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PubMedDate not supplied

Determination of heavy metals and pesticides in ginseng products.

Medicinal plants may carry residuals of environmentally persistent pesticides or assimilate heavy metals in varying degrees. Several factors may influence contaminant accumulation, including species, level and duration of contaminant exposure, and topography. As part of a program for assessment of the quality of herbal medicines, we have analyzed 21 over-the-counter ginseng (Panax ginseng) products in various dosage forms. Chromium, mercury, and arsenic were undetectable above their limits of detection in both liquid and solid samples; while cadmium, lead, and nickel were present in the majority of samples. The chlorinated pesticide levels varied widely. In most samples, the total concentration of pesticides was below 100 ppb; while in 5 samples the total concentration exceeded 100 ppb.

Arsenic↗

PubMed2007

Thermodynamical and quantum-chemical characterization and chemometrical selection of representative congeners of trans-chloroazoxybenzene.

Polychlorinated trans-azoxybenzenes (PCt-AOBs) consist a group of 399 theoretically possible congeners, which are toxicologically and environmentally relevant compounds. Some of PCt-AOBs have been identified as by-side impurity in technical grade 3,4-dichloroaniline (3,4-DCA), and also in derived of this chemical pesticides such as Diuron, Linuron or Propanil. In this study 31 quantum-chemical descriptors were in silico generated and used to characterize all 399 PCt-AOBs. Further, the basic thermodynamic and quantum-chemical property data matrix of PCt-AOBs made was interpreted with an aid of the Principal Component Analysis (PCA). The PCA of these data matrix created a three-dimensional model that explained 77.31% (63.79% + 8.87% + 4.65%) of the total variance. Polarizability, molecular weight, logarithm of the n-octanol/water partition coefficient, molecular refraction, valence molecular index, kappa index, molecular connectivity index, thermal capacity and entropy were the best positively correlated descriptors, which all are connected with molecular shape and size of the molecules. They all are explained by the first principal component (PC1), while energy of the highest occupied molecular orbital, Gibbs free energy in gas phase, standard heat of formation, the total particle energy and thermal energy were negatively correlated. The PC2 depended on polarizability vector Z and energy of the lowest unoccupied molecular orbital, while the PC3 was negatively impacted by the most positive partial charge on atoms. The congeners of trans-PCAOBs substituted with chlorine at positions 2' (ortho position) are non-planar. 119 Congeners of trans-chloroazoxybenzene (Ct-AOB) could be classified amongst stereoisomers (analogues) to highly toxic and environmentally persistent 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). Data obtained after PCA were further used to create Fractional Factorial Design of PCt-AOBs and eight congeners, i.e., 2',3'-DiCt-AOB (no. 11), 2,2',5-TrCt-AOB (no. 32), 3',4'-DiCt-AOB (no. 24), 2,4,5-TrCt-AOB (no. 58), 2,2',3,4',5,5'-HeCt-AOB (no. 271), 2,2',3',4',5,5',6'-HpCt-AOB (no. 360), 2,3,3',4,4',5',6-HpCt-AOB (no. 364) and 2,2',3,3',4',5',6'-HpCt-AOB (no. 337), which probably are the best describers of the whole group, could be assigned.

Chlorobenzenes↗

PubMed2005

Biofilm formation and phenotypic variation enhance predation-driven persistence of Vibrio cholerae.

Persistence of the opportunistic bacterial pathogen Vibrio cholerae in aquatic environments is the principal cause for seasonal occurrence of cholera epidemics. This causality has been explained by postulating that V. cholerae forms biofilms in association with animate and inanimate surfaces. Alternatively, it has been proposed that bacterial pathogens are an integral part of the natural microbial food web and thus their survival is constrained by protozoan predation. Here, we report that both explanations are interrelated. Our data show that biofilms are the protective agent enabling V. cholerae to survive protozoan grazing while their planktonic counterparts are eliminated. Grazing on planktonic V. cholerae was found to select for the biofilm-enhancing rugose phase variant, which is adapted to the surface-associated niche by the production of exopolymers. Interestingly, grazing resistance in V. cholerae biofilms was not attained by exopolymer production alone but was accomplished by the secretion of an antiprotozoal factor that inhibits protozoan feeding activity. We identified that the cell density-dependent regulator hapR controls the production of this factor in biofilms. The inhibitory effect of V. cholerae biofilms was found to be widespread among toxigenic and nontoxigenic isolates. Our results provide a mechanistic explanation for the adaptive advantage of surface-associated growth in the environmental persistence of V. cholerae and suggest an important contribution of protozoan predation in the selective enrichment of biofilm-forming strains in the out-of-host environment.

