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Andrew Turner - One of the best experts on this subject based on the ideXlab platform.

  • bioaccessibility and mobilisation of copper and zinc in Estuarine Sediment contaminated by antifouling paint particles
    2010
    Co-Authors: David Jones, Andrew Turner
    Abstract:

    Abstract Clean Estuarine Sediment amended with antifouling paint particles has been digested in biologically relevant reagents in order to evaluate the bioaccessibilities of Cu and Zn to deposit feeders in coastal environments where boat maintenance is important. Concentrations of Cu and Zn in the Estuarine Sediment of about 20 and 70 μg g−1, respectively, increased to about 930 and 330 μg g−1, respectively, on addition of 1.3% of a composite of fractionated paint particles collected from a boat repair facility. Seawater containing the vertebrate bile salt, sodium taurocholate, representative of surfactants in the digestive environment of deposit feeders, mobilised significantly greater quantities of metal (up to about 2 μg g−1 of both Cu and Zn) than seawater alone, presumably through complexation and exchange reactions. Seawater solutions of the protein, bovine serum albumin (BSA), a surrogate for proteinaceous material and amino acids encountered in the digestive tract, mobilised even greater quantities of metal (up to about 80 and 40 μg g−1 of Cu and Zn, respectively) via strong complexation, although addition of taurocholate reduced this capacity through interactions between the two reagents. Overall, and through feeding, burrowing and bioirrigation, infaunal invertebrates are predicted to greatly accelerate the rate of mobilisation and local dispersal of metals in Sediment contaminated by antifouling paint particles.

  • accumulation of cu and zn from antifouling paint particles by the marine macroalga ulva lactuca
    2009
    Co-Authors: Andrew Turner, Heather Pollock, Murray T Brown
    Abstract:

    The marine macroalga, Ulva lactuca, has been exposed to different concentrations of antifouling paint particles (4–200 mg L �1 ) in the presence of a fixed quantity of clean Estuarine Sediment and its photosynthetic response and accumulation of Cu and Zn monitored over a period of 2 days. An immediate (<2 h) toxic effect was elicited under all experimental conditions that was quantitatively related to the concentration of contaminated particles present. Likewise, the rate of leaching of both Cu and Zn was correlated with the concentration of paint particles added. Copper accumulation by the alga increased linearly with aqueous Cu concentration, largely through adsorption to the cell surface, but significant accumulation of Zn was not observed. Thus, in coastal environments where boat maintenance is practiced, discarded antifouling paint particles are an important source of Cu, but

  • surfactant induced mobilisation of trace metals from Estuarine Sediment implications for contaminant bioaccessibility and remediation
    2009
    Co-Authors: Anu Singh, Andrew Turner
    Abstract:

    Abstract The mobilisation of metals (Al, Fe, Cd, Cu, Mn, Ni, Pb, Sn, Zn) from contaminated Estuarine Sediment has been examined using commercially available surfactants. Metal release by the anionic surfactant, sodium dodecyl sulphate (SDS), increased with increasing amphiphile concentration up to and above its critical micelle concentration (CMC). Metal mobilisation by the bile acid salt, sodium taurocholate, and the nonionic surfactant, Triton X-100, however, did not vary with amphiphile concentration. SDS was the most efficient surfactant in mobilising metals from the sample, and Cd, Cu and Ni were released to the greatest extents (12–18% of total metal at [SDS] > CMC). Metal mobilisation appeared to proceed via complexation with anionic amphiphiles and denudation of hydrophobic host phases. Surfactants may play an important role in the solubilisation of metals in the digestive environment of deposit-feeding animals and, potentially, in the remediation of metal-contaminated soil and Sediment.

