Regional assessment of herbicide sorption and degradation in two sampling years

Sorption and degradation of the herbicide 2,4-D [2,4-dichlorophenoxyacetic acid] were determined for 123 surface soils (0 to 15 cm) collected in 2002 and in 2004 between 49 degrees to 60 degrees north longitude and 110 degrees to 120 degrees west latitude in Alberta, Canada. The soils were characterized by soil organic carbon content (SOC), pH, electrical conductivity, soil texture, cation exchange capacity, carbonate content, and total soil microbial activity. The 2,4-D sorption coefficients, Kd and Koc, were highly variable with coefficients of variation of 89 and 59%, respectively, at the provincial scale. Both Kd and Koc were well described by regression models with SOC and soil pH as variables, regardless of scale. Surprisingly, variations in 2,4-D mineralization were much smaller than variations in sorption. Variability in total 2,4-D mineralization was particularly low, with a coefficient of variation of only 7% at the provincial scale. Average 2,4-D half-lives in ecoregions ranged from 1.7 to 3.5 d, much lower than the field dissipation half-life of 10 d reported for 2,4-D in general pesticide property databases. Regression models describing degradation parameters were generally poor or not significant because 2,4-D mineralization was only weakly associated with measured 2,4-D sorption parameters and soil properties. As such, regional variations in herbicide sorption coefficients should be measured or calculated based on soil properties, to assign distinct pesticide fate model input parameters when estimating 2,4-D off-site transport at the provincial scale. Spatial variations in herbicide degradation appear less important for Alberta as 2,4-D half-lives were similar in soils across the province. The rapid mineralization of 2,4-D is noteworthy because 2,4-D is widely used in Alberta and perhaps adaptation of soil microbial communities allowed for accelerated degradation regardless of soil properties or the extent of 2,4-D sorption by soil.     

Relationship between blood concentrations of heavy metals and cytogenetic and endocrine parameters among subjects involved in cleaning coastal areas affected by the 'Prestige' tanker oil spill

The sinking of the 'Prestige' oil tanker in front of the Galician coast (NW of Spain) in November 2002 offered a unique opportunity to analyze intermediate cytogenetic and endocrine effects among people exposed to the complex mixture of substances that oil constitutes, including several toxic heavy metals. In this work we evaluated the relationship between exposure to heavy metals (blood concentrations of aluminium, cadmium, nickel, lead and zinc) and genotoxic parameters (sister chromatid exchanges, micronucleus test and comet assay) or endocrine parameters (plasmatic concentrations of prolactin and cortisol) in subjects exposed to 'Prestige' oil during cleaning tasks developed after the spillage. Concentrations of lead were significantly related to the comet assay even after adjusting by age, sex and smoking. Cortisol concentrations were significantly influenced by aluminium, nickel (both, inversely) and cadmium (positively). Women had clearly higher concentrations of prolactin and cortisol, even when adjusting by age, smoking, cadmium, aluminium or nickel. Plasmatic cortisol was jointly influenced by gender, smoking and aluminium or nickel (all p<0.05). In women there was a strong relationship between concentrations of cadmium and prolactin (beta=0.37, p=0.031). When the effects of cadmium, aluminium and nickel on cortisol were simultaneously assessed, only the latter two metals remained statistically significant. Among parameters analysed, cortisol appeared to be the most sensitive to the effects of metal exposure. Plasma levels of cortisol deserve further evaluation as a potentially relevant biomarker to assess the effects of exposure to heavy metals.     

PAH desorption from river floodplain soils using supercritical fluid extraction

Sequential supercritical fluid extraction (SFE) was performed in order to estimate desorption of PAHs from river floodplain soils which contain coal and coal-derived particles. Original soils, soils' light fractions (ρ < 2 g cm⁻³), and <63 μm fractions were studied for PAHs' desorption kinetics. Desorption data were successfully described using a two-site model. Desorption rate constants were one order of magnitude lower than those of “slow” and “very slow” desorption rates from other studies. This suggests very slow and extremely slow desorption. Estimated time scales releasing 99% of total extractable contaminants ranged from decades for 2-4-ring PAHs and hundreds of years for 5-6-ring PAHs. We demonstrate that, despite high soil PAH concentrations which are due to coal and coal-derived particles, the general environmental risk is reduced by the very slow and extremely slow desorption rates.     

