【摘要】 沉积物被认为是水环境中污染物残留程度的"指示剂",能够客观地反映其污染状况。本文开展了滇池草海及其入湖河口国家监控断面表层沉积物中优先控制的16种PAHs污染特征及其风险评估研究,阐明了这类污染物的残留水平、分布、组成、来源、随季节变化情况等,评估了该湖区范围存在的生态环境风险,为该流域PAHs的防治对策制定提供依据。结果表明:PAHs在草海及其入湖河口沉积物中均有检出,ΣPAHs在雨季和旱季残留水平分别为706~11510 ng/g和787~12271 ng/g;草海北部区域PAHs的残留量相对较高,对生态环境构成了较大地潜在危害;PAHs残留主要以中环芳烃为主,高环和低环芳烃次之;TEQs和TEQcarc的值由高到低的顺序均为:S1>R1>R3>R2>S3>R4>R5>S2;8种致癌性PAHs在一定程度上能够反映沉积物中PAHs的潜在毒性;源解析表明该地区PAHs主要来自燃烧源,且以生物质燃烧为主导;与国内外污染状况相比,草海及其入湖河口PAHs残留水平处于中等水平,而d Ban A、Ba P、Bb F和Ba A所占比重较大,应被列为PAHs污染治理的重点。更多还原

【Abstract】 Sediment is identified as the indicator on residual levels of persistent toxic substances(PTS) in aquatic environments, which can reflect the whole pollution status. Pollution characteristics and risk assessment of the sixteen PAHs controlled priority in surface sediment collected from the National Water Quality Monitoring Stations in Lake Caohai and its estuaries were investigated. The objectives were to track their contamination levels, distribution characteristics, composition transformations, sources and seasonal variability, and to provide more comprehensive fundamental data for risk assessment and contamination control of PAHs in the valley. Residuals of PAHs in Lake Caohai and its estuaries were found ubiquitously. Residual levels of ΣPAHs in wet and dry season were up to 706~11510 and 787~12271 ng/g, respectively. High residuals of PAHs in northern areas of Lake Caohai could pose potential risk to aquatic organisms. Medium molecular weight PAHs were dominant, followed by high and less molecular weight PAHs. Values of TEQs and TEQcarc in the sampling sites were ranked in the order of S1>R1>R3>R2>S3>R4>R5>S2. To some extent, the eight carcinogenic PAHs represented the toxic potential of PAHs. The PAHs in the region came mainly from combustion sources, especially biomass burning. Compared with other regions and countries, residual levels of PAHs in Lake Caohai and its estuaries were amoderate. The d Ban A, Ba P, Bb F and Ba A, as the four dominant PAHs, should be listed as the priority controlled contaminations in the valley.更多还原