Cadmium leaching from micro-lysimeters planted with the hyperaccumulator Thlaspi caerulescens: experimental findings and modeling

The use of heavy metal hyperaccumulating plants has the potential to become a promising new technique to remediate contaminated sites. We investigated the role of metal mobilization in the Cd hyperaccumulation of Thlaspi caerulescens (J. & C. Presl, 'Ganges'). In a micro-lysimeter experiment we investigated the dynamics of Cd concentration of leachate as well as Cd removal by plant uptake in four treatments: (i) Control (bare soil), (ii) T. caerulescens, (iii) nonhyperaccumulator Brassica juncea (L.) Czern. ('PI 426308'), and (iv) co-cropping of the hyperaccumulator and nonhyperaccumulator. The experimental findings were analyzed using one- and two-site rate-limited desorption models. Co-cropping of T. caerulescens and B. juncea did not enhance metal uptake by B. juncea. Although Cd uptake of T. caerulescens was 10 times higher than that of B. juncea, the Cd concentration of leachate of the T. caerulescens treatment did not decrease below that of the B. juncea treatment. The Cd depletion in leachate was well reproduced by the two-site rate-limited desorption model. The optimized desorption coefficient was three orders of magnitude higher in the rhizosphere than in the bulk soil. Our results indicate that T. caerulescens accelerates the resupply of Cd from soil pointing to an important role of kinetic desorption in the hyperaccumulation by T. caerulescens.     

Road accidents,an occupational risk

Road accidents sustained at work represent between 20% and 40% of work fatalities in most industrialised countries, yet few data on occupational road accident risk factors have been published. A case control study was performed to assess the role of work-related risk factors in the occurrence of occupational road accidents. A preliminary qualitative study was carried out to identify possible occupational factors in occupational road accidents, and to draw up the case control study. Cases were recruited from the Rhône road trauma registry (France), controls from voting lists. A telephone interview was performed. Exposure to road risk was measured as a percentage of work time. One hundred and forty-six cases and 440 matched controls were interviewed. Accident risk was found to increase with exposure. Driving was associated with more difficult working conditions than found in jobs not involving driving. These difficulties, however, were not systematically associated with increased occupational road accident risk. Among factors which still emerge after adjustment for road risk exposure, there are scheduling issues (inflexible schedule organisation, lack of consecutive rest-days, lack of flexibility in performing the work), difficulties of communication with superiors, low seniority in the activity, low educational level and physical constraints at work. This study highlights some possible occupational road accident risk factors. Given the chosen case/control methodology, the findings may be considered as advancing our knowledge of the subject, but need confirmation by further studies.     

Spatial modelling for the development of agri-environmental programs

Spatial modelling of environmental indicators has been well established in landscape ecology and in nature conservation on regional and national scales over the recent past. Yet, using spatial information as a basis for the coordination of environmental measures on a trans-national European level reveals several shortcomings and hindrances, ranging from data quality issues and methodological aspects to discussions on how to define ecological indicators across Europe. This paper analyzes the potential of spatial modelling for the development and implementation of agri-environmental measures as part of rural development policies, discussing critical aspects of spatial environmental modelling as well as chances, trends and demands.     

Environmental–sanitary risk analysis procedure applied to artificial turf sports fields

Owing to the extensive use of artificial turfs worldwide, over the past 10 years there has been much discussion about the possible health and environmental problems originating from styrene-butadiene recycled rubber. In this paper, the authors performed a Tier 2 environmental–sanitary risk analysis on five artificial turf sports fields located in the city of Turin (Italy) with the aid of RISC4 software. Two receptors (adult player and child player) and three routes of exposure (direct contact with crumb rubber, contact with rainwater soaking the rubber mat, inhalation of dusts and gases from the artificial turf fields) were considered in the conceptual model. For all the fields and for all the routes, the cumulative carcinogenic risk proved to be lower than 10^?6 and the cumulative non-carcinogenic risk lower than 1. The outdoor inhalation of dusts and gases was the main route of exposure for both carcinogenic and non-carcinogenic substances. The results given by the inhalation pathway were compared with those of a risk assessment carried out on citizens breathing gases and dusts from traffic emissions every day in Turin. For both classes of substances and for both receptors, the inhalation of atmospheric dusts and gases from vehicular traffic gave risk values of one order of magnitude higher than those due to playing soccer on an artificial field.     

Near real time satellite tracking of striped marlin (Kajikia audax) movements in the Pacific Ocean

High-resolution satellite locations were obtained from striped marlin using Argos transmitters attached to the upper lobe of the caudal fin. Twenty-six striped marlin were tagged off New Zealand (2005–2007) and tracked as far as the central Pacific Ocean. Caudal fin mounted Argos tags generated 1,524 locations during a total of 659 tracking days [mean 25 (±21.24) days per fish and 2.3 (±2.30) locations per day]. 38% of locations have an estimated accuracy of ±1 km or better. Displacement rates from high quality locations ranged from 2.9 to 170.8 km in a 24 h period, with a mode at 20–30 km and a mean of 45 km/day. The caudal fin attachment methodology and antenna configuration was adjusted each season to improve transmission life and data quality, with the best results obtained in the last year of deployments (2007). The longest track duration was 102 days, with a total displacement of 4,959 km and a total track distance from all locations received of 6,850 km. Tag shedding and antenna failure appear to have limited the duration of tracks from SPOT tags. The high temporal and spatial resolution data revealed behaviours not previously observed in striped marlin, including associations to subsurface bathymetric features. High resolution location data such as these are useful inputs for statistical models used to investigate habitat selection and switching between different behavioural modes. The geolocations calculated using ukfsst estimates from PAT tag data had RMS errors of 1.01° latitude and 0.59° longitude when compared with SPOT tag Argos locations.     

Copolymerization of 2,4-dichlorophenol with humic substances by oxidative and photo-oxidative biomimetic catalysis

We evaluated the catalytic activity of a water-soluble iron-porphyrin in an oxidative coupling reaction to form covalent bonds between 2,4-dichlorophenol (2,4-DCP) and humic molecules. The biomimetic catalysis in the presence of H₂O₂ was tested in the dark and in daylight, and changes in reaction products were revealed by high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR) spectroscopy. In all conditions, iron-porphyrin was effective in promoting complete disappearance of 2,4-DCP, although catalyst activity was enhanced in daylight (with a maximum turnover number of 85.13). Further evidence of the occurred covalent coupling between 2,4-DCP and humic molecules was revealed by diffusion-ordered nuclear magnetic resonance (DOSY-NMR) spectroscopy that showed a reduced diffusivity of 2,4-DCP after the catalytic reaction. These findings indicate that iron-porphyrin is an efficient catalyst for the covalent binding of polyhalogenated phenols to humic molecules, thereby suggesting that the copolymerization reactions may become a useful technology to remediate soils and waters contaminated by halogenated phenols and their analogues.