Development and application of long-term sublethal whole sediment tests with Arenicola marina and Corophium volutator using Ivermectin as the test compound

Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required.     

Differential responses of the freshwater wetland species Juncus effusus L. and Caltha palustris L. to iron supply in sulfidic environments

Sulfur pollution can lead to serious problems in freshwater wetlands, including phosphorus eutrophication and sulfide toxicity. We tested the effects of anaerobic iron-rich groundwater discharge in fens, simulated by iron injection, on two characteristic species (Juncus effusus and Caltha palustris) in a sulfidic environment. Biomass production of C. palustris roots showed an optimum response to the combined addition of iron and sulfide, with highest values at intermediate concentrations of both substances. Iron deficiency apparently occurred at low iron concentrations, while at high iron concentrations, growth was decreased. For J. effusus, in contrast, no toxic effects were found of both iron and sulfide. This could be explained by larger radial oxygen loss (ROL) of J. effusus and could not be explained by differences in phosphorous concentrations. The results of our experiments confirm that iron-rich groundwater discharge has the potential to affect vegetation composition through toxicity modification in sulfidic environments.     

On the presence of enriched amounts of 235U in hot particles from the terrestrial area affected by the Palomares accident (Spain)

The characterisation by ICP-MS of an isolated Pu-U hot particle originating from the nuclear weapons accident in Palomares (Spain) shows, for the first time, that its uranium content is highly enriched in (235)U. The enrichment has been confirmed by independent analyses of two surface soil samples collected in a heavily contaminated area close to the impact point of one of the bombs. This finding clarifies better the composition of the weapons involved in the accident and is of importance when the inventory of U and Pu in the contaminated area are to be calculated.     

Effects of metals on life cycle parameters of the earthworm Eisenia fetida exposed to field-contaminated, metal-polluted soils

Two control and eight field-contaminated, metal-polluted soils were inoculated with Eisenia fetida (Savigny, 1826). Three, 7, 14, 21, 28 and 42 days after inoculation, earthworm survival, body weight, cocoon production and hatching rate were measured. Seventeen metals were analysed in E. fetida tissue, bulk soil and soil solution. Soil organic carbon content, texture, pH and cation exchange capacity were also measured. Cocoon production and hatching rate were more sensitive to adverse conditions than survival or weight change. Soil properties other than metal concentration impacted toxicity. The most toxic soils were organic-poor (1-10 g C kg(-1)), sandy soils (c. 74% sand), with intermediate metal concentrations (e.g. 7150-13,100 mg Pb kg(-1), 2970-53,400 mg Zn kg(-1)). Significant relationships between soil properties and the life cycle parameters were determined. The best coefficients of correlation were generally found for texture, pH, Ag, Cd, Mg, Pb, Tl, and Zn both singularly and in multivariate regressions. Studies that use metal-amended artificial soils are not useful to predict toxicity of field multi-contaminated soils.     

Comparison between the accumulation capacity of four lichen species transplanted to a urban site

The capacity to accumulate trace elements from the atmosphere of the lichens Hypogymnia physodes, Parmelia sulcata, Pseudevernia furfuracea and Usnea gr. hirta transplanted to an urban site of N Italy was compared. Twenty-nine elements (Al, As, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hg, I, K, La, Mg, Mn, Ni, Pb, Rb, Sb, Sc, Se, Sm, Th, Ti, V, Zn) were analyzed by Instrumental Neutron Activation Analysis (INAA) and Electro-Thermal Atomic Absorption Spectroscopy (ET-AAS). The ratio between the concentrations of each element in exposed samples to that of control samples (exposed-to-control ratio and EC ratio) was used to investigate the accumulation rates of lichen thalli. The results showed that in general elements did not exhibit well defined trends, but rather showed fluctuations, and indicated that H. physodes, P. furfuracea and U. gr. hirta have a similar accumulation capacity, while that of P. sulcata is lower.     

