Distribution,source apportionment and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in intertidal sediment of Asaluyeh,Persian Gulf

Surface sediment samples were collected from intertidal zone of Asaluyeh, Persian Gulf, to investigate distribution, sources and health risk of sixteen polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 1.8 to 81.2 μg kg^?1 dry weight, which can be categorized as low level of pollution. Qualitative and quantitative assessments showed that PAHs originated from both petrogenic and pyrogenic sources with slight pyrogenic dominance. Source apportionment using principal component analysis indicated that the main sources of PAHs were fossil fuel combustion (33.59%), traffic-related PAHs (32.77%), biomass and coal combustion (18.54%) and petrogenic PAHs (9.31%). According to the results from the sediment quality guidelines, mean effects range-median quotient (M-ERM-Q) and benzo[a]pyrene toxic equivalents (BaP_eq), low negative ecological risks related to PAH compounds would occur in the intertidal zone of Asaluyeh. The total benzo[a]pyrene (BaP) toxic equivalent quotient (TEQ^carc) for carcinogenic compounds ranged from 0.01 to 7 μg kg^?1-BaP_eq, indicating low carcinogenic risk. The human health risk assessment of PAH compounds via ingestion and dermal pathways suggests low and moderate potential risk to human health, respectively.     

Residual levels and health risk of polycyclic aromatic hydrocarbons in freshwater fishes from Lake Small Bai-Yang-Dian, Northern China

The residual levels of polycyclic aromatic hydrocarbons (PAHs) in the liver, brain, gill and muscle tissues of four common edible freshwater fish species including crucian carp, snakehead fish, grass carp and silver carp collected from Lake Small Bai-Yang-Dian in northern China were measured by GC-MS. The distribution and composition pattern of PAHs in the fish tissues, and the effects of lipid contents in fish tissues and the octanol-water partition coefficient (Kow) of PAHs congeners on them were analyzed. The human health risk of PAHs though fish consumptions was estimated. The following results were obtained: (1) The average residual levels of total PAHs (PAH₁₆) on wet weight base in the different tissues of each fish species ranged from 4.764 to 144.254 ng/g ww. The differences in the average residual levels on wet weight base for PAH₁₆ within four fish species were not statistically significant (P > 0.05); however, these within four fish tissues were statistically significant (P < 0.01). (2) There were very similar distribution patterns of PAH congeners among both the fish tissues and the fish species, as indicated by statistically significant positive interrelationships (R = 0.58-0.97, P < 0.01 or P < 0.05). Low molecular weight (LMW) PAHs predominated the distribution in the fish tissues, accounting for 89.97% of total PAHs. Phe was the most dominant component, according for 37.79% of total PAHs, followed by Ant (18.59%), Flo (12.59%), Nap (10.79%), Fla (9.82%) and Pyr (6.43%). (3) The PAHs residues and distribution in the fish tissues are dependent on both the Kow of PAH congeners and the lipid contents in the fish tissues. There was a significant positive relationship (R = 0.7116, P < 0.0001) between lipid contents and PAHs residual levels. The statistically significant negative relationships (P < 0.05) were found between LogKow and log-transformed PAHs contents on wet weight base for all fish tissues except for the muscle tissue of snakehead fish, the brain and liver tissues of crucian carp. (4) The risk levels of total PAHs were lower than 10⁻⁵ for the muscle tissues of four studied fish species and for the brain tissues of grass carp and snakehead fish; while these were higher than 10⁻⁵ for the brain tissues of crucian carp and silver carp. The risk levels of total PAHs in the liver tissues of four studied fish species except for snakehead fish exceeded 10⁻⁵ for 2-4.5 times. However, the potency equivalent concentration (PEC) of total PAHs in four studied fish tissues were still lower than the maximum permissible BaP limits for crops and baked meat and for plants in the national criterions. The distributions of PAH congeners in fish were well simulated by a level III fugacity model, especially for low molecule weight PAHs.     

