青岛市市售贝类中多环芳烃与多氯联苯的含量水平、组成特征及居民健康影响风险评估

目的　通过分析青岛市贝类中多氯联苯（PCBs）和多环芳烃（PAHs）含量水平和组成特征,对本市市售贝类的居民食用健康进行初步评估。方法　全市采集200份贝类样品采用气相色谱-质谱法测定贝类中PCBs与PAHs的含量;利用其平均含量,并结合青岛市居民对贝类的平均食物消费量,计算贝类中PCBs和PAHs的接触风险和致癌风险指数,评估青岛市居民贝类中PCBs和PAHs的食用健康风险。结果　贝类中PCBs和PAHs的含量范围分别为未检出（ND）~168.66和ND~84.76μg/kg,中高氯联苯与中环芳烃在贝类中的比例较高;接触风险指数范围分别为0.191~0.399和1.12×10-5~1.44×10-4,皆小于1;总致癌风险指数范围为2.45×10-5~4.43×10-5,均在可接受致癌风险范围内。结论　青岛市居民对贝类水产品的食用健康风险较低,但PCBs各风险指数均高于PAHs,应加以重点关注。     

Chemical methods for determination of hydroxylated metabolites of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in biological material

This review presents methods for the analysis of hydroxylated metabolites of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in humans and animals. These metabolites serve as biomarkers of human and animal exposure to the mentioned pollutants, but some metabolites also have toxic properties. Most are analysed in urine, which is the most accessible sample, but they can also be analysed in human and animal liver, bile, and adipose tissue.Their analysis is important for assessing bioavailability of aromatic pollutants and their toxicity in human organism, but also the toxicity of metabolites themselves. Advancements in analytical methods have made it possible to analyse multiple metabolites in a sample at the same time. New extraction techniques and more precise and selective qualitative and quantitative analyses can now detect very low metabolite concentrations. An extra advantage is that these simple techniques require less chemicals and time.     

Influence of desorption and contact time on sediment-water distribution of spiked polychlorinated biphenyls and polycyclic aromatic hydrocarbons: relation with in situ distribution

The long-term sediment-water distribution of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), spiked to Lake Ketelmeer (The Netherlands) sediment, was studied using a gas-purge technique. Contact times varied from 2 to 1,461 d for the PCBs and from 5 to 100 d for the PAHs. Purge-induced desorption experiments lasted 300 to > 4,000 h. The initial distribution coefficients that were observed during the first part of the experiment were close to literature values for distribution after short contact times. The distribution coefficients increased during the purge-induced desorption experiments. The final distribution coefficients that were observed during the last part of the experiment were one to two orders of magnitude higher than the initial values and were close to distribution coefficients reported earlier for in situ PCBs and PAHs present in a field-contaminated sediment for years to decades. The change in distribution coefficients during a gas-purge experiment may resemble the long-term change in a field sediment. Final distribution coefficients seem to be a more relevant measure for the distribution coefficients of hydrophobic organic chemicals in aged field sediments than values obtained after short contact times.     

Accumulation of metals,polychlorinated biphenyls,and polycyclic aromatic hydrocarbons in sediments from the lower Passaic River,New Jersey

Thirteen sediment cores of 1.5–6 m depth were collected from the lower Passaic River in Newark, New Jersey and assayed for metals, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and Aroclor^® and coplanar polychlorinated biphenyls (PCBs). Chronological profiles of chemical concentrations at specified depths and sediment accumulation rates in each core were determined by ¹³⁷Cs and ²¹⁰Pb radioisotope measurements. Temporal concentrations of these chemicals were compared to available benchmark sediment toxicity values to assess historic and current toxic hazards to aquatic organisms. Elevated concentrations of several metals, including copper, lead, mercury, nickel, and zinc, were found in surface and buried sediments at concentrations that greatly exceeded Long and Morgan (1991) Effects Range-Low (ER-L) and Effects Range-Median (ER-M) values. Aroclors^® 1242, 1248, and 1254 and several PAHs were also found at concentrations exceeding Long and Morgan (1991) benchmark toxicity values. In general, the highest metal and PAH concentrations were found in sediment deposited prior to the 1960s. Elevated PCB concentrations were found in sediment deposited between 1950 and 1980. The results indicate that the lower Passaic River is heavily contaminated due to recent and historical municipal and industrial discharges from local and up-stream sources. The primary sources of PCBs, PAHs, and metals appear to be discharges of industrial effluents either directly into the waterway or through combined sewer overflows. Additional inputs are probably from urban runoff entering through combined sewer overflows and storm drains.     

