Organochlorine chemicals in seafood: occurrence and health concerns

Dioxins and furans in breast milk: a case study of mothers from southern Rio de Janeiro, Brazil

A study of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (dl-PCBs) was conducted in a pooled sample of breast milk from 27 primiparous mothers living in 12 locations in the meso-region industrial area of southern Rio de Janeiro, Brazil, between August 2012 and July 2013. Questionnaires with questions regarding food habits, social and economic conditions and places of dwelling were applied. Milk was collected between four and six weeks after delivery from mothers were breast-feeding only one infant. The toxic equivalency (TEQ) of PCDD/Fs, and dl-PCBs were 10.6, 4.77, 6.96 TEQ pg/g, respectively. The understanding and identification of pollution sources may be helpful for applying better counter measures against breast milk dioxin contamination. It is important for pregnant women to have a diet that is as free as possible from chemical contaminants. Further research must be undertaken in the context of epidemiological investigations to more accurately assess the effects of these compounds. The background contamination by PCDD/Fs, and dl-PCBs in mothers living at industrial area in Rio de Janeiro is lower than that generally found in industrialized countries.

Method development for the simultaneous determination of polybrominated, polychlorinated, mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls and polybrominated diphenyl ethers in fish

An analytical methodology was developed for simultaneous determination of five groups of persistent organic pollutants (POPs) including polybrominated, polychlorinated and mixed brominated-chlorinated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs, PCDD/DFs and PXDD/DFs, respectively), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in fish samples. The presented analytical approach was based on well established and robust method for determination of PCDD/DFs and PCBs, which was augmented with gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) to include PBDEs, as well as poorly investigated PBDD/DFs and PXDD/DFs at toxicologically significant levels. Intensive clean-up and fractionation procedures in combination with optimized instrumental parameters provided reliable detection and quantification of these compounds. The application of (13)C12-labeled surrogates of analyzed compounds allowed the internal standardization and accurate measurement of selected contaminants. The developed procedure was validated while taking into account the Commission Regulation (EU) 252/2012 requirements for PCDD/DFs and PCBs, and was used to measure the occurrence of priority POPs in Baltic wild salmon.

Polychlorinated biphenyl (PCB) concentrations and congener composition in masu salmon from Japan: a study of all 209 PCB congeners by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS)

We collected two subspecies of masu salmon: Oncorhynchus masou masou from four localities (southern Sea of Japan northward to Hokkaido) and O. masou ishikawae from upstream from Ise Bay close to a heavy industrial area. All 209 PCB congeners were analyzed using HRGC/HRMS. PCA ordination of congener concentrations divided data into three groups: (i) ssp. masou from Hokkaido, (ii) ssp. masou from the other regions and (iii) ssp. ishikawae. The highest ∑ PCB concentration (40.39 ng/wet wt) was in ssp. ishikawae followed by ssp. masou from southern waters; however the TEQdioxin-like PCBs was highest in ssp. masou from southern water (1.96 pg-TEQdioxin-like PCBs/g wet wt.) due to the high proportion of congener #126 in its complement (#126 has the highest toxic equivalency factor among congeners). There is likely a contamination source offshore in the southern Sea of Japan and/or along the migratory route of ssp. masou.

Distribution of polycyclic aromatic hydrocarbon (PAH) residues in several tissues of edible fishes from the largest freshwater lake in China, Poyang Lake, and associated human health risk assessment

The residual levels, tissue distribution and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in edible fishes, bighead carp (Aristichthys nobilis) and silver carp (Hypophthalmichthys molitrix), from the largest freshwater lake in China, Poyang Lake, were studied. PAH concentrations ranged from 105 to 513ng g(-1)ww and from 53.9 to 401ng g(-1)ww in different tissues of bighead carp and silver carp, respectively. Low molecular weight (LMW) PAHs were the predominant compounds, suggesting the gill-water transfer might be the major exposure route for PAHs in the studied fish species. Tissue distribution indicated that the hepatobiliary system accumulated higher concentrations of PAHs than the extrahepatic tissues with bile being the most predominant tissue for both species. Composition analysis demonstrated that PAHs were from the combined petrogenic and pyrogenic origin, and the gasoline combustion might be the main source. A preliminary evaluation of human health risk using benzo[a]pyrene (BaP) potency equivalent concentration (PEC) as well as the incremental lifetime cancer risk (ILCR) indicated that PAHs in fish would induce potential carcinogenic effects.

Concentrations of organochlorine pesticides and polychlorinated biphenyls in human serum and their relation with age, gender, and BMI for the general population of Bizerte, Tunisia

Human serum samples (n = 113) from Bizerte, northern Tunisia, collected between 2011 and 2012 were analyzed for 8 organochlorine pesticides (OCPs) including p,p'-dichlorodiphenyltrichloroethane (DDT) and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexane isomers, dieldrin, and heptachlor and 12 polychlorinated biphenyls (PCBs) congeners. Concentrations of these residues in serum were determined by gas chromatography with electron capture detector and total cholesterol (CHOL) and triglycerides (TG) levels were evaluated by enzymatic colorimetric method. HCB, p,p'-DDE, PCB-138, PCB-153, and PCB-180, were the most abundant organochlorine compounds (OCs) detected in >95 % of the study subjects. The mean levels of p,p'-DDE and HCB in serum were 168.8 and 49.1 ng g(-1) lipid, respectively. The sum PCBs concentrations ranged from 37.5 to 284.6 ng g(-1) lipid in the samples, with mean and median value of 136.1 and 123.2 ng g(-1) lipid, respectively. The PCB profile consisted of persistent congeners, such as PCB-138, PCB-153, and PCB-180 which contributed for approximately 82.7 % to the ∑PCBs. Statistical analysis showed that most OCs correlated significantly with age, considering all samples together or with gender differentiation. The present study shows that the levels of p,p'-DDE and ∑DDTs were significantly higher in females than in males (p < 0.05), while PCBs levels were significantly higher in male (p < 0.05) than in females. No statistically significant association was found between body mass index and concentration of any organochlorine pesticide or PCB congeners 153, 138, 180, or ∑PCBs.

