Alan G. Scarlett

Association of urinary bisphenol A concentration with medical disorders and laboratory abnormalities in adults.

CONTEXT Bisphenol A (BPA) is widely used in epoxy resins lining food and beverage containers. Evidence of effects in animals has generated concern over low-level chronic exposures in humans. OBJECTIVE To examine associations between urinary BPA concentrations and adult health status. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional analysis of BPA concentrations and health status in the general adult population of the United States, using data from the National Health and Nutrition Examination Survey 2003-2004. Participants were 1455 adults aged 18 through 74 years with measured urinary BPA and urine creatinine concentrations. Regression models were adjusted for age, sex, race/ethnicity, education, income, smoking, body mass index, waist circumference, and urinary creatinine concentration. The sample provided 80% power to detect unadjusted odds ratios (ORs) of 1.4 for diagnoses of 5% prevalence per 1-SD change in BPA concentration, or standardized regression coefficients of 0.075 for liver enzyme concentrations, at a significance level of P < .05. MAIN OUTCOME MEASURES Chronic disease diagnoses plus blood markers of liver function, glucose homeostasis, inflammation, and lipid changes. RESULTS Higher urinary BPA concentrations were associated with cardiovascular diagnoses in age-, sex-, and fully adjusted models (OR per 1-SD increase in BPA concentration, 1.39; 95% confidence interval [CI], 1.18-1.63; P = .001 with full adjustment). Higher BPA concentrations were also associated with diabetes (OR per 1-SD increase in BPA concentration, 1.39; 95% confidence interval [CI], 1.21-1.60; P < .001) but not with other studied common diseases. In addition, higher BPA concentrations were associated with clinically abnormal concentrations of the liver enzymes gamma-glutamyltransferase (OR per 1-SD increase in BPA concentration, 1.29; 95% CI, 1.14-1.46; P < .001) and alkaline phosphatase (OR per 1-SD increase in BPA concentration, 1.48; 95% CI, 1.18-1.85; P = .002). CONCLUSION Higher BPA exposure, reflected in higher urinary concentrations of BPA, may be associated with avoidable morbidity in the community-dwelling adult population.

Diamonds in the rough: Identification of individual naphthenic acids in oil sands process water

Expansion of the oil sands industry of Canada has seen a concomitant increase in the amount of process water produced and stored in large lagoons known as tailings ponds. Concerns have been raised, particularly about the toxic complex mixtures of water-soluble naphthenic acids (NA) in the process water. To date, no individual NA have been identified, despite numerous attempts, and while the toxicity of broad classes of acids is of interest, toxicity is often structure-specific, so identification of individual acids may also be very important. Here we describe the chromatographic resolution and mass spectral identification of some individual NA from oil sands process water. We conclude that the presence of tricyclic diamondoid acids, never before even considered as NA, suggests an unprecedented degree of biodegradation of some of the oil in the oil sands. The identifications reported should now be followed by quantitative studies, and these used to direct toxicity assays of relevant NA and the method used to identify further NA to establish which, or whether all NA, are toxic. The two-dimensional comprehensive gas chromatography-mass spectrometry method described may also be important for helping to better focus reclamation/remediation strategies for NA as well as in facilitating the identification of the sources of NA in contaminated surface waters.

Occurrence of the marine antifouling agent irgarol 1051 within the Plymouth Sound locality: Implications for the green macroalga Enteromorpha intestinalis

Abstract Water samples taken from the Plymouth Sound locality were analysed for the presence of the s-triazine herbicide Irgarol 1051, which is an ingredient of antifouling paints used on pleasure boats and ships. Irgarol 1051 was detected at all sampling sites within the Sound; the highest levels were found in close proximity to areas of high boat density, especially where water flow was restricted within marinas. Concentrations within the semi-enclosed Sutton Harbour were less than values predicted from leach rate data. The highest detected concentration of over 120 ng dm−3 significantly inhibited the growth of Enteromorpha intestinalis spores under laboratory conditions; the no effect concentration was 22 ng dm−3. Photosynthetic efficiency in the adult frond of E. intestinalis from Sutton Harbour marina was inhibited by Irgarol 1051 in the laboratory with an EC 50 (72 h) of 2.5 |Gmg dm−3. A small adverse impact on E. intestinalis reproduction within the harbour is therefore likely. More polluted sites identified elsewhere in Europe will suffer proportionally greater impact.

Profiling oil sands mixtures from industrial developments and natural groundwaters for source identification.

