Contaminated Sediments News

Recent Journal Articles of Interest

• Evaluation of a fluorometric screening method for predicting total PAH concentrations in contaminated sediments - This study evaluated a fluorometric screening method to estimate total PAH concentrations in sediments collected from the St. Louis River Area of Concern (AOC) in northeastern Minnesota. A PAH surrogate standard consisting of eight PAHs commonly found in the St. Louis River system was used to calibrate the screening method. PAH concentrations measured by GC/MS were compared to the estimates from the screening method in order to evaluate the fluorometric screening. Regression analysis of log transformed estimated versus true PAH concentration yielded an r(2) of 0.72 (n=86). The study also investigated the rates of false positive and false negative predictions relative to different sediment effects concentrations (SECs) for total PAHs. The rate of false positive predictions was shown to increase as the SEC criteria value decreased, while false negative rates remained consistently low (below 7%). The authors discuss their methodological recommendations which led to a three-fold reduction in false negatives.

  Source: Peterson, G. et al.; Evaluation of a fluorometric screening method for predicting total PAH concentrations in contaminated sediments. Environmental Monitoring and Assessment 78(2):111-129, September 2002

• Comparative study of extraction methods for the determination of PAHs from contaminated soils and sediments - Four methods were compared by this study regarding the extraction efficiency of 16 EPA PAHs. Methods evaluated included: German method of the Verband Deutscher Landwirtschaftlicher Untersuchungs und Forschungsanstalten (VDLUFA), two methods of the International Organization for Standardization using shaking (ISO A) and Soxhlet extraction (ISO B) and an ultrasonic method. Extraction efficiency for each method was evaluated in five soils and three sediments. The authors did not find any significant differences in extraction efficiency of the four methods for less polluted samples. However, for highly polluted soils, extraction efficiency decreased in the following order: VDLUFA method > ISO A > ultrasonic method > ISO B.

  Source: Song, Y. et al.; Comparative study of extraction methods for the determination of PAHs from contaminated soils and sediments; Chemosphere 48(9):993-1001, September 2002

• Direct evidence of sequestration in sediments affecting the bioavailability of hydrophobic organic chemicals to benthic deposit-feeders - Biota to sediment accumulation factors (BSAF) of hydrophobic organic compounds for deposit feeders are highly variable, possibly because of differences in. sequestration or the presence of slowly desorbing fractions in the sediment. In this study, the authors investigated whether the observed relationship between bioavailability and sequestration is causal. The study measured BSAF values and sequestration status of PAHs and PCBs in a manipulated sediment as well as in the original, unmanipulated sediment. The manipulation resulted in reduction of the rapidly desorbing fraction while other factors such as contact time and sediment properties remained constant. BSAF values did not remain constant but were proportional to the reduction in rapidly desorbing fractions. The authors conclude that these results provide direct evidence of a causal relationship between sequestration and bioavailability to deposit-feeders. As a result, the authors suggest that traditional use of the equilibrium partitioning model be modified to account for variation in the sequestration status of HOC in sediments.

  Source: Kraaij, R. Et al.; Direct evidence of sequestration in sediments affecting the bioavailability of hydrophobic organic chemicals to benthic deposit-feeders; Environmental Science & Technology 36(16):3525-3529 August 15, 2002

• Mercury speciation in sediments of a tropical coastal environment - This study measured the concentrations of mercury species (mercuric mercury, methyl-mercury and dimethyl-mercury) in the sediments of Sepetiba Bay (Brazil) and compared these with geochemical parameters in order to investigate the seemingly odd behavior of mercury speciation in tropical sediments when compared with the results obtained in temperate environments. Twenty-eight sediment samples were analyzed for mercury, while organic carbon and total sulphur contents and redox potential were also measured in order to outline the geochemical characteristics of the sediments. While mercuric mercury presented concentrations ranging between 22.65 and 134.61 ng g(-1), methyl-mercury concentrations ranged between < 2.0 and 4.4 ng g(-1). Only a few dimethyl-mercury concentrations were relatively high (up to 14.6 ng g(-1)). The results of mercuric mercury presented a positive correlation with sulphur contents, which shows that mercury is not forming stable sulphide complexes even under very reducing conditions. The authors conclude that this would render mercury available for the formation of methyl- or dimethyl-mercury that would be both fixed in the sediments and volatilized.

