Contaminated Sediments News

Recent Journal Articles of Interest

• Influence of Sediment and Feeding on Elimination of PAHs in Amphipods - The authors studied the elimination of selected PAH congeners by Diporeia spp., a sediment-dwelling amphipod. Elimination of non-polar organic contaminants (such as PAHs) was thought to be dominated by fecal elimination in this amphipod, which encapsulates the fecal material in a peritrophic membrane. This study tested elimination of PAHs in the presence of three solid substrates, and also under water-only conditions. The results showed in general that substrates with a higher sorptive capacity had a greater influence on the elimination process. The presence of a solid substrate enhanced elimination. The study found that elimination via the fecal route was generally insignificant, except for the elimination of BaP in the presence of sediment. The authors conclude that these results refute the earlier hypothesis that fecal elimination is the dominant route of elimination for Diporeia spp. Rather, the main mechanism for elimination of contaminants is primarily via passive diffusion from the organism with subsequent sorption to the solid substrate.

  Source: Lotufo, GR., Landrum, PF. 2002. The influence of sediment and feeding on the elimination of polycyclic aromatic hydrocarbons in the freshwater amphipod, Diporeia spp. Aquat Toxicol; 58(3-4):137-49.

• NOAA Sediment Quality Guidelines Applied to Australian Harbor - Sediment quality guidelines (SQGs) developed by NOAA were applied to the highly contaminated sediments of Port Jackson (Australia) to estimate possible adverse biological effects of contaminants to benthic animals. Sediments in the Port Jackson estuary are polluted by a wide range of contaminants. The NOAA guidelines indicated that lead, zinc, DDD, and DDE are the most likely contaminants to cause adverse biological effects in Port Jackson. The NOAA SQGs were also used to estimate the probability of sediment toxicity for contaminant mixtures. This was done by determining the number of contaminants exceeding an upper guideline value (effects range medium, or ERM) to predict probable adverse biological effects. Based on the results of this analysis, about 1% of the harbor has sediment containing more than ten contaminants exceeding their respective ERM concentrations. Based on NOAA data, these sediments have an 80% probability of being toxic. Sediment with six to ten contaminants exceeding their respective ERM guidelines extend over approximately 4% of the harbor and have a 57% probability of toxicity. These areas are located in the landward reaches and in proximity to the most industrialised part of the bay. The validity of using the NOAA SQGs outside North America has not yet been demonstrated, but the screening approach used here was to identify contaminants of concern and to determine areas of environmental risk.

  Source: Birch, GF, Taylor, SE. 2002. Application of sediment quality guidelines in the assessment and management of contaminated surficial sediments in Port Jackson (Sydney Harbour), Australia. Environ Manage; 29(6):860-70.

• Assessment of Dioxins and Furans in Sediment and Crabs Near Pulp Mills - This study was undertaken to find out whether coastal sediment contamination conditions had changed as a result of the reduction in output of dioxins and furans by pulp and paper mills in British Columbia. In the late 1980s, mill process changes and source controls at mills along the British Columbia coast resulted in dramatic reductions in both the concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and the TEQ (2,3,7,8-TCDD toxic equivalents). But questions lingered regarding whether the sediments were acting as contaminant sources or sinks, whether crab uptake pathways had stayed the same, and whether improvement was faster at some sites than others. This study interpreted PCDD/F sources and composition trends at different sites using sediment and crab principal components analysis (PCA) models. The authors also used two indices, one that measured the relative inputs of chlorine bleaching PCDFs and PCP-related PCDDs, and one index that measured the relative inputs of PCP wood preservatives and pulp mill effluents. The study found that proportions chlorine bleaching TCDFs have generally decreased in importance from all sites. However, the results also showed that PCDFs produced during chlorine bleaching accumulate in crabs more readily than the PCDDs. The authors state that because the PCA composition for the harbor sites has not changed much since the mid-1990s, this is an indication that the ecosystem may not be actively recovering.

  Source: Yunker MB, Cretney WJ, Ikonomou MG. 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. Environ Sci Technol; 36 (9):1869-78.

• Predicting the Fate of Sediment and Pollutants in River Floodplains - The authors present a model of the future redistribution and radioactive decay of cesium from sediment in floodplains at the Los Alamos National Laboratory, New Mexico. The model was constructed using a theory of sediment redistribution in alluvial valley floors that tracks particle-bound pollutants, and in addition considers sediment storage within floodplains. The model was designed to specifically include particle exchange with the floodplain, which the authors feel is a factor too often ignored by the use of hydrodynamic models of in-channel processes. Results of the model show that floodplain storage significantly reduces the rate of sediment delivery, allowing 50% of the cesium currently residing in the valley floor to decay radioactively before leaving National Lab site. The rate of sediment overturn in the valley was found to be significantly controlled by the sediment exchange rate with the floodplain (as determined by sensitivity analysis). This outcome underscores the fact that flood plain sedimentation and erosion can have a strong influence on the redistribution of contaminants in floodplain environments. The authors also discuss the implications of these results on different river basin management scenarios.