Synthesis and evaluation as biodegradable herbicides of halogenated analogs of L-meta-tyrosine

L-meta-tyrosine is an herbicidal nonprotein amino acid isolated some years ago from fine fescue grasses and characterized by its almost immediate microbial degradation in soil (half-life <24 h). Nine monohalogenated or dihalogenated analogs of this allelochemical have been obtained through a seven-step stereoselective synthesis from commercial halogenated phenols. Bioassays showed a large range of biological responses, from a growth root inhibition of lettuce seedling similar to that noted with m-tyrosine [2-amino-3-(2-chloro-5-hydroxyphenyl)propanoic acid or compound 8b] to an increase of the primary root growth concomitant with a delay of secondary root initiation [2-amino-3-[2-fluoro-5-hydroxy-3-(trifluoromethyl)phenyl]propanoic acid or compound 8h]. Compound 8b was slightly less degraded than m-tyrosine in the nonsterilized nutritive solution used for lettuce development, while the concentration of compound 8h remained unchanged for at least 2 weeks. These data indicate that it is possible to manipulate both biological properties and degradation of m-tyrosine by halogen addition.

Behavioral changes following PCB 153 exposure in the spontaneously hypertensive rat - an animal model of Attention-Deficit/Hyperactivity Disorder

Background

Attention-Deficit/Hyperactivity Disorder (ADHD) is a behavioral disorder affecting 3-5% of children. Although ADHD is highly heritable, environmental factors like exposure during early development to various toxic substances like polychlorinated biphenyls (PCBs) may contribute to the prevalence. PCBs are a group of chemical industrial compounds with adverse effects on neurobiological and cognitive functioning, and may produce behavioral impairments that share significant similarities with ADHD. The present study examined the relation between exposure to PCB 153 and changes in ADHD-like behavior in an animal model of ADHD, the spontaneously hypertensive rats (SHR/NCrl), and in Wistar Kyoto (WKY/NHsd) controls.

Methods

SHR/NCrl and WKY/NHsd, males and females, were orally given PCB 153 dissolved in corn oil at around postnatal day (PND) 8, 14, and 20 at a dosage of 1, 3 or 6 mg/kg bodyweight at each exposure. The control groups were orally administered corn oil only. The animals were behaviorally tested for exposure effects from PND 37 to 64 using an operant procedure.

Results

Exposure to PCB 153 was associated with pronounced and long-lasting behavioral changes in SHR/NCrl. Exposure effects in the SHR/NCrl depended on dose, where 1 mg/kg tended to reduce ADHD-like behaviors and produce opposite behavioral effects compared to 3 mg/kg and 6 mg/kg, especially in the females. In the WKY/NHsd controls and for the three doses tested, PCB 153 exposure produced a few specific behavioral changes only in males. The data suggest that PCB 153 exposure interacts with strain and sex, and also indicate a non-linear dose–response relation for the behaviors observed.

Conclusions

Exposure to PCB 153 seems to interact with several variables including strain, sex, dose, and time of testing. To the extent that the present findings can be generalized to humans, exposure effects of PCB 153 on ADHD behavior depends on amount of exposure, where high doses may aggravate ADHD symptoms in genetically vulnerable individuals. In normal controls, exposure may not constitute an environmental risk factor for developing the full range of ADHD symptoms, but can produce specific behavioral changes.

Environmental toxins

This review comprehensively summarizes the effects of more than 15 mostly used pesticides on male reproductive physiology, as recent experimental and epidemiological research have indicated their alarming impact on overall human health. Mechanisms have described that pesticide exposure damages spermatozoa, alter Sertoli or Leydig cell function, both in vitro and in vivo and thus affects semen quality. But, the literature suggests a need for more intricate research in those pesticides that are defined as mutagens or carcinogens and directly affect the hypothalamic–pituitary–gonadal axis. This literature review also proposes specific solutions to overcome these health effects.

Pesticides residues in okra (non-target crop) grown close to a watermelon farm in Ghana

The study looked at the levels of pesticides in okra grown close to a watermelon farm herein referred to as a non-target crop. The watermelon received some pesticide application in the course of its cultivation, and the okra which was not meant to be sprayed was also affected by the pesticide. About 500 okra samples were collected for a period of 6 weeks and pesticides extracted with 1:1 n-hexane and dichloromethane which was analysed with Agilent 2222 GC/MS coupled with 389 auto-sampler. The results confirmed accumulation of significant levels of pesticides in the non-target crop (okra grown close to watermelon farm). Levels of organochlorine pesticides ranged from 3.10 to 7.60 μg/kg whilst the organophosphorus pesticides had levels ranging from 2.80 to 2016.80 μg/kg. The synthetic pyrethroid pesticide mean levels also ranged from 0.10 to 4.10 μg/kg and were below World Health Organization/Food and Agriculture Organization-recommended residue levels, and though not appearing to constitute a grave threat to life, their occurrence is a concern, and pre-emptive techniques must be developed to thwart the contaminations. Though the non- target crop was not treated directly with the pesticides, some level of contamination with organochlorine and organophosphorus pesticides persisted in the crops. It can be inferred that application of pesticides affected the adjoining crops, meaning that inter-cropping and mix-cropping might not be acceptable when one of the crops requires pesticide application. It is important for the farmers to be trained to ensure proper application of pesticide to minimise its impact on the health of consumers.

