Effect of hot smoking on the content of selected polychlorinated biphenyl congeners in herring (Clupea harengus) slices

Herring ( Clupea harengus) (as well as sprat and mackerel) is a fish species intensively harvested by the Polish fishing fleet. Its relatively low price and the habits of Polish consumers contribute to its high economic importance in Poland. Among 125.6 thousand tons of marine fish harvested in 2006, herring constituted 22.2 thousand tons (including 7.6 thousand tons harvested from the North Sea). Fish are usually subjected to various culinary treatments, which can influence the concentrations of contaminants in final products. Therefore, the present study aimed at determining the effect of three non- ortho-polychlorinated biphenyl (PCB) congeners (PCB 77, PCB 126, and PCB 169) and three mono- ortho-PCB congeners (PCB 114, PCB 156, and PCB 157) in the tissues of herring slices. Concentrations of dry matter and lipids in the final product were increased by 15.9 and 20.5%, respectively. Brining, which preceded the process of smoking, did not significantly influence concentrations of PCB congeners in herring slices. However, smoking resulted in significant ( p < 0.05) changes in concentrations of three non- -ortho PCBs. The biggest dynamics of losses in relation to smoking duration was observed for PCB 77 (30.2%). For PCB 126, the biggest losses occurred after 1 h of drying, followed by slight changes after 1.5 and 2 h of proper smoking and another increase of losses in the final product after 2.5 h. The duration of smoking did not significantly influence PCB concentrations in wet weigh, as their losses in lipids were much bigger. The observation is derived from strong negative correlations between concentrations of the congeners in lipids and lipid concentrations in herring slices during hot smoking ( r ranging from -0.824 to -0.950). Although the lipid concentration in the smoked fish increased, the PCB content diminished. It shows that during drying of the fish slices, PCBs codistilled with water vapor, settling on the walls of the smoking chamber and smoking trolleys. During the proper smoking, the compounds released with the smoke back to the smoking chamber and settled on the surface of smoked fish together with the disperse phase of the smoke (aerosol). Hot smoking contributed to a reduction of toxic equivalents (TEQs) by 22.7% (converted into lipids 41.9%), and in the final product, it amounted to 0.0188 +/- 0.0023 ng TEQ/kg of wet weight (0.0977 +/- 0.0064 ng TEQ/kg of lipids). The reduction was significantly higher than resulting from hot smoking of mackerel slices, when TEQs were reduced by 17.9% wet weight (converted into lipids 31.7%).     

白洋淀鱼类体内多氯联苯积累特征及其毒性评价

针对持久性有机污染物在水生生物体内易于积累的特性,利用气相色谱与质谱联用技术（GC-MS）,检测了白洋淀8种鱼类体内多氯联苯（PCBs）含量,并分析了同系物组成特征。根据白洋淀鱼类检测到同系物情况,计算毒性当量（TEQ）并进行评价。白洋淀8种鱼类体内PCBs平均含量范围是55.85~1 485.74 ng.g-1脂肪重,从高到低的顺序依次为黄颡〉黄鳝〉乌鳢〉泥鳅〉鲤鱼〉鳙鱼〉鲫鱼〉鲇鱼。在8种鱼类PCB同系物组成中,四氯联苯和五氯联苯是主要的同系物,其相对百分含量为52.0%~84.3%。这种组成模式反映了白洋淀地区有多氯联苯工业品的使用历史。8种鱼类体内PCBs的毒性当量（TEQ）范围是0.09~1 412.87 pg TEQ.g-1脂肪重,其大小顺序依次为鳙鱼〉鲫鱼〉鲇鱼〉黄颡〉黄鳝〉鲤鱼〉乌鳢〉泥鳅。结果表明,白洋淀淀区部分鱼类已经受到PCBs一定程度的污染,应引起重视。     

Transfer and accumulation of persistent organochlorine compounds from bovine dams to newborn and suckling calves

