九龙江口微塑料与抗生素抗性基因污染的分布特征

Distribution of Microplastic and Antibiotic Resistance Gene Pollution in Jiulong River Estuary

河口区域普遍存在微塑料(MPs)和抗生素抗性基因(ARGs)污染,同时微塑料还可能富集ARGs,从而扩大ARGs的传播范围.本研究以福建省九龙江口为调查区域,首次分析了九龙江口不同采样点水样以及沉积物中的MPs分布特征,同时测定各样品中8种常见的ARGs丰度,并对二者之间的丰度进行相关性分析.结果表明:(1)九龙江河口水环境中微塑数浓度范围为2~66 n·L^(-1),沉积物中含量范围(以dw计)为8~85 n·kg^(-1),85%以上的微塑料粒径在1 mm以下,微塑料材质主要为聚乙烯(PE)、聚丙烯(PP)和聚苯乙烯(PS);(2)九龙江河口优势的ARGs为四环素类抗性基因tetC和tetG以及磺胺类抗性基因sul2,水中ARGs丰度随盐度增加呈递减趋势;(3)九龙江水体中MPs浓度、 ARGs相对丰度和一类整合子基因intI1丰度呈两两正相关性,说明微塑料可能促进了水体中ARGs的传播和水平基因转移(HGT).

Pollution from microplastics(MPs) and antibiotic resistance genes(ARGs) is prevalent in estuarine regions. MPs may also enrich ARGs and increase the spread of ARGs. This study investigated the distribution characteristics of MPs in surface water and sediments from different stations in Jiulong River estuary for the first time, determined eight common ARGs abundance in each sample, and analyzed the correlation between MPs content and ARGs abundance. The results showed:(1) MPs concentrations in the Jiulong River estuary water environment ranged from 2 to 66 n·L^(-1), and the sediment content range(dw) was 8 to 85 n·kg^(-1). The main materials of MPs detected were polypropylene(PP), polystyrene(PS), and polyethylene(PE). More than 85% of the MPs were smaller than 1 mm.(2) The predominant ARGs in the estuary were tetracycline resistance genes tetC and tetG and sulfonamide resistance gene sul2;the relative abundance of ARGs in the surface water showed a significant negative correlation with salinity.(3) A positive correlation existed among MPs concentration, ARGs relative abundance, and class1 integron gene intI1, which implied that MPs may promote the spread of ARGs in seawater.