Spatial and temporal trends of contaminants in mussel sampled around the Icelandic coastline

Contaminants have been determined in blue mussels (Mytilus edulis) at 11 locations around the Icelandic coastline from 1990 to 2010. The aim of the present study was to investigate if there has been a change in concentration of contaminants around the Icelandic coastline for the last two decades and if the concentrations and changes, if present, were consistent between locations. Concentrations of the persistent organic pollutants, p,p'-dichlorodiphenyldichloroethene (p,p'-DDE), hexachlorobenzene (HCB), α-hexachlorocyclohexane (α-HCH), polychlorinated biphenyl (PCB-153) and trans-nonachlor, have decreased at most of the sampling locations in Iceland in recent years. However, an increasing trend was found at a few locations that could be explained by anthropogenic activity. The concentration levels of the persistent organics were much lower than found at the Norwegian, USA and Chinese coasts, especially levels of p,p'-DDE. The concentration of copper and selenium had a consistent pattern of change and concentration between locations over the period which showed a decreasing trend in recent years. The trace elements arsenic, cadmium, mercury and zinc showed more variation in concentration between locations, the concentration of arsenic, mercury and zinc was fairly stable over the period, whereas there were fluctuations in cadmium concentrations. The concentrations of cadmium and zinc were observed to be somewhat higher than found in mussels from Norway, USA and China but values of mercury and lead were much lower in the mussel sampled in Iceland. The higher concentrations of cadmium and zinc can be explained by the volcanic activity in Iceland but no major anthropogenic sources of trace elements are known in Iceland.

QSPR modeling of n-octanol/air partition coefficients and liquid vapor pressures of polychlorinated dibenzo-p-dioxins

The molecular geometries of 75 polychlorinated dibenzo-p-dioxins (PCDDs) were optimized using B3LYP/6-31G(*) method. The calculated structural parameters were taken as theoretical descriptors to establish two new novel QSPR models for n-octanol/air partition coefficients (log K(OA)) and subcooled liquid vapor pressure (log P(L)) of PCDDs. The R(2) values of the two models are 0.983 and 0.985 respectively. Their standard deviations of prediction in modeling (SD) are 0.174 and 0.230 respectively. The results of leave-one-out (LOO) cross-validation for training set show that the two models exhibited optimum stability and good predictive power.

Polycyclic aromatic hydrocarbons and halogenated persistent organic pollutants in canned fish and seafood products: smoked versus non-smoked products

In this study, levels of several groups of environmental contaminants represented by PAHs, PCBs, organochlorine pesticides and polybrominated diphenyl ethers were determined in various types of canned smoked and non-smoked fish and seafood products (54 samples) obtained from the Czech market. PAHs were detected in all of the studied samples, and at least one of the target halogenated persistent organic pollutants was present above the LOQ in 85% of the samples. The levels of PAHs, PCBs, organochlorine pesticides (mainly DDTs) and polybrominated diphenyl ethers found in the canned products varied in the range of 1.4-116 µg kg(-1), 0.6-59.6 µg kg(-1), 0.6-82.7 µg kg(-1) and 0.1-2.1 µg kg(-1) can content, respectively. Smoked sprats were the most contaminated fish product (n = 12) in which the highest levels of both PAHs and persistent organic pollutants were found. In 67% of the samples of smoked sprats in oil, the level of benzo[a]pyrene exceeded the maximum level of 5 µg kg(-1) established for smoked fish by European Union legislation. The distribution of target analytes between oil and fish fractions was also assessed. Significantly higher levels of PAHs were measured in the oil fraction.

Determination of chlorinated pesticides, polychlorinated biphenyls, and polybrominated diphenyl ethers in human milk from Bizerte (Tunisia) in 2010

Thirty persistent organohalogen compounds including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in breast milk samples (n=36) of primipara and multipara mothers from Bizerte in 2010. The analytical procedure involved the application of liquid-liquid extraction and gas chromatography with electron capture detector (GC-ECD) or mass spectrometry detector (GC-MS) for identification and quantification. Organohalogen compounds were found in all the analyzed samples, with predominance of p,p'-DDE, p,p'-DDT, p,p'-DDD, HCB and PCBs. The mean concentration of ∑DDTs in breast milk was 1163.9 ng g(-1) lipid wt. The ratio of p,p'-DDE/p,p'-DDT was low, suggesting that there is fresh intake of commercial DDT products in Bizerte. The mean levels of HCB and PCB were 286.8 and 331.2 ng g(-1) lipid wt respectively. These results were compared with the levels obtained in a previous study carried out in the same area in 2003. A general decrease of ∑DDTs levels and an increase of PCB levels were observed. Among the 10 PBDE congeners evaluated, BDE-28, BDE-47, BDE-99, BDE-66, BDE-138, BDE-100, BDE-154, BDE-153, and BDE-183 were detected in the analyzed samples at different frequency. The total PBDE concentrations ranged from 2.5 to 22.6 ng g(-1) lipid wt in the samples, with a mean and median value of 10.7 and 9.8 ng g(-1) lipid wt respectively. To our knowledge, this is the first data of PBDEs in Tunisian human milk. The present study shows that age and parity are factors influencing the levels of some organohalogen compounds in human milk.