4种甲氧基丙烯酸酯类杀菌剂不同剂型对斑马鱼急性毒性效应

采用半静态法测定了4种甲氧基丙烯酸酯类杀菌剂原药及制剂对斑马鱼(Brachydonio rerio)急性毒性。结果表明,以实测浓度计,250 g·L~(-1)嘧菌酯悬浮剂对斑马鱼的96 h半数致死浓度(LC50)值为0.539 mg·L~(-1),急性毒性为高毒,95%嘧菌酯原药和50%嘧菌酯水分散粒剂对斑马鱼的LC50(96 h)值分别为1.09和1.21 mg·L~(-1),急性毒性均为中毒;98%啶氧菌酯原药和22.5%的啶氧菌酯悬浮剂对斑马鱼的LC50(96 h)值分别为0.0974和0.0972 mg·L~(-1),急性毒性均为剧毒;95%吡唑醚菌酯原药、15%吡唑醚菌酯悬浮剂和250 g·L~(-1)吡唑醚菌酯乳油对斑马鱼的LC50(96 h)值为0.0613、0.0549和0.0487 mg·L~(-1),急性毒性均为剧毒;95%醚菌酯原药和50%醚菌酯水分散粒剂对斑马鱼的LC50(96 h)值分别为0.468和0.702 mg·L~(-1),急性毒性均为高毒。这4种甲氧基丙烯酸酯类杀菌剂对斑马鱼均有较高风险,会对其他水生生物也存在潜在的风险。     

Effects of benzo[a]pyrene toxicity on morphology and ultrastructure of Hordeum sativum

Many studies have been devoted to investigation of toxic benzo(a)pyrene (BaP) compound, but studies involving changes at the cellular level are insufficient to understand the mechanisms of polycyclic aromatic hydrocarbons (PAHs) effect on plants. To study the toxicity of BaP, a model vegetation experiment was conducted on cultivation of spring barley (Hordeum sativum distichum) on artificially polluted BaP soil at different concentrations. The article discusses the intake of BaP from the soil into the plant and its effect on the organismic and cellular levels of plant organization. The BaP content in the organs of spring barley was determined by the method of saponification. With an increase in the concentration of BaP in the soil, its content in plants also rises, which leads to inhibition of growth processes. The BaP content in the green part of Hordeum sativum increased from 0.3 µg kg^?1 in control soil up to 2.6 µg kg^?1 and 16.8 µg kg^?1 under 20 and 400 ng/g BaP applying in soil, as well as in roots: 0.9 µg kg^?1, 7.7 µg kg^?1, 42.8 µg kg^?1, respectively. Using light and electron microscopy, changes in the tissues and cells of plants were found and it was established that accumulation of BaP in plant tissues caused varying degrees of ultrastructural damage depending on the concentration of pollutant. BaP had the greatest effect on the root, significant changes were found in it both at histological and cytological levels, while changes in the leaves were observed only at the cytological level. The results provide significant information about the mechanism of action of BaP on agricultural plants.

     

高分子量多环芳烃--苯并[a]芘的生物降解研究进展

多环芳烃(PAHs)是一类广泛分布于海洋环境中的含有两个以上苯环的有机化学污染物.苯并[a]芘(BaP)是一种由5个苯环组成的分布广泛、致癌性极强的多环芳烃化合物,人们将其作为多环芳烃的指示物,通过研究其在环境中的产生、迁移、转化、降解及毒理作用来判断多环芳烃的污染情况.BaP已成为国内外环境监测的重要指标之一.本文综述了不同环境中BaP的来源与分布,BaP在环境中的行为,微生物对BaP的代谢途径,以及微生物降解BaP的相关限制因子,并结合作者在这方面研究的部分工作与目前国际研究的热点,提出值得进一步探究的有关问题.图4表3参51     