The maternal-fetal and neonatal transfers of polychlorinated dibenzo- p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in the blood and milk of dams and in the blood of newborn and suckling calves. Calf blood toxic equivalent quantities (TEQs) were drastically increased by suckling. Blood concentrations of individual congeners were greater in suckling calves than in newborn calves, excluding octachlorodibenzo- p-dioxin (O 8CDD); O 8CDD did not readily transfer to milk but was readily absorbed by the gastrointestinal tract and remained in systemic circulation longer than other congeners. Congener concentrations in milk were correlated with maternal blood levels, and those in suckling calf blood were dependent on their concentrations in milk. These results suggest that neonatal calves absorb more lipophilic organochlorine compounds than prenatal fetuses, that those compounds that are transferred from dams to calves are associated not only with lipid transport but also with other carriers, and that the distribution of congeners is structure-dependent.     

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in fish and meat

We investigated the cooking-induced changes in concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) using mackerel and beef. The concentrations of dioxins (29 congeners) were determined by isomer specific analyses and were compared between uncooked and cooked samples. The cooking procedures examined in this study included grilling as a fillet, boiling as a fillet, and boiling as tsumire (small, hand-rolled balls) for mackerel and boiling as a slice, broiling as a slice, and broiling as a hamburger for beef. Three trials were carried out for each cooking method. Generally, concentrations of dioxins were reduced in every cooking trial. When nondetected congener concentrations were assumed to be half the limit of detection for mackerel, the maximum percentage reductions of total concentrations given as 2,3,7,8-tetraCDD equivalents (TEQ) were 31% in grilling as a slice, 14% in boiling as a slice, and 21% in boiling as tsumire under the conditions of this study. In contrast, for beef, the reductions were 42% in boiling as a slice, 42% in broiling as a slice, and 44% in broiling as a hamburger. These results suggest that ordinary cooking processes with heating undoubtedly reduce the dioxin content in animal products, and the reductions estimated should be considered when dioxin intake is evaluated using contamination data for individual food items.     

Polycyclic Aromatic Hydrocarbons, Polychlorinated Biphenyls and Trace Metals in Sediments from a Coastal Lagoon (Northern Adriatic, Italy)

Surface sediments (0–5 cm) were analysed to provide information on levels, spatial trends and sources of the 16 USEPA polycyclic aromatic hydrocarbons (PAH), 15 polychlorinated biphenyls (PCBs) and trace metals (copper, chromium, mercury, nickel and zinc) in channel and wetland habitats of Pialassa Baiona lagoon (Italy). The highest levels of PAHs, PCBs and Hg (3,032–87,150, n.d.–3,908 and 1.3–191 mg kg⁻¹) were mainly found at channel habitats close to industrial sources. Pyrogenic PAH inputs were significant, with a predominance of four-ring PAHs and combustion-related PAHs in both channel and wetland habitats. Among PCB congeners, chlorination class profiles show that penta- and hexachlorinated PCBs are the most prevalent homologues accounting for approximately 33% and 47% of the total PCB concentrations in channel sediments. Total toxicity equivalent factors (TEQs) of potentially carcinogenic PAHs varied from 348 to 7,879 μg kg⁻¹ and from 4.3 to 235 μg kg⁻¹ in channel and wetland sediments; calculated TEQs for dioxin-like PCB congeners at channel habitats ranged from n.d. to 86.7 μg kg⁻¹. Comparison of PAHs, PCBs and metal levels with Sediment Quality Guidelines suggests that more concern should be given to the southern area of the lagoon for potential risks of carcinogenic PAHs, dioxin-like PCBs and mercury.     

PCBs and Organochlorine Pesticides in Lake Orta (Northern Italy) Sediments

PCB congeners and organochlorine pesticides (DDT, lindane and HCB) distribution were studied in Lake Orta sediments. The results indicated a contaminated area in the nor-them part of the sub-basin. The observed high levels of organochlorine compounds (OCs) may he explained by the focusing phenomenon, ie. the preferential transport of lighter and smaller particles from the emission sources to this area. The PCBs and DDT values were correlated with the organic carbon content and the heavy metal contamination. The toxicity of the sediment samples was related also to PCB content. PCBs and OCs pollution of Lake Orta was of the same order of magnitude as in Lake Como, which is the most contamined lake in Northern Italy.     

