基于小流域尺度的目标抗生素排放量估算方法——以梅江流域为例

抗生素的大量使用和排放造成的环境污染和生态风险问题日益突出,抗生素排放量的估算是评价流域内抗生素污染程度的重要指标,但目前抗生素排放量估算方法尚不完善。本研究以梅江流域为例,建立了适合小流域尺度的典型抗生素排放量估算方法,计算了四环素类抗生素(TCs)向不同环境相的排放量并分析了其主要来源。结果表明:2016年梅江流域TCs排放量为8 558.1 kg,不同行政区抗生素排放量差异较大,其中梅江镇受人口密度及养殖密度影响,抗生素排放量最大,高达1 224.4 kg;同时流域内不同抗生素的排放量也有所不同,其大小顺序为强力霉素(DXC)土霉素(OTC)四环素(TC)金霉素(CTC);TCs受排放源、排放途径等因素影响,以进入环境水相及土壤相为主,其中进入水相中的抗生素主要来自人类及生猪粪便,进入土壤相中的抗生素主要来自生猪及三黄鸡粪便。梅江小流域抗生素具有潜在的生态风险,应加强抗生素使用管理。该研究为我国小尺度流域目标抗生素排放量的估算提供了十分有效的方法。

Estimation Method of Target Antibiotics Emissions in Small Watershed, Case of Meijiang River Basin

Environmental pollution problems are increasing seriously due to over utilizations and emissions of antibiotics. Estimations of antibiotic emissions are key index on evaluation of antibiotic pollution level in river basin. However, there is a lack of well-founded and commonly accepted estimation method of antibiotics emissions. In this study, an estimation method for typical antibiotics emissions in small watershed is established based on Meijiang River Basin. Emissions of tetracycline antibiotics (TCs), which released into different environment phases, were calculated, and main sources of TCs were analyzed, respectively. The results showed that the total emissions of TCs in Meijiang River Basin were 8 558.06 kg in 2016, and their distribution varied with population and breeding density in different districts, in which Meijiang Town had the largest emissions up to 1 224.4 kg. The emissions of four TCs types in the river basin ranked in the following order: doxycycline>oxtetracycline>tetracycline>chlortetracycline. Affected by emission sources, emission paths, and other factors, TCs were mainly released into soil phase and water phase. TCs detected in the soil phase were mainly from pig and sanhuang chicken manure, and TCs detected in the water phase were mostly from human and pig manure. The result indicates that TCs pollution in Meijiang River Basin may cause potential ecological risk, and therefore the management of antibiotics utilization should be enhanced. This research could provide a very effective method for the estimation of antibiotics emissions in small watersheds of China, as well.