  Source: Wasserman, J. et al.; Mercury speciation in sediments of a tropical coastal environment. Environmental Technology 23( 8):899-910 August 2002

• Predicting amphipod toxicity from sediment chemistry using logistic regression models - The authors developed individual chemical logistic regression models from a large database of matching sediment chemistry and toxicity data for 37 chemicals of potential concern in contaminated sediments. The models were designed to predict the probability of toxicity, based on the standard 10-d survival test for the marine amphipods Ampelisca abdita and Rhepoxynius abronius. The individual chemical regression models were combined into a single model, using either the maximum (P-Max model) or average (P-Avg model) probability predicted from the chemicals analyzed in a sample, in order to estimate the probability of toxicity for a sample. The average predicted probability of toxicity (from the P-Max model) closely matched the incidence of toxicity, while the magnitude of the toxic effect in the amphipod test increased as the predicted probability of toxicity increased. The authors discuss a number of options for applying the logistic models, including estimating the probability of observing acute toxicity to estuarine and marine amphipods in 10-d toxicity tests at any given chemical concentration or estimating the chemical concentrations that correspond to specific probabilities of observing sediment toxicity.

  Source: Field, L. et al.; Predicting amphipod toxicity from sediment chemistry using logistic regression models. Environmental Toxicology and Chemistry / SETAC 21( 9):1993-2005 September 2002

• Polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxinlike polychlorinated biphenyls in sediments and mussels at three sites in the lower Great Lakes - This study measured levels of contaminants (including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-substituted and mono-ortho-substituted dioxinlike polychlorinated biphenyls (DLPCBs)) in sediments and freshwater mussels at three sites in the lower Great Lakes. The researchers also compared the impacts of mussel colonization on sediment quality, and found that significant impacts on contaminant levels of colonized sediment, compared to noncolonized sediment, were observed at two sites exhibiting high mussel population densities. No differences were observed at a site with lower mussel densities. Contaminant concentrations were significantly greater in colonized sediment, compared to noncolonized sediment, at the two impacted sites. The sediments were determined to be the primary sink for contaminants because areal estimates of PCDD/PCDF and DLPCB toxicity equivalents (TEQs) were 3.3% in sediments, compared to 0.16% average in mussel biomass. The authors interpret observed differences between colonized and noncolonized sediment to suggest that mussels are capable of influencing the chemical properties of sediment they colonize.

  Source: Marvin, C. et al; Polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxinlike polychlorinated biphenyls in sediments and mussels at three sites in the lower Great Lakes, North America. Environmental Toxicology and Chemistry / SETAC, 21(9):1908-1921 September 2002

• Assessment of chlorinated dibenzo-p-dioxin and dibenzofuran trends in sediment and crab hepatopancreas from pulp mill and harbor sites using multivariate- and index-based approaches - Dramatic reductions in contaminants (polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the TEQ (2,3,7,8-TCDD toxic equivalents)) from coastal British Columbia pulp mills since the 1980s have raised a number of questions. This study was undertaken to investigate some of those questions: whether sediments were acting as contaminant sources or sinks, whether crab uptake pathways have stayed the same since the mills ceased producing PCDD/Fs, and whether improvement was faster at some sites than others. The researchers interpreted PCDD/F sources and trends for the coastal sites using sediment and crab PCA (principal components analysis) models. Additionally, two indices were used: one index measured the relative inputs of chlorine bleaching PCDFs and PCP (pentachlorophenol)-related PCDDs, and the other measured the relative inputs of PCP wood preservatives and pulp mill effluents. Results indicated that PCDFs produced during chlorine bleaching accumulate from sediments to crabs more readily than the PCDDs but that the chlorine bleaching TCDFs have generally decreased in importance. The PCA composition for the harbors did not show change, indicating that the ecosystem may not be recovering. The authors also conclude that the main route of PCDD/Fs into crabs shifted from uptake via a pelagic food web incorporating effluent-borne PCDD/Fs associated with suspended particulate matter to uptake via a benthic food web.