The profile of congeners of polychlorinated biphenyls in soils of Moscow

The profiles of 19 indicative and dioxin-like congeners of polychlorinated biphenyls (PCBs) in the surface soils of distinct types of land use in Moscow are investigated. The penta- and hexachlorobiphenyls (46.7 and 31.6%, respectively) contribute significantly to the PCB spectrum. They used to make up the bulk of coolants and insulating fluids for electrical equipment, especially transformers. Among the congeners, the indicative PCB-101, -110, -138, and -153 and dioxin-like congeners PCB-105 and -118 dominate. They possess extremely high persistence and capability of bioaccumulation and exert harmful toxic influence, which should be taken into account when estimating an urban ecosystem??s ecotoxicological state.     

Einfluß polychlorierter Biphenyle auf die mikrobielle Aktivität in Böden

Effects of polychlorinated biphenyls on soil microbial activity In laboratory experiments the microbial toxicity of the PCB congeners 5 (2, 3-Dichlorobiphenyl), 8 (2, 4′-Dichlorobiphenyl), 29 (2. 4, 5-Trichlorobiphenyl) and 77 (3, 3′, 4, 4′-Tetrachlorobiphenyl) which is supposed to be extremely toxic to wildlife was investigated using Parabrownearth-Ap and Podsol-Ahe horizon material. In addition the technical PCB mixtures Arochlor 1242 and 1260 were tested. Microbial toxicity was measured by means of long-term respiration (CO₂-evolution), short-term respiration (CO₂-evolution 12 h, after addition of glucose), and dehydrogenase activity (TTC reduction) tests. 1 mg/kg of the Dichlorobiphenyls 5 and 8 reduced the long-term and short-term respiration of the Podsol-Ahe during the whole experiment (35 and 28 days, respectively). The Trichlorobiphenyl 29 became effective after addition of 10 mg/kg. No effect except a short stimulation of long-term respiration was observed for PCB 77 (Tetrachloro-PCB). Due to its higher sorption capacity, all PCB congeners reduced the microbial activity of the Parabrownearth-Ap to a lower degree. In general the toxicity of PCBs decreased with increasing degree of chlorination in both soil horizons. The technical mixtures reduced the long-term respiration only after high additions of 50 mg/kg (Podsol-Ahe) and 100 mg/kg (Parabrownearth-Ap), respectively. Arochlor 1242 proved to be more toxic than Arochlor 1260.     

Composition of PCBs and PAHs in the Montreal Urban Community Wastewater and in the Surface Water of the St. Lawrence River (Canada)

Samples of treated wastewater drawn from the effluent of the Montreal Urban Community (MUC), Canada, and surface water samples from the St. Lawrence River were collected in 1993 and 1994 and analysed for PCBs and PAHs. The average concentrations of Σ13 PCBs and Σ14 PAHs in the effluent were 1.34 ± 0.71 ng L-1 and 326 ± 229 ng L-1, respectively. PCB concentrations in the effluent did not show any clear seasonal pattern in the effluent but PAH concentrations increased during the winter period. In the effluent plume, both PCB and PAH concentrations increased significantly between the upstream control site and the effluent outfall, and subsequently decreased. The profiles of PCB congeners were similar within the effluent plume and also among water masses of the St. Lawrence River. PAH profiles were also similar within the effluent plume, but were different across the two water masses of the St. Lawrence River. Based on the composition of PCB congeners, atmospheric inputs appear to represent the major source of PCBs in the St. Lawrence River. The sources of PAHs in the MUC effluent and in the St. Lawrence River water would appear to be, respectively, petroleum products and combustion-derived products.     