  Source: Malmon DV, Dunne T, Reneau SL. 2002. Predicting the fate of sediment and pollutants in river floodplains . Environ Sci Technol; 36(9):2026-32.

• Hormone Variation in Alligators Exposed to Contaminated Sediments - The researchers studied variation in levels of plasma thyroxine (T4) in juvenile alligators (Alligator mississippiensis) from 3 different sites of varying contamination (T4 is a hormone known to be affected by organochlorine contaminants). Based on historical sediment data, high, low, and intermediate contaminant exposure sites were chosen for sampling. In 1999, alligators from the intermediate contamination site had the highest T4 concentrations. In 2000, alligators from the low contamination site had the highest T4 concentrations. Alligators from all sites had higher T4 concentrations in May 2000 compared to May 1999. The results did not show any sexual dimorphism among mean T4 concentrations within any of the sites. The authors conclude that mean plasma T4 concentrations did not match the available data regarding sediment contaminant levels.

  Source: Gunderson MP, Bermudez DS, Bryan TA, Crain DA, Degala S, Edwards TM, Kools SA, Milnes R, Guillette LJ Jr. 2002. Temporal and spatial variation in plasma thyroxine (T4) concentrations in juvenile alligators collected from Lake Okeechobee and the northern Everglades, Florida, USA. Environ Toxicol Chem; 21(5):914-21.

• Landscape Metrics and Estuarine Sediment Contamination - This paper reports on the use of a quantitative relationship between landscape metrics and sediment contamination to analyze 75 small estuarine systems across the mid-Atlantic and southern New England regions of the USA. The method was originally developed for small systems in the Chesapeake, so adjustment for differing hydrology, sediment characteristics, and sediment origins was included in the analysis. Statistical models were created for sediment metals, organics, and total PAHs. The variation in sediment metals levels was explained with landscape metrics including the percent of nonforested wetlands, percent of urban area, and point source effluent volume and metals input. The first two metrics were also important for sediment organics and total PAH levels. Sediment characteristics and hydrology were found to be important in mitigating the influence of these landscape metrics on contamination levels.

  Source: Paul JF, Comeleo RL, Copeland J. 2002. Landscape metrics and estuarine sediment contamination in the mid-Atlantic and southern New England regions. J Environ Qual; 31(3):836-45.

• Biological Responses of Worms Exposed to PAHs - The impact of the sediment-associated PAH fluoranthene on the behavior, reproduction, and toxicokinetics of the worm Lumbriculus variegates was examined. At the lowest test concentration, the number of worms increased, but at the intermediate level the number of worms was lower and similar to the control after exposure. Worms exposed to the intermediate level of PAH also exhibited increased reproduction when fed a trout chow mixture. Based on total biomass, the intermediate exposure level with food was the only treatment higher than the nonfed control. The behavioral responses of the worms were measured as changes in biological burial rate, which increased toward a plateau as the concentration increased from the control to the highest level of PAH in sediment. Uptake and elimination rates of the contaminant declined with increasing treatment concentration. The authors explained this disconnect between increasing burial rates and decreasing toxicokinetics rates demonstrates that the toxicokinetic processes are dominated by uptake and elimination to interstitial water.

  Source: Landrum PF, Gedeon ML, Burton GA, Greenberg MS, Rowland CD. 2002. Biological responses of Lumbriculus variegatus exposed to fluoranthene-spiked sediment. Arch Environ Contam Toxicol;42(3):292-302.

• Multiple Stressor Effects on Benthic Biodiversity - The authors report on the use of historical environmental monitoring data (1984-1999) and GIS technology to identify the combinations of natural and anthropogenic stressors that best accounted for observed patterns of benthic biodiversity in Chesapeake Bay. GIS was used to link spatial databases for benthic biodiversity, water quality, and sediment contaminant concentrations. A statistical model was used to explain observed patterns of benthic biodiversity. The results showed that natural stressors alone accounted for as much as 34% of the variation in benthic biodiversity, and combinations of anthropogenic contaminants accounted for as much as 48% of the variation. The consideration of both types of stressors accounted for approximately 73% of the observed variation in benthic biodiversity of Chesapeake Bay. The authors conclude that these results suggest that benthic biodiversity is a function of complex interactions among natural and anthropogenic stressors, and that new risk assessment methodologies must be developed to assess the risk of multiple stressors at a regional scale.