Levels of polychlorinated biphenyls and organochlorine pesticides in edible shellfish from Xiamen (China) and estimation of human dietary intake

Xiamen is a representative coastal city in China. Shellfish is widely consumed by local people. A broad spectrum of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were measured in representative shellfish from Xiamen. Despite being banned many years ago, these chemicals were still detected at varying levels. The total PCB levels ranged from 0.48 to 3.28 ng/g wet wt. for the shellfish surveyed. The tetra-, penta- and hexa-PCB congeners were found to be predominant. The estimated WHO-TEQ PCB intakes through shellfish consumption ranged from 0.063 to 0.102 pg/kg body wt. for Xiamen adults and children, which were significantly lower than tolerable weekly intake. Among OCPs, DDTs were predominant, followed by aldrin-like chemicals and endosulfans. The increase in aldrin-like chemicals and endosulfans, and the decrease in DDTs were observed in this study when compared to historical data in Xiamen. HCHs, chlordanes, HCB, heptachlors and mirex were detected with low concentrations in the shellfish. The estimated intakes of OCPs were several orders lower than tolerable daily intakes. However, the high carcinogenic risk of aldrin and dieldrin were found in the measured shellfish species. p,p'-DDD, p'p-DDT, α-HCH and β-HCH in certain species should also be concerned for their potential carcinogenic risks.

A review of endosulfan, dichlorvos, diazinon, and diuron--pesticides used in Jamaica

The global agricultural sector is the primary user of pesticides, consuming more than three billion kilograms of pesticides annually. Although pesticides are beneficial in controlling the proliferation of pests, they have been associated with adverse human and ecological impacts. Approximately 87% of the annually imported pesticides in Jamaica are applied within agricultural or household settings. However, in Jamaica, the potential impact on humans, their property, and the environment is unknown, as the fate of many of the locally applied pesticides has not been established. This review discusses four pesticides extensively applied in agricultural practices in Jamaica - endosulfan, diazinon, diuron, and dichlorvos. The information presented is essential for the development of fate and transport models of these chemicals. Consequently, health and ecological impact assessments may be conducted from the generated models.

Polychlorinated biphenyls and organochlorine pesticides in plasma of older Canadians

No nationwide study has ever measured polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) body burden in Canadians aged 65 years and over. The objective of this study was to determine plasma concentrations of PCB congeners and OCPs in participants from a sub-cohort of the Canadian Study of Health and Aging and to examine the effects of socio-demographic, anthropometric and lifestyle characteristics on selected organochlorine concentrations. Archived plasma samples collected from 2023 subjects were analyzed by gas chromatography-mass spectrometry using negative chemical ionization for 15 PCB congeners and 11 OCPs. Descriptive statistics were used to report PCB congeners and OCP plasma concentrations. Multivariate models were used to study whether age at blood collection, sex, education, body mass index, rural residence, geographic region, smoking status and alcohol intake influences PCB 153, the most abundant congener, and the major OCP (beta-hexachlorocyclohexane, hexachlorobenzene, trans-nonachlor, p,p'-DDE) plasma concentrations. Statistical analyses were restricted to 1979 subjects and 17 organochlorine compounds for which at least 50% of the samples had concentrations above the limit of detection. Of these, 775 were men (mean age: 82.2 years) and 1204 were women (mean age: 84.6 years). The median concentrations (ng/g lipid) of PCB 153 in the plasma of men and women were 70.9 and 75.4, respectively. The levels of the sum of PCBs and the sum of dioxin-like PCBs were 276 and 31.3 for men, and 300 and 45.5 for women, respectively. The median concentrations (ng/g lipid) of p,p'-DDE, the most abundant OCP, were 565 for men and 828 for women. All compounds were positively and significantly intercorrelated (rs=0.39-0.99; p<0.001). Except for trans-nonachlor, the multivariate models revealed that age and male sex were the determining characteristics that showed, respectively, strongly positive and negative associations with selected organochlorine concentrations. These plasma concentrations from a large population based study can be considered as baseline data for body burdens of older Canadians.

Non-dioxin-like PCBs in ten different fish species from the Danube river in Serbia

This work has been developed to examine the level of non-dioxin-like (ndl) PCBs (28, 52, 101, 138, 153 and 180) in (a) ten different freshwater fish species from the Danube river, (b) two sampling points: up and downstream of the industrial zone of the city of Pancevo (ecological hot spot in Serbia) and (c) two time points i.e., in 2001 and 2006. Obtained results would serve to analyse spatial, temporal and congener profile characteristics of ndl PCBs cumulated in fish tissues due to environmental pollution. Sixty-four samples of the following species were collected: wels (Silirus glanus), pike (Esox lucius), bream (Abramis brama), crucian carp (Carassius carassius), pike pearch (Stizostedion lucioperca), barbel (Barbus barbus), tench (Tinca tinca), sterlet (Acipenser ruthenus L.), common carp (Cyprinus carpio) and bighead carp (Hypophthalmichthys nobilis). Gas chromatography coupled with electron capture detector was used for analysis of ndl PCBs. Total ndl PCBs content in upstream samples ranged from 2.7 to 98.1 ng/g and from 4.9 to 68.3 ng/g in 2001 and 2006, respectively. During the 5 years, ndl PCBs content increased significantly in downstream samples i.e., ndl PCBs varied from 13.7 to 46.1 ng/g and from 14.4 to 107.2 ng/g in 2001 and 2006, respectively. PCBs 138 and 180 were predominant congeners in 2001, while in 2006 the most abundant PCB congeners were 138 and 153. In 2006, the presence of PCB 28 and PCB 52 has indicated a recent contamination event. Data on continual monitoring of PCBs in all relevant environmental compartments together with appropriate biomonitoring data are expected to give comprehensive insight into the fate and behaviour profile of these contaminants.

