Using bald eagles to indicate the health of the Great Lakes' environment

The bald eagle (Haliaeetus leucocephalus) is one of the most studied birds of North America, and a great amount of natural life‐history information, including the response of various stressors on the eagles' ability to reproduce, are well known. In Michigan, the eagle has been chosen to track the trends of bioaccumulative compounds of concern across watersheds in the state. The state has been divided into major watersheds, and 20% of these are surveyed each year. A control area in northern Minnesota, Voyageurs National Park, is also sampled annually. We report here on the methods used, the preliminary results of the 1999 field season, and how differences in mercury concentrations varied over a 10‐year period. Mercury in feathers of nestling eagles declined over time only in Lakes Michigan and Huron, but have not decreased among other subpopulations in Michigan. Concentrations of polychlorinated biphenyls (PCBs) and 4,4′‐DDE in blood plasma from nestling eagles have declined over time for most subpopulations; however, they remain greater for breeding areas associated with the Great Lakes' food web. Sea eagles of the genus Haliaeetus are a good sentinel species to track trends in bioaccumulative compounds in aquatic systems.     

Organochlorine Contaminants of Wintering Ducks Foraging on Detroit River Sediments

Organochlorine analysis was performed on carcasses of 13 diving ducks from a 1981 wintering population that foraged on contaminated sediments in the lower Detroit River. Mean total PCB concentrations were 10 mg/kg for seven lesser scaups (Aythya affinis), 11 mg/kg for three greater scaups (A. marila), and 7.6 mg/kg for three goldeneyes (Bucephala clangula). Highest mean levels of other residues were measured for hexachlorobenzene (1.7 mg/kg) in goldeneyes, and transnonachlor (0.33 mg/kg) and 4,4’-DDE (1.3 mg/kg) in greater scaup. Quantitative analysis of 72 PCB congeners also was applied to water, seston, sediment, benthie oligochaetes, and carp from the same site. Principal congeners in most of the samples included some of the more toxic and persistent PCBs. Results of a multivariate analysis indicated that ratios of more conservative to less conservative PCBs did not vary significantly among ducks (α = .05), but differed from those in carp, oligochaetes, and sediment. For the February through March period of fat mobilization, concentrations of total PCB in lipid were inversely correlated with percent lipid (r = 0.76) in ducks. The percentage of conservative PCBs increased slightly. The distribution and partitioning of organochlorines, including toxic PCB congeners, varied considerably within this water column-sediment-fauna ecosystem. Estimates of toxic exposure based on total PCB values may be unreliable.     

Preliminary Assessment of Contaminants in Soft Sediments of the Detroit River

Soft sediments from the Detroit River were analyzed for the USEPA priority pollutants to generally characterize contaminant distribution. Forty-three were detected. Highest heavy metal concentrations were found in the Trenton Channel and immediately downstream of Grosse Ile. They ranged from an area mean (N = 2) of 0.19 mg/kg mercury to 338.7 mg/kg zinc (dry weight). Polynuclear aromatic hydrocarbons ranged from 0.1 mg/kg to 38.8 mg/kg (mean, N = 2) with the highest levels near Grosse Ile. PCBs ranged from 0.015 mg/kg to 1.7 mg/kg (mean, N = 2). Organochlorine pesticides were not detected except for a trace of heptachlor in one sample. Sediment contamination in the Detroit River is widespread with higher concentrations on the U.S. side downstream of the Rouge River and in the Trenton Channel. The significance of these in-place pollutants to biota and as a source to Lake Erie is still unknown.     

固相萃取净化-气相色谱-质谱法测定染料中7种指示性多氯联苯

本文建立了以固相萃取(SPE)前处理净化、结合气相色谱-质谱(GC-MS)测定染料中7种指示性多氯联苯的分析方法。该法将染料样品经溶剂萃取后,通过固相萃取(SPE)净化、浓缩,气相色谱-质谱采用选择离子监测模式(SIM)测定,以保留时间和特征离子定性,外标法定量。     

多氯联苯（PCBS）分配系数的估算和预测

基于烷烃分子距边矢量,将以原子为基准的距离－边数 量扩展为以基团为基准的距离－边数矢量。研究发现新分子距边矢量与多氯联苯正辛醇／水分配系数的对数有很好的线性关系：ｌｏｇＫｏｗ＝４．１０８８４＋０．５２４２３７ｕ１－０．０９２９０６２ｕ２ｎ＝３７,ｒ＝０．０９９０８,Ｓ＝０．１７７５,ＥＶ＝０．９８１１,Ｆ＝１８６８。     