珠江三角洲典型地区表层农田土壤中多氯联苯残留状况

采集了珠江三角洲典型区域384个表层农田土壤样品,分析了其中常见6种土壤多氯联苯(PCB28、PCB52、PCB101、PCB138、PCB 153与PCB180)的残留状况.研究结果表明:6种多氯联苯总量(Σ6PCBs)的检出率为78.13％,其平均值为0.42 μg/kg. PCB138的检出率与含量高于其他5种PCBs;土壤中6种多氯联苯的残留状况存在很大的差异;PCB101的检出率最低,仅为10.16％,但其平均值(0.11 μg/kg)较高,主要源于某点位PCB101高达32.44 μg/kg,土壤受到了严重污染.线性相关关系分析结果表明:土壤有机质、黏粒含量则与PCB52存在显著正相关关系.总体而言,低氯代的PCBs含量与土壤理化性质具有一定的相关性,高氯代的PCBs呈现典型的点位污染且在点位土壤中其含量显著高于低氯代同系物.     

兰州地区PCBs的长距离传输潜力及其总持久性模拟研究

运用TaPL3（version3.00）模型计算了7种PCBs同系物在兰州地区通过大气和水体的特征迁移距离（CTD）及其总持久性（Po）v,讨论了其长距离传输潜力（LRTP）和Pov之间的关系,并以PCB28为例,应用灵敏度分析方法对模型的不确定性进行了研究。结果显示,兰州地区PCB28、PCB52、PCB77、PCB101、PCB138、PCB153和PCB180通过大气的CTDair在250～2500km之间,Pov在500～33000d之间,PCB138、PCB153和PCB180对源区影响较大;通过水体的CTDwater在6500～61000km之间,Pov在850～36000d之间,PCB28、PCB52、PCB77和PCB101对源区影响较大。7种PCBs的同系物LRTP和Pov之间没有直接的联系,就排放到大气中的PCBs而言,对Pov和CTD影响最大的参数都是理化参数;就排放到水体中的PCBs而言,Pov比CTD更依赖于PCBs的理化性质,而CTD比Pov更依赖于环境条件。同国外的研究相比,兰州地区PCB28通过大气的CTDair偏低,通过水体的CTDwater偏高,PCB28通过大气和水体的Pov都偏高。     

Plant secondary metabolites, biphenyl, and hydroxypropyl-β-cyclodextrin effects on aerobic polychlorinated biphenyl removal and microbial community structure in soils

Biphenyl and several plant secondary metabolites (PSM) (carvone, isoprene, limonene, naringin, and coumarin) and surfactant (hydroxypropyl-β-cyclodextrin, (HP-β-CD)) have been shown to improve aerobic polychlorinated biphenyl (PCB) removal by several bacterial species. The objective of this study was to determine whether these treatments also affect PCB removal and microbial community structure in a high organic matter soil (Pahokee soil series with 67% organic matter) and low organic matter soil (Woolper soil series with 6% organic matter), as determined by monitoring changes in PCB levels and phospholipid fatty acids (PLFA) profiles in laboratory microcosms amended with these compounds. Biphenyl enhanced di-chlorinated and tri-chlorinated biphenyl removal in both soils, but PSM did not improve removal of these congeners. On the contrary, HP-β-CD decreased PCB removal when used in combination with biphenyl. Two-way analysis of variance indicated that HP-β-CD significantly increased tetra- and penta-chlorinated biphenyl removal from the high organic matter soil, but not from the low organic matter soil. Principal components analysis of PLFA data indicated that HP-β-CD increased proportions of 18:1ω7c associated with Gram-negative bacteria, but decreased 10me16 and 10me17 lipid associated with Gram-positive bacteria, while biphenyl and PSMs had no detectable effects on soil microbial communities. PCB removal was not correlated to any PLFA. In conclusion, PSM previously shown to enhance PCB removal in soil-free systems were not effective in two divergent soils evaluated in this study, and HP-β-CB had increase, decrease, or no effect on PCB removal depending on types of PCB congeners, soils, and co-amendments.     