Shellfish from Todos os Santos Bay, Bahia, Brazil: treat or threat?

This study determined the concentrations of major and trace elements in shellfish (oysters, clams and mussels) and conducted an assessment of the health risks due to the consumption of contaminated seafood. Samples were collected at 34 sites along Todos os Santos Bay, Brazil. The elements were determined by ICP OES and Hg by Direct Mercury Analysis. Relatively high concentrations of trace elements (As, Zn, Se and Cu) were found in seafood tissues. Potential daily intake of As, Co, Se, Zn and Cu associated to shellfish consumption suggested relevant non-carcinogenic risk for all studied locations. Copper was the element that posed the greatest non-carcinogenic risk, while Pb posed the highest carcinogenic risk. Health risks for humans were greatest from the consumption of mussels. Contaminated shellfish offer the greatest risk for children, subsistence fishers and subsistence shellfish consumers.

Largemouth bass (Micropterus salmoides) and striped mullet (Mugil cephalus) as vectors of contaminants to human consumers in northwest Florida

The health benefits of regular consumption of fish and seafood have been espoused for many years. However, fish are also a potential source of environmental contaminants that have well known adverse effects on human health. We investigated the consumption risks for largemouth bass (Micropterus salmoides; n = 104) and striped mullet (Mugil cephalus; n = 170), two commonly harvested and consumed fish species inhabiting fresh and estuarine waters in northwest Florida. Skinless fillets were analyzed for total mercury, inorganic arsenic, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F), polychlorinated biphenyls (PCBs), and organochlorine pesticides. Contaminant levels were compared to screening values (SV) calculated using U.S. Environmental Protection Agency (EPA) recommendations for establishing consumption advisories. Largemouth bass were found to contain high levels of total mercury at all sampling locations (0.37-0.89 ug/g) and one location exhibited elevated total PCBs (39.4 ng/g). All of the samples exceeded Florida fish consumption advisory trigger levels for total mercury and one location exceeded the U.S. EPA SV for total PCBs. As a result of the high mercury levels, the non-cancer health risks (hazard index-HI) for bass were above 1 for all locations. Striped mullet from several locations with known point sources contained elevated levels of PCBs (overall range 3.4-59.3 ng/g). However, total mercury levels in mullet were low. Eight of the 16 mullet sampling locations exceeded the U.S. EPA SV for total PCBs and two locations exceeded an HI of 1 due to elevated PCBs. Despite the elevated levels of total PCBs in some samples, only two locations exceeded the acceptable cancer risk range and therefore cancer health risks from consumption of bass and mullet were determined to be low at most sampling locations.

Risk characterization for mercury, dichlorodiphenyltrichloroethane and polychlorinated biphenyls associated with fish consumption in Serbia

The aim of this work was to assess the risk due to mercury (Hg), dichlorodiphenyltrichloroethane (DDT) and non-dioxin-like polychlorinated biphenyls (ndl PCBs) intake via fish consumption in Serbia. We have developed 24 scenarios using four concentration levels (mean, maximum, 50th and 95th percentile) of contaminants, determined in 521 samples of fish products available on Serbian market; two consumption levels (Food and Agriculture Organization/World Health Organization data and recommendation of American Heart Association); and three body weights (5th, 50th and 95th percentile). All the values concerning the intake of DDT are below the corresponding health based guidance value. Calculated weekly intake of Hg using maximal concentration, intake of 340g/week and 5th percentile of body weight exceeded the provisional tolerable weekly intake (PTWI). When maximal and 95th percentile concentration of ndl PCBs was used, weekly intakes exceeded a "guidance value" with one exception i.e., when 95th percentile of concentration along with 95th percentile of body weight were used. Concerning Hg and ndl PCBs, when extreme concentrations were used, HIs exceeded the value of 1, indicating that fish and fishery products may pose a threat to consumer's health.

Placental docosahexaenoic and arachidonic acids correlate weakly with placental polychlorinated dibenzofurans (PCDF) and are uncorrelated with polychlorinated dibenzo-p-dioxins (PCDD) or polychlorinated biphenyls (PCB) at delivery: a pilot study

Long chain polyunsaturated fatty acids (LC-PUFA), ARA (arachidonic acid, 20:4n-6) and DHA (docosahexaenoic acid, 22:6n-3) have positive effects and environment pollutants, polychlorinated dibenzo-p-dioxins/dibenzofurans(PCDD/F) and polychlorinated biphenyls (PCB) have negative effects on neural development during early life. Placental dioxin/PCB serves as markers for cumulative exposure to fetus. Fatty acid composition of placenta depends on nutrient supply during pregnancy, serving as indicators for fetal ARA and DHA accretion. This study investigated correlation between placental PCDD/F and PCB toxic equivalent (TEQ) and LC-PUFA in 34 pregnant women from Taiwan. Placental PCDF TEQ were inversely correlated with placental ARA (p=0.020), C20:3n-6 (p=0.01), C22:4n-6 (p=0.04), C22:5n-6 (p<0.01) and with DHA (p=0.03), but ARA and DHA did not vary with PCDD, dioxin-like and indicator PCB. After adjustment for age and body mass index, a one-unit PCDF TEQ increase was associated with 1.021%w/w and 0.312%w/w decreases in ARA (β=-1.021, p=0.03) and DHA (β=-0.312, p=0.03). Since ARA and DHA were unrelated to three classes of toxins, and a weak negative association was found with PCDF, these data provide no basis for discouraging marine fish consumption during pregnancy for Taiwan women on the basis of these organics. Pregnant women should consume fish for its unique package of nutrients while avoiding few species with high organic pollutant or mercury contamination.