Effect of coumaphos on cholinesterase activity, hematology, and biochemical blood parameters of bovines in tropical regions of Mexico

To assess the effect of coumaphos [O-(3-chloro-4-methyl-2-oxo-2H-1-benzopyran-7-yl) O,O-diethyl phosphorothioate] exposure on physiological responses during bovine production, acetylcolinesterase (AChE) and butyrylcholinesterase (BuChE) activities were measured in whole blood, erythrocytes, and plasma of healthy male steers (Bos Taurus x Bos indicus) sprayed with coumaphos at a non-lethal dose of 1 mg kg(- 1) body weight per day once every 14 (in vivo group) or 21 days (southern and central groups). Coumaphos topically administered at 1 mg/kg body weight per day to cattle under normal management practices in tropical areas produced a significant inhibition in erythrocyte (RBC) AChE and BuAChE activities when compared to baseline levels. RBC-AChE activity for the in vivo group decreased 71.3% (P < 0.05) and BuChE activity 59.1% (P < 0.05); RBC-AChE activity decreased 55.1% (P < 0.05) (southern group) and 43.4% (P < 0.05) (central group). Compared to the control specimens, steers from in vivo, southern, and central groups after 150 days of exposure had lower (P < 0.05) leukocyte count, absolute lymphocyte, erythrocyte, and platelet counts. Decreases in RBC-AChE activities correlated with decreased lymphocyte (r = 1.000, p = 0.01), erythrocyte (r = 1.000, p = 0.003), and platelet counts (r = 0.841, p = 0.036). Significantly increased BUN levels (P < 0.05) correlated with the decrease in RBC-AChE activities (r = - 0.997, p = 0.047) and with the decrease in absolute red blood cell (r = - 0.883, p = 0.020) and lymphocyte (r = - 0.825, p = 0.043) counts; increased (P < 0.05) total plasma protein levels correlated with the decrease in RBC-AChE activities (r = -0.998, p = 0.043), absolute red blood cell (r = - 0.998, p = 0.040), lymphocyte (r = - 0.893, p = 0.017), and platelet (r = -0.855, p = 0.030) counts. The physiological responses correlated with the erythrocyte acetylcholinesterase inhibition could be considered as early indicators or warning responses of bovine exposures to organophosphorus pesticides (OPs).     

Combined effect of diuron and simazine on photosystem II photochemistry in a sandy soil and soil amended with solid olive-mill waste

Diuron (3-(3,4-dichlorophenyl)- = 1,1-dimethylurea) and simazine (6-chloro-N(2), N(4)-diethyl-1,3,5-triazine-2,4-diamine) are soil-applied herbicides used in olive crops. The objective of this study is to investigate the effect of these herbicides on Photosystem II photochemistry of Olea europaea L., and whether the amendment of soil with an organic waste (OW) from olive oil production industry modifies this effect. For this purpose, herbicide soil adsorption studies, with unamended and OW-amended soil, and chlorophyll fluorescence measurements in adult olive leaves, after one, two and three weeks of soil herbicide treatment and/or OW amendment, were performed. Soil application of these herbicides reduced the efficiency of Photosystem II photochemistry of olive trees due to chronic photoinhibition, and this effect is counterbalanced by the addition of OW to the soil. OW reduces herbicide uptake by the plant due to an increase in herbicide adsorption.     

The impact of sewage irrigation on the uptake of mercury in corn plants (Zea mays) from suburban Beijing

The impact of sewage irrigation on the uptake and translocation of mercury (Hg) in corn plants (Zea mays) was investigated. Corn plants were harvested the same day from two nearby fields in suburban Beijing, one irrigated historically with sewage effluent, and one irrigated solely with groundwater. Hg content was analyzed in the soil, roots and stems, while percent moisture and soil organic content were analyzed in the soil samples. The concentration of Hg in the soil and roots, and the soil organic content were not significantly different between the two fields, despite the historic practice of sewage irrigation. Hg content in roots was positively correlated with soil Hg concentration (r=0.95, n=6). The transfer coefficients between roots and stems were significantly higher in the control site (control: 2.06, sewage-irrigated: 0.44, p<0.05), indicating that the barrier effect of the roots was not consistent between the two fields.     

Promoting the O3 flux concept for European forest trees

Tropospheric ozone (O3) levels are predicted to stay high, being a factor within "global change" with potential effects on the carbon sink strength of forest trees. Hence, new approaches to O3 risk assessment and their validation are required, although appropriate databases for adult trees are scant. Approaches based on external O3 exposure are presently being evaluated against the ones on O3 flux into leaves, as the cumulative uptake has the capacity for deriving O3 risk from cause-effect relationships. The effective dose, however, needs to account for the trees' O3 defence and tolerance in addition to O3 uptake. The current status of promoting the preferable mechanistic O3 flux concept is highlighted for major regions of Europe, addressing refinements and simplifications needed for routine use. At the pan-European scale, however, the flux-based concept is ready for use in O3 risk assessment and has the potential of meso-scale application at the forest ecosystem level.     

Challenges in quantifying biosphere-atmosphere exchange of nitrogen species

Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.