Biofilms↗

PubMed2003

Concentrations of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) in vacuum cleaner dust collected in Japanese homes.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are shown to be globally distributed, environmentally persistent and bioaccumulative. Although there is evidence that these compounds exist in the serum of non-occupationally exposed humans, the pathways leading to the presence of PFOS and PFOA are not well characterized. The concentrations of PFOS and PFOA in the vacuum cleaner dust collected in Japanese homes were measured. The compounds were detected in all the dust samples and the ranges were 11-2500 ng g(-1) for PFOS and 69-3700 ng g(-1) for PFOA. It was ascertained that PFOS and PFOA were present in the dust in homes, and that the absorption of the dust could be one of the exposure pathways of the PFOS and PFOA to humans. With regard to risk management, it is important to consider the usage of PFOS and PFOA in the indoor environment in order to avoid further pollution.

Absorption↗

PubMed2005

High incidence of central precocious puberty in a bounded geographic area of northwest Tuscany: an estrogen disrupter epidemic?

The potential health consequences of human exposure to environmental estrogen disrupters are not known. Because many chemical compounds are environmentally persistent, toxic and estrogen-active, they can dysregulate the hypothalamic-pituitary-gonadal axis, potentially inducing reproductive disorders such as central precocious puberty (CPP). We performed a multi-center analysis of CPP distribution in northwest Tuscany (NWT), an area of 5990 km2 with 1,280,895 inhabitants. Study criteria consisted of recorded CPP diagnoses and prescriptions of gonadotropin-releasing hormone analogs from January 1, 1998 to December 1, 2003. Although similar CPP prevalences were found in four major cities of NWT (Livorno, Lucca, Massa and Pisa) (mean 30.4 per 100,000 children, standard deviation 18.6; p > 0.05), Viareggio area (< 300 km2) with 19,219 child inhabitants (0-14 years of age) had the highest CPP prevalence: more than 161 CPP cases per 100,000 children. Living in Viareggio area significantly increased the risk of CPP (relative risk (RR) 5.73, 95% confidence interval (CI) 3.5-9.3; rate/risk difference 0.133%, p < 0.05). Annual CPP incidence in the Viareggio area was relatively constant and significantly higher than in other NWT areas (RR 5.04, 95% CI 2.3-11.2; rate/risk difference 0.03%, p < 0.05). Indeed, 47% of total NWT cases were distributed in the countryside (300?km2) surrounding Viareggio. Specifically, three villages - Camaiore, Pietrasanta and Stazzema - in Viareggio presented the highest CPP frequency: 216.1, 393.5 and 274.0 CPP cases per 100,000 children, respectively (RR 9.59, 95% CI 1.71-16.6; rate/risk difference 0.26%, p < 0.05). Owing to the definite geographic distribution of CPP and because increasing distance (km) from Pietrasanta rarefied CPP frequency, we suggest environmental factors (e.g. estrogen disrupter pollution) as major CPP determinants in NWT.

Adolescent↗

PubMed2006

Mycobacterium avium subsp. paratuberculosis in lake catchments, in river water abstracted for domestic use, and in effluent from domestic sewage treatment works: diverse opportunities for environmental cycling and human exposure.

