We examined acute (2 h exposure of 5-day-old larvae) and subchronic (exposure from fertilization up to an age of 11 days) effects of NiCl2·6H2O on embryos and larvae of zebrafish (Danio rerio), both alone and in combination with oxygen depletion. The following endpoints were recorded: acute exposure: locomotory activity and survival; subchronic exposure: hatching rate, deformations, locomotory activity (at 5, 8 and 11 days) and mortality. In acute exposures nickel chloride (7.5-15 mg Ni/L) caused decreasing locomotory activity. Oxygen depletion (<=2.45 ± 0.16 mg O2/L) also resulted in significantly reduced locomotory activity. In the subchronic test, exposure to >=10 mg Ni/L resulted in delayed hatching at an age of 96 h, in decreased locomotory activity at an age of 5 days, and increased mortality at an age of 11 days (LC20 = 9.5 mg Ni/L). The observed LOEC for locomotory activity (7.5 mg Ni/L) is in the range of environmentally relevant concentrations. Since locomotory activity was already affected by acute exposure, this parameter is recommended to supplement commonly recorded endpoints of toxicity. Increasing concentrations of nickel chloride and decreasing concentrations of oxygen lead to reduced vitality and locomotory activity in Danio rerio embryos and larvae.

Some of the greatest forest health impacts in North America are caused by invasive forest insects and pathogens (e.g., emerald ash borer and sudden oak death in the US), by severe outbreaks of native pests (e.g., mountain pine beetle in Canada), and fires exacerbated by changing climate. Ozone and N and S pollutants continue to impact the health of forests in several regions of North America. Long-term monitoring of forest health indicators has facilitated the assessment of forest health and sustainability in North America. By linking a nationwide network of forest health plots with the more extensive forest inventory, forest health experts in the US have evaluated current trends for major forest health indicators and developed assessments of future risks. Canada and Mexico currently lack nationwide networks of forest health plots. Development and expansion of these networks is critical to effective assessment of future forest health impacts.

Upcoming decades will experience increasing atmospheric CO2 and likely enhanced O3 exposure which represents a risk for the carbon sink strength of forests, so that the need for cause-effect related O3 risk assessment increases. Although assessment will gain in reliability on an O3 uptake basis, risk is codetermined by the effective dose, i.e. the plant's sensitivity per O3 uptake. Recent progress in research on the molecular and metabolic control of the effective O3 dose is reported along with advances in empirically assessing O3 uptake at the whole-tree and stand level. Knowledge on both O3 uptake and effective dose (measures of stress avoidance and tolerance, respectively) needs to be understood mechanistically and linked as a pre-requisite before practical use of process-based O3 risk assessment can be implemented. To this end, perspectives are derived for validating and promoting new O3 fluxbased modelling tools.

The effect of nitrogen on biomass production, shoot elongation and relative density of the mosses Pleurozium schreberi, Hylocomium splendens and Dicranum polysetum was studied in a chamber experiment. Monocultures were exposed to 10 N levels ranging from 0.02 to 7.35 g N m-2 during a 90-day period. All the growth responses were unimodal, but the species showed differences in the shape parameters of the curves. Hylocomium and Pleurozium achieved optimum biomass production at a lower N level than Dicranum. Pleurozium had the highest biomass production per tissue N concentration. Tolerance to N was the widest in Dicranum, whereas Hylocomium had the narrowest tolerance. Dicranum retained N less efficiently from precipitation than the other two species, which explained its deviating response. All species translocated some N from parent to new shoots. The results emphasize that the individual responses of bryophytes to N should be known when species are used as bioindicators. Boreal bryophytes display differences in their sensitivity to nitrogen.

Thirteen soils collected from 11 provinces in eastern China were used to investigate the butachlor adsorption. The results indicated that the total organic carbon (TOC) content, clay content, amorphous Fe2O3 content, silt content, CEC, and pH had a combined effect on the butachlor sorption on soil. Combination of the data obtained from the 13 soils in the present study with other 23 soil samples reported by other researchers in the literature showed that Koc would be a poor predictive parameter for butachlor adsorption on soils with TOC content higher than 4.0% and lower than 0.2%. The soils with the ratio of clay content to TOC content (RCO) values less than 60 adsorbed butachlor mainly by the partition into soil organic matter matrix. The soils with RCO values higher than 60 apparently adsorbed butachlor by the combination of the partition into soil organic matter matrix and adsorption on clay surface. The relative importance of organic matter and clay in butachlor adsorption in soil will depend on the ratio of clay content to total organic carbon content.