  • enzymatic mobilisation of trace metals from Estuarine Sediment
    2006
    Co-Authors: Andrew Turner
    Abstract:

    Abstract Proteinase K, a non-specific protease that is representative of enzymes encountered in the digestive environment of deposit-feeding organisms, has been employed to determine the nature and extent of enzymatic mobilisation of trace metals (Al, Fe, Mn, As, Cu, Pb and Zn) from contaminated Estuarine Sediment. The extent of metal release by the enzyme was critically dependent on whether and how the sample had been dried and, for all metals except Mn, mobilisation was greatest when the sample had not been dried. The fraction of metal available to the enzyme, f e , defined as the amount of metal released from undried Sediment after 4 h incubation relative to the total metal concentration, was less than 1% in all cases. Significantly, however, there was a strong correlation between f e and published factors defining the enrichment of metals in the gut fluids of the deposit-feeding lugworm, Arenicola marina . This suggests that, at least qualitatively, the mechanics of metal mobilisation in situ are replicated by the commercial enzyme. Thermally denaturing the enzyme resulted in mobilisation that was greater than (As and Cu) or similar to (all other metals) release engendered by the active enzyme, suggesting that the principal mechanism of metal mobilisation is not related to proteolysis but more likely involves complexation or exchange with component amino acids of the enzyme.

  • Sorption of ionic surfactants to Estuarine Sediment and their influence on the sequestration of phenanthrene.
    2005
    Co-Authors: Tracey Jones-hughes, Andrew Turner
    Abstract:

    The sorption of an anionic surfactant (sodium dodecyl sulfate; SDS) and a cationic surfactant (hexadecyl trimethylammonium bromide; HDTMA) to Estuarine Sediment has been studied in river water and seawater. Sorption isotherms for SDS were essentially linear in both waters, suggesting a nonspecific, hydrophobic interaction between the SDS tail and particle surface. Sorption of HDTMA was considerably greater, more nonlinear, and more sensitive to water composition. These observations were attributed to a combination of both electrostatic and hydrophobic interactions between the surfactant and particle surface, the formation of admicelles, and salinity-induced structural alteration of the hydrophobic tail of the HDTMA molecule. Presence of SDS caused a reduction in the sorption of phenanthrene to Estuarine Sediment because of the competitive effects of the surfactant tail for hydrophobic sorption sites on the particle surface. Conversely, the presence of HDTMA caused significant enhancement in phenanthrene sequestration because of head-on sorption of surfactant molecules and a resulting, more hydrophobic particle surface. The most persistent feature of our results was an inverse dependence of unit sorption on particle concentration, and an empirical algorithm defining the effect was used to calculate the Sediment-water fractionation of realistic concentrations of reactants in the Estuarine water column. The results of these calculations, and the more general findings of this study, significantly improve our understanding of both the transport and fate of ionic surfactants in the Estuarine environment, and the effects that these surfactants have on the partitioning of hydrophobic organic micropollutants.

Qiufang Zhang - One of the best experts on this subject based on the ideXlab platform.

  • abundance and composition of denitrifiers in response to spartina alterniflora invasion in Estuarine Sediment
    2013
    Co-Authors: Qiufang Zhang, Jingjing Peng, Qian Chen, Xiaoru Yang, Youwei Hong
    Abstract:

    Nitrite reduction is regulated by nitrite reductase encoded by nirK and nirS genes. This study aimed to investigate the abundance and composition of nirK- and nirS-containing denitrifiers in response to Spartina alterniflora invasion at the Jiulong River estuary, China. The Sediment samples (depth: 0-5.0 and 5.1-20 cm) were collected from 3 vegetation zones, 1 dominated by the exotic plant S. alterniflora, 1 dominated by the native plant Kandelia candel, and 1 dominated by the native plant Cyperus malaccensis, and from an unvegetated flat zone. nirK- and nirS-containing denitrifier population sizes were lower in the invaded and nonvegetated zones than in those dominated by native K. candel and C. malaccensis, which were impacted by depth - vegetation species interaction. The ratios of nirS to nirK abundance ranged from 42.10 to 677.27, with the lowest ratio found for the upper layer in the invaded zone. The nirK-containing denitrifier compositions showed a 35% similarity between invaded zone and others. Most of the sequences of nirK genes recovered from the S. alterniflora zone were specific and distinct from those of nirK genes recovered from other vegetation types; nirS genes in the invaded zone were highly divergent. These results reveal that S. alterniflora invasion has a significant effect on the abundance and composition of both nirK- and nirS-containing denitrifiers, and nirS-containing denitrifiers were less responsive to invasion than nirK-containing denitrifiers.

