Zinc detection in oil-polluted marine environment by stripping voltammetry with mercury-free nanoporous gold electrode.

Detection of Zn(II) in oil-polluted seawater via square-wave anodic stripping voltammetry (SW-ASV) utilizing thin gold electrodes sputtered onto nanoporous poly(acrylic acid)-grafted-poly(vinylidene difluoride) (PAA-g-PVDF) membrane is herein reported. Prior to SW-ASV, PAA grafted nanopores demonstrated to efficiently trap Zn(II) ions at open circuit. This passive adsorption followed a Langmuir law. An affinity constant of 1.41 L [Formula: see text]mol[Formula: see text] and a maximum Zn(II) adsorbed mass q[Formula: see text] of 1.21 [Formula: see text]mol g[Formula: see text] were found. Applied SW-ASV protocol implied an accumulation step (- 1.2 V for 120 s) followed by a stripping step (- 1.2 to 1 V; 25 Hz; step: 4 mV; amplitude: 25 mV; acetate buffer (pH 5.5)). It revealed a Zn redox potential at - 0.8 V (Ag/AgCl pseudo-reference). Multiple measurements in synthetic waters close to the composition of production waters exhibited a decreasing precision with the number of readings R (1.65[Formula: see text] (R = 2) and 6.56[Formula: see text] (R = 3)). These membrane-electrodes should be used as disposable. The intra-batch mean precision was 14[Formula: see text] (n = 3) while inter-batches precision was 20[Formula: see text] (n = 15). Linear and linear-log calibrations allow exploitation of Zn(II) concentrations ranging from 10 to 500 [Formula: see text]g L[Formula: see text] and 100 to 1000 [Formula: see text]g L[Formula: see text] respectively. The LOD was 4.2 [Formula: see text]g L[Formula: see text] (3S/N). Thanks to obtained calibration, a detected Zn(II) content of 1 ppm in a raw production water from North Sea oil platform was determined.

An uranyl sorption study inside functionalised nanopores.

Sorption mechanism of uranyl by poly(bis[2-(methacryloyloxy)ethyl] phosphate) (PB2MP) functionalised polyvinylidene fluoride (PVDF) track-etched membranes, PB2MP-g-PVDF, was investigated. It was found that uranyl sorption obeyed Langmuir isotherm model giving a maximum U(VI) membrane uptake of 6.73 µmol g-1 and an affinity constant of 9.85 â‹… 106 L mol-1. XPS and TRPL measurements were performed to identify sorbed uranyl oxidation state and its environment. Uranyl was found to be mainly in its hexavalent state, i.e. U(VI), showing that the trapping inside the PB2MP-g-PVDF nanoporous membranes did not change the ion speciation. Two sorbed uranyl life-times (τ1 = 8.8 µs and τ2 = 102.8 µs) were measured by TRPL which pointed out different complexations taking place inside the nanopores. Uranyl sorption by PB2MP-g-PVDF membranes was also found to be pH dependent demonstrating the highest performance at circumneutral pH. In addition, TRPL was demonstrated to be not only a remarkable technique for U(VI) characterization, but also an alternative to voltammetry detection for trace on-site uranyl monitoring using PB2MP-g-PVDF nanoporous membranes.

Baseline data for distribution of contaminants by natural disasters: results from a residential Houston neighborhood during Hurricane Harvey flooding.

Hurricane Harvey made landfall in Texas August 25, 2017, bringing massive rains and flooding that impacted soils in a residential neighborhood in East Houston. Trace elements, organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ether fire retardants (PBDEs) and polychlorinated biphenyls (PCBs) were determined in 24 soil samples. The highest concentrations found in soils were total PAHs, which ranged from 1,310 µg/kg to 85,700 µg/kg with a mean of 12,600 µg/kg. Analysis of specific PAH ratios indicate the source of the PAHs were dominated by pyrogenic rather than petrogenic sources. Chlordanes were detectable in the area where the likely local source is for ant control. The trace metal concentrations were below any environmental health concern concentrations but As, Cd, Hg, Pb, Se, Ag, Zn were enriched over the crustal abundance. While Hurricane Harvey was responsible for the redistribution of many contaminants, the large volume of rain and floodwater likely transported contaminants from the land areas and into the Houston Ship Channel and Galveston Bay. The findings from this study will serve as baseline data for determining the mobilization of contaminants caused by natural disasters.