冷熏对高白鲑理化性质及肌球蛋白构象的影响

以新疆塞里木湖高白鲑为研究对象,研究冷烟熏过程对鱼肉理化性质及肌球蛋白构象的影响。冷熏温度为(20±2)℃,发烟温度140℃,冷熏时间分别为0、6、12、18、24 h,研究冷熏鱼肉理化性质(含水率、水分活度、色泽、质构特性、TVB-N)及肌球蛋白构象(蛋白浓度、总巯基含量、Ca^2+-ATPase、表面疏水性)变化。研究结果表明,冷熏0~24h,鱼肉含水率由75.75%下降至53.03%,水分活度(Aw)由0.988下降至0.952;鱼肉亮度值(L^*)显著降低(P<0.05),红度值(a^*)缓慢增加,黄度值(b^*)显著增加(P<0.05);表征鱼肉质构特性的剪切力与韧性均呈明显上升趋势(P<0.05);鱼肉挥发性盐基氮(TVB-N)由9.81上升至14.23 mg/100g;肌球蛋白浓度、总巯基含量、Ca^2+-ATPase活性均显著降低(P<0.05),表面疏水性增加(P<0.05);综上,控制冷熏时间12~18 h有利于提高冷熏鱼肉品质,降低鱼肉肌球蛋白变性与氧化程度。该研究为特色淡水鱼冷熏制品开发与烟熏过程中蛋白氧化调控提供理论依据与技术参考。     

Uptake of polychlorinated biphenyls (PCBs) from an aqueous medium by polyethylene, polyvinyl chloride, and polystyrene films

The sorption of selected polychlorinated biphenyl (PCB) congeners (from tri to deca chlorinated) by three food-packaging plastic films [polyethylene, polyvinyl chloride (PVC), and polystyrene] from an aqueous solution was investigated. From the data generated, PCB uptake, partition, and diffusion coefficients were calculated for the various films. Polyethylene exhibited the highest PCB uptake, diffusion, and partition coefficients when compared to the other materials. Although PVC indicated larger sorption diffusion and partition coefficients for the lower chlorinated congeners than polystyrene, a reversal of this trend was observed for the higher congeners. For polyethylene and PVC, the PCB uptake decreased as the chlorine numbers in the congeners increased, confirming the correlation between increasing chlorination and increasing cohesive density within the PCB molecules. For polystyrene, the uptake decreased from tri to penta congeners, but showed an increase for the hexa, and then a decreased uptake until the deca chlorination. A comparison of the molecular sizes of the PCB congeners showed that the partition (Ke) and sorption diffusion (Ds) coefficients generally decreased with their increasing molar volumes. The resulting Ke values were used to determine the extent of sorption because these values indicate the affinity of PCBs for the plastic films. Results from this study can be of practical importance for cases of product quality related to the transfer of contaminants from the product to the packaging materials.     

Enzyme-linked immunosorbent assay with monoclonal and single-chain variable fragment antibodies selective to coplanar polychlorinated biphenyls

Coplanar polychlorinated biphenyls (Co-PCBs) consisting of non-ortho and mono-ortho-chlorinated PCBs are dioxin-like compounds and cause wide contamination in the environment. To monitor Co-PCB residues, it was attempted to establish an enzyme-linked immunosorbent assay (ELISA) with monoclonal and recombinant antibodies selective to Co-PCBs. When 3,3',5,5'-tetrachlorobiphenoxybutyric acid (PCBH)-keyhole limpet hemocyanin conjugate was immunized into mice, two monoclonal antibodies, Mab-0217 and Mab-4444, were obtained. 3,3',5,5'-Tetrachlorobiphenyl (PCB80) was determined with an IC(50) value of 2.6 and 0.46 ng mL(-1) in ELISA based on Mab-0217 and Mab-4444, respectively. Mab-4444 cross-reacted with Co-PCB congeners, except for PCB77 and PCB81. Mab-0217 reacted with PCB80 and cross-reacted with PCB111. A single-chain variable fragment (scFv) antibody derived from Mab-4444 was produced in recombinant Escherichia coli cells. The scFv antibody showed nearly the same sensitivity toward PCBH as the parent monoclonal antibody in ELISA. These results clearly suggested that Mab-4444 and its scFv antibodies were suitable for monitoring the representative congeners of Co-PCBs.     

