珠江口伶仃洋水域沉积物中多环芳烃及其生态风险评价

为了研究珠江口伶仃洋水域沉积物中多环芳烃(PAHs)的分布特征、来源及评价PAHs对海洋生物的生态风险,于2010年6月采集珠江口伶仃洋水域20个站位的表层沉积物,采用GC-MS分析方法对沉积物中的16种PAHs含量进行分析测定。研究结果表明:珠江口伶仃洋水域沉积物中16种多环芳烃总含量范围是143.90~522.67 ng/g,平均含量287.05 ng/g,与国内外发达地区相比,该水域沉积物中PAHs污染处于中等水平。本实验采用目前较为常用的比值法(如荧蒽/芘、芘/苯并(a)芘)对调查区域沉积物中的PAHs来源进行分析研究,结果表明,大部分站位沉积物中的PAHs可能主要来源于石油污染,仅一小部分站位PAHs来源于煤等化石燃料的燃烧。利用效应区间低中值法评价珠江口伶仃洋水域沉积物中PAHs的生态风险,结果表明,在所设的20个站位中,有3个站位处的沉积物中的苊和芴对生物可能具有一定的生态风险,而其他站位沉积物中所有PAHs的含量均未达到生态风险评价标准,可以确定该水域沉积物中PAHs对生物具有潜在生态风险的可能性很小;有9个站位处的沉积物中的茚并(1,2,3-c,d)芘对生物可能存在生态风险;利用平均效应中值商法评价PAHs对珠江口伶仃洋水域的生态风险,认为所有站位处PAHs对生物体的潜在的综合生态风险的可能性较小。

Polycyclic aromatic hydrocarbons and risk assessment in the surface sediments from Lingdingyang, Pearl River Estuary

Polycyclic aromatic hydrocarbons(PAHs) have two or more benzene rings,are persistent in the envi-ronment,and are carcinogenic,teratogenic,and mutagenic to most organisms,including humans.We evaluated the distribution and source of PAHs near Lingdingyang in the Pearl River Estuary.We measured the concentration of sixteen polycyclic aromatic hydrocarbons(PAHs) in the surface sediments collected at 20 sites in June,2010 using GC-MS.We detected 15 PAHs at all sites,but the distribution of the remaining PAHs was uneven.Concentrations ranged from 143.9–522.67 ng/g(mean: 287.05 ng/g),and were not particularly high when compared with other developed areas throughout the world.The highest levels occurred near the NanSha port of GuangZhou and Shenzhen Baoan district.This is likely due to discharge from logistics,oil,and auto manufacture.The PAHs were divided into five groups based on the number of rings(maximum = 3).We used the isomer ratios(e.g.,phenan-threne/anthracene and fluoran-thene/pyrene) to assess the origins of PAHs.The ratio of fluoranthene/pyrene was below 1 at 85% of sites,suggesting that the contribution of petroleum to PAHs was high,and that coal fuel com-bustion contributed relatively little.To confirm this,we used the Pyr/B(a)P ratio method and obtained similar re-sults.We used the low-mid level of the effect range and the quotient of the mid-value of the mean effect to assess the ecological risk.Our analysis suggests that the risk to organisms is small if the PAH content is lower than the ERL.However,if the PAH content is between the ERL and ERM,there may be some risk and if the content is >ERM,the risk is high.The levels of two PAHs(Ace and Fl) were between the ERL and ERM at three sites.All other PAHs were below the ERL,so posed little risk.We detected high molecular weight PAHs I(1,2,3)P] at 9 sites.These PAHs have no minimum safety value so likely pose a risk to organisms living at these sites.All MERM-Q values were below 0.1 indicating that the risk was low at all sites.