Mycobacterium avium subsp. paratuberculosis from infected animals enters surface waters and rivers in runoff from contaminated pastures. We studied the River Tywi in South Wales, United Kingdom, whose catchment comprises 1,100 km2 containing more than a million dairy and beef cattle and more than 1.3 million sheep. The River Tywi is abstracted for the domestic water supply. Between August 2002 and April 2003, 48 of 70 (68.8%) twice-weekly river water samples tested positive by IS900 PCR. In river water, the organisms were associated with a suspended solid which was depleted by the water treatment process. Disposal of contaminated slurry back onto the land established a cycle of environmental persistence. A concentrate from 100 liters of finished water tested negative, but 1 of 54 domestic cold water tanks tested positive, indicating the potential for these pathogens to access domestic outlets. In the separate English Lake District region, with hills up to 980 m, tests for M. avium subsp. paratuberculosis in the high hill lakes and sediments were usually negative, but streams and sediments became positive lower down the catchment. Sediments from 9 of 10 major lakes receiving inflow from these catchments were positive, with sediment cores indicating deposition over at least 40 to 50 years. Two of 12 monthly 1-liter samples of effluent and a single 100-liter sample from the Ambleside sewage treatment works were positive for M. avium subsp. paratuberculosis. Since Lake Ambleside discharges into Lake Windermere, which is available for domestic supply, there is a potential for these organisms to cycle within human populations.

Animals↗

PubMed2006

Dioxin-induced chloracne--reconstructing the cellular and molecular mechanisms of a classic environmental disease.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is among the most toxic pollutants known to date that serves as a prototype for a group of halogenated hydrocarbon compounds characterized by extraordinary environmental persistence and unique ability to concentrate in animal and human tissues. TCDD can elicit a complex array of pleiotropic adverse effects in humans, although chloracne, a specific type of acne-like skin disease, is the only consistent manifestation of dioxin intoxication, thus representing a 'hallmark' of TCDD exposure. Chloracne is considered to be one of the most specific and sensitive biomarkers of TCDD intoxication that allows clinical and epidemiological evaluation of exposure level at threshold doses. The specific cellular and molecular mechanisms involved in pathogenesis of chloracne are still unknown. In this review, we summarize the available clinical data on chloracne and recent progress in understanding the role of the dioxin-dependent pathway in the control of gene transcription and discuss molecular and cellular events potentially involved in chloracne pathogenesis. We propose that the dioxin-induced activation of skin stem cells and a shift in differentiation commitment of their progeny may represent a major mechanism of chloracne development.

Acneiform Eruptions↗

PubMed2005

Degradation and effects of the potential mosquito larvicides methazolamide and acetazolamide in sheepshead minnow (Cyprinodon variegatus).

To test for environmental persistence in order to determine the potential of carbonic anhydrase inhibitors as larvicides, the decomposition and degradation of samples containing methazolamide (MTZ) and acetazolamide (ACZ) in aqueous solution were monitored under different conditions. Additionally, nontarget species impact was assessed in an acute toxicity test using sheepshead minnow (Cyprinodon variegatus). The fish were exposed for 120 h to 10(-3) and 10(-4) M each compound in replicate seawater tanks. In the high-MTZ treatment, all fish died within 48 h, while mortality in the low-MTZ treatment was 27% at 120 h. In the high-ACZ treatment mortality reached 83% at 120 h. We observed no mortality for the lowest dose of ACZ. Tissue samples were collected from the fish to investigate absorption of the compounds. In the gills, MTZ concentrations were around 40 microg g(-1) and ACZ reached concentrations up to 80 microg g(-1). Liver concentrations were low for MTZ probably due to metabolism.

Acetazolamide↗

PubMed2007

Organochlorine exposures during pregnancy and infant size at birth.

BACKGROUND: Organochlorines, including polychlorinated biphenyls (PCBs) and pesticides, are environmentally persistent contaminants that concentrate in the food chain as well in human adipose tissue and readily cross the placenta. METHODS: To follow up on studies suggesting an association of organochlorine exposure with reduced birth size, we investigated the association of PCBs and organochlorine pesticides (including p,p'-dichlorodiphenyl dichloroethene [p,p'-DDE], the major degradation product of p,p'-dichlorodiphenyl trichloroethane [p,p'-DDT], and hexachlorobenzene [HCB]), with birth weight, crown-heel length, and head circumference. We evaluated a cohort of 722 infants born between 1993 and 1998 to mothers residing near a PCB-contaminated harbor and Superfund site in New Bedford, Massachusetts. RESULTS: Small negative associations were observed for PCBs and birth weight; associations were weaker for birth length and head circumference. There was evidence for effect modification by smoking during pregnancy on the association between PCBs and birth weight. No associations were found with p,p'-DDE or HCB for any measures of birth size. CONCLUSIONS: This study supports the growing literature that demonstrates at most a weak association between very low-level organochlorine exposure and birth size.