Early warning sensors for monitoring mercury in water.

Poly-4-vinylpyridine grafted poly(vinylidene difluoride) (P4VP-g-PVDF) nanoporous polymer electrodes were found to be sensitive for Hg(II) analysis. The fabrication and characterization of functionalized nanoporous membrane-electrodes by FESEM and FTIR are presented. Functionalized nanopore charge state versus a large range of pH (1-10) was investigated by registering the streaming potential. This isoelectric point is achieved at the pKa of P4VP (pH = 5). Mercury adsorption at solid-liquid interface obeys a Langmuir law. A protocol for accurate Hg(II) analysis at ppb level was established. Calibration curves were performed and different real water samples (mineral water, ground water, surface water) were spiked and analyzed. The resulting sensor is intended to be integrated into existing systems or used standalone as portable devices. A first generation prototype exhibiting its own integrated potentiostat, its software and set of membrane-electrode pads is presented.

Concentration, composition and sources of PAHs in the coastal sediments of the exclusive economic zone (EEZ) of Qatar, Arabian Gulf.

Surface sediments were collected from sixteen locations in order to assess levels and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments of Qatar exclusive economic zone (EEZ). Samples were analyzed for 16 parent PAHs, 18 alkyl homologs and for dibenzothiophenes. Total PAHs concentration (∑PAHs) ranged from 2.6 ng g(-1) to 1025 ng g(-1). The highest PAHs concentrations were in sediments in and adjacent to harbors. Alkylated PAHs predominated most of the sampling locations reaching up to 80% in offshore locations. Parent PAHs and parent high molecular weight PAHs dominated location adjacent to industrial activities and urban areas. The origin of PAHs sources to the sediments was elucidated using ternary plot, indices, and molecular ratios of specific compounds such as (Ant/Phe+Ant), (Flt/Flt+Pyr). PAHs inputs to most coastal sites consisted of mixture of petroleum and combustion derived sources. However, inputs to the offshore sediments were mainly of petroleum origin.

Perfluorooctane sulfonate in oysters, Crassostrea virginica, from the Gulf of Mexico and the Chesapeake Bay, USA.

Concentrations of perfluorooctane sulfonate (PFOS), a metabolite of several sulfonated perfluoroorganic compounds, were measured in oysters collected from 77 locations in the Gulf of Mexico and Chesapeake Bay of the United States. PFOS was detected in oysters collected from 51 of the 77 locations at concentrations ranging from < 42 to 1,225 ng/g on a dry weight basis. This study provides baseline data for future monitoring programs to examine long-term trends in concentrations of PFOS.

Historical contamination of PAHs, PCBs, DDTs, and heavy metals in Mississippi River Delta, Galveston Bay and Tampa Bay sediment cores.

Profiles of trace contaminant concentrations in sediment columns can be a natural archive from which pollutant inputs into coastal areas can be reconstructed. Reconstruction of historical inputs of anthropogenic chemicals is important for improving management strategies and evaluating the success of recent pollution controls measures. Here we report a reconstruction of historical contamination into three coastal sites along the US Gulf Coast: Mississippi River Delta, Galveston Bay and Tampa Bay. Within the watersheds of these areas are extensive agricultural lands as well as more than 50% of the chemical and refinery capacity of the USA. Despite this pollution potential, relatively low concentrations of trace metals and trace organic contaminants were found in one core from each of the three sites. Concentrations and fluxes of most trace metals found in surface sediments at these three sites, when normalized to Al, are typical for uncontaminated Gulf Coast sediments. Hydrophobic trace organic contaminants that are anthropogenic (polycyclic aromatic hydrocarbons, DDTs, and polychlorinated biphenyls) are found in sediments from all locations. The presence in surface sediments from the Mississippi River Delta of low level trace contaminants such as DDTs, which were banned in the early 1970's, indicate that they are still washed out from cultivated soils. It appears that the DDTs profile in that sediment core was produced by a combination of erosion processes of riverine and other sedimentary deposits during floods. Most of the pollutant profiles indicate that present-day conditions have improved from the more contaminated conditions in the 1950-1970's, before the advent of the Clean Water Act.