Destabilized lysosomes and elimination of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in eastern oysters (Crassostrea virginica)

Contaminated oysters from near the Galveston Bay Ship Channel ([GBSC], TX, USA) were transplanted into clean aquariums in order to investigate the recovery of their lysosomal health. Destabilized lysosomes in the oyster hemocytes recovered from 81% to 34% after 23 d of elimination. Chemical analyses showed that transplanted oysters eliminated organic chemicals they had accumulated in their tissue. Enhanced lysosomal health (i.e., decreased lysosomal destabilization) was correlated positively with lower tissue concentrations of chemicals. This study indicates that lysosomal destabilization is a transient biomarker, which indicates only the current status (e.g., within one month) of chemical exposure and potential adverse biological effects. Analytical measurements revealed that polycyclic aromatic hydrocarbons (PAHs) generally were eliminated faster than polychlorinated biphenyls (PCBs) by a factor of 5 to 7. Body burdens of PCBs decreased exponentially, while the elimination pattern of PAHs were biphasic, representing a faster elimination during the early phase of elimination and, subsequently, a much slower elimination. This indicates that elimination of PAHs in the oysters is more complex and may include additional mechanisms compared to the uptake and elimination of PCBs.     

Effects of dose and particle size on activated carbon treatment to sequester polychlorinated biphenyls and polycyclic aromatic hydrocarbons in marine sediments

Recent laboratory studies show that mixing activated carbon with contaminated sediment reduces the chemical and biological availability of hydrophobic organic contaminants. In this study, we test the effects of varying the activated carbon dose and particle size in reducing the aqueous availability of polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) and the uptake of PCBs by two benthic organisms. We mixed PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay (CA, USA), for one month with activated carbon, at doses of 0.34, 1.7, and 3.4% dry mass basis. We found that increasing the carbon dose increased the effectiveness in reducing PCB bioaccumulation. In 56-d uptake tests with the benthic organisms Neanthes arenaceodentata and Leptocheirus plumulosus, PCB bioaccumulation was reduced by 93 and 90%, respectively, with 3.4% carbon. Increasing the dose also increased the effectiveness in reducing PCB and PAH aqueous concentrations and uptake by semipermeable membrane devices and quiescent flux of PCBs to overlying water. Decreasing activated carbon particle size increased treatment effectiveness in reducing PCB aqueous concentration, and larger-sized activated carbon (400-1,700 microm) was ineffective with a contact period of one month. We invoke a numerical model based on intraparticle diffusion in sediment and activated carbon particles to help interpret our experimental results. This model was useful in explaining the trends for the effect of activated carbon dose and particle size on PCB aqueous concentrations in well-mixed systems.     

Passive air sampling of polycyclic aromatic hydrocarbons and polychlorinated naphthalenes across Europe

This study presents concurrently sampled ambient air data for a range of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated naphthalenes (PCNs) at the continental scale. This was achieved with a passive air sampling system, by deploying polyurethane foam disks, which were prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for six weeks, collected, resealed, and returned to the laboratory for analysis. The study area was Europe, a region with a history of extensive persistent organic pollutants usage and emission, and with marked national differences in population density, the degree of urbanization and industrial and agricultural development. Samplers were deployed at remote, rural, and urban locations in 22 countries. Calculated air concentrations were broadly in line with those obtained by conventional active air sampling techniques, for both compound classes and for compounds existing predominantly in the gas and particle phases. The geographical compound distribution reflected suspected regional emission patterns and highlighted localized source areas. Both PAH and PCN levels varied by more than two orders of magnitude. The implications for sources are discussed.     