The objective of this study was to identify chemical components that could distinguish chemical mixtures in oil sands process-affected water (OSPW) that had potentially migrated to groundwater in the oil sands development area of northern Alberta, Canada. In the first part of the study, OSPW samples from two different tailings ponds and a broad range of natural groundwater samples were assessed with historically employed techniques as Level-1 analyses, including geochemistry, total concentrations of naphthenic acids (NAs) and synchronous fluorescence spectroscopy (SFS). While these analyses did not allow for reliable source differentiation, they did identify samples containing significant concentrations of oil sands acid-extractable organics (AEOs). In applying Level-2 profiling analyses using electrospray ionization high resolution mass spectrometry (ESI-HRMS) and comprehensive multidimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF/MS) to samples containing appreciable AEO concentrations, differentiation of natural from OSPW sources was apparent through measurements of O2:O4 ion class ratios (ESI-HRMS) and diagnostic ions for two families of suspected monoaromatic acids (GC × GC-TOF/MS). The resemblance between the AEO profiles from OSPW and from 6 groundwater samples adjacent to two tailings ponds implies a common source, supporting the use of these complimentary analyses for source identification. These samples included two of upward flowing groundwater collected <1 m beneath the Athabasca River, suggesting OSPW-affected groundwater is reaching the river system.

Occurrence of the antifouling herbicide, Irgarol 1051, within coastal-water seagrasses from Queensland, Australia

Abstract The s-triazine herbicide Irgarol 1051 is now widely distributed throughout European coastal waters. In Australia, the compound is not registered for use as a biocide in antifouling paints. To investigate contamination, seagrasses were sampled from the east coast of Queensland and within the Great Barrier Reef Marine Park. A green alga was also sampled from the Outer Barrier Reef. Tissues were analysed for the presence of Irgarol 1051 using solvent extraction followed by quantification with GC-MS and confirmation by GC-MS-MS. Irgarol 1051 was detected at nine of the ten locations sampled. Concentrations of up to 118 ng g−1 wet weight leaf tissue were recorded in samples from the Gold Coast (near Brisbane) which is the highest plant tissue concentration yet reported. Antifouling paint purchased within Australia was analysed by GC-MS (full scan) and found to contain Irgarol 1051. The concentrations of Irgarol 1051 reported within the Australian coastal environment are potentially toxic and the possible consequences for long-lived herbivores (such as the dugong) and for endosymbiotic algae of corals, are discussed.

Risk posed by the antifouling agent Irgarol 1051 to the seagrass Zostera marina

Irgarol 1051 (2-(tert-butylamino)-4-cyclopropylamino)-6-(methylthio)-1,3,5-triazine) is a triazine herbicide that is increasingly being used to boost the effectiveness of antifouling paints. Estuarine plants, such as the marine angiosperm Zostera marina L. (eelgrass) may accumulate, and be affected by, Irgarol 1051, in locations with high boat densities. Bioconcentration of Irgarol 1051 within Zostera tissue was determined in field plants and laboratory semi-static exposure experiments. Effects of Irgarol 1051 upon the growth rate and photosystem II photosynthetic efficiency of Zostera were examined over a concentration range of 0 to 25 μg dm−3. Growth rate was assessed by comparison of leaf specific biomass ratios, and was found to be reduced at and above an Irgarol 1051 concentration of 10 μg dm−3. Photosynthetic efficiency was assessed using fluorescence induction kinetics: efficiency was significantly reduced at 0.18 μg dm−3 (0.4 μg g−1 dry weight leaf tissue) and a 10-day EC50 value of 2.5 μg dm−3 (1.1 μg g−1) calculated. Longer-term exposure revealed a 36-day EC50 value of 0.2 μg dm−3. Uptake of Irgarol 1051 was rapid within the Zostera leaves: tissue concentrations (dry weight basis) in excess of 300 times the water concentration were found within 2 days of exposure. Leaf concentrations in excess of 14 times root tissue concentration were found. Estuaries sampled in S.W. England had low aqueous Irgarol 1051 contamination, typically <0.003 μg dm−3, but Zostera leaf tissue concentrations (dry weight basis) were up to 25 000 times the aqueous values; this was only 15 times below the 10-day EC50 value. The reported results will enable the level of risk to isolated Zostera meadows from Irgarol 1051 to be assessed based on leaf tissue concentration and also have implications for the siting of marinas.

Aromatic naphthenic acids in oil sands process-affected water, resolved by GCxGC-MS, only weakly induce the gene for vitellogenin production in zebrafish (danio rerio) larvae

Process waters from oil sands industries (OSPW) have been reported to exhibit estrogenic effects. Although the compounds responsible are unknown, some aromatic naphthenic acids (NA) have been implicated. The present study was designed to investigate whether aromatic NA might cause such effects. Here we demonstrate induction of vitellogenin genes (vtg) in fish, which is a common bioassay used to indicate effects consistent with exposure to exogenous estrogens. Solutions in water of 20-2000 μg L(-1) of an extract of a total OSPW NA concentrate did not induce expression of vtg in larval zebrafish, consistent with earlier studies which showed that much higher NA concentrations of undiluted OSPW were needed. Although 20-2000 μg L(-1) of an esterifiable NA subfraction of the OSPW NA concentrate did induce expression, this was of much lower magnitude to that induced by much lower concentrations of 17α-ethynyl estradiol, indicating that the effect of the total NAs was only weak. However, given the high NA concentrations and large volumes of OSPW extant in Canada, it is important to ascertain which of these esterifiable NA in the OSPW produce the effect. Up to 1000 μg L(-1) of an OSPW subfraction containing only alicyclic NA, and considered by most authors to be NA sensu stricto, did not produce induction; but, as predicted, 10-1000 μg L(-1) of an aromatic NA fraction did. Such effects by the aromatic acids are again consistent with those of only a weak estrogenic substance. These findings may help to focus studies of the most environmentally significant OSPW-related pollutants, if reproduced in a greater range of OSPW.

