A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) for monitoring chlorinated trace organic contaminants in Hong Kong coastal waters.
ABSTRACT A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) was carried out at five sites, representing a gradient of contaminant concentrations, in Hong Kong coastal waters. Mussels, originally collected from a "clean" location, were deployed along with SPMDs at each site for 30 days. Analyses for chlorinated pesticides and polychlorinated biphenyls (PCBs) indicated that SPMDs have potential as monitoring tools, and to some extent can overcome the problems associated with mussels, such as natural variability, differing age, sex, and physical condition. However, in most cases, SPMDs failed to rank the sites in the same order as mussels in terms of contaminant concentrations. Nonetheless, in localities where mussels cannot survive--as shown at Kwun Tong in the present experiment--SPMDs may be valuable in providing an indication of potentially bio-available lipophilic pollutants.
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ABSTRACT: In this work, a simple, inexpensive and very selective membrane assisted passive sampler (MAPS) that does not use organic solvents, based on a thin walled silicone hollow fibre membrane for extraction of ionizable organic compounds in water bodies is reported. The potential for passive sampling of basic compounds is demonstrated. By changing the acceptor solution from acidic to basic conditions, the MAPS can be successfully used to extract acidic organic compound. The influence of environmental factors such as temperature, sample matrix and hydrodynamics on enrichment factors and sampling rates have been investigated in order to calibrate the passive sampler for measurement of TWA concentration of triazines. The selectivity, extraction efficiency and enrichment factor of the developed sampler has been compared to the Chemcatcher passive sampler. It was found that the chemical uptake of basic triazine compounds into the passive sampler remained linear and integrative throughout the 7 days exposure periods. For atrazine, propazine, prometryne and terbutryne a large 3 days time lag was experienced. A plot of natural logarithms of the amount taken up by the sampler against exposure time gave linear relationship for these compounds. The sampling rates for individual triazine compounds increased with change of hydrodynamic conditions from static to turbulent. The presence of 20 mg L(-1) humic substances in solution was found to have no significant effect on the concentration of compounds trapped in the acceptor solution. Once these compounds are trapped in the acceptor solution they do not diffuse back during the deployment period. A strong dependence of the sampling rates on the type of protective cover used was noted. Stainless steel protective cover was found to be the better than the iron mesh as it did not rust during deployment. The detection limits on HPLC with UV detection ranged from 0.50 to 4.50 μg L(-1) for MAPS, 0.40 to 3.50 μg L(-1) for Chemcatcher passive sampler and 0.35 to 4.50 μg L(-1) for SPE with 7 days exposure of passive samplers. Preliminary field trial of the potential of the MAPS to monitor ionizable triazine compounds in Hartebeespoort dam found west of Johannesburg, South Africa was compared to Chemcatcher and SPE technique with C(18) sorbents for grab samples. No quantifiable amounts of triazine compounds were found in any of the deployed passive samplers in the preliminary field applications. Triazine compounds were also not detected in grab samples after SPE. However, data from laboratory studies support the feasibility of MAPS to measure the freely dissolved fraction of ionizable organic chemicals in water. The MAPS also exhibited slightly better selectivity towards matrix components found in natural water compared to SPE technique or Chemcatcher with C(18) disk as trapping media.Analytica chimica acta 05/2011; 694(1-2):75-82. · 4.31 Impact Factor
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ABSTRACT: This paper details how activity-based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree ), can be used to better inform risk management decision-making at multiple points in the process of assessing and managing contaminated sediment sites. Because Cfree is a better predictor of bioavailability than total bulk sediment concentration (Ctotal ) for four key endpoints included in conceptual site models (benthic organism toxicity, bioaccumulation, sediment flux, and water column exposures), PSMs can increase certainty in site investigation and management. Because of their small size, the use of PSDs presents particular challenges with respect to representative sampling for estimating average concentrations and other metrics relevant for exposure and risk assessment. These challenges can be addressed by designing studies that account for sources of variation associated with the PSDs and spatial scales. Possible applications of PSMs include: quantifying spatial and temporal trends in bioavailable contaminants; identifying and evaluating contaminant source contributions; calibrating site-specific models; and, improving weight-of-evidence based decision frameworks. PSM data can be used to: assist in delineating sediment management zones based on likelihood of exposure effects; monitor remedy effectiveness; and, evaluate risk reduction after sediment treatment, disposal, or beneficial reuse following management actions. Examples are provided illustrating why PSMs and Cfree should be incorporated into contaminated sediment investigations and study designs to better understand and focus on contaminant bioavailability, more accurately estimate exposure to sediment-associated contaminants, and better inform risk management decisions. Research and communication needs for encouraging broader use are discussed. Integr Environ Assess Manag © 2013 SETAC.Integrated Environmental Assessment and Management 12/2013;
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ABSTRACT: A distinct lack of historical and current data on the status of organic pollutant contaminants within the South African marine environment is evident. This has highlighted the need for more current organic pollutant assessments. Reference mussels and SPMDs were transplanted at five South African harbour sites to assess organic bioaccumulation in brown mussels (Perna perna) and semi-permeable membrane devices (SPMDs). Spatial patterns of PAH and PCB contaminants were determined by GC-MS and GC-ECD after appropriate sample preparation. Significant (p<0.05) spatial differences were observed between the sites. Results indicate no correlations between the passive device and the transplanted mussels; however the SPMDs provided complementary information on the presence of dioxin-like PCBs within the environment not detected by the mussel. The results indicate that information provided by both the mussels and SPMDs allow for a more in depth scrutiny of environmental conditions as a result of anthropogenic influence.Marine pollution bulletin 05/2011; 63(5-12):91-7. · 2.63 Impact Factor