Status of persistent organic pollutants in the sediment from several estuaries in China.

Sediment samples from three estuaries on the east coast of China were analyzed for persistent organic pollutants. Total PCB, PAH, and DDT concentrations in the sediments from Minjiang, Jiulongjiang, and Zhujiang estuaries ranged from 2 to 14 ng/g, 400 to 1500 ng/g, and 6 to 73 ng/g, respectively, in the sediments from these estuaries. The sources of PAH contamination were inferred from PAH compositions, with pyrogenic PAHs being the dominant source for Minjiang Estuary and petroleum related PAHs being the primary contributors to Jiulongjiang and Zhujiang estuaries. The high concentrations of DDT in the sediments from these estuaries were likely the result of widespread use of DDT in China in the 1960s and 1970s. Butyltin compounds were detected in the sediment from Jiulongjiang Estuary and Victoria Harbor, Hong Kong. Presence of butyltin compounds probably result from the shipping activities in these estuaries. Butyltin compounds were not detected in the sediments from Minjiang and Zhujiang estuaries. Contaminant concentrations were generally below levels expected to affect benthic organisms with the exception of DDTs.

The geographic distribution of population health and contaminant body burden in gulf of Mexico oysters.

As part of NOAA's National Status and Trends Mussel Watch Program, oysters were sampled along the Gulf of Mexico coast each winter from 1986 to 1993 (The present analysis deals with 1986-1993 Mussel Watch data; the Mussel Watch project itself continues at this printing) and analyzed for trace metal, polynuclear aromatic hydrocarbons and pesticide body burden, plus a series of biological variables designed to assess population status and health. We identified contaminant and biological variables in which large-scale spatial processes played an important role in establishing population values by examining the likelihood that neighboring bays tended to have populations with body burdens or population attributes more similar than expected by chance. Local or watershed-dependent factors, such as land use and freshwater inflow, are important in controlling the bay-to-bay variation in body burden in most contaminants. However, the bay-to-bay variations in body burden of some metals (As, Cd, Hg, Ni, Se) appear to be principally influenced by larger-scale climatic factors. These metals and the biological variable shell length demonstrated a strong degree of similarity between bays over a large regional area reminiscent of the pattern shown by climatic factors, such as temperature and precipitation. In contrast, among the organics, none of the PAHs showed even a moderately strong climatic signal. Among the pesticides, only two did (dieldrin, total DDTs). These pesticides and the biological variables, reproductive stage and Perkinsus marinus prevalence and infection intensity, had spatial patterns that suggested both a local and a regional influence to their geographic distributions. This same pattern is exhibited by freshwater runoff. Metal contaminants also behaved distinctively compared to organics in the temporal influence of climate in establishing the interannual variability in body burden. For the organics, trends in interannual variability were strongly influenced by climate, whereas spatial trends were not. In contrast, most metals were unaffected by climatic forcing both spatially and temporally. However, all of the metals having a spatial pattern strongly influenced by climate (As, Cd, Hg, Ni, Se) also exhibited interannual variations related to variations in climate.

Butyltin compounds in sediments from the commercial harbor of Alexandria City, Egypt.

Tributyltin (TBT), dibutyltin (DBT), and monobutyltin (MBT) compounds were quantitatively determined in surface-sediment samples collected from 23 sites in the commercial harbor of Alexandria City, Egypt. Butyltin concentrations in sediments varied widely depending on the sample location, ranging from less than 0.1 to 186 ng g(-1) of Sn for MBT, less than 0.1 to 379 ng g(-1) of Sn for DBT, and 1 to 2,067 ng g(-1) of Sn for TBT Elevated TBT concentrations, ranging from 727 to 2,067 ng g(-1) of Sn were observed in harbors, marinas, and near ship-repair facilities, indicating that the butyltin-containing, antifouling paints of boats and vessels are the major source of butyltin contamination. The TBT concentration decreased rapidly away from potential source areas of boat docking and repair facilities. The high relative concentrations of TBT in the sediments indicated that degradation processes in the sediments are minor, probably due to the anoxic sedimentary conditions at the sampling sites and/or relatively fresh input of TBT to these sites.