Adult↗

PubMed2000

Polychlorinated biphenyl (PCB) exposure in relation to thyroid hormone levels in neonates.

Polychlorinated biphenyls (PCBs) are industrially produced environmentally persistent compounds. In developed countries all humans have detectable levels in blood and other tissues. PCBs alter thyroid hormone metabolism in animal experiments, and human data suggest background-level exposure may have similar effects in neonates. We evaluated this possible effect among 160 North Carolina children whose in utero PCB exposure was estimated on the basis of the mother's PCB levels in milk and blood, in 1978-1982 (estimated median PCB level in milk at birth, 1.8 mg/kg lipid). Their umbilical cord sera were thawed in 1998 and assayed for total thyroxine, free thyroxine, and thyroid stimulating hormone. We found that PCB exposure was not strongly related to any of the thyroid measures. For example, for a one unit change in milk PCB concentration (mg/kg lipid), the associated multivariate-adjusted increase in thyroid stimulating hormone level was 7% (95% confidence limits (CL) = -6, 21). Despite the possibility of sample degradation, these data suggest that within the range of background-level exposure in the United States, in utero PCB exposure is only slightly related to serum concentration of total thyroxine, free thyroxine, and thyroid stimulating hormone at birth.

Adult↗

PubMed2005

Monitoring tricyclazole residues in rice paddy watersheds.

Pesticide application to rice paddies may affect the quality of environmental resources such as groundwater and surface water. The distribution of residues of tricyclazole, an environmentally persistent fungicide used widely in Italy, was monitored in the network of surface water bodies surrounding the main rice production area in Italy. The location of monitoring sites was based on the potential risk for contamination with tricyclazole. This was determined as a function of the area of rice grown, the geographical distribution of rice crops susceptible to the pest, and sales of tricyclazole. Monitoring sites were also located to represent different spatial scales (farm, catchment and basin). For water samples taken shortly after application in July and August, the highest concentrations of tricyclazole were measured at the farm sites. However, residues were also detected at the catchment and basin scale. The 95% of the measured residue levels was below 9.80, 1.20 and 1.15 microg l(-1), at the farm, catchment and basin scales, respectively. In sediment, tricyclazole residues were detected in 12 out 176 samples collected with the 95% of the measured residue levels below the concentration of 0.03 mg kg(-1). Residues were sporadically detected in samples taken after the crop was harvested in November and December. Variables such as the scale of sampling, the season and the year, were significant in determining pesticide residue distribution. The type of water body was less significant.

Environmental Monitoring↗

PubMed2004

Ecotoxicological effects at contaminated sites.

Contamination sites pose significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects on terrestrial, groundwater and aquatic ecosystems. At severely contaminated sites, acute effects occur, but the core problem lies in long-term chronic effects. Ecotoxicological effects occur at all levels of biological organization, from the molecular to the ecosystem level. Not only certain organisms may be affected, but the ecosystems as a whole, both terrestrial and aquatic, in its function and structure. Contaminants at large contaminated sites often share critical properties such as high acute and/or chronic toxicity, high environmental persistence, often high mobility leading to contamination of groundwater, and high lipophilicity leading to bioaccumulation in food webs. Contaminants present at polluted sites occur as mixtures, therefore interactions between individual compounds are of importance. The bioavailability is a key factor for ecotoxicological effects of contaminants. This is demonstrated by a case study on organotins. Organotins belong to the most toxic pollutants known so far for aquatic life. Widespread contamination of harbor sediments occurs globally due to the ongoing use of organotins in antifouling paints in large ships. In lake sediments, tributyl- and triphenyltin are very persistent and bioavailable to biota even after a long time. Bioavailability of these compounds is dependent on pH and organic matter. Organotins are accumulated in sediments, but remobilization occurs when contaminated sediments are disturbed and dredged. A key question in dealing with contaminated sites is the assessment and evaluation of the toxicity of contaminants to the environment. Usually, established OECD tests and whole effluent toxicity tests are performed for an ecotoxicological evaluation and for hazard assessment. However, these assays are often expensive, laborious and sometimes not sensitive enough. As a consequence, we have used fast and reliable in vitro systems such as fish cell lines for the evaluation of sediments and landfill leachates contaminated by polychlorinated hydrocarbons (PAH). Determination of cytotoxicity as a measure for acute toxicity, and induction of cytochrome P4501A (CYP1A) as a biomarker of exposure and toxicity were found to be important measures, which can be used for hazard and risk assessment. We have developed a concept for the ecotoxicological evaluation of PAH contamination based on induction equivalents, which can be applied for aquatic and terrestrial ecosystems. One of the key question and present gaps, however, includes the long-term chronic ecotoxicological effects on soil and aquatic biota, which are largely unknown.