  Source: Preston BL, Shackelford J. 2002. Multiple stressor effects on benthic biodiversity of Chesapeake Bay: implications for ecological risk assessment. Ecotoxicology;11(2):85-99.

• Accelerated Fractionation of Heavy Metals in Contaminated Sediments - This paper discusses a new method for conducting an accelerated sequential extraction of trace elements from solid samples. It had previously been shown that rotating coiled columns (RCCs) used in counter-current chromatography could be applied to the dynamic leaching of heavy metals from sediments. The authors tested this and obtained a solid sample as the stationary phase under the action of centrifugal forces, while different aqueous solutions were continuously pumped through. This procedure only required 4 to 5 hours, whereas traditional sequential extraction requires several days. In addition, the new method results in minimal loss of the solid sample. In the scenarios tested, the recoveries of readily leachable forms of lead, zinc, and cadmium were higher using the dynamic extraction in RCC method. Continuous extraction in RCC may help to estimate the contents of leachable forms and their potential risk for the environment better than traditional sequential extraction.

  Source: Fedotov, P S, Zavarzina, A G, Spivakov, B Ya, Wennrich, R, Mattusch, J, Titze, K de P C, Demin, V V. 2002. Accelerated fractionation of heavy metals in contaminated soils and sediments using rotating coiled columns. J Environ Monit; 4(2):318-24.

• Multielement Sequential Extraction Method for Metal Partitioning in Sediments - This paper describes the use of an experimental design approach for the optimisation of a multielement extraction method. The method passes one extractant solution at varying pH through a contaminated soil sample using centrifugation. Factors such as the nature and concentration of the acid and the rate of centrifugation were studied in order to obtain the optimum conditions. Once optimum conditions had been obtained, sequential leaches were analyzed and chemometrics were used to identify the composition of each component.

  Source: Santamaria-Fernandez R, Moreda-Pineiro A, Hill SJ. 2002. Optimization of a multielement sequential extraction method employing an experimental design approach for metal partitioning in soils and sediments. J Environ Monitr; 4(2):330-6.

• Biomagnification of Dioxins and Furans in Ducks and Their Prey - This study measured concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs) in common cormorants, tufted ducks, and their prey (fish and bivalves). The muscle tissues of cormorants had higher total PCDDs/DFs-TEQ than those of tufted ducks, and results of cluster analysis indicated that the residue distribution pattern of PCDD/DF homologues was different between the two species. Biomagnification factors (BMFs) were estimated from bivalves as prey to ducks, and the biota-sediment accumulation factors (BSAFs) of PCDDs/DFs were estimated using shijimi clam and fish samples against sediment from the lake. Results of these analyses are further discussed by the authors.

  Source: Kang YS, Yamamuro M, Masunaga S, Nakanishi J. 2002. Specific biomagnification of polychlorinated dibenzo-p-dioxins and dibenzofurans in tufted ducks (Aythya fuligula), common cormorants (Phalacrocorax carbo) and their prey from Lake Shinji, Japan. Chemosphere; 46(9-10):1373-82.

• Recent Sedimentary History of Anthropogenic Impacts on a Mexican Estuary - Changes in nutrient fluxes to the Culiacan Estuary in Mexico were studied with the use of 210Pb geochronology and sediment profiles of nutrients (carbon, phosphorus and nitrogen). C:N:P elemental ratios showed that excess nutrient input began in 1948 when the area was cleared for agricultural use. Nutrient input increased around the 1970s, along with population growth in Culiacan City. Other ratio measurements made during the study indicate that nutrient enrichment in this area is mostly influenced by sewage that comes down the Culiacan River.

  Source: Ruiz-Fernandez AC, Hillaire-Marcel C, Ghaleb B, Soto-Jimenez M, Paez-Osuna F. 2002. Recent sedimentary history of anthropogenic impacts on the Culiacan River Estuary, northwestern Mexico: geochemical evidence from organic matter and nutrients. Environ Pollut 2002; 118(3):365-77.

• Effects of Oil and Grease on the Vaporization of Organic Compounds from Contaminated Sediments - Often sediments contaminated with hazardous compounds such as polynuclear aromatic hydrocarbons (PAHs) are dredged and stored in confined disposal facilities, and many of theses sediments also contain substantial amounts of oil and grease. This study was conducted to determine variations in the volatilization of sediment contaminants under the presence of oil and gas. An uncontaminated sediment sample was spiked with motor oil and PAHs. The air emission flux of three compounds (dibenzofuran, phenanthrene, and pyrene) from the oily sediment was compared to that from the same sediment without oil. The flux measurements for all three compounds were significantly lower in the presence of oil. In addition to the experiment, a model was built to test whether the oil served as an additional compartment for the partitioning of the chemicals. The comparison of experimental data and the model results showed that this was in fact the case.