Identification of an aliphatic epoxide and the corresponding dihydrodiol as novel congeners of zearalenone in cultures of Fusarium graminearum

The mycotoxin zearalenone (ZEN) is produced by various Fusarium fungi and frequently found as a contaminant in food and feed. There are reports in the literature that several closely related analogues of ZEN are also formed in cultures of Fusarium species. We have therefore analyzed the organic extract from a 40 day culture of Fusarium graminearum by LC-DAD-MS and detected 15 compounds, which could be congeners of ZEN because of their ultraviolet, mass spectroscopy, and tandem mass spectroscopy spectra. In addition to confirming the previously reported α- and β-stereoisomers of 5-hydroxy-ZEN and 10-hydroxy-ZEN, we identified seven ZEN congeners for the first time. One of the major novel congeners was shown by nuclear magnetic resonance spectroscopy and chemical synthesis to have the structure of an aliphatic ZEN epoxide, whereas two minor products proved to be the corresponding dihydrodiols. In addition, three stereoisomers of a cyclization product of the dihydrodiols, carrying a spiro-acetal group, were identified as fungal products for the first time. The latter may be artifacts, because the ZEN epoxide and dihydrodiol are unstable under acidic conditions and rearrange easily to the spiro-acetal compounds.     

基于数值模拟的红枣片不同干燥方式热质传递仿真与试验

为揭示并对比红枣片热风干燥、红外热风干燥及红外真空脉动干燥中的传热传质及干燥动力学特性,并填补关于果蔬红外真空脉动干燥数值模型的研究空白。该研究使用菲克扩散定律、安托因方程及比尔朗伯定律等控制方程分别建立了针对3种干燥方式的红枣片三维热质传递耦合数值模型,并利用试验数据对模型的可靠性进行验证。该研究基于枣片的实际几何尺寸进行建模并利用COMSOL求解。结果表明：1）与热风干燥相比,红外热风与红外真空脉动干燥分别缩短了46.43%和41.07%的干燥时间,且仿真结果与实测值吻合较好;2）温度场模拟图显示红外辐射可有效对红枣片内部进行加热,干燥20 min时红外热风和红外真空干燥的物料中心温度较热风干燥分别提高了11.33%和5.59%;3）模拟数据显示红外真空脉动干燥中的压力变化对干燥动力学产生了明显影响,其中含水率和干燥速率随压力脉动分别呈现阶梯状和峰状分布,并且干燥速率对压力变化的敏感性随着物料含水率的下降而下降;4）将测得的红枣片品质及质构特性与仿真数据进行综合对比,给出了关于分段组合干燥研究方向的见解,并对果蔬干燥数值模型的发展方向进行展望。该研究建立并验证了红枣片3种干燥方式下...     

Determination of polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins/dibenzofurans in marine products

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in plastics and textile coatings, and these compounds have been recognized as ubiquitous environmental contaminants. Furthermore, it is considered a serious problem that polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs), having toxicities similar to those of chlorinated dioxins, are generated by the manufacture of brominated flame retardants (BFRs) such as PBDEs, and formed by the combustion of substances containing BFRs. Several congeners of PBDD/DFs and PBDEs have been detected in the adipose tissue of the Japanese. Although food is suspected as an exposure source, little information is available regarding the levels of these brominated compounds in food, as compared with information regarding dioxin or polychlorinated biphenyls. It is necessary to investigate the levels of these brominated organic compounds in various foods and to estimate their influence in the case of human exposure. We developed an efficient method of analyzing PBDEs and PBDD/DFs contents in food samples using accelerated solvent extraction and determined the concentrations in several marine products such as raw fish, processed foods, and seaweed purchased in Japan. A recovery test (n = 5) using the method and involving dried fish showed acceptable recoveries of 57.7-78.5% (RSD 5.4-15.9%) for PBDEs and 50.0-56.4% (RSD 1.5-7.9%) for PBDD/DFs. In the analysis of marine product samples, several congeners of PBDEs were detected in raw fish, processed fish, and seaweed; the highest concentration of sigmaPBDEs was detected in yellowtail (1161 pg/g whole basis), followed by mackerel (553.5 pg/g whole basis). The most dominant congener present in these marine samples was 2,2',4,4'-tetraBDE (#47).     