Animals↗

PubMed2003

Ecotoxicological problems associated with contaminated sites.

Contamination sites pose significant environmental hazards for terrestrial and aquatic ecosystems. They are important sources of pollution and may result in ecotoxicological effects. At severely contaminated sites acute effects occur, but the core problem lies in possible long-term chronic effects. Ecotoxicological effects occur at all levels of the biological organization, from the molecular to the ecosystem level. Not only certain organisms may be affected, but the ecosystems as a whole in its function and structure. Contaminants at large contaminated sites often share critical properties such as toxicity, high environmental persistence, often high mobility prone to contamination of groundwater, and high lipophilicity resulting in bioaccumulation in food webs. Contaminants present at polluted sites occur as mixtures; therefore, interactions between individual compounds may be of importance. The bioavailability is a key factor responsible for ecotoxicological effects of contaminants: only the bioavailable fraction induces ecotoxicological effects, as shown for organotin compounds. Organotins belong to the most toxic pollutants known so far for aquatic life. Widespread contamination of harbor sediments occurs globally due to the ongoing use of organotins in antifouling paints on large ships. In lake sediments, tributyl- and triphenyltin are very persistent and bioavailable to biota even after a long time. The bioavailability of organotins is dependent on the pH and the content of organic matter. Organotins accumulate in sediments, but remobilization occurs during disturbance and dredging. A key question in dealing with contaminated sites is whether, and to what extent ecotoxicity occurs. Usually, established OECD tests and whole effluent toxicity tests are performed for an ecotoxicological evaluation and for risk assessment. However, these assays are often expensive, laborious and sometimes not sensitive enough. As a consequence, we have used rapid and inexpensive in vitro systems such as fish cell lines for the evaluation of sediments and landfill leachates, which were contaminated by polycyclic aromatic hydrocarbons (PAHs). The determination of cytotoxicity as a measure for acute toxicity, and the induction of cytochrome P4501A (CYP1A) as a biomarker of exposure and effects were found to be important measures, which can be used for hazard and risk assessment. We have developed a concept for the ecotoxicological evaluation of PAH contamination based on induction equivalents, which can be applied for aquatic and terrestrial ecosystems. One of the key question and present gaps, however, includes the long-term chronic ecotoxicological effects of single compounds and mixtures on soil and aquatic biota at contaminated sites. This should be addressed in the future.

Animals↗

PubMed2006

Multiple hormonal activities of UV filters and comparison of in vivo and in vitro estrogenic activity of ethyl-4-aminobenzoate in fish.