山西工矿区土壤二氧化硫与多环芳烃复合污染对小麦种子萌发和幼苗生长的影响

以小麦为供试植物,山西工矿区生黄土为供试土壤,进行了土壤中二氧化硫(SO2)与多环芳烃(PAHs)单一及复合污染对小麦种子萌发率及小麦幼苗株高、根伸长和地下生物量影响的研究,以期考察复合污染的生态毒性效应。结果表明,小麦种子萌发对SO2与PAHs单一及复合污染均不敏感;SO2和PAHs单一污染时,小麦幼苗的株高与根伸长均受到一定程度的影响,低浓度SO2或PAHs处理对小麦生长起促进作用,高浓度则为抑制作用;小麦幼苗株高与SO2浓度呈显著负相关(r=-0.954,P<0.05),但与PAHs浓度的相关性不显著;SO2与PAHs复合污染条件下,对小麦幼苗株高或根伸长的联合作用多体现为协同作用,在低浓度情况下(SO2<500mg·kg-1)表现为协同促进;当SO2达到500～1000mg·kg-1时,对小麦幼苗株高或根伸长的联合作用均体现为协同抑制。SO2和PAHs单一污染时,小麦幼苗地下生物量与SO2、PAHs浓度均为显著负相关(rPAHs=-0.953,rSO2=-0.916,P<0.05);复合污染条件下,在SO2浓度为10mg·kg-1时,对地下生物量的联合作用多体现协同促进作用;而在SO2浓度为1000mg·kg-1,PAHs为50～100mg·kg-1时,对地下生物量的联合作用均体现为协同抑制作用。多元逐步回归分析进一步表明,SO2与PAHs复合污染条件下,小麦幼苗株高、根伸长都受到了SO2及PAHs的共同影响,而SO2是影响小麦幼苗地下生物量的主要因素。     

Risk assessment of human exposure to polycyclic aromatic hydrocarbons via shrimp (<Emphasis Type="Italic">Macrobrachium felicinum</Emphasis>) consumption along the Imo River catchments,SE Nigeria

Shrimp species (Macrobrachium felicinum) collected from estuarine mangrove area of the Imo River is an important route of exposure to polycyclic aromatic hydrocarbons (PAHs). The estuarine associated sediment (EAS) composited sample showed higher TPAH, ΣAlkyl, ΣPAH_carc and ΣPAH_EPA concentrations (550.84, 172.36, 413.17 and 482.11 ng/g dry weight—dw) than their mean concentrations in shrimp samples (509.39 ± 354.21, 31.38 ± 18.49, 52.10 ± 1.35 and 460.06 ± 330.76 ng/g wet weight—ww), respectively. Among the individual PAHs congeners, phenanthrene was the dominant species detected in the EAS accounting for 21.02 % of the total PAH load and the decreasing order of 3- > 2- > 5- > 4- > 6-ring contamination was found. A different pattern predominated by naphthalene was observed for the shrimp species, suggesting that the organisms have different selectivity for a range of PAHs congeners. These variations may be attributed to different degree of bioavailability of these compounds, characteristic sandy lithology of the EAS and the protective capacity of soot particles associated with liquid fossil fuel combustion masking the uptake of high molecular weight PAHs by the organisms. Cancer risk associated with consumption of shrimps in the region was assessed using estimated daily intake (EDI) and compared with standards. The EDI values for naphthalene, benzo(a)pyrene and ∑PAH_carc were lower than the USEPA benchmarks and EFSA levels of concern values for adult and children population, suggesting low probability of developing cancer.     

