Shrub communities as inhibitors of plant succession in southern Quebec

The purpose of our research was to identify shrub species growing in southern Quebec that inhibit ecological succession in power-line corridors. Results are presented in three parts. First, clonal characteristics that allowed the establishment of stable communities were identified. Second, successional vector analysis identified those species that have the potential to inhibit succession. In poorly drained sites those species wereCornus stolonifera, C. obliqua, Salix petiolaris, andSpiraea alba. In well-drained sites, those species wereZanthoxylum americanum, Rubus idaeus, Spiraea alba, Rhus typhina, andThuja occidentalis. Third, analysis of variance showed that there is a significantly larger number of tree seedlings found in adjacent herbaceous communities than found under the dense cover ofCornus stolonifera, C. obliqua, Salix petiolaris, Spiraea alba, Rhus typhina, Rubus idaeus, Thuya occidentalis, andZanthoxylum americanum. These results indicate that the planting of selected shrub species could, through biological control, delay reforestation.     

Vinyl Chloride Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on vinyl chloride was carried out specifically for the marine environment, according to the methodology laid down in the European Union (EU) risk assessment Regulation (1488/94) and the Technical Guidance Documents for New and Existing Substances (TGD, 1996). Vinyl chloride is used for the production of polyvinyl chloride (PVC). The study consisted of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Exposure Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 6 studies for fish, 3 studies for invertebrates and one for algae have been evaluated. The appropriate assessment factors have been used to calculate a PNEC of 210 microg/l based on short-term exposure. For coastal waters and estuaries a worst case PEC of 0.15 microg/l is derived. For river waters a typical and worst case PEC of <0.008 and 0.4 microg/l is derived, respectively. These concentrations, which do not take into account any dilution within the sea, correspond to safety margins from 500 to 250,000 between the aquatic effect and the exposure concentration. Vinyl chloride is not a 'toxic, persistent and liable to bioaccumulate' substance sensu the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of vinyl chloride does not present a risk to the marine aquatic environment.     

1,1,1-Trichloroethane Marine Risk Assessment with Special Reference to the Osparcom Region: North Sea

This risk assessment on 1,1,1-trichloroethane was carried out specifically for the marine environment, accordingly to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). 1,1,1-trichloroethane is being phased out of most uses because of its ozone depletion potential (ODP) under the Montreal Protocol. Production for emissive uses has already been phased out end 1995 in Europe and 1996 in the United States, Japan and other industrial countries. The risk assessment study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 14 studies for fish, 7 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic studies have been taken into account and the appropriate assessment factors have been used to calculate a PNEC value of 21 microg/l based on long term exposure. The PEC was derived from monitoring data. The PEC was set at 0.206 microg/l (worst case) and 0.024 microg/l (typical case) for coastal waters and estuaries and 0.6 microg/l (worst case) and <0.1 microg/l (typical case) for river waters. The calculated PEC/PNEC ratios, which do not take into account any dilution factor within the sea, correspond to a safety margin of 35 to 1000 between the aquatic effect and the exposure concentration. 1,1,1-trichloroethane is not a 'toxic, persistent and liable to bioaccumulate' substance according to the criteria as mentioned by the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of 1,1,1-trichloroethane does not present a risk to the marine aquatic environment.     

Characterisation of road sediments near Bordeaux with emphasis on phosphorus

Road sediments from the region of Bordeaux (France) were analysed for trace metals, hydrocarbons (including Polycyclic Aromatic Hydrocarbons, PAHs) and phosphorus. The aim of the study was to assess their potential risk for the environment. The sediments were collected by means of a sweeper. The particles are mostly sandy clay loam and silty clay loam with 5.6-8.3% CaO. Heavy metal concentrations are generally below the French and Dutch standards for polluted soils, but a few samples have higher concentrations, e.g., 547 mg kg(-1) for Zn, and 222 mg kg(-1) for Pb. PAH concentrations are above the Dutch target value for polluted soils, and could be a threat to the environment: pyrene (2600 microg kg(-1)) and fluoranthene (1400 microg kg(-1)) have the highest concentrations, whereas chrysene (340 microg kg(-1)) has the lowest. Consequently, these sediments must be considered as waste according to the French circular no 2001-39 from 18 June 2001 and cannot be disposed of anywhere. The Standards Measurements and Testing (SMT) protocol for sequential extraction of phosphorus in sediments was used to determine the forms of phosphorus in the samples. Total phosphorus concentration is 620 mg kg(-1) on average, with a maximum of 933 mg kg(-1); organic phosphorus content is low (36 mg kg(-1) on average). The protocol could be slightly amended, especially with regards to organic phosphorus at low concentrations and could then be used for the determination of phosphorus in other materials such as sludge from detention ponds.     

Integrated Assessment of Swiss GHG Mitigation Policies After 2012

The residential sector presents a great potential for greenhouse gases (GHG) mitigation. We perform an integrated assessment of different mitigation policies for Switzerland focusing on the residential sector. We analyze the case of pure incentive taxes and technical regulations. For our analysis, we have coupled a general equilibrium model with a Swiss residential energy model. We find that a progressive GHG tax of more than 200 USD2000/tCO₂ eq is necessary to reach a target of 50% reduction of GHG emissions in 2050. Finally, we also find that efficiency-based technical regulations provide limited additional abatement incentives.     

Growth and bleaching of the coral Oculina patagonica under different environmental conditions in the western Mediterranean Sea

The success that the putative alien species Oculina patagonica is able to survive under different environmental conditions may be benefiting its establishment and spreading along the Mediterranean Basin. Our objectives were to determine the response of this species, in terms of growth and bleaching, under different environmental conditions. Field data on colony growth and bleaching were obtained for a period of 18 months (from June 2010 to December 2011), in the Alicante Harbour (38°20′11″N, 00°29′11″W) and the Marine Protected Area of Tabarca (38°09′59″N, 00°28′56″W). Additionally, data on sedimentation rates, chlorophyll a concentration and organic matter were also collected. Moreover, the role of light over growth and bleaching of the coral was also studied with a field experiment. Our results showed that growth rates were similar among localities (eutrophic and oligotrophic environments), decreasing with increasing perimeter of the colony. Growth rates were at a minimum during cold months (13 °C) and enhanced during warm months until a threshold temperature; thereafter, bleaching was observed (>28 °C), being adverse for coral growth. In addition, light attenuation could act such as local stress, increasing the coral bleaching with the increase in seawater temperature. Our findings confirmed that O. patagonica has a broad tolerance to seawater temperature, irradiance and trophic water conditions, in addition to its ability to thrive through bleaching events, mainly in eutrophic environments, probably related to food availability.