Air-water exchange of polycyclic aromatic hydrocarbons in the New York-New Jersey, USA, Harbor Estuary

Polycyclic aromatic hydrocarbons (PAHs, n = 36) were measured in the gas and particle phases in the atmosphere and the dissolved and particle phases in the waters of the New York-New Jersey Harbor Estuary, USA, during a weeklong intensive field campaign in July 1998. Mean total (gas + particulate) phenanthrene and pyrene concentrations were 3.3 and 0.33 ng/m3, respectively, over Raritan Bay, and 14 and 1.1 ng/ml, respectively, over New York Harbor. Similar PAH profiles (p values < 0.01) in the atmospheric gas phase and the dissolved phase in water demonstrate the close coupling of the air and water compartments. Air-water exchange fluxes of PAHs estimated using shore-based air data lead to erroneous flux estimates when compared to those derived using over-water air samples. The gross absorptive air-water flux dominates atmospheric loadings (wet, dry particle, gas absorption) to the estuary for PAHs of molecular weight < 234 g/mol. Dry particle deposition is increasingly more important for the higher-molecular-weight, particle-bound PAH species. Gross volatilization dominates gross absorption for the majority of PAHs in the New York-New Jersey Harbor Estuary.     

焦炉工职业性多环芳烃暴露特征的研究

目的 探讨焦炉工职业性多环芳烃暴露特征。方法 个体采样、高效液相色谱法测定作业环境中多环芳烃含量,以分析焦炉工职业暴露特征,并引入毒性当量因子概念,评价焦炉工职业性多环芳烃暴露的致癌潜能。结果 焦化厂炉顶工多环芳烃职业暴露水平明显高于炉侧工和炉底工,差异有统计学意义(P<0.05);焦炉工多环芳烃职业暴露中非致癌性物质所占比例>70％,致癌性物质中苯并(a)芘(B[a]Py)占总B[a]Py等当量浓度的65.5％-72.4％;多环芳烃职业暴露总量和B[a]Py及芘含量呈正相关(r2分别为0.84和0.94,P<0.05)。结论 焦炉工职业性多环芳烃暴露水平较高且具有一定的致癌潜能,致癌性物质以B[a]Py为主。     

Determination of polycyclic aromatic hydrocarbons in industrial harbor sediments by GC-MS

Analysis of the 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority pollutant list was carried out in sediment samples of an industrial port in the southern Kaohsiung Harbor of Taiwan which is supposed to be extensively polluted by industrial wastewater discharges. The determination and quantification of PAHs in sediment samples were performed using gas chromatography coupled to mass spectrometry (GC-MS) with the aid of deuterated PAH internal standards and surrogate standards. The total concentrations of the 16 PAHs varied from 4,425 to 51,261 ng/g dw, with a mean concentration of 13,196 ng/g dw. The PAHs concentration is relatively high in the river mouth region, and gradually diminishes toward the harbor region. Diagnostic ratios showed that the possible source of PAHs in the industrial port area could be coal combustion. As compared with the US Sediment Quality Guidelines (SQGs), the various observed levels of PAHs exceeded the effects range median (ERM), and could thus cause acute biological damages. The results can be used for regular monitoring, and future pollution prevention and management should target the various industries in this region for reducing pollution.     

Watershed-based sources of polycyclic aromatic hydrocarbons in urban storm water

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic compounds, ubiquitous in the air and water of urban environments, and have been shown to accumulate in coastal estuarine and marine sediments. Although previous studies have documented concentrations and loads of PAHs in urban runoff, little is known about the sources and temporal patterns of PAH loading from storm water. This study characterized the sources and temporal patterns of PAHs in urban storm water by analyzing PAH concentrations and loads from a range of homogeneous land use sites and in-river mass emission sites throughout the greater Los Angeles, California, USA, region. Samples were collected at 30- to 60-min intervals over the course of a storm during multiple storm events over a four-year period in order to investigate PAH sources and inter- and intrastorm patterns in loading. Polycyclic aromatic hydrocarbon storm fluxes ranged from 1.3 g/km2 for the largely undeveloped Arroyo Sequit watershed to 223.7 g/km2 for the highly urbanized Verdugo Wash watershed, with average storm fluxes being 46 times higher in developed versus undeveloped watersheds. Early-season storms repeatedly produced substantially higher loads than comparably sized late-season storms. Within individual storms, PAHs exhibited a moderate first flush with between 30 and 60% of the total PAH load being discharged in the first 20% of the storm volume. The relative distribution of individual PAHs demonstrated a consistent predominance of high-molecular-weight compounds indicative of pyrogenic sources.     