Hydrocarbons contamination and microbial degradation in mangrove sediments of the Niger Delta region (Nigeria)

The distribution of aliphatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), and their degradability by bacteria in epipelic and benthic sediments from Qua Iboe Estuary mangrove ecosystem and associated creeks were investigated. The research findings revealed that total aliphatic hydrocarbons in sediments ranged from 16.82 mg·kg ^?1 to 210 mg kg ^?1, wheras total PAHs ranged from 6.30 to 35.55 mg·kg ^?1 dry weight of sediment. Low molecular mass (i.e. the 2–3-ring) PAHs were predominant in almost all the sampling points, whereas the higher molecular masses (4-, 5- and 6-ring PAHs) had the lowest concentrations. In general, the sediment samples ES ₂ (39.7%), ES ₃ (24.8%), BS ₁ (46.7%), BS ₂ (49.9%) and BS ₃ (44.2%) showed<50% contributions of Σ combustion–derived PAH (COMP-PAH) concentration to the Σ PAH concentrations, whereas ES ₁ (57%) contained>50% of COMP-PAHs. Our results have also shown that many mangrove bacteria have strong capacity to utilise Qua Iboe Light (QL) crude oil as the sole source of carbon and energy, while lower number of bacterial species including Bacillus sp., Micrococcus sp., Pseudomonas aeruginosa, Alcaligenes sp. and Flavobacterium sp. exhibited detectable PAHs degradability; and as such may serve as efficient degraders of QL crude oil contamination of mangrove ecosystem.     

Inhibitory effect of arachidonic acid on venom acetylcholinesterase

The venom of krait (Bungarus sindanus), an Elapidae snake, contains high level of acetylcholinesterase (AChE) activity. The effect of arachidonic acid on krait (Bungarus sindanus) venom AChE (acetylcholine hydrolase, EC 3.1.1.7) was studied using kinetic methods. This study evaluated for the first time whether arachidonic acid acts as potential AChE inhibitor of krait venom. Kinetic studies, using Line-Weaver Burk and Dixon plots, indicated that the inhibition produced by arachidonic acid was non-competitive, i.e., both k_m and V _max fell with increase in the concentration of arachidonic acid. The concentration of arachidonic acid required to inhibit 50% of enzymatic activity was found to be 1.9?µM while the inhibitory constant (K_i ) was 1.4?µM. The present results suggest that essential fatty acid (arachidonic acid) may also be used as an inhibitor of snake venom AChE.     

两种典型持久性有机污染物对草履虫急性毒性初探

滴滴涕和苯并芘这两种典型持久性有机污染物在环境中已广泛分布,因此,本研究利用单细胞真核模式生物-草履虫来研究其急性毒性效应,结果发现其毒性效应存在显著的剂量效应关系.DDT和BaP的半数致死浓度分别为126.012 mg·L-1和180.167 mg·L-1,且这两种污染物的浓度和概率间存在很好的线性关系.不同浓度的D...     

Effects of hydroxypropyl-β-cyclodextrin on pyrene and benzo[α]pyrene: bioavailability and degradation in sotil

Effect of hydroxypropyl-β-cyclodextrin (HPCD) on the bioavailability and biodegradation of the polycyclic aromatic hydrocarbons (PAHs) pyrene (PYR) and benzo[α]pyrene (BaP) in spiked soils was investigated in 14-week incubation experiments. To evaluate the effect of HPCD in soils with a different matrix, humic substance (HS) was added into soil samples. A 6-h Tenax TA extraction method was used to evaluate pollutants bioavailability. The biodegraded and extracted fractions were compared to evaluate the impact of HPCD on PAHs biodegradation. Results indicated positive effects of HPCD on fast desorption behaviours of PAHs. The biodegraded fraction was consistent with that of the extracted for PYR. However, in terms of BaP, the results were contrary which suggests that biological factors may be limiting factors for BaP pollution remediation. HS weakened the HPCD solubilisation effect while accelerated the decay of PYR and BaP, also implying that bioavailability was not the sole factor limiting PAH biodegradation. In addition, analysis of microbial communities demonstrated that HPCD inhibited the growth of some soil bacteria while HS promoted the evolution of some soil microorganisms. A limited population of hydrocarbon degrader populations led to observing incomplete PAH biodegradation even in the presence of HPCD.     