Anthropogenic organic contaminants in water, sediments and benthic organisms of the mangrove-fringed Segara Anakan Lagoon, Java, Indonesia

Segara Anakan, a mangrove-fringed coastal lagoon in Indonesia, has a high diversity of macrobenthic invertebrates and is increasingly affected by human activities. We found > 50 organic contaminants in water, sediment and macrobenthic invertebrates from the lagoon most of which were polycyclic aromatic compounds (PACs). Composition of PACs pointed to petrogenic contamination in the eastern lagoon. PACs mainly consisted of alkylated PAHs, which are more abundant in crude oil than parent PAHs. Highest total PAC concentration in sediment was above reported toxicity thresholds for aquatic invertebrates. Other identified compounds derived from municipal sewage and also included novel contaminants like triphenylphosphine oxide. Numbers of stored contaminants varied between species which is probably related to differences in microhabitat and feeding mode. Most contaminants were detected in Telescopium telescopium and Polymesoda erosa. Our findings suggest that more attention should be paid to the risk potential of alkylated PAHs, which has hardly been addressed previously.

Levels and distribution of polybrominated diphenyl ethers and organochlorine compounds in sea turtles from Japan

Three species of sea turtles (green, hawksbill and loggerhead turtles) stranded along the coasts or caught (by-catch) around Ishigaki Island and Kochi, Japan were collected between 1998 and 2006 and analyzed for six organohalogen compounds viz., PBDEs, PCBs, DDTs, CHLs, HCHs and HCB. The present study is the first and foremost to report the occurrence of organohalogen compounds in the sea turtles from Japan. Among the compounds analyzed, concentrations of PCBs, DDTs and CHLs were the highest in all the turtle samples. PBDEs were ubiquitously present in all the turtle species. Comparing with the other two species, concentrations of organohalogens in green turtle were relatively low and decreasing trend in the concentrations were noted with increasing carapace length. Concentrations of OCs in sea turtles from the coasts of Ishigaki Island and Kochi were relatively low as compared to those from other locations in the world.

Review on the use of enzymes for the detection of organochlorine, organophosphate and carbamate pesticides in the environment

Pesticides are released intentionally into the environment and, through various processes, contaminate the environment. Three of the main classes of pesticides that pose a serious problem are organochlorines, organophosphates and carbamates. While pesticides are associated with many health effects, there is a lack of monitoring data on these contaminants. Traditional chromatographic methods are effective for the analysis of pesticides in the environment, but have limitations and prevent adequate monitoring. Enzymatic methods have been promoted for many years as an alternative method of detection of these pesticides. The main enzymes that have been utilised in this regard have been acetylcholinesterase, butyrylcholinesterase, alkaline phosphatase, organophosphorus hydrolase and tyrosinase. The enzymatic methods are based on the activation or inhibition of the enzyme by a pesticide which is proportional to the concentration of the pesticide. Research on enzymatic methods of detection, as well as some of the problems and challenges associated with these methods, is extensively discussed in this review. These methods can serve as a tool for screening large samples which can be followed up with the more traditional chromatographic methods of analysis.

Environmental contaminants and human health in the Canadian Arctic

The third Canadian Arctic Human Health Assessment conducted under the Canadian Northern Contaminants Program (NCP), in association with the circumpolar Arctic Monitoring and Assessment Programme (AMAP), addresses concerns about possible adverse health effects in individuals exposed to environmental contaminants through a diet containing country foods. The objectives here are to: 1) provide data on changes in human contaminant concentrations and exposure among Canadian Arctic peoples; 2) identify new contaminants of concern; 3) discuss possible health effects; 4) outline risk communication about contaminants in country food; and 5) identify knowledge gaps for future contaminant research and monitoring. The nutritional and cultural benefits of country foods are substantial; however, some dietary studies suggest declines in the amount of country foods being consumed. Significant declines were found for most contaminants in maternal blood over the last 10 years within all three Arctic regions studied. Inuit continue to have the highest levels of almost all persistent organic pollutants (POPs) and metals among the ethnic groups studied. A greater proportion of people in the East exceed Health Canada's guidelines for PCBs and mercury, although the proportion of mothers exceeding these guidelines has decreased since the previous assessment. Further monitoring and research are required to assess trends and health effects of emerging contaminants. Infant development studies have shown possible subtle effects of prenatal exposure to heavy metals and some POPs on immune system function and neurodevelopment. New data suggest important beneficial effects on brain development for Inuit infants from some country food nutrients. The most successful risk communication processes balance the risks and benefits of a diet of country food through input from a variety of regional experts and the community, to incorporate the many socio-cultural and economic factors to arrive at a risk management decision that will be the most beneficial in Arctic communities.