Dependency of polychlorinated biphenyl and polycyclic aromatic hydrocarbon bioaccumulation in Mya arenaria on both water column and sediment bed chemical activities

The bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) by the filter-feeding soft-shell clam Mya arenaria was evaluated at three sites near Boston (MA, USA) by assessing the chemical activities of those hydrophobic organic compounds (HOCs) in the sediment bed, water column, and organisms. Polyethylene samplers were deployed to measure the activities of HOCs in the water column. Sediment activities were assessed by normalizing concentrations with sediment-water sorption coefficient values, including adsorption to black carbon in addition to absorption by organic carbon. Likewise, both lipids and proteins were considered in biota-water partition coefficients used to estimate chemical activities in the animals. Chemical activities of PAHs in M. arenaria were substantially less than those of the corresponding bed sediments in which they lived. In contrast, chemical activities of PCBs in M. arenaria often were greater than or equal to activities in the corresponding bed sediments. Activities of PAHs, such those of pyrene, in the water column were undersaturated relative to the sediment. However, some PCBs, such as congener 52, had higher activities in the water column than in the sediment. Tissue activities of pyrene generally were in between the sediment and water column activities, whereas activity of PCB congener 52 was nearest to water column activities. These results suggest that attempts to estimate bioaccumulation by benthic organisms should include interactions with both the bed sediment and the water column.     

Organochlorine compounds (polychlorinated biphenyls and pesticides) and polycyclic aromatic hydrocarbons in populations of Hexaplex trunculus affected by imposex in the lagoon of Venice, Italy

Concentrations of polychlorinated biphenyls (PCBs), organochlorine pesticides, and polycyclic aromatic hydrocarbons (PAHs) were measured in gastropods from the Lagoon of Venice, Italy. The visceral coil and the rest of the soft body of organisms (Hexaplex trunculus) sampled at two stations inside the lagoon and three stations on the seaward side were analyzed to evaluate their contamination levels. Preferential accumulation of PCBs and pesticides in the visceral coil (>80%) compared with the rest of the soft body was observed, whereas on average, PAHs showed no preferential partitioning. Differences between levels of organochlorine contaminants in the gastropods highlighted a gradient of pollution from the stations inside the lagoon (PCBs, 45-363 ng/g; pesticides, 4-51 ng/g) to the sea (PCBs, 13-131 ng/g; pesticides, 2-29 ng/g). The possible role of the three classes of contaminants, in addition to that of organotin compounds (OTCs), previously analyzed in the same samples, in causing one of the anatomic modifications because of imposex in this gastropod also was studied. A modeling approach by partial least squares (PLS) in latent variables was applied to explain the penis length of imposex-affected females with concentrations of organic pollutants. The synergistic role of PCBs, pesticides, and OTCs was evidenced, whereas the contribution of PAHs appeared to be very low.     

Bioavailability of polycyclic aromatic hydrocarbons in field-contaminated Anacostia River (Washington, DC) sediment

Sediment-water partitioning behavior and bioavailability of five polycyclic aromatic hydrocarbons (PAHs; phenanthrene, pyrene, chrysene, benzo[k]fluoranthene, and benzo[a]pyrene) were measured in field-contaminated sediment collected from moderately polluted regions of the Anacostia River (Washington, DC, U.S.A.). Much of the sediment PAH burden was resistant to desorption: Effective partition coefficients were 2- to 10-fold greater than expected from literature values, and more than 80% of PAHs remained sorbed after treatment of the sediment with a nonionic polymeric adsorbent (Amberlite XAD-2) for 20 h. Bioaccumulation, elimination, and assimilation of each PAH in the deposit-feeding tubificid oligochaete Ilyodrilus templetoni were measured and compared with the equivalent measurements from laboratory-inoculated sediment. Ilyodrilus templetoni effectively accessed the desorption-resistant fraction of these organic contaminants, as exhibited by high single-gut passage assimilation efficiencies (ASEs) of the five PAHs (60% < ASE < 90%). However, steady-state accumulations of PAHs by I. templetoni were very low and consistent with low pore-water concentrations. The present results suggest that steady-state accumulation of PAHs is controlled by pore-water concentrations and is not necessarily related to route of uptake or assimilation efficiencies.     

