Contamination in sediments, bivalves and sponges of McMurdo Sound, Antarctica

This study examined the concentrations of total hydrocarbons (THC), polychlorinated biphenyls (PCB), polyaromatic hydrocarbons (PAH), and trace metals (Cu, Zn, Cd, Pb, Hg and As) in marine sediments off Scott Base (NZ) and compared them with sediments near the highly polluted McMurdo Station (US) as well as less impacted sites including Turtle Rock and Cape Evans. The Antarctic mollusc, Laternula elliptica and three common sponge species were also analysed for trace metals. The mean THC concentration in sediments from Scott Base was 3 fold higher than the pristine site, Turtle Rock, but 10 fold lower than samples from McMurdo Station. McMurdo Station sediments also contained the highest concentrations of PAHs, PCBs and the trace metals, Cu, Zn, Pb, Cd and Hg. Copper was significantly higher in bivalves from McMurdo Station than other sites. Trace metal concentrations in sponges were generally consistent within sites but no spatial patterns were apparent.     

Transport of lead and diesel fuel through a peat soil near Juneau, AK: a pilot study

A set of peat column experiments was used to determine the transport potential of lead (Pb) and diesel range organics (DRO) in palustrine slope wetlands near Juneau, AK. This project is important to southeast Alaskan communities because limited land resources are forcing development of regional wetlands. This study was instigated by concerns that proposed modifications to a nearby rifle range using DRO-contaminated soil posed a potential risk to an anadromous fish-bearing stream 250 m from the site. Three pairs of peat columns were extracted from the rifle range for analysis, one pair along and two pairs across the natural bedding planes of the soil. One column in each pair was spiked with Pb and DRO and the other was used as a control. Approximately 1-year worth of water (171 cm) was passed through each column and leachate was collected at regular intervals. The results showed that substantial DRO transport only occurred along the bedding planes. Leads was surprisingly mobile, both along and across the bedding planes with estimated soil-water partition coefficients several orders of magnitude lower than commonly published values, probably because the peat was heavily Pb-loaded by lead from bullets and because the peat's acidic, organic-rich environment enhanced Pb mobility. The chemical outflow behavior agreed with a simple macropore transport model. These results underscore the need for caution when developing regional wetlands.     

Toxicity of copper in sewage sludge

Sewage sludge is a source of organic matter and nutrients, but a major obstacle for its recycling is that the municipal wastewater sludge has low but significant levels of contaminants. This investigation, on the acute toxicity of copper in sewage sludge, was conducted with three organisms, Daphnia magna, Lemna minor and Raphanus sativus (seeds). The toxicity of the leakage water from sewage sludge spiked with CuSO(4) was studied for 64 days. The toxicity increased during the first 8-16 days and then started to decrease. The first increase in toxicity was due to ammonia, but after 32 days, a dose-related effect of copper was found. After 64 days, L. minor had an EC50 of 3800 mg Cu/kg dw for 7 days growth inhibition, a LOEC of 3200 mg Cu/kg dw and a NOEC of 1600 mg Cu/kg dw. D. magna had an EC50 of 18100 mg Cu/kg dw (24-h immobility) and a NOEC of 12800 mg Cu/kg dw. Root elongation of R. sativus was reduced at 25600 mg Cu/kg dw. Both for Daphnia and Lemna, the pH of the leakage water had an effect of the toxicity. This means that chemical speciation and bioavailability is very important for the hazard assessment of copper in sludge and soil.     

Occurrence of potential bacterial pathogens in coastal areas of the Adriatic Sea

A monitoring program was carried out in bathing waters along the sea-coast of the Adriatic Sea. The investigation was aimedat obtaining a quali-quantitative picture of microorganisms ofanthropic origin and of a more strictly autochthonous origin and at verifying the existence of possible reciprocal correlations and combinations of relationship between them. Results showed that the concentrations of indicators of faecal contamination, whether within or over the values established by legislation, are not always related to the presence and density of microorganisms of environmental origin but the regression modelsused can help to describe how these latter microorganisms can bein relation to levels of the other parameters. The difficultyis evident of the predictability of health effects swimming-associated; for this reason more complex models that are currently used should be taken into account for minimising the risk for bathers.     