Dietary intake and potential health risk of DDTs and PBDEs via seafood consumption in South China

A total of 602 seafood samples, including fish, shrimps, crabs and molluscs, were analyzed for a suite of persistent halogenated compounds. The residual levels of DDTs (sum of o,p'- and p,p'-DDT, DDD, and DDE) and polybrominated diphenyl ethers (PBDEs) varied significantly among different species, and ranged from non-detectable (nd) to 699 ng/g and nd to 5.93 ng/g, respectively. Comparison of the levels of DDTs and PBDEs in mussel samples worldwide suggested that South China is probably one of the most DDT-polluted areas, but is moderate at most in terms of PBDE contamination. Combined with a recent dietary survey at the same sampling locations, dietary intakes of DDTs and PBDEs by local residents via seafood consumption for all age groups were estimated to be 147-564 and 4.7-18.5 ng/day, or 8.5-12.9 and 0.27-0.46 g/kg bw/day, respectively. Among the different seafood types, fish contributed the largest portion of the dietary intakes of DDTs (57%), followed by molluscs (38%). Similarly, the dietary intakes of PBDEs were also dominated by fish (45%) and molluscs (45%). Assessment based on several available guidelines suggested that though no significant human health risk associated with the dietary intake of PBDEs, a lifetime cancer risk from dietary exposure to DDTs remains a probability. Because dietary intake of DDTs was dominated by fish and molluscs, added concern should be paid to fish and molluscs.

Reconcilable differences: the use of reference material to reduce methodological artifacts in the reporting of organochlorine pesticides and polychlorinated biphenyls

Numerous long-term monitoring programs have assessed spatial and temporal trends of organochlorine (OC) pesticides and polychlorinated biphenyls (PCBs). Changes in analytical approaches (e.g., gas chromatography coupled with electron capture detection [GC-ECD] versus mass spectrometric detection [GC-MSD]) can reveal artifacts in the reported concentrations. In-house reference material (RM) was used to determine the analytical artifacts in the measurement of OCs and PCBs in Great Lake herring gull eggs previously analyzed from 1994 to 1996 (GC-ECD) and 1997 to 1999 (GC-MSD). Approximately 19.0% of the variability of PCB congeners in gull eggs was associated with analytical artifacts, and differences among colonies were obscured. Although the discrepancy in sum PCBs (SigmaPCBs) was fairly small (2.1%), some congeners varied considerably between methods (> 60%). After statistically removing the artifacts, only 1.4% of the variability in PCBs of herring gull eggs was associated with artifacts, and differences among gull colonies became apparent. After excluding OCs near the detection limit in the RM, statistically removing the artifacts reduced some of the differences between methods for OCs. Analytical artifacts may potentially render inferences difficult, confounded, and erroneous. When combining contaminant data obtained using different methods, the methods should be assumed to give different results unless demonstrated otherwise. Assessments of the compatibility of analytical methodologies should be made using an appropriate RM.

Effects of methyl mercury in combination with polychlorinated biphenyls and brominated flame retardants on the uptake of glutamate in rat brain synaptosomes: a mathematical approach for the study of mixtures

Regulatory limit values for toxicants are in general determined by the toxicology of the single compounds. However, little is known about their combined effects. Methyl mercury (MeHg), polychlorinated biphenyls (PCBs), and brominated flame retardants (BFRs) are dominant contaminants in the environment and food. MeHg is a well known neurotoxicant, especially affecting the developing brain. There is increasing evidence that PCB and BFRs also have neurotoxic effects. An enhanced effect of these toxicants, due to either synergistic or additive effects, would be considered as a risk for the fetal development. Here we studied the combinatorial effects of MeHg in combination with PCB or BFR on the reuptake of glutamate in synaptosomes. To provide the optimal conclusion regarding type of interaction, we have analyzed the data using two mathematical models, the Löewe model of additivity and Bliss' model of independent action. Binary and ternary mixtures in different proportions were made. The toxicants had primarily additive effects, as shown with both models, although tendencies towards synergism were observed. MeHg was by far the most potent inhibitor of uptake with an EC(50) value of 0.33 microM. A reconstituted mixture from a relevant fish sample was made in order to elucidate which chemical was responsible for the observed effect. Some interaction was experienced between PCB and MeHg, but in general MeHg seemed to explain the observed effect. We also show that mixture effects should not be assessed by effect addition.

PCBs contamination in farmed European sea bass from different Italian rearing systems

The chemical composition and the level of twelve PCB congeners (IUPAC Nos. 18, 28, 31, 44, 52, 101, 118, 138, 149, 153, 180 and 194) were determined in 133 specimens of European sea bass (Dicentrarchus labrax), collected from four Italian aquaculture facilities: extensive valley, semi-intensive ponds, intensive concrete tanks and sea-cages. Fish muscle composition varied based on the rearing system (P<0.001): moisture was higher and fat concentration was lower in fish from the extensive system in comparison to fish from intensive tanks; intermediate values were found in fish from semi-intensive ponds and sea-cages. Concentrations of the 12 measured PCBs (PCB(tot)) and of the seven indicator congeners (PCB(7)) (Nos. 28, 52, 101, 118, 138, 153 and 180), when expressed on fat weight, were lower in extensively-reared sea bass (112.0 and 74.6 ng g(-1) fat, respectively) with respect to sea bass from the other systems (average values: 179.7 and 123.2 ng g(-1) fat) (P<0.001). When the values were expressed on fresh muscle weight, PCB(tot) and PCB(7) were lower in extensively-reared sea bass (3.412 and 2.266 ng g(-1)fw), intermediate in fish from semi-intensive ponds (15.398 and 10.632) and sea cages (13.123 and 8.882), and higher in specimens from the intensive tanks (18.176 and 12.440) (P<0.001). PCB 153 was the most abundant in all of the rearing systems. Within farm, muscular fat content and slaughter weight were positively correlated (r=0.79). PCB(7) concentration expressed in ng g(-1) fat and in ng g(-1) fw was positively correlated with both fish slaughter weight (r=0.71 and 0.73) and muscular fat concentration (r=0.86 and 0.96).