Investigation on sampling artifacts of particle associated PAHs using ozone denuder systems

Polycyclic aromatic hydrocarbons （PAHs） are complex organic compounds which are identified as significant carcinogenic to human health. PAHs （mainly in particle phase） are susceptible to atmospheric oxidant gases, especially ozone, nitrogen oxides （NOx）, hydroxyl radical （OH）, and could be degraded on filters during sampling process, leading to an underestimation of ambient PAH concentrations. The goal of this work was to investigate particle associated PAHs sampling artifacts caused by ozone in summer of Beijing. Comparative sampling systems were operated simultaneously during the whole campaign, one with activated carbon ozone denuder, the other being set as conventional sampling system. Activated carbon denuder was testified to be highly efficient to eliminate ozone from air stream. In general, nine particle-bound PAHs observed from conventional sampler were all lower than those from ozone denuder system. The total PAHs （particle phase） concentration was averagely underestimated by 35.9% in conventional sampling procedure. Benzo[a]pyrene （BaP） had the highest percentage of mass loss. founded to have influences Ambient temperature was on PAHs sampling artifacts. High temperature can increase loss of particle associated PAHs during sampling.     

Polycyclic aromatic hydrocarbons in Syrian olive oils and their likely daily intakes

The levels of 16 US Environmental Protection Agency polycyclic aromatic hydrocarbons (16 EPA PAHs) in Syrian olive oils have been determined. Forty-two samples including commercial extra virgin and virgin olive oils, and virgin olive oils from olive mills were analyzed. Only naphthalene (NAP) was detected in all olive oil samples under investigation. Among the studied 16 EPA PAHs, the highest maximum concentration was also observed for NAP (120 μg kg^?1). Moreover, three samples exceeded the European Union (EU) maximum level of 2 μg kg^?1 for benzo[a]pyrene (BaP) in oils and fats, and only one sample exceeded the EU maximum level of 10 μg kg^?1 for the sum of benz[a]anthracene, chrysene, BaP, and benzo[b]fluoranthene (PAH4). The likely daily intakes of the total sum of 16 EPA PAHs, the sum of eight genotoxic PAHs, the sum of PAH4, the BaP, and the BaP equivalent through consumption of Syrian olive oils were estimated.     

Evaluation of 3-hydroxy-benzo[a]pyrene levels in Nile tilapia (Oreochromis niloticus) after waterborne exposure to Benzo[a]pyrene

3-Hydroxy-benzo[a]pyrene (3-OH-BaP), a toxic compound with the ability to covalently bind with the macromolecules (proteins and DNA), is one of the major phenolic metabolites of benzo[a]pyrene (BaP). The purpose of this study was to evaluate the presence of 3-OH-BaP in the bile and plasma of Nile tilapia by HPLC with fluorescence detection, after waterborne exposure to BaP (10 and 100?µg?L^?1). Metabolites were detected in bile and plasma, and conjugates of 3-OH-BaP (glucuronide and/or sulphate conjugates) were the majority forms in both biological fluids, glucuronide 3-OH-BaP being the main metabolite in bile. Our data suggest that extrahepatic tissues as intestine or gill are important in BaP metabolism and need to be the considered sources of metabolites released into the blood. Although, low levels of 3-OH-BaP in toxic form (free form) were detected in plasma, one cannot exclude the possibility of circulating the levels leading to adverse effects.     

UVR-induced toxicity of sludge and polycyclic aromatic hydrocarbons on seed germination and seedling growth of Triticum aestivum L.