  • impacts of spartina alterniflora invasion on abundance and composition of ammonia oxidizers in Estuarine Sediment
    2011
    Co-Authors: Qiufang Zhang, Jingjing Peng, Qian Chen, Hongbing Yin
    Abstract:

    Spartina alterniflora widely invades coastal wetland in China and might change nitrification in Sediment. Both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) are involved in nitrification in this environment. The objective of this study was to examine the effect of S. alterniflora invasion on abundance and composition of AOA and AOB. The abundance and composition of AOA, AOB, and total bacteria in the Sediments from S. alterniflora-invaded native mangrove vegetated and unvegetated zones at two depths of 0–5 cm (O) and 5–20 cm (R) were investigated using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis. Relationships were also determined between Sediment properties and the AOB and AOA population sizes. Compared with native mangrove vegetated zone, the archaeal amoA gene abundance was reduced by 11.3-fold (O) and 46.1-fold (R), but the bacterial amoA gene abundance was increased by 9.8-fold (O) and 1.8-fold (R), respectively, in the S. alterniflora-invaded zone. The AOA abundance was always higher than AOB, especially in the native mangrove zone. Both AOA and AOB population sizes in the upper layer (O) were bigger than those in the deeper layer (R). Little difference was found in the AOB community composition among different zones, while diversity of AOA community was increased by the presence of S. alterniflora. This study demonstrated that the S. alterniflora invasion affects the abundance of both AOA and AOB, but only affects the community composition of AOA in the tidal Sediments.

Eddy Y. Zeng - One of the best experts on this subject based on the ideXlab platform.

  • mediated distribution pattern of organic compounds in Estuarine Sediment by anthropogenic debris
    2016
    Co-Authors: Lian-jun Bao, Shu Tao, Eddy Y. Zeng
    Abstract:

    Natural organic matter and grain size are considered as important parameters dictating the transport and fate of organic compounds in Sediment. However, increasing evidence suggested that manufactured debris may alter the underlying mechanisms for biogeochemical cycling of organic compounds. To examine this assumption, Estuarine Sediment and embedded debris were collected from a fishery base in Guangdong Province of South China and analyzed for organophosphorus flame retardants (OPFRs), phthalates (PAEs), organotin compounds (OTs) and dichlorodiphenyltrichloroethanes (DDTs). Coarse-size debris (>200μm) were heterogeneously distributed in Sediment, and most abundant near the boat maintenance facilities, aquaculture zone and shipping channel. The median concentrations of OPFRs, OTs, PAEs and DDTs in debris were 11, 0.2, 11 and 3.9μgg(-1) dry sample weight(-1), respectively, 1 to 3 orders of magnitude greater than those in bulk Sediment (19, 60, 240 and 570ngg(-1) dry sample weight(-1), respectively). Furthermore, OPFRs, OTs and PAEs were mostly (>99%) enriched in coarse-size (63-2000μm) Sediment, and there was no significant correlation (p>0.05) between the concentrations of OPFRs, OTs and PAEs in bulk and size-fractioned Sediment samples and total organic carbon or grain size, similar to the distribution pattern of DDTs reported previously. When distinct debris were removed from the light-density (<1.7gcm(-3)) fraction of coarse-size (200-2000μm) Sediment, the concentration levels of OPFRs, OTs, PAEs and DDTs declined by 84%, 59%, 55% and 7%, respectively. Obviously, debris irregularly distributed in Sediment can alter the Sediment sorption capacity for OPFRs, OTs and PAEs, and thus may undermine the significance of organic matter and grain size to the distribution of organic chemicals in Sediment. Finally, commonly used procedures for preparing Sediment samples and screening of debris may disturb the grain size distribution or underestimate the abundance of heavy-density debris, resulting in flawed Sediment quality assessment.