  Source: Ravikrishna, R., Valsaraj, K. T., Thibodeaux, L. J., Reible, D. D. 2002. Effects of oil and grease on the vaporization of organic compounds from contaminated sediments. Environmental Engineering Science; 19(2):101-113

• Emission to Air of Volatile Organotins from Contaminated Sediments - Dredged harbor sediments contaminated with tributyltin (TBT) were tested to determine their contribution to air pollution with respect to organotin compounds. Methylbutyltins that sorbed to the analytical substrate were analysed by gas chromatography, while other butyltins were converted into butyltin hydrides prior to analysis by gas chromatography. Results showed that TBT-contaminated sediments released mainly methylbutyltins, but seawater did not significantly release this contaminant, even on prolonged evaporation using mechanical agitation and active ventilation. The authors suggest that emission of methylbutyltins from contaminated sediments probably occurs only from the surface of the sediment, and they also discuss the environmental and management implications of these results.

  Source: Vella, Alfred J., Vassallo, Roderick. 2002. Emission to air of volatile organotins from tributyltin contaminated harbour sediments. Applied Organometallic Chemistry; 16(5):239-244

• What Controls the Mixed-Layer Depth in Deep-Sea Sediments? - This study was undertaken to investigate the dependence of the mixed-layer depth (also called the depth of biogenic particle mixing) on different biogeochemical characteristics. To do this, the authors compiled a set of deep-sea estimated measures of mixed-layer depth, particulate organic carbon (POC) flux, biogenic mixing intensity (Db), and POC reactivity from 36 sites in three oceans. Results of this compilation showed that mixed-layer depth varies systematically with POC flux. Further analysis suggested that the mixed-layer depth is much more likely to be controlled by POC flux than biogenic mixing intensity, and that the mixed-layer depth is negatively related to oxygen penetration into the sediment. The authors conclude that because there is not much food available to benthos in the deep sea, POC flux controls the size and activities of the sediment-mixing benthos, which, in turn, control the thickness of the mixed-layer depth.

  Source: Smith, C. R., Rabouille, C. 2002. What controls the mixed-layer depth in deep-sea sediments? The importance of POC flux. Limnology and Oceanography; 47(2): 418-426

• Trace Metal Ingestion and Assimilation by the Green Mussel - The authors investigated trace metal ingestion and assimilation by the green mussel Perna viridis. Uptake of the metals (cadmium, selenium, and zinc) was through a mixture of diatoms and sediment at concentrations both above and below the pseudofeces production levels. Diatoms and sediment were labeled with different radio labels, and through comparison of the ratios of these labels in the particle mixture, mussel tissues and pseudofeces, the authors demonstrated that the mussels were able to selectively ingest the diatom particles at a high particle load. Efficiency of selection for diatoms increased with increasing amount of sediments in the particle mixture. The assimilation of selenium and zinc by the mussels was reduced with the presence of sediment within the mussel gut, which the authors suggest was due to the resorption of metals onto the sediment, leading to a quicker passage of metals through the digestive tract and a lower proportion of metals subjected to digestion. However, the presence of diatoms did not significantly affect metal assimilation from ingested sediment. The authors conclude that particle selection may potentially alter metal influx from ingested food sources, particularly at high particle concentrations. Selective feeding of nutritious particles, in addition to high assimilation efficiency, may increase metal influx into mussels via their diet.

  Source: Ke, C., Wang, W. 2002. Trace metal ingestion and assimilation by the green mussel Perna viridis in a phytoplankton and sediment mixture. Marine Biology. 140(2):327-335

• Conference on Contaminated Soils, Sediments & Water - The 18th Annual International Conference on Contaminated Soils, Sediments & Water will be held October 21-24, 2002 in Amherst, Massachusetts. The theme of this year's conference is "Expediting and Economizing Cleanups," and live equipment demonstrations will augment the exhibition section. Visit the conference website www.umasssoils.com for more information.

• Second International Conference on the Remediation of Contaminated Sediments - The Second International Sediment Remediation Conference will be held in the autumn of 2003 in Venice, Italy. Organizers say the city is an ideal setting for a conference on this topic because of the sediments remediation efforts being exerted there by the local, regional, and national governments. The Call for Abstracts brochure is expected to be available in July 2002, and abstracts to be considered for the program will be due in December 2002. To request a copy of the Call for Abstracts, visit the Sediment Remediation Conference website.

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