Canada's Ecological Monitoring and Assessment Network: Where we are at and Where we are Going

Canada has established a National Ecological Monitoring and Assessment Network (EMAN). The Network's operating objective is to understand what changes are occurring in the ecosystems and why. Each site is designed to have long-term multidisciplinary monitoring programs in place with supporting research and manipulation experiments. About 85 sites have been incorporated into the network. A Directory of EMAN Sites is available and a list of the Goals, Objectives and Deliverables (GODs) for many sites is also available. Information can be obtained on the EMAN's website at http://www.cciw.ca/eman/. The network is operated in conjunction with a program of developing national environmental indicators, with increasing emphasis on indicators of sustainable development. A series of environmental assessments are being produced that are issue and/or area focused. The assessment are designed as support for policy decisions. The national coordinating office supports the overall program of data gathering, reporting environmental indicators and produce assessments.     

Reducing hazard vulnerability: towards a common approach between disaster risk reduction and climate adaptation

Over the past few decades, four distinct and largely independent research and policy communities--disaster risk reduction, climate change adaptation, environmental management and poverty reduction--have been actively engaged in reducing socio-economic vulnerability to natural hazards. However, despite the significant efforts of these communities, the vulnerability of many individuals and communities to natural hazards continues to increase considerably. In particular, it is hydro-meteorological hazards that affect an increasing number of people and cause increasingly large economic losses. Arising from the realisation that these four communities have been largely working in isolation and enjoyed only limited success in reducing vulnerability, there is an emerging perceived need to strengthen significantly collaboration and to facilitate learning and information exchange between them. This article examines key communalities and differences between the climate change adaptation and disaster risk reduction communities, and proposes three exercises that would help to structure a multi-community dialogue and learning process.     

Contaminants evaluation of Marais des Cygnes National Wildlife Refuge in Kansas and Missouri,USA

At the new Marais des Cygnes National Wildlife Refuge in Linn County, Kansas, and Bates County, Missouri, USA, we evaluated long-lived contaminants before acquisition of the land for the refuge. We sampled sediments at 16 locations and fish at seven locations. The samples were analyzed for metals and for chlorinated hydrocarbon compounds. Selected sediment samples also were analyzed for aliphatic hydrocarbons. Arsenic concentrations in sediment samples from six locations were elevated compared to US norms, but arsenic was not detected in any fish composite. Mercury concentrations in largemouth bass from two locations were comparable to the 85th percentile concentrations in nationwide fish collections. Most sediment concentrations of other metals were unlikely to have detrimental effects on biota. No chlorinated hydrocarbons were detected in any sediment sample. Chlordane compound concentrations in fish composites from two sites at the eastern end of the sampling area were 0.127 and 0.228 μg/g wet weight, respectively, which are high enough to cause concern. Most aliphatic hydrocarbons detected were found at low concentrations and probably were natural in origin. We concluded that there are no serious contaminants concerns within the project area, but past use of arsenical pesticides may mean a legacy of elevated soil arsenic levels in parts of the area and some use of banned pesticides such as chlordane and DDT likely is still occurring near the refuge.     

Evaluating the impact of HIA on urban reconstruction decision-making. Who manages whose risks?

Practitioners and academic researchers increasingly look to evaluation of health impact assessment (HIA) to improve its practice, its efficiency and its legitimacy. Evaluation is also used to account to policy-makers, who express doubts that the benefits of HIA justify its costs. Until recently evaluation of HIA focused on instrument design and procedures but now the focus needs to shift to analysis of the interaction of HIA and decision-making. Multiple case studies have been applied to identify the conditions in which HIA produces the desired benefits. These studies used analytical concepts derived from the literature on evaluation, knowledge utilization, science of sociology and knowledge management.This paper describes a case study in which the strategic motives of the decision-makers affected the impact of an HIA. This HIA comprised of a quantitative environmental model ‘City & Environment’ that was used to assess environmental health impacts of an urban reconstruction plan in a Dutch city. The evaluation of the HIA shows that the decision to follow the recommendations of the HIA was part of a damage control strategy. The more HIA goals deviate from the policy problem and the less HIA is embedded in institutional procedures, then the more HIA impact will be subject to strategic decision-making behaviour. Appropriate cognitive and social strategies are needed to avoid ‘negative learning’ in those the HIA seeks to influence.