UV filters have been detected in surface water, wastewater and fish, and some of them are estrogenic in fish. At present, little is known about their additional hormonal activities in different hormonal receptor systems despite their increasing use and environmental persistence. Besides estrogenic activity, UV filters may have additional activities, both agonistic and antagonistic in aquatic organisms. In our study, we investigate a series of UV filters for multiple hormonal activities in vitro in human receptor systems and evaluate the predictive value of these findings for the activity in fish in vitro and in vivo. First we systematically analysed the estrogenic, antiestrogenic, androgenic, and antiandrogenic activity of 18 UV filters and one metabolite in vitro at non-cytotoxic concentrations with recombinant yeast systems carrying either a human estrogen (hERalpha) or androgen receptor (hAR). All 19 compounds elicited hormonal activities, surprisingly most of them multiple activities. We found 10 UV-filters having agonistic effects towards the hERalpha. Surprisingly, we identified for the first time six UV filters with androgenic activities and many of them having pronounced antiestrogenic and antiandrogenic activities. As much as 17 compounds inhibited 4,5-dihydrotestosterone activity in the hAR assay, while 14 compounds inhibited estradiol activity in the hERalpha assay, indicating antiandrogenic and antiestrogenic activity, respectively. In particular, the antiandrogenic activities of phenyl- and benzyl salicylate, benzophenone-1 and -2, and of 4-hydroxybenzophenone were higher than that of flutamide, a known hAR antagonist. In a second series of experiments, we investigated the predictive power of the hERalpha assay for aquatic organisms by further investigating the estrogenic UV filter ethyl 4-aminobenzoate (Et-PABA) in vitro and in vivo in fish. Et-PABA showed estrogenic activity in a recombinant yeast system carrying the rainbow trout estrogen receptor (rtERalpha) with higher activity than in the hERalpha assay. In addition, Et-PABA induced vitellogenin after 14 days of exposure in juvenile fathead minnows at 4394mug/L. Our study shows estrogenic activity of this UV filter in fish both in vitro and in vivo. In conjunction with in vitro human receptor-based systems our results give a more detailed picture about distinct hormonal activities of UV filters occurring in aquatic systems. We conclude that receptor-based assays are important for in vitro assessment of UV-filters prior to or concurrently with in vivo assays, which ultimately provide data for the environmental risk assessment of these important personal care products.

Androgen Antagonists↗

PubMed2005

Comparison of EDTA and EDDS as potential soil amendments for enhanced phytoextraction of heavy metals.

Phytoextraction has been proposed as an alternative remediation technology for soils polluted with heavy metals or radionuclides, but is generally conceived as too slow working. Enhancing the accumulation of trace pollutants in harvestable plant tissues is a prerequisite for the technology to be practically applicable. The chelating aminopolycarboxylic acid, ethylene diamine tetraacetate (EDTA), has been found to enhance shoot accumulation of heavy metals. However, the use of EDTA in phytoextraction may not be suitable due to its high environmental persistence, which may lead to groundwater contamination. This paper aims to assess whether ethylene diamine disuccinate (EDDS), a biodegradable chelator, can be used for enhanced phytoextraction purposes. A laboratory experiment was conducted to examine mobilisation of Cd, Cu, Cr, Ni, Pb and Zn into the soil solution upon application of EDTA or EDDS. The longevity of the induced mobilisation was monitored for a period of 40 days after application. Estimated effect half lives ranged between 3.8 and 7.5 days for EDDS, depending on the applied dose. The minimum observed effect half life of EDTA was 36 days, while for the highest applied dose no decrease was observed throughout the 40 day period of the mobilisation experiment. Performance of EDTA and EDDS for phytoextraction was evaluated by application to Helianthus annuus. Two other potential chelators, known for their biodegradability in comparison to EDTA, were tested in the plant experiment: nitrilo acetic acid (NTA) and citric acid. Uptake of heavy metals was higher in EDDS-treated pots than in EDTA-treated pots. The effects were still considered insufficiently high to consider efficient remediation. This may be partly due to the choice of timing for application of the soil amendment. Fixing the time of application at an earlier point before harvest may yield better results. NTA and citric acid induced no significant effects on heavy metal uptake.

Biodegradation, Environmental↗

PubMed2004

Infant exposure to polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls (PCDD/Fs, PCBs)--correlation between prenatal and postnatal exposure.

Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are recognized environmental endocrine disruptors, which are environmentally persistent and may bio-accumulate in human bodies. Pregnant and nursing women may pass these pollutants to their babies both trans-placentally and lactationally. We measured and examined correlations of the levels of PCDD/Fs and PCBs in perinatal venous serum, placenta, umbilical-cord serum (representing prenatal exposure), and breast milk (postnatal exposure). Subjects included pregnant women without clinical complication between the ages of 25 and 35, who delivered their babies during 2000.12.01 and 2001.11.30 in central Taiwan. A total of 20 participants were randomly selected from those provided the four biological specimens for analysis of 17 PCDD/Fs, and 12 dioxin-like PCBs and six indicator PCBs using high-resolution gas chromatography/high-resolution mass spectrometry. Higher PCDD/F levels were found in placenta (10.3 TEq-pg/g lipid) and venous serum (9.1 TEq-pg/g lipid) compared to those in breast milk (7.6 TEq-pg/g lipid). Pearson and Spearman correlation analyses showed well association of PCDD/F and PCB levels between different specimens. The total dioxin/PCB level in milk, venous and cord serum can be well predicted by that in placenta through regression functions. This first study of multi-specimen correlation further established rather consistent ratios of these chemical concentrations in various specimens relative to those in venous serum.