Polychlorinated biphenyls (PCBs) in bulk soil and particle size separates of soils in a rural community

In a rural community (Stephanskirchen, Southern Germany) situated near a waste incineration plant six A horizons were sampled to determine 14 polychlorinated biphenyls (PCBs) in bulk soil and particle size separates (clay, silt, fine and coarse sand) and to test the suitability of alkaline saponification for PCB extraction. The PCB concentrations were higher in alkaline saponification extracts than in Soxhlet extracts. However, the extraction efficiency of up to fourfold chlorinated PCBs was lower and more than sevenfold chlorinated PCBs were destroyed. Nevertheless, alkaline saponification was suitable to determine the indicator congeners 28, 52, 101, 138, 152, and 180. The sum of the PCB concentrations ranged from 8.4 to 59.5 μg kg^?1 which was as high as in soils of big cities. However, the concentrations did not reach the threshold value for agricultural purposes of 200 μg kg^?1 as proposed in literature for the sum of the six indicator congeners. The hexachlorinated PCBs 138 and 153 were the most abundant (together > 50% in all samples) whereas PCB 1 could not be detected in any sample. On the average, PCB concentrations increased as particle size decreased. When normalized to C_org, however, the fine sand fraction had the highest PCB concentrations. A slight decrease of lower chlorinated PCBs as particle size decreased indicated an increasing state of degradation. The PCB compositions in the emissions of a comparable waste incineration plant (Bamberg, Bavaria) and in Stephanskirchen soils differed markedly. Therefore, we did not get any indications that waste incineration was a main source of PCBs in the examined soils. Instead, higher chlorinated technical PCB mixtures such as Clophen A 60 or Aroclor 1260 may be the most important sources.     

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Fish and piscivorous bird eggs collected in 2003 from Lake Maggiore (Italy), were analysed for PCB and DDT contamination. Lake Maggiore has been severely polluted by DDT through production of the pesticide within its catchment. Although agricultural application of DDT was banned in Italy in the 1978, industrial production continued until 1996, with enough contamination of water and soil for serious bioaccumulation in the lake biota. PCB and DDT concentrations in a whitefish (Coregonus macrophthalmus Nusslin 1882) were seen to be dependent on season and fish age, but not on sex. The average increase of the lipid-normalised concentration of DDTs and PCBs was two-fold across season and also across age, resulting in an overall increase of four fold. The seasonal variation was related to the eco-physiological cycle of the fish and to the contamination dynamic of the lake, while the effect of the fish age was explained on the base of biomagnification-related mechanisms. A fugacity model was applied to predict the age-dependent bioaccumulation potential of PCBs, whose concentrations were rather stable in recent years in the lake. Predicted values for compounds with negligible biotransformation were in good agreement with experimental data (calculated vs. experimental mean difference of 14%), and a relationship between the increase of experimental age-dependent concentration and K _ow was observed. The good correspondence between the predicted and the measured values for most PCB congeners confirmed the general inability of fishes to biotransform these compounds. On the contrary, the importance of biotransformation processes was recognised in birds; eggs of a fish eating bird (Podiceps cristatus) from the same area selectively bioaccumulated p,p′-DDE. For PCBs, congener 149 appears to be completely metabolized by the bird species, and congeners 95, 101, 132, 151 and 174 were reduced as well. The role of the meta–para free position on at least one phenyl ring of PCB congeners in biotransformation processes was confirmed.