  Source: Yunker, M. et al.; Assessment of chlorinated dibenzo-p-dioxin and dibenzofuran trends in sediment and crab hepatopancreas from pulp mill and harbor sites using multivariate- and index-based approaches. Environmental Science & Technology 36(9):1869-1878 May 1, 2002

• An overview of toxicant identification in sediments and dredged materials - The authors provide a review of the use of Toxicity Identification and Evaluation (TIE) methods in sediments and dredged materials for both fresh and marine waters. TIEs, developed by the EPA, are used to characterize and identify chemicals causing acute toxicity in sediments and dredged materials. Most sediment TIEs have been performed on interstitial waters. Preliminary evidence from these TIEs reveals certain patterns in causes of sediment toxicity: for instance, there is usually no one predominant cause of toxicity, as multiple causes of toxicity can be detected in a single sample. Also, the role of ammonia is very prominent in these interstitial waters. If sediments are divided into marine or freshwater, TIEs performed on interstitial waters from freshwater sediments indicate a variety of toxicants in fairly equal proportions, while TIEs performed on interstitial waters from marine sediments have identified only ammonia and organics as toxicants, with metals playing a minor role. Preliminary evidence from whole sediment TIEs indicates that organic compounds play a major role in the toxicity of marine sediments, with almost no evidence for either metal or ammonia toxicity. The authors note that interpretation of these results may be skewed because only a small number of interstitial water (n = 13) and whole sediment (n = 5) TIEs have been completed.

  Source: Ho, K. et al.; An overview of toxicant identification in sediments and dredged materials. Marine Pollution Bulletin 44(4):286-293 April 2002

• Landscape metrics and estuarine sediment contamination in the mid-Atlantic and southern New England regions - This study developed quantitative relationships between landscape metrics and sediment contamination for 75 small estuarine systems across the mid-Atlantic and southern New England regions of the USA.. Because of the different characteristics and dynamics of the estuaries across these regions, adjustment for differing hydrology, sediment characteristics, and sediment origins were included in the analysis. Statistical models for sediment metals, organics, and total PAHs were developed. Results showed that the percent area of nonforested wetlands, percent area of urban land, and point source effluent volume and metals input were the landscape metrics most important for explaining the variation in sediment metals levels. The metrics important for sediment organics levels and total PAHs were percent area of urban land and percent area of nonforested wetlands. The authors discuss this example of how statistical models can be developed relating landscape metrics to estuarine sediment contamination for distributions of land cover and point source discharges.

  Source: Paul, J. et al.; Landscape metrics and estuarine sediment contamination in the mid-Atlantic and southern New England regions. Journal of Environmental Quality 31(3):836-845 May - June 2002

• Cadmium-induced production of a metallothioneinlike protein in Tubifex tubifex (Oligochaeta) and Chironomus riparius (Diptera): correlation with reproduction and growth - This study exposed laboratory-cultured oligochaetes and chironomids to sediments artificially enriched with a range of cadmium (Cd) concentrations. Both organisms accumulated Cd in a concentration-dependent manner. The concentration of a metallothioneinlike protein (MTLP) increased with increasing Cd exposure. After reaching a threshold of Cd exposure, the whole-body endpoints of reproductive output and growth declined significantly. MTLP and Cd tissue concentrations were more sensitive indicators of exposure than the whole-body endpoints. In the chironomid, MTLP concentration and tissue Cd concentration were both significantly elevated above control levels after exposure to Cd dry sediment treatment. The authors suggest that MTLP and tissue Cd concentrations can be used to predict exposure to and the effects of metals at the individual or population level.

  Source: Gillis, P. et al.; Cadmium-induced production of a metallothioneinlike protein in Tubifex tubifex (Oligochaeta) and Chironomus riparius (Diptera): correlation with reproduction and growth. Environmental Toxicology and Chemistry / SETAC 21(9):1836-1844 September 2002

• Uptake and loss of chlorpyrifos and atrazine by Juncus effusus l. in a mesocosm study with a mixture of pesticides - This study was conducted to examine the fate and effects of varying mixtures of three pesticides (chlorpyrifos, atrazine, and monosodium methanearsonate) and mercury-contaminated sediment to a common freshwater macrophyte. Doses of pesticides used in the study represented those similar to a typical runoff or direct spray application. The measured chlorpyrifos levels in leaves were highest on day 1, but levels in both leaves and water dropped rapidly and were at background levels by day 32. Atrazine remained near nominal concentrations in the water through day 16 and reached maximum accumulation in the leaves on day 16. The chemical mixture affected uptake of chlorpyrifos more strongly than atrazine. After the second dose, the macrophyte showed a similar uptake pattern for both compounds, with no diminished capacity for uptake of either compound. The differences observed in their uptake and loss behavior are related to the greater volatility of chlorpyrifos, the higher solubility of atrazine, and the more efficient transport of atrazine to the root zone.