Occurrence and profiles of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in soils from a typical e-waste recycling area in Southeast China

Surface soils collected from Taizhou, a typical e-waste recycling area in Southeast China, were analyzed for the residues of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) by using microwave-assisted extraction and gas chromatography -mass spectrometry (GC-MS). The total concentrations of 16 PAHs in US EPA's priority list (ΣPAHs), six indicator PCBs (ΣPCBs), 15 OCPs widely used in China (ΣOCPs) in soils ranged from 125 to 4737?ng/g (average: 854 ng/g), from not detected to 55.4?ng/g (3.16?ng/g), and from 47.9 to 820?ng/g (276?ng/g), respectively. Individual PAHs were ubiquitously found in soil samples with detected ratio of 96% and their residual levels were comparable with those of serious polluted sites. Principal component analysis in combination with diagnostic ratios suggested that the combustion of coal, wood, and plastic wastes that are closely associated with illegal and unsafe recycling operations of e-wastes was the main source of PAHs in this area. Compared with other polluted sites, the PCBs residues in soils were generally low except for those in the major recycling site. The residual levels of OCPs in this region were also relatively higher and hexachlorocyclohexane (HCH), dichlorodiphenyltrichloroethane (DDT) and its metabolite forms including dichlorodiphenyldichloroethane (DDD) and dichlorodiphenyldichloroethylene (DDE), hexachlorobenzene (HCB), and dicofol were dominant species. The composition analysis indicated that the HCHs residues in soils might originate from the application of lindane (pure?γ-HCH) and parts of DDTs possibly from the wide use of dicofol with high impurity of DDT compounds in this region.     

重庆市某区小学女生多环芳烃内暴露水平及其与青春发动时相的关系

目的建立同时测定尿中4种多环芳烃(PAHs)代谢物的检测方法,研究重庆市某区女童青春发动时相提前与体内多环芳烃暴露水平的关系。方法研究对象采用目的性抽样,对重庆市某区4所小学1~4年级女生进行一般情况的问卷调查、生长发育的体格检查、并收集尿液,采用高效液相色谱-质谱联用法(HPLC-MS)对样品中4种PAHs代谢物进行定性和定量检测。结果 4种PAHs代谢物标准曲线相关性高,方法检出限为0.1 ng/mL。研究共调查女童737名,青春发动时相提前组209人,正常组528人。尿液检测结果显示4种PAHs代谢物检出率为100%,4种代谢物的检出浓度范围分别为1-羟基芘0.01~4.77 ng/mL,2-羟基萘0.15~50.00ng/mL,2-羟基芴0.06~12.59 ng/mL及9-羟基菲0.29~23.17 ng/mL。青春发动时相提前组和正常组在2-羟基芴(Z=-1.996)和9-羟基菲(Z=-3.161)暴露水平上差异具有统计学意义(P<0.05),控制了肥胖因素后,青春发动时相提前组9-羟基菲(Z=-3.012)暴露水平仍高于正常组(P<0.05)。结论该方法适用于4种PAHs代谢物的同时检测,研究地区女童青春发育早期均有PAHs暴露,且PAHs暴露可能是女童青春发动时相提前的因素之一。     

Impact of polychlorinated biphenyl and polycyclic aromatic hydrocarbon sequestration in sediment on bioaccumulation in aquatic food webs