Associating Ecosystem Service Losses with Indicators of Toxicity in Habitat Equivalency Analysis

Habitat equivalency analysis (HEA) was developed as a tool to scale mitigation or restoration when habitat is contaminated by hazardous substances or has been otherwise harmed by anthropogenic activities. Applying HEA involves balancing reductions in habitat quality against gains from restoration actions, and quantifying changes in habitat quality in terms of ecological services. We propose a framework for developing ecological service definitions and measures that incorporate knowledge about the impacts of chemical contaminants on biota. We describe a general model for integrating multiple lines of evidence about the toxicity of hazardous substances to allow mapping of toxicological inputs to ecological service losses. We provide an example of how this framework might be used in a HEA that quantifies ecological services provided by estuarine sediments contaminated with polycyclic aromatic hydrocarbons.     

Effects of pH and cyclodextrins on pentachlorophenol degradation (mineralization) by white-rot fungi

White-rot fungi (WRF) such as Trametes hirsuta completely degrade (mineralize) pentachlorophenol (PCP) and many other organopollutants. This has led to them being used to decontaminate various substrates (e.g. soil) through biorememediation. However, because PCP is a biocide, it can inhibit fungal growth and thereby its own degradation. It was hypothesized that substrate pH might affect PCP degradation, because when the pH is lower than 4.7 (the pKa for PCP) the phenol predominates, while at higher pH the phenate does. These two PCP species differ markedly in physical and biological properties. The effect of cyclodextrins was also investigated since it is known that the inclusion complexes these form with PCP differ in bioavailability and toxicity from non-complexed PCP. Tests were first made in liquid and agar media (where conditions are relatively easy to control), and then in a sawdust, because it is a common target matrix for WRF bioremediation. Results with the liquid and agar media showed that growth in the presence of inhibitory PCP concentrations decreased as the pH decreased, consistent with the phenol being more toxic. Growth in sawdust was less affected by PCP regardless of the pH, presumably because the PCP sorbed to the wood which decreased its bioavailability. Some cyclodextrins markedly decreased the PCP's toxicity in liquid, agar and sawdust media. Rates of PCP mineralization (measured from production of (14)CO(2) from (14)C PCP) in liquid cultures containing 0.5 mgkg(-1) PCP (a sub-inhibitory concentration) were similar from pH 2.5-7.5, indicating that the phenol and the phenate were equally degradable. Degradation of a growth inhibiting concentration on sawdust (1,000 mgkg(-1)) could be increased slightly by lowering the pH below the pKa, this increasing sorption to the wood. Degradation increased more when the pH was raised well above the pKa, presumably due to the phenate being less toxic and more soluble, making it more available to the degradative system. Although some cyclodextrins decreased growth inhibition, they also interfered with degradation. If this interference could be overcome, cyclodextrins could be used to increase the maximal PCP concentration that could be treated by WRF bioremediation.     

Correction to: Status and trends of circumpolar peregrine falcon and gyrfalcon populations

While collating contributions and comments from 36 researchers, the coordinating authors accidentally omitted Dr. Suzanne Carrière from the list of contributing co-authors. Dr. Carrière’s data are described in Tables 1 and 3, Figure 2 and several places in the narrative. The new author list is thus updated in this article.     

反复等向加卸载路径下粉质黏土变形特性研究

黏土的变形特性与应力路径密切相关,直接影响到相关工程的安全性。针对三峡库岸某路基边坡粉质黏土,采用应力路径控制试验系统,开展了两组等向固结应力状态下反复多次的加卸载试验,揭示了土体的体积变形发展规律,发现再固结过程呈现为一条先平缓后变陡的曲线,说明前期固结压力范围内的再加载也会产生不可恢复的塑性变形,且变形速率随加卸载循环次数逐渐减小。最后,结合试验曲线特点,建立了土体再固结系数与加卸载次数及应力状态相关的数学模型,能够较好的模拟反复等向加卸载条件下土样的体变特征,且可预测土体经历更多次加卸载循环中的次固结过程,为土体的持续塑性变形分析和预测提供参考。