多氯代9,10-菲醌的热力学性质及稳定性的理论研究

采用密度泛函理论(DFT),在B3LYP/6-31G*水平上对135个多氯9,10-菲醌(PCPQ)系列化合物进行全优化和振动分析,得到各分子在298.15K,101.3kPa状态下的热力学参数。设计等键反应,计算了PCPQ系列化合物的标准生成焓(ΔfHθ)和标准生成自由能(ΔfGθ)。用SPSS13.0对这些热力学参数与氯原子的取代位置及取代数目(NPCS)进行多元线性回归,得出相关方程。结果表明:PCPQ系列化合物的Sθ、ΔfHθ和ΔfGθ与NPCS之间有很强的相关性。根据异构体标准生成自由能的相对大小,从理论上求得异构体的相对稳定性。同时,发现氯原子取代模式对扭角(C-C(=O)-C(=O)-C)有很大的影响。     

加速溶剂萃取/GC-ECD分析土壤中多氯联苯的研究

为研究加速溶剂萃取土壤中的多氯联苯的方法,以土壤中8种多氯联苯为标样,进行了加速溶剂提取实验,并用佛罗里硅土柱净化,再用GC ECD气相色谱仪测定。实验优化了萃取条件,在20 g土壤样中添加50 ng多氯联苯混标,在实验温度100℃,萃取压力为10.3 MPa,萃取时间为20 min条件下用35 mL丙酮/正己烷混合液提取,并用GCECD测得多氯联苯回收率为95.63%~100.2%;相对标准偏差为0.95%~9.58%;方法检出限为0.089~0.882 ng/g。为进行比较,同时进行了超声波辅助提取和索式提取实验。结果表明:加速溶剂提取时间短,有机溶剂用量少,并且提取回收率高。     

无机盐离子对鼠李糖脂增溶多氯联苯的影响研究

探讨了几种具代表性的无机盐离子对鼠李糖脂(RL)增溶2,2’,4,4’-四氯联苯的影响。结果表明,适当增加Na+、Mg2+、Ca2+的浓度对RL增溶2,2’,4,4’CB有显著的促进作用,且Mg2+的促进作用比Na+的大,但当Mg2+浓度大于0.8 mmol/L时,促进作用减弱。当Ca2+浓度超过0.2mmol/L时,RL开始产生沉淀,导致RL对2,2’,4,4’CB的增溶作用逐渐降低。无机阴离子对RL增溶2,2’,4,4’CB的影响很小。     

Mammalian Cytochrome P450-Dependent Metabolism of Polychlorinated Dibenzo-p-dioxins and Coplanar Polychlorinated Biphenyls

Polychlorinated dibenzo-p-dioxins (PCDDs) and coplanar polychlorinated biphenyls (PCBs) contribute to dioxin toxicity in humans and wildlife after bioaccumulation through the food chain from the environment. The authors examined human and rat cytochrome P450 (CYP)-dependent metabolism of PCDDs and PCBs. A number of human CYP isoforms belonging to the CYP1 and CYP2 families showed remarkable activities toward low-chlorinated PCDDs. In particular, human CYP1A1, CYP1A2, and CYP1B1 showed high activities toward monoCDDs, diCDDs, and triCDDs but no detectable activity toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-tetraCDD). Large amino acids located at putative substrate-recognition sites and the F-G loop in rat CYP1A1 contributed to the successful metabolism of 2,3,7,8-tetraCDD. Rat, but not human, CYP1A1 metabolized 3,3'',4,4'',5-pentachlorobiphenyl (CB126) to two hydroxylated metabolites. These metabolites are probably less toxic than is CB126, due to their higher solubility. Homology models of human and rat CYP1A1s and CB126 docking studies indicated that two amino acid differences in the CB126-binding cavity were important for CB126 metabolism. In this review, the importance of CYPs in the metabolism of dioxins and PCBs in mammals and the species-based differences between humans and rats are described. In addition, the authors reveal the molecular mechanism behind the binding modes of dioxins and PCBs in the heme pocket of CYPs.     

Partitioning of PCBs from air to clothing materials in a Danish apartment

Polychlorinated biphenyl (PCB) contamination of buildings continues to pose an exposure threat, even decades after their application in the form of calks and other building materials. In this research, we investigate the ability of clothing to sorb PCBs from contaminated air and thereby influence exposure. The equilibrium concentration of PCB‐28 and PCB‐52 was quantified for nine used clothing fabrics exposed for 56 days to air in a Danish apartment contaminated with PCBs. Fabric materials included pure materials such as cotton and polyester, or blends of polyester, cotton, viscose/rayon, and/or elastane. Air concentrations were fairly stable over the experimental period, with PCB‐28 ranging from 350 to 430 ng/m³ and PCB‐52 ranging from 460 to 550 ng/m³. Mass accumulated in fabric ranged from below detection limits to 4.5 mg/g of fabric. Cotton or materials containing elastane sorbed more than polyester materials on a mass basis. Mass‐normalized partition coefficients above detection limits ranged from 10^5.7 to 10^7.0 L/kg. Clothing acts as a reservoir for PCBs that extends dermal exposure, even when outside or in uncontaminated buildings.