  • Significance of antifouling paint flakes to the distribution of dichlorodiphenyltrichloroethanes (DDTs) in Estuarine Sediment
    2015
    Co-Authors: Chen-chou Wu, Lian-jun Bao, Shu Tao, Eddy Y. Zeng
    Abstract:

    Abstract Recently published literature indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paint flakes were heterogeneously distributed within Estuarine Sediments. However, the significance of antifouling paint flakes in the fate and transport of DDT compounds and other organic pollutants in Estuarine Sediment is yet to be adequately addressed. To fill this knowledge gap, Estuarine Sediment and paint flakes from cabin and boat surfaces were collected from a fishery base in Guangdong Province of South China and analyzed for DDT compounds. Coarse fractioned samples collected from the vicinity of boat maintenance facilities contained appreciable amounts of colorful particles, which were identified as paint flakes by Fourier transform infrared spectroscopy. The highest concentrations of DDXs (sum of DDTs and its metabolites) occurred in the heavy-density (>1.7 g cm −3 ) fraction of coarse-size (200–2000 μm) Sediments from near the boat maintenance facilities, suggesting the importance of paint flakes in the distribution pattern of “hot spots” in Estuarine Sediment. Moreover, the desorption rates of DDT compounds from paint flakes and the heavy-density fraction of coarse-size Sediment were both extremely slow. Apparently, unevenly distributed paint flakes in Sediment can artificially inflate the sorption capacity of heavy-density Sediment for DDT compounds, and therefore can substantially change the environmental fate and behavior of hydrophobic organic chemicals in Estuarine Sediment. Finally, commonly used source diagnostic indices of DDT compounds were mostly grain-size and density dependent in Sediment, as a result of the occurrence of paint flakes, which may strongly compromise the outcome of any source diagnostics efforts.

  • chlorinated and polycyclic aromatic hydrocarbons in riverine and Estuarine Sediments from pearl river delta china
    2002
    Co-Authors: Bixian Mai, Guoying Sheng, Yuehui Kang, Zheng Lin, Gan Zhang, Yushuan Min, Eddy Y. Zeng
    Abstract:

    Abstract Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and Estuarine Sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine Sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the Estuarine Sediment samples are in the range 6–1658 ng/g, while concentrations of PCBs are in the range 10–339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine Sediment samples, whereas the PAH concentration ranges from 323 to 14,812ng/g in the Sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the Sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that Sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.

Daoji Li - One of the best experts on this subject based on the ideXlab platform.

  • microplastics in Sediments of the changjiang estuary china
    2017
    Co-Authors: Guyu Peng, Dongqi Yang, Bangshang Zhu, Huahong Shi, Lei Su, Daoji Li
    Abstract:

    Abstract Microplastics are plastics that measure less than 5 mm in diameter. They enter the marine environment as primary sources directly from industrial uses, as well as secondary sources resulting from the degradation of large plastic debris. To improve the knowledge of microplastic pollution in China, we investigated samples from 53 Estuarine Sediment locations collected with a box corer within the Changjiang Estuary. Microplastics ( The abundance of microplastics in the Changjiang Estuary was mapped. The mean concentration was 121 ± 9 items per kg of dry weight, varying from 20 to 340 items per kg of dry weight. It was found that the concentration of microplastics was the highest on the southeast coast of Shanghai. The distribution pattern of microplastics may be affected by the Changjiang diluted water in summer. All of the microplastics collected were categorized according to shape, color and size. Among which fiber (93%), transparent (42%) and small microplastics (

  • microplastics in Sediments of the changjiang estuary china
    2017
    Co-Authors: Guyu Peng, Dongqi Yang, Bangshang Zhu, Huahong Shi, Lei Su, Daoji Li
    Abstract:

    Abstract Microplastics are plastics that measure less than 5 mm in diameter. They enter the marine environment as primary sources directly from industrial uses, as well as secondary sources resulting from the degradation of large plastic debris. To improve the knowledge of microplastic pollution in China, we investigated samples from 53 Estuarine Sediment locations collected with a box corer within the Changjiang Estuary. Microplastics ( The abundance of microplastics in the Changjiang Estuary was mapped. The mean concentration was 121 ± 9 items per kg of dry weight, varying from 20 to 340 items per kg of dry weight. It was found that the concentration of microplastics was the highest on the southeast coast of Shanghai. The distribution pattern of microplastics may be affected by the Changjiang diluted water in summer. All of the microplastics collected were categorized according to shape, color and size. Among which fiber (93%), transparent (42%) and small microplastics (

John Cheng - One of the best experts on this subject based on the ideXlab platform.