Soils from Aveiro, Glasgow, Ljubljana, Sevilla and Torino have been investigated in view of their potential for translocation of potentially toxic elements (PTE) to the atmosphere. Soils were partitioned into five size fractions and Cr, Cu, Ni, Pb and Zn were measured in the fractions and the whole soil. All PTE concentrated in the <10 μm fraction. Cr and Ni concentrated also in the coarse fraction, indicating a lithogenic contribution. An accumulation factor (AF) was calculated for the <2 and <10 μm fraction. The AF values indicate that the accumulation in the finer fractions is higher where the overall contamination is lower. AF for Cr and Ni are particularly low in Glasgow and Torino. An inverse relationship was found between the AF of some metals and the percentage of <10 μm particles that could be of use in risk assessment or remediation practices.

An analytical procedure for the determination of Hg in otter (Lontra longicaudis) feces was developed, to separate fish scales for the identification of the animal diet. Samples were washed with ultra-pure water and the suspension was sampled and transferred for digestion. The solubilization was performed with nitric-perchloric acid mixture, and detection carried out by the atomic fluorescence spectrometry (AFS). The quality of the analytical procedure was assessed by analyzing in-house standard solutions and certified reference materials. Total Hg concentrations were in the range of 7.6-156 ng g-1 (July 2004), 25.6-277 ng g-1 (January 2005) and 14.6-744 ng g-1 (May 2005) that is approximately the same order of magnitude for all samples collected in two reservoirs at the Tiete River, Brazil. Although Hg concentrations varied with sampling periods and diet, high levels were correlated to the percentage of carnivorous fish scales present in the otter feces. The importance of otter feces preparation for Hg analysis, focusing the food web.

A field intercomparison experiment of the disjunct eddy covariance (DEC) and the conventional eddy covariance (EC) techniques was conducted over a grass field. The half-hourly water vapor fluxes measured by the DEC were within the estimated uncertainty from the fluxes measured by the EC. On the average there was a slight overestimation (<10%) of the fluxes measured by the DEC during the day and underestimation during the night as compared to the fluxes measured by the EC. As this bias does not appear in the simulated DEC measurements it is likely to be due to instrumental problems. The insensitivity of the quality of the fluxes measured by the DEC method to the deficiencies in the gas analysis shows the robustness of this new approach for measuring the surface-atmosphere exchange of trace gases. Results from the first field intercomparison between a new state-of-the-art trace gas flux measurement technique and the direct eddy covariance measurements are reported in this paper.

Elemental mercury (Hg0) is a metal with a number of atypical properties, which has resulted in its use in myriad anthropogenic processes. However, these same properties have also led to severe local subsurface contamination at many places where it has been used. As such, we studied the influence of various parameters on Hg(II) sorption onto pyrite (pH, time, Hg(II) concentration), a potential subsurface reactive barrier. Batch sorption studies revealed that total Hg(II) removal increases with both pH and time. X-ray absorption spectroscopy analysis showed that a transformation in the coordination environment at low pH occurred during aging over 2 weeks, to form an ordered monolayer of monodentate Hg–Cl complexes on pyrite. In column studies packed with pure quartz sand, the transport of Hg(II) was significantly retarded by the presence of a thin pyrite-sand reactive barrier, although dissolved oxygen inhibited Hg(II) sorption onto pyrite in the column. Pyrite may be an effective subsurface reactive barrier for Hg in groundwater.

We determined metal contents of co-occurring algae Padina crassa and Sargassum sp. in Port Jackson (Australia), and relationships between metal levels and the abundance of epifaunal amphipods. Copper, lead and zinc concentrations were amongst the highest yet recorded in these algae. Copper, manganese and lead concentrations were far greater in P. crassa than Sargassum sp., possibly due to the low growth of P. crassa in proximity to contaminated sediments. However, in manipulative experiments the proximity of algae to sediments did not explain these differences. The abundance of herbivorous amphipods correlated negatively with the copper content of P. crassa, but not with the lower concentrations in Sargassum sp. The greater contamination of P. crassa led to patchy distributions of metals in algal beds and recolonisation experiments showed Sargassum sp. acts as a refuge from contaminants for epifauna. The contamination of macroalgae may pose threats to epifauna in harbours around the world. The accumulation of metals by macroalgae may pose ecological threats to herbivorous epifauna in ports and harbours worldwide.