Comparative toxicity of two oil dispersants, superdispersant-25 and corexit 9527, to a range of coastal species

The acute toxicity of the oil dispersant Corexit 9527 reported in the literature is highly variable. No peer-reviewed data exist for Superdispersant-25 (SD-25). This study compares the toxicity of the two dispersants to a range of marine species representing different phyla occupying a wide range of niches: The marine sediment-dwelling amphipod Corophium volutator (Pallas), the common mussel Mytilus edulis (L.), the symbiotic snakelocks anemone Anemonia viridis (Forskål), and the seagrass Zostera marina (L.). Organisms were exposed to static dispersant concentrations for 48-h and median lethal concentration (LC50), median effect concentration (EC50), and lowest-observable-effect concentration (LOEC) values obtained. The sublethal effects of 48-h exposures and the ability of species to recover for up to 72 h after exposure were quantified relative to the 48-h endpoints. Results indicated that the anemone lethality test was the most sensitive with LOECs of 20 ppm followed by mussel feeding rate, seagrass photosynthetic index and amphipod lethality, with mussel lethality being the least sensitive with LOECs of 250 ppm for both dispersants. The results were consistent with current theory that dispersants act physically and irreversibly on the respiratory organs and reversibly, depending on exposure time, on the nervous system. Superdispersant-25 was found overall to be less toxic than Corexit 9527 and its sublethal effects more likely to be reversible following short-term exposure.

Differentiation of two industrial oil sands process-affected waters by two-dimensional gas chromatography/mass spectrometry of diamondoid acid profiles

RATIONALE Processing of the oil sands of Canada has produced large amounts of process-affected water (OSPW). Concerns have been raised over the possible environmental impacts of any leakage of OSPW from storage lagoons which contain toxicants, including organic acids. Natural weathering of oil sands deposits may also produce the toxicants, including the acids. Therefore, there is a need for differentiation of the possible natural and industrial sources of such toxicants and also for methods suitable for monitoring changes in the composition of OSPW during long-term storage. METHODS Here we show in a simple preliminary study of the two samples currently available to us, by use of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry (GCxGC/ToF-MS), the distributions of methyl esters of individual isomeric diamondoid acids in OSPW from lagoons with different histories and from different industrial operators. RESULTS We show that the distributions of methyl esters of individual isomeric diamondoid acids, including methyladamantane carboxylic and ethanoic acids, identified by comparison with data for reference compounds, can be differentiated readily. The use of acids with known structures, each verified by authentic acids, known toxicities and known and/or predictable physicochemical properties, to distinguish the different sources is advantageous, since factors likely to control the fate and dispersion of the acids can then more easily be predicted. It is postulated that the differences observed in the relative amounts of some of the acids result from variable extents of bacterial transformation of the organic matter in OSPW. CONCLUSIONS The differences in distributions of diamondoid acids clearly vary between the two samples of OSPW and may prove very useful for monitoring the fate of different sources of OSPW both in storage and in the wider environment, once a wider collection of representative samples is available for study.

Compositional heterogeneity may limit the usefulness of some commercial naphthenic acids for toxicity assays

Naphthenic acids are considered variously as monocarboxylic acids fitting the formula C(n)H(2n+z)O(2) (where z is a zero or negative even integer), as only alicyclic (i.e. non-aromatic) monocarboxylic acids fitting this formula (z≤0), or simply as those carboxylic acids occurring in petroleum products or crude oils that have been formed through biodegradation of hydrocarbons. Such acids are known constituents of the process-affected water associated with some expanding oil sands industries, of some immature and biodegraded crude oils, of produced water discharges from oil production platforms and are used as biocides and as components in the manufacture of steel radial tyres. As a result of these potential vectors of the acids into the environment, various naphthenic acid mixtures which are available commercially have been used for a range of toxicity studies. However, as some manufacturers make clear, but which is not often emphasised in the toxicity studies, a range of different quality naphthenic acids is produced commercially. It has been suggested previously, and we showed recently and elucidate further herein, that such commercial mixtures therefore sometimes contain toxic components other than carboxylic acids. For example, we identify herein by two-dimensional comprehensive gas chromatography-mass spectrometry, a range of C(0-6) alkylphenols in a batch of commercial naphthenic acids. Since these compounds are known toxicants, the contribution of such non-carboxylic acids, if any, to the toxicity attributed previously to the acids, should also be considered. This will be reflected in the concentrations and effective toxicities of such components. In order to establish the toxicity of the acids per se, assays of pure synthetic carboxylic acids of the type now known to be present in naphthenic acids from petroleum or oil sands may be more appropriate than tests of the toxicity of largely unknown, heterogeneous, mixtures.