  • determination of total lead in lipstick development and validation of a microwave assisted digestion inductively coupled plasma mass spectrometric method
    2010
    Co-Authors: Nancy M Hepp, William R Mindak, John Cheng
    Abstract:

    J. Cosmet. Sci., 60, 405–414 (July/August 2009) Synopsis Recent reports describing the presence of lead (Pb) in lipsticks have suggested that, under ordinary use, the potential amount of Pb exposure is harmful. To permit independent assessment of the Pb contamination, a method for determining total Pb in lipstick using microwave-assisted digestion and analysis employing inductively coupled plasma–mass spectrometry (ICP–MS) was developed and validated. Since lipsticks may contain fats, oils, pigments, dyes, and minerals, several reference materials (RM) were analyzed, including coal, wear metals in oil, organic Pb in oil, milk powder, and Estuarine Sediment. With the exception of the RM with mineral content (Estuarine Sediment), complete recovery of Pb from the RMs was obtained by simple nitric acid (HNO3) digestion. Complete recovery of Pb from Estuarine Sediment was achieved only when hydrofluoric acid (HF) was added to the digestion mix, followed by treatment with excess boric acid (H3BO3) to neutralize the HF and to dissolve insoluble fluorides. Commercial lipsticks were tested for total Pb by the validated method. The detection limit was estimated to be 0.04 μg Pb/g. The average value obtained for the lipsticks was 1.07 μg g­1. Undigested material was present in some lipstick digests when only HNO3 was used, and generally lower Pb values were obtained. All of the Pb levels found by the U.S. Food and Drug Administration (FDA) were within the range the agency would expect to find in lipsticks formulated with permitted color additives and other ingredients prepared under good manufacturing practice (GMP) conditions. This method will be useful for the FDA and industry in helping to ensure the safety of cosmetic products.

  • determination of total lead in lipstick development and validation of a microwave assisted digestion inductively coupled plasma mass spectrometric method
    2010
    Co-Authors: Nancy M Hepp, William R Mindak, John Cheng
    Abstract:

    Recent reports describing the presence of lead (Pb) in lipsticks have suggested that, under ordinary use, the potential amount of Pb exposure is harmful. To permit independent assessment of the Pb contamination, a method for determining total Pb in lipstick using microwave-assisted digestion and analysis employing inductively coupled plasma-mass spectrometry (ICP-MS) was developed and validated. Since lipsticks may contain fats, oils, pigments, dyes, and minerals, several reference materials (RM) were analyzed, including coal, wear metals in oil, organic Pb in oil, milk powder, and Estuarine Sediment. With the exception of the RM with mineral content (Estuarine Sediment), complete recovery of Pb from the RMs was obtained by simple nitric acid (HNO(3)) digestion. Complete recovery of Pb from Estuarine Sediment was achieved only when hydrofluoric acid (HF) was added to the digestion mix, followed by treatment with excess boric acid (H(3)BO(3)) to neutralize the HF and to dissolve insoluble fluorides. Commercial lipsticks were tested for total Pb by the validated method. The detection limit was estimated to be 0.04 microg Pb/g. The average value obtained for the lipsticks was 1.07 microg/g. Undigested material was present in some lipstick digests when only HNO(3) was used, and generally lower Pb values were obtained. All of the Pb levels found by the U.S. Food and Drug Administration (FDA) were within the range the agency would expect to find in lipsticks formulated with permitted color additives and other ingredients prepared under good manufacturing practice (GMP) conditions. This method will be useful for the FDA and industry in helping to ensure the safety of cosmetic products.