Benzofurans↗

PubMed2004

Contaminant residues in snapping turtle (Chelydra s. serpentina) eggs from the Great Lakes-St. Lawrence River basin (1999 to 2000).

To determine temporal and geographic variations of environmentally persistent pollutants, the concentrations of several contaminants were measured in snapping turtle eggs in 1999 and 2000. Contaminants included polychlorinated biphenyls (PCBs), non- ortho PCBs, polychlorinated dibenzodioxins and furans, organochlorine pesticides, and total mercury. Egg collection sites within the St. Lawrence Area of Concern (AOC) and the Territory of Akwesasne included Turtle Creek, Snye Marsh, and Raquette River. Additional contaminated sites were Gray's Creek (within the St. Lawrence AOC boundary), Coote's Paradise (Hamilton Harbour AOC), and the Territory of Walpole Island (St. Clair AOC). Reference sites were Lake Sasajewun, Algonquin Provincial Park in central Ontario, and in close proximity to the St. Lawrence Area AOC, Hoasic Creek and Cooper Marsh. Eggs from clutches collected from Akwesasne contained the highest concentrations of contaminants. Mean total PCB concentrations for Akwesasne clutches ranged from 1,900 to 61,000 ng/g wet weight (w.w.), which was 360 to 3,100 times higher than the mean concentrations at the reference sites. The high levels of contaminants in eggs, from sites within Akwesasne, were consistent with trends reported in the past and reflect the influence of the proximity of heavy industry. Current contaminant concentrations in clutches from Coote's Paradise are comparable with those recorded in 1989 and 1990 but are 200 to 800 times lower than concentrations reported in 1984 and 1988. Eggs from Lake Sasajewun contained relatively low contaminant levels, which is consistent with atmospheric deposition. Our results support that snapping turtles are good indicators of temporal and geographic contaminant trends.

Animals↗

PubMed2004

Fluorotelomer alcohol biodegradation yields poly- and perfluorinated acids.

The widespread detection of environmentally persistent perfluorinated acids (PFCAs) such as perfluorooctanoic acid (PFOA) and its longer chained homologues (C9>C15) in biota has instigated a need to identify potential sources. It has recently been suggested that fluorinated telomer alcohols (FTOHs) are probable precursor compounds that may undergo transformation reactions in the environment leading to the formation of these potentially toxic and bioaccumulative PFCAs. This study examined the aerobic biodegradation of the 8:2 telomer alcohol (8:2 FTOH, CF3(CF2)7CH2CH2OH) using a mixed microbial system. The initial measured half-life of the 8:2 FTOH was approximately 0.2 days mg(-1) of initial biomass protein. The degradation of the telomer alcohol was monitored using a gas chromatograph equipped with an electron capture detector (GC/ECD). Volatile metabolites were identified using gas chromatography/ mass spectrometry (GC/MS), and nonvolatile metabolites were identified and quantified using liquid chromatography/ tandem mass spectrometry (LC/MS/MS). Telomer acids (CF3(CF2)7CH2COOH; CF3(CF2)6CFCHCOOH) and PFOA were identified as metabolites during the degradation, the unsaturated telomer acid being the predominant metabolite measured. The overall mechanism involves the oxidation of the 8:2 FTOH to the telomer acid via the transient telomer aldehyde. The telomer acid via a beta-oxidation mechanism was furthertransformed, leading to the unsaturated acid and ultimately producing the highly stable PFOA. Telomer alcohols were demonstrated to be potential sources of PFCAs as a consequence of biotic degradation. Biological transformation may be a major degradation pathway for fluorinated telomer alcohols in aquatic systems.

Bacteria, Aerobic↗