  Source: Lytle, J. and T. Lytle; Uptake and loss of chlorpyrifos and atrazine by Juncus effusus l. in a mesocosm study with a mixture of pesticides. Environmental Toxicology and Chemistry / SETAC 21(9):1817-1825 September 2002

• Sediment quality criteria in use around the world - The author provides a review of sediment quality criteria with an international scope. Although there have been numerous sediment quality guidelines (SQGs) developed during the past 20 years, most have been developed in North America. Some of these guidelines have been adopted by various regulatory agencies in other countries and are being used as cleanup goals in remediation activities and to identify priority polluted sites. While some SQGs have been found to be relatively good predictors of significant site contamination, they also have several limitations. For instance, false positive and false negative predictions are frequently recorded for many chemicals. Also, the guidelines are chemical specific and do not establish causality where chemical mixtures occur. The author discusses a number of limitations and concludes that SQGs should be used only in a "screening" manner or in a "weight-of-evidence" approach.

  Source: Burton, G.; Sediment quality criteria in use around the world. Limnology 3( 2): 65-75 August, 2002 .

• Inventory of marine biotest methods for the evaluation of dredged material and sediments - This paper reports on an inventory of marine biotest methods for the evaluation of dredged material and sediments that was compiled for the German government. For the inventory, relevant assays were identified from the literature and experts from several countries contributed to a questionnaire survey on established and developing procedures. Comparative analyses and evaluation of the biotest methods were conducted with regard to their sensitivity, specificity, applicability, variability, cost-effectiveness, aspects of animal ethics, standardization and application for monitoring. The authors describe how the available information was integrated to rate the validity of the methods and their relevance for assessing impacts on ecosystems.

  Source: Nendza, M; Inventory of marine biotest methods for the evaluation of dredged material and sediments. Chemosphere 48(8):865-883, September 2002

• Comparison of different extraction techniques for the determination of polychlorinated organic compounds in sediment - This study evaluated the performance of various enhanced extraction techniques in two different laboratories. Techniques evaluated included accelerated solvent extraction, microwave-assisted extraction, Soxhlet extraction, ultrasonic extraction and fluidized-bed extraction for the determination of polychlorinated organic compounds in dry sediment. The results of the two laboratories were in good agreement, and showed that the extraction yields from the batch extraction methods were lower than those from the dynamic techniques. The results show that accelerated solvent extraction exhibited higher extraction efficiency than the standard procedure, Soxhlet extraction.

  Source: Martens, D. et al.; Comparison of different extraction techniques for the determination of polychlorinated organic compounds in sediment, Anal Bioanal Chem 372(4):562-568, February 2002

• Reviewing the impact of metals and PAHs on macroinvertebrates in urban watercourses - This review focuses on the sources and impacts of zinc, nickel, copper and oil derivative PAH contaminants on macroinvertebrates in urban streams. The literature indicates that reduced species diversity has been identified at a number of urban sites, but the reasons for this are not well understood. The reviewer compares literature evidence with field evidence and notes that there is still a need for field studies of urban water quality parameters. The author concludes that forecasting the ecological status of watercourses would likely benefit from data on sediment chemistry and the interaction effects of metals and PAHs.

  Source: Beasley, G.; Reviewing the impact of metals and PAHs on macro invertebrates in urban watercourses. Progress in Physical Geography 26(2): 236-270, 2002

• Historical and present fluxes of mercury to Vermont and New Hampshire lakes inferred from 210Pb dated sediment cores - In this study, researchers measured mercury fluxes to the sediments of ten small drainage lakes across Vermont and New Hampshire for the period 1800 to present. Total mercury fluxes to sediments ranged from 5 to 17 mug m(-2) yr(-1) during pre-industrial times, and from 21 to 83 mug m(-2) yr(-1) presently. Current-day direct atmospheric mercury deposition to the study region was estimated at 21 mug m(-2) yr(-1) which agrees well with measured mercury deposition. Based on these data, the authors suggest that mercury fluxes to lake sediments have declined in recent decades owing to reductions in atmospheric mercury deposition to the lake surface.

  Source: Kamman, N. and D. Engstrom; Historical and present fluxes of mercury to Vermont and New Hampshire lakes inferred from 210Pb dated sediment cores. Atmospheric Environment 36(10):1599-1609, April 2002