It is not clear whether sequestration or aging of organic chemicals like polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) limits accumulation in higher levels of aquatic food chains. Therefore, the effect of aging on accumulation was studied in 1(-m3) model ecosystems that mimicked fish-dominated, macrophyte-dominated, and fish- and macrophyte-dominated shallow lakes. Also treatments without fish and macrophytes were included. General characteristics, biomasses, total (Soxhlet-extractable), and labile (6-h Tenax-extractable) PCB and PAH concentrations in sediment and biota were monitored over time. Accumulation data for PCB 28, PCB 149, and fluoranthene (native to the sediment taken from the field) were compared to those for spiked analogues PCB 29, PCB 155, and fluoranthene-d10. Labile fractions for spiked compounds were higher than for their native analogues and decreased over time, suggesting sequestration in the sediment. In the majority of cases, 6-h Tenax-extractable concentrations correlated better with concentrations in biota than Soxhlet-extractable concentrations. Ecosystem structure affected food web accumulation, but replicate variability was too high to detect clear treatment effects. Differences in accumulation between spiked compounds and their native analogues indicated an effect of aging for invertebrates, macrophytes, and benthivorous fish. Thus, aging may translate directly into reduced uptake at higher trophic levels.     

Bioavailability of polycyclic aromatic hydrocarbons sequestered in sediment: microbial study and model prediction

In field studies and remediation projects, contaminants persist in soil and sediment much longer than would be estimated based on contaminant physical and chemical properties; such observations indicate that a fraction of contaminants in soil/sediment is much less available to the degrading microorganisms or chemical reagents. Many researchers attribute this reduced availability/ bioavailability to the sequestration (also referred to as resistant desorption or desorption hysteresis) of contaminants in soil/sediment. In the present research, desorption and bioavailability of naphthalene, phenanthrene, and fluoranthene were studied to evaluate the impact of sequestration on the biodegradability of these three polycyclic aromatic hydrocarbons (PAHs). Experimental results indicate that only desorbed PAHs are bioavailable and that the bioavailability of sequestered PAHs could be well predicted with a modified bioavailability model, which uses a biphasic desorption model to replace the conventional adsorption/desorption model. Findings in the present study might have important implications for site remediation: After the initial stage of remediation (i.e., after the readily desorbable fraction of contaminants is removed from soil/sediment), desorption of sequestered contaminants becomes the rate-limiting step of remediation. In this stage, the availability of contaminants is so low that even aggressive remediation would have little effect on overall mass reduction. Thus, a more cost-effective approach for site remediation might consist of an initial aggressive treatment followed by plume control, such as monitored natural attenuation.     

Polychlorinated naphthalenes, biphenyls, dibenzo-p-dioxins, and dibenzofurans as well as polycyclic aromatic hydrocarbons and alkylphenols in sediment from the Detroit and Rouge Rivers, Michigan, USA

Sediment from the upper Detroit and lower Rouge Rivers in southeastern Michigan, USA, were analyzed to examine the distribution of polychlorinated naphthalenes (PCNs), biphenyls (PCBs), dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs) as well as polycyclic aromatic hydrocarbons (PAHs) and alkylphenolic compounds such as butylphenol, octylphenol, and nonylphenol (NP). Sediments from a non-point source location in Lake Michigan were also analyzed for target compounds. Concentrations of target compounds in the upper Detroit and lower Rouge Rivers varied considerably among locations, and notable spatial variation existed. Concentrations of PCNs and PCDDs/PCDFs in sediments from the upper Detroit and lower Rouge Rivers ranged from 0.08 to 187 ng/g and 69 to 1420 pg/g dry weight, respectively. Total PCBs, PAHs, and NP concentrations ranged from 8 to 25,000, 17 to 44,000, and < 10 to 60,000 ng/g dry weight, respectively. Concentrations of all target compounds except PCNs were significantly correlated with total organic carbon content of sediments. Similarly, concentrations of PCBs, PCDDs, and PCDFs were significantly correlated with each other. The distribution of organic contaminants in the upper reaches of the Detroit River and lower Rouge River suggested the presence of localized, but multiple, sources of contamination for each compound class. Conners Creek combined sewer overflow has been identified as one of the potential sources for the upper Detroit River, where the highest concentrations PCBs and PCDDs/PCDFs were found. Polycyclic aromatic hydrocarbon and NP concentrations were consistently high in sediment from the lower Rouge River. Analysis of data from selected locations suggested that PCNs contributed a greater proportion of the dioxin-like activity than PCBs and PCDDs/PCDFs contributed.