Removal of dioxins and dioxin-like PCBs from fish oil by countercurrent supercritical CO2 extraction and activated carbon treatment

It has been known that fish oils are prone to contamination by polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs). In this study, the removal of contaminants from fish oil by countercurrent supercritical CO(2) extraction (CC-SCE) and activated carbon treatment was investigated. Fish oil was treated by CC-SCE at 70 degrees C and 30MPa and with a CO(2)/oil ratio of 72; this resulted in a 93% reduction in the sum of PCDDs, PCDFs and DL-PCBs concentration level by and 85% reduction in toxic equivalency (TEQ). CC-SCE uses 40% less CO(2) and yields 30% more refined oil than semi-batch-type processes. Subsequent treatment by activated carbon reduced the concentration level by 94% and TEQ by 93%. CC-SCE is effective for the removal of DL-PCBs, whereas activated carbon treatment is effective for the removal of PCDD/Fs. These results reveal that the combination of CC-SCE and activated carbon treatment is applicable to the removal of PCDD/Fs and DL-PCBs from fish oil.

Historical milestones and discoveries that shaped the toxicology sciences

Knowledge of the toxic and healing properties of plants, animals, and minerals has shaped civilization for millennia. The foundations of modern toxicology are built upon the significant milestones and discoveries of serendipity and crude experimentation. Throughout the ages, toxicological science has provided information that has shaped and guided society. This chapter examines the development of the discipline of toxicology and its influence on civilization by highlighting significant milestones and discoveries related to toxicology. The examples shed light on the beginnings of toxicology, as well as examine lessons learned and re-learned. This chapter also examines how toxicology and the toxicologist have interacted with other scientific and cultural disciplines, including religion, politics, and the government. Toxicology has evolved to a true scientific discipline with its own dedicated scientists, educational institutes, sub-disciplines, professional societies, and journals. It now stands as its own entity while traversing such fields as chemistry, physiology, pharmacology, and molecular biology. We invite you to join us on a path of discovery and to offer our suggestions as to what are the most significant milestones and discoveries in toxicology. Additional information is available on the history section of Toxipedia (www.toxipedia.org).

Distribution of polychlorinated biphenyls and organochlorine pesticides in human breast milk from various locations in Tunisia: levels of contamination, influencing factors, and infant risk assessment

The concentrations of dichlorodiphenytrichloroethane and its metabolites (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexane isomers (HCHs), dieldrin, and 20 polychlorinated biphenyls (PCBs) were determined in 237 human breast milk samples collected from 12 locations in Tunisia. Gas chromatography with electron capture detector (GC-ECD) was used to identify and quantify residue levels on a lipid basis of organochlorine compounds (OCs). The predominant OCs in human breast milk were PCBs, p,p'-DDE, p,p'-DDT, HCHs, and HCB. Concentrations of DDTs in human breast milk from rural areas were significantly higher than those from urban locations (p<0.05). With regard to PCBs, we observed the predominance of mid-chlorinated congeners due to the presence of PCBs with high K(ow) such as PCB 153, 138, and 180. Positive correlations were found between concentrations of OCs in human breast milk and age of mothers and number of parities, suggesting the influence of such factors on OC burdens in lactating mothers. The comparison of daily intakes of PCBs, DDTs, HCHs, and HCB to infants through human breast milk with guidelines proposed by WHO and Health Canada shows that some individuals accumulated OCs in breast milk close to or higher than these guidelines.

Monitoring of polychlorinated biphenyl contamination and estrogenic activity in water, commercial feed and farmed seafood

We evaluated the concentration and congener distribution of seven "target" polychlorinated biphenyls (PCBs) present in water collected in different aquaculture farms of the Mediterranean area, commercial feeds, and farmed seafood. PCBs were present in feed and in tissues of all the analysed organisms at levels ranging from 1.96 ng g(-1) to 124.00 ng g(-1) wet weight, and in 10.5% of the water samples, at levels from under detection limit to 33.0 ng l(-1) with total PCB concentrations significantly higher in samples from the Tyrrhenian Sea than the Adriatic Sea. PCB congener distribution in tissues resembled that of feed, suggesting that commercial feed is an important source of PCBs. The estrogenicity of organic extracts of the samples was also evaluated by using an in vitro yeast reporter assay. Estrogenic activity higher than 10% of the activity induced by 10 nM 17 beta-estradiol was observed in 20.0% of seafood samples and 15.8% of water samples. Seafood and water samples from the Tyrrhenian Sea were more frequently estrogenic than the Adriatic ones (16.45 versus 4.08%). A significant correlation of total PCB concentrations on biological activity was observed for sea bass and mussels from the Adriatic Sea (p < 0.045 and p < 0.04, respectively), and for sea bass of the Tyrrhenian Sea (p = 0.05). These results indicate the need of an integral approach in the exposure assessment to potential toxic compounds for human via food.