Characterization of the H4IIE rat hepatoma cell bioassay for evaluation of environmental samples containing polynuclear aromatic hydrocarbons (PAHs).

The H4IIE rat hepatoma cell bioassay has been extensively used to assess the toxic equivalents (TEQs) of complex mixtures of halogenated aromatic hydrocarbons in environmental samples. However, there is often a discrepancy between bioassay induction results and toxic equivalents calculated from chemical analysis of samples; the former generally yield higher bioassay-TEQs. Polynuclear aromatic hydrocarbons (PAHs) are a class of chemicals which can significantly contribute to induction-TEQs. Benzo(a)pyrene (BAP), dibenz(a, h)anthracene (DBA), benz(a)anthracene (BA), benzo(k)fluoranthene (BkF), benzo(b)fluoranthene (BbF), chrysene (Chr), and indeno(1,2,3-c,d) pyrene (IdP) are carcinogenic PAHs found in environmental samples, including oysters collected from Galveston Bay. The induction potency of these PAHs relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was determined individually in rat hepatoma H4IIE cells seeded in 6-well plates, and the induction-derived equivalency factors (EFs) relative to TCDD were 0. 000354, 0.00203, 0.000025, 0.00478, 0.00253, 0.00020, 0.0011 for BAP, DBA, BA, BkF, BbF, Chr, and IdP, respectively. Dilutions of a reconstituted PAH mixture containing 23 PAHs (744 to 4466 ng/g total PAHs) with constant percentages of BAP (4.5%), DBA (3.5%), BA (2.4%), BkF (3.7%), BbF (3.5%), Chr (4.7%), and IdP (4.2%) yielded bioassay-derived induction-EQs that ranged from 0.52 to 1.44 ng/g. Oysters exposed in the laboratory to the same PAH mixture for 30 days differentially accumulated the PAHs with time. Bioassay-EQs for these oyster extracts ranged from 0.94 to 5.79 ng/g. These results were similar to the chemically calculated EQs which varied from 0.81 to 3.13 ng/g.

Toxaphene, PCB, DDT, and Chlordane Analyses of Beluga whale blubber.

Beluga whales bioaccumulate organochlorines from their environment. Blubber samples of Beluga Whales from Alaska's north coast contain organochlorines, including Toxaphene (polychlorinated camphenes) PCBs, DDTs and chlordane. Toxaphene was the organochlorine pesticide found in the highest concentration in all samples with the exception of the 6 year old male where PCBs were highest. The source of these organochlorines is likely global distillation from lower latitudes. Males had higher concentrations than females and the oldest male had higher concentration than the younger male. Females exhibit a decrease in concentrations with age. The fetus had about 10% higher concentrations for all organochlorines compared to the mother. Transplacental transfer of organochlorines and lactation lower the contaminant concentration in females. Older females have lower contaminate concentrations likely due to continual reproductive success. Consumption of older males will expose humans to higher levels of organochlorines.

Organochlorine pesticides and polychlorinated biphenyls (PCBs) in sediments and biota from four US Arctic lakes.

Organochlorine (OC) concentrations in surface sediment, snails (Lymnea sp.), and two freshwater fish species (grayling, Thymallus arcticus; and lake trout, Salvelinus namaycush) from four lakes in the US Arctic were determined. In surface sediment, chlorinated benzenes (including hexachlorobenzene, HCB), and p,p'-DDT were the primary analytes detected (max = 0.7 ng/g dry wt), while individual polychlorinated biphenyl (PCB) congeners were always below 0.1 ng/g. A wider range of compounds and higher concentrations were found in lake trout, the top predatory fish species in the same lakes. The concentration ranges for hexachlorocyclohexanes (HCHs), chlordane-related compounds (CHLORs), DDTs, and PCBs in lake trout and grayling were similar to those reported for other arctic freshwater fish (1-100 ng/g wet wt), but one to two orders of magnitude lower than Great Lakes salmonids. Nitrogen isotope analysis confirmed that differences in OC concentrations between grayling and lake trout are explained partly by differences in food web position.