The depletion of the ozone layer and enhancement of solar radiation may exert an adverse influence on the ecosystem. Phototoxicity of sludge and polycyclic aromatic hydrocarbons (PAHs) under ultraviolet radiation (UVR) to seedling was studied. Seeds of wheat (Triticum aestivum) were planted in sludge and PAHs (anthracene (An), benzo(a)pyrene (BaP) and pyrene (Py)) with and without UVR. Toxicity of sludge increased in the presence of UVR in wheat. UVB radiation was found to be more hazardous than UVA radiation. Results demonstrated that An, BaP and Py induced phototoxicity at various concentrations (1–10?µg/mL) under UVA (1.5?mW/cm²) or UVB (1.08?J/cm²) exposure. The pattern of phototoxicity was An?>?Py?>?BaP to shoot length, root length, and fresh weight; chlorophyll, protein content, enzyme activity of catalase and α-amylase were reduced while the activity of superoxide dismutase and starch was enhanced. Reduction in seedling growth and biochemical parameters may be related to less photosynthesis, less nutritional uptake, and distortion of root cap. Thus, the synergistic effect may be due to alterations in photosynthesis, phytohormones, or nutritional uptake.     

Greenhouse effect of clusterization of CO2 and CH4 with atmospheric moisture

Carbon dioxide and methane are major compounds involved in global warming. The process of CO₂ and CH₄ molecules absorption by water clusters was investigated by the molecular dynamics method. The frequency spectra of dielectric permittivity for systems consisting of (H₂O) _n , (CO₂) _i (H₂O)₁₀ and (CH₄) _i (H₂O)₁₀ clusters mixed in various proportions were determined. The IR radiation absorption spectra of these systems were calculated and compared. Also, the radiating power of these systems was established. The capture of greenhouse gases’ molecules by ultra disperse water media reduces the ability of the media to absorb the Earth’s radiation, i.e., it reduces the greenhouse effect.     

Genetic toxicology of metal compounds: An examination of appropriate cellular models †

Bacterial systems have not had success predicting metal carcinogenicity. Hypotheses explaining this failure are examined. Using a broad genetic endpoint, λ prophage induction, under sub‐toxic growing conditions, genotoxicity is seen for compounds of chromium, manganese, lead, molybdenum and tungsten. Copper, manganese, arsenic and molybdenum compounds enhanced UV mutagenesis in E. coli WP2.

The toxicity of metal compounds to cultured mammalian cells correlates well with rat oral LD₅₀ values. Whereas insolubility can present problems in bacterial studies, concentrations of metal compounds toxic to mammalian cells can be determined even in the presence of precipitate, and sometimes [Pb(NO₃)₂, BaCl₂ and BeCl₂] occurs only in its presence. PbS and MnS, which are insoluble, are much more toxic than the more soluble compounds Pb(NO₃)₂ and MnCl₂. These results demonstrate the importance of cellular phagocytosis of insoluble metal compounds as a factor in studying the toxicity and genotoxicity of metal compounds.     

热带砖红壤生长的小白菜吸收和累积PAHs的特征

为了了解和掌握热带土壤栽培的小白菜（Brassica rapa L. Chinensis Group.）对多环芳烃（PAHs）污染物的吸收和累积规律,为热带土壤的安全利用及农产品安全生产提供科学依据,于2013 年5-9 月在海南省农垦科学院海口试验站网室内进行了小白菜盆栽试验.各处理土壤分别施加3 种单体 PAHs 的质量分数梯度为0、0.4、0.8、1.6、3.2 mg·kg^-1,撒播小白菜种子出苗后,每盆留苗6 株,自然条件,常规管理,各处理小白菜培养30 d 后收获.小白菜和土壤样品,用超声水浴萃取,层析小柱净化后,利用气相色谱-质谱法测定样品中的3 种PAHs.结果表明,小白菜根和叶中3 种PAHs 累积量随土壤施加质量分数的升高而增加,根部和叶对Phe 最大累积量分别为86.25 ng·g^-1 和37.18 ng·g^-1,而对 BaP 的最大累积量分别为20.78 ng·g^-1 和3.56 ng·g^-1;小白菜根对Phe 与Fla 的生物富集系数较大,且二者无明显差异,但对 BaP 的生物富集系数较小,且差异显著（P=0.006）;3 种PAHs 单体在各种处理土壤中的残留在 84.49%-94.03%之间,各单体之间无明显差异,各处理之间也无明显差异.说明热带土壤生长的小白菜根和叶中3 种单体 PAHs 浓度显著低于其土壤中的浓度,且根部积累3 种单体PAHs 的浓度显著高于其叶中的浓度;小白菜叶对BaP 的吸收和累积量极少;小白菜根更易吸收和累积Phe 和Fla;小白菜生长30 d 后,绝大部分PAHs 仍残留在土壤中.     

