environ. 2011 Jan 1;409(3):540-7. doi: 10.1016/j.scitotenv.2010.10.033. Epub 2010 Nov 18.
Spreading of urban wastewater on agricultural land may lead to concomitant input of organic and inorganic pollutants. Such multiple pollution sites offer unique opportunities to study the fate of both heavy metals and pharmaceuticals. We examined the occurrence and fate of selected antibiotics in sandy-textured soils, sampled four years after cessation of 100 years irrigation with urban wastewater from the Paris agglomeration. Previous studies on heavy metal contamination of these soils guided our sampling strategy. Six antibiotics were studied, including quinolones, with a strong affinity for organic and mineral soil components, and sulfonamides, a group of more mobile molecules. Bulk samples were collected from surface horizons in different irrigation fields, but also in subsurface horizons in two selected profiles. In surface horizons, three quinolones (oxolinic acid, nalidixic acid, and flumequine) were present in eight samples out of nine. Their contents varied spatially, but were well-correlated one to another. Their distributions showed great similarities regarding spatial distribution of total organic carbon and heavy metal contents, consistent with a common origin by wastewater irrigation. Highest concentrations were observed for sampling sites close to irrigation water outlets, reaching 22 μg kg(-1) for nalidixic acid. Within soil profiles, the two antibiotic groups demonstrated an opposite behavior: quinolones, found only in surface horizons; sulfamethoxazole, detected in clay-rich subsurface horizons, concomitant with Zn accumulation. Such distribution patterns are consistent with chemical adsorption properties of the two antibiotic groups: immobilization of quinolones in the surface horizons ascribed to strong affinity for organic matter (OM), migration of sulfamethoxazole due to a lower affinity for OM and its interception and retention in electronegative charged clay-rich horizons. Our work suggests that antibiotics may represent a durable contamination of soils, and risks for groundwater contamination, depending on the physicochemical characteristics both of the organic molecules and of soil constituents.
农业土地上的城市污水扩散可能导致有机和无机污染物的同时输入。这种多污染地点为研究重金属和药物的命运提供了独特的机会。我们研究了在停止使用巴黎城市群城市污水灌溉 100 年后的沙质土壤中选定抗生素的出现和命运。对这些土壤重金属污染的先前研究指导了我们的采样策略。研究了六种抗生素，包括与有机和矿物土壤成分具有强烈亲和力的喹诺酮类药物，以及一组更具移动性的分子磺胺类药物。在不同灌溉场的表层采集了大量样本，但在两个选定剖面的次表层也采集了样本。在表层，九份样本中有八份存在三种喹诺酮类药物（奥索林酸、萘啶酸和氟甲喹）。它们的含量在空间上有所变化，但彼此之间相关性很好。它们的分布与总有机碳和重金属含量的空间分布非常相似，这与通过污水灌溉的共同来源一致。在靠近灌溉出水口的采样点观察到最高浓度，萘啶酸的浓度达到 22μgkg-1。在土壤剖面中，这两种抗生素组表现出相反的行为：喹诺酮类药物仅存在于表层；磺胺甲恶唑在富含有机质的次表层中检测到，同时伴随着 Zn 的积累。这种分布模式与两种抗生素组的化学吸附特性一致：由于与有机物（OM）的强亲和力，喹诺酮类药物在表层中固定化；磺胺甲恶唑由于对 OM 的亲和力较低而迁移，并在带负电荷的富含粘土的层次中被截留和保留。我们的工作表明，抗生素可能代表土壤的持久污染，并取决于有机分子和土壤成分的物理化学特性，对地下水污染构成风险。