NIST SRM 1945, whale blubber, NIST SRM 1974a, organics in mussel tissue, and NIST SRM 1941a, organics in marine sediment as certified reference materials for polychlorinated dioxins and furans in marine ecosystems.

Few natural matrix Standard Reference Materials are available for the validation of analytical methods measuring polychlorinated dioxins and furans (PCDDs and PCDFs) in marine ecosystems. The concentrations of PCDDs and PCDFs in NIST SRM 1945, SRM 1974a, and SRM 1941a are of interest because the analysis of marine mammal, mussel tissues and sediments have become important tools in the determination of organochlorine contamination of the environment. Because these SRMs have been demonstrated to be homogenous for other organic contaminants, they would be expected to be reliable standards for validation of polychlorinated dioxins and furans in marine mammals, mussels and sediments as well.

Analysis of Gulf of Mexico bottlenose dolphins for organochlorine pesticides and PCBs.

Organochlorine concentrations were determined in blubber samples from 33 Tursiops truncatus stranded on the Texas and Florida coastlines. All tissues had measurable concentrations of 4,4'-DDE (0.18-70.7 microg/g lipid weight) and SigmaPCB (4.1-149 microg/g lipid weight). Pesticide and PCB concentrations were similar to those reported in Tursiops truncatus from the Atlantic coast of the United States and the southeast coast of Africa. Organochlorine concentrations were highest in mature males, and differences in the SigmaPCB/SigmaDDT ratios between mature and immature males suggests a recent decrease in DDT uptake, related to the commercial DDT ban in the US in 1971, as well as dietary differences between younger and older animals. Analysis of a female and her calf indicate that females reduce their own organochlorine body burden through transplacental transfer. However, no reduction of some higher molecular weight PCBs was found. Transplacental transfer rates of 5.1% for SigmaDDT and 3.7% for SigmaPCB were determined based on a stranded female and her full term, unborn calf. Predictions of uptake and depuration rates of organochlorines based on gender in Tursiops truncatus agree with clearance rates from previous studies.

Sediment contamination and biological effects in a Chesapeake Bay marina.

Complementary measures of sediment toxicity, sediment chemistry and benthic community structure were evaluated at stations within and on the outside perimeter of an enclosed marina on the Bohemia River, a northeastern tributary to Chesapeake Bay. Sediment concentrations of polynuclear aromatic hydrocarbons, copper and tributyltin (TBT) were elevated at stations inside the marina basin. A 28 day partial life-cycle test with the amphipod Hyalella azteca indicated no significant lethal effects associated with test sediments. However, amphipods exposed to sediments collected from three stations inside the marina basin were significantly larger than amphipods from control sediments, possibly as the result of hormesis. Sediment pore water from two out of the three stations eliciting enhanced amphipod growth caused a reduction in light emission by luminescent bacteria in the Microtox(®) assay. Furthermore, sediments from these two stations contained the greatest measured concentrations of copper and TBT. Benthic infaunal communities that typically reflect environmental degradation were found exclusively at stations within the marina basin. The area of environmental impact appears to be localized to the enclosed basin, as the marina design limits flushing and, hence, contaminant export.

Polynuclear aromatic hydrocarbon contaminants in oysters from the Gulf of Mexico (1986-1990).

Polynuclear aromatic hydrocarbon (PAH) contaminant concentrations in 870 composite oyster samples from coastal and estuarine areas of the Gulf of Mexico analyzed as part of National Oceanographic and Atmospheric Administration's (NOAA's) National Status and Trends (NS&T) Mussel Watch Program exhibit a log-normal distribution. There are two major populations in the data. The cumulative frequency function was used to deconvolute the data distribution into two probability density functions and calculate summary statistics for each population. The first population consists of sites with lower PAH concentration probably due to background contamination (i.e. stormwater runoff, atmospheric deposition). The second population are sites with higher concentrations of PAHs associated with local point sources of PAH input (i.e. small oil spills, etc.). The temporal pattern for the mean concentration of the populations from the Gulf of Mexico is consistent with large-scale climatic factors such as the El Niño cycles which affect the precipitation regime.