Organic composition in the dry season rainwater of Guangzhou, China

This paper reports the results from a study of the organic composition of rainwater collected at Tianhe district of Guangzhou city, P.R. China, during the dry season. Several special setups of a pyrex bottle with a glass funnel were used for the collection of the rainwater. Three fractions (aliphatics, PAHs and fatty acids) were separated from the total extracted organic compounds and identified with GC-MS. The molecular diagnostic ratios were utilized for the source reconciliation. The aliphatic hydrocarbon and the biomarkers (triterpanes and steranes) distribution show a characteristic of the petrochemical source in the rainwater samples. The PAHs diagnostic ratios [e.g. MP/P, MPI, Fl/ (Fl + Py)] indicated vehicular emissions. The fatty acids ratios (e.g. C_18:1/C_18:0 and C_18:2/C_18:0) reflect the contribution of cooking emissions, while the higher plant waxes play little part. Moreover, the values of MP/P, MPI, BaA/(BaA + CT) and BeP/(BeP + BaP) reflected the origin of the long-distance transportation to some extent. On the whole, for the dry season rainwater, all molecular diagnostic ratios indicated the complexity of the organic composition of the rain, which have the characteristics of both a local emission contribution and a long-distance transportation contribution.     

Isomer‐specific determination and toxic evaluation of potentially hazardous coplanar PCBs,dibenzofurans and dioxins in the tissues of “Yusho” PCB poisoning victim and in the causal oil

In the light of new discoveries on the extremely toxic non‐ortho coplanar 3,3’,4,4'‐tetra‐ (T₄CB), 3,3’,4,4’,5‐penta‐(P₅CB) and 3,3'4,4’,5,5'‐hexachlorobiphenyl (H₆CB) and their mono‐ and di‐ortho analogs, tissue samples of a Yusho poisoning victim and Yusho causal oils were subjected to a thorough congener/isomer‐specific investigation for polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo‐p‐dioxins (PCDDs). Among the many PCB congeners detected in Yusho oil, non‐ortho coplanar T₄CB constituted 3.1%, P₅CB‐0.17% and H₆CB‐0.0072% in total PCBs. Their concentrations in liver and adipose tissue were 130–700 (T₄CB), 54–720 (P₅CB) and 50–380 (H₆CB) pg/g on wet weight basis. The observed concentrations in adipose tissue were two to four fold higher than that detected in unexposed individuals. Among the PCDFs identified, toxic 2,3,7,8‐substituted isomers including 2,3,4,7,8‐P₅CDF were the dominant ones. Tetra‐ through hepta‐CDDs were detected in the oil, whereas octa‐CDD was the dominant isomer in the patient. A comparison with KC‐400 revealed enrichment of coplanar PCBs in Yusho oil along with toxic PCDFs. Enrichment was highest for 3,3'4,4'5,5'‐H₆CB followed by 3,3’,4,4'5‐P₅CB. A comparative toxic evaluation of these chemical groups in Yusho patient's adipose tissue based on “2,3,7,8‐T₄CDD Toxic Equivalent Analysis” revealed accountable toxic contribution from coplanar PCBs. This analysis also confirmed that 2,3,4,7,8‐P₅CDF was the principal causative agent in Yusho poisoning.