Solute transport modeling under cultivated sandy soils and transient water regime

Drainable lysimeters offer the possibility to integrate heterogeneous solute leaching conditions caused by row crops and transient water regime, and to conveniently measure water and solute fluxes at the drainage outlet. To compare solute leaching behavior in and around drainable lysimeters operating under a transient water regime in potato (Solanum tuberosum L.) fields, parameters of the convective lognormal transfer (CLT) function model were fitted using bromide (Br-) flux concentrations (Cf) measured in lysimeters and from Br- resident concentrations (Cr) measured in adjacent soil cores. Expected mean values Ez(I) obtained from Cr and Cf CLT parameters were equivalent and well correlated (R2 = 0.78). However, estimated median values mu of the CLT function were smaller when derived from Cr (1.05 to 1.28) compared with Cf (1.23 to 2.14). Most mu values were also smaller than previously reported values for a 30-cm reference depth, indicating that 50% of solute mass would leach more readily in these coarse sandy soils. Higher variance and dispersion of Cr compared with those of Cf could be related to a smaller sampling support (sample size/sampling area) in the case of Cr measured by soil coring, or to disruption of solute transport mechanisms in the repacked lysimeter. Retained Br- in the top soil layer after 12 to 17 cm of cumulative drainage was indicated by measured Cr. Neither CLT function simulated well residual topsoil Cr values, indicating that Br- plant cycling or preferential flow probably interfered even though tuber Br- uptake was relatively small.     

Photodegradation and Biodegradation Study of a Starch and Poly(Lactic Acid) Coextruded Material

To simulate the behavior of agricultural mulch coextruded poly(lactic acid)(PLA)/starch films, two stages were carried out. The first was an ultraviolet treatment (UV) at 315 nm, during which glass transition temperature T_g, weight, and molecular weight (MW) decreased and a separation between PLA and starch phase was observed. For the second stage, the mineralization of the carbon of the material was followed using the ASTM (D 5209–92 and 5338–92) and ISO/CEN (14852 and 14855) standard procedures. To measure the biodegradability of polymer material, the assessment of the carbon balance allowed determination of the distribution between the carbon rate used to the biomass synthesis or the respiration process (released CO₂), as well as the dissolved organic carbon into the culture medium and the carbon in the residual insoluble material. The influence of the nature of the medium and the standardized procedures on the final rate of biodegradation was investigated. Whatever the standardized method, the biodegradation percentage was significantly stronger in liquid medium (92.4–93.4) than on inert medium (80–83%). In the case of the compost process, only released CO₂ was measured and corresponded to 79.1–80.3%.     

UN/ECE ICP Materials Dose-response Functions for the Multi-pollutant Situation

A “multi-pollutant exposure programme” reflecting the new pollution situation where SO₂ is no longer the dominating pollutant has been performed by the International Co-operative Programme on Effects on Materials, including Historic and Cultural Monuments (ICP Materials) within the activities of the Convention on Long-range Transboundary Air Pollution. The main results obtained in the period 1997–2003 are summarised. Dose-response functions are presented for carbon steel, zinc, copper, bronze and limestone. Parameters involved in the functions include besides SO₂ and pH, which were included in the previously developed functions from ICP Materials, also the effect of particulate matter and HNO₃.     

Sustainable development strategies: Tools for policy coherence

Many different approaches for national sustainable development strategies (NSDS) have been proposed since 1992, with some components common to all. A country's national strategy should be designed to help mainstream environmental concerns into policy. More broadly, it should coordinate local policy with global concerns, as well as integrate scientific knowledge into policy and development planning. The peer review mechanism for national strategies was piloted by France, and also involved representatives of countries from the North and the South as well as stakeholders. The peer review process allows countries to share their experience and information, and can assist them in identifying their own path to sustainable development. The business community can also contribute to sustainable development through provision of local and global public goods. Another input to sustainable development could come from the International Organization for Standardization (ISO) and its Guidance Standard on Social Responsibility (ISO 26000), as a coordinating mechanism between voluntary initiatives and binding obligations (such as international conventions). ISO standards and guidelines should therefore be integrated with national sustainable development strategies and local Agenda 21 frameworks.     

Characterising sources and sinks of rural VOC in eastern France

Fifty non-methane hydrocarbons (NMHC) and seventeen carbonyl compounds were measured at a French rural site from 1997 to 2001, as part of the EMEP programme. Data handling was based on an original source-receptor approach. First, the examination of the levels and trends was completed by the comparison of the seasonal distribution of rural and urban VOC/acetylene ambient ratios. This analysis has shown that most of the compounds derived from mixing and photochemical transformation of mid-range transported urban pollutants from the downwind urban area. Then, identified sources and sinks were temporally apportioned. Urban air masses mixing explains, at least, 80% of the wintertime levels of anthropogenic NMHC and isoprene. In summer, photochemistry dominates the day-to-day distribution of anthropogenic NMHC whilst summertime isoprene is also controlled by in-situ biogenic emissions. Then, the results of C(1)-C(3) carbonyls were discussed with respect to their direct biogenic and anthropogenic emissions and photochemical production through the [carbonyl/auto-exhaust tracers] emission ratio. Diluted vehicle exhaust emissions mainly contribute to the total content of lower aldehydes in winter while other processes control lower ketones. Secondary production is predominant in summer with at least a 50% high intensity. Its dependence upon temperature and radiation is also demonstrated. Finally, the importance of the primary and secondary biogenic production of acetone and formaldehyde is assessed. In particular, biogenic contribution would explain 37 +/- 25% of acetone levels in summer.     

Pigeon orientation: effects of the application of magnets under overcast skies

 To verify the existence of a magnetic compass in birds, researchers have often released homing pigeons under overcast skies that are equipped with bar magnets on various parts of their body. In particular, Keeton was successful in finding disorientation in overcast conditions in a first series of tests, but not in a second series. The experiments reported here attempt to explain this contradiction on the basis of findings obtained by releasing pigeons equipped in a way similar to that reported in Keeton's tests and pigeons equipped in a way similar to that reported by other authors. Received: 15 November 1999 / Accepted in revised form: 28 February 2000     

Evaluation of lipid peroxidation as a toxicity bioassay for plants exposed to copper

Agricultural soils may contain toxic levels of copper (Cu) due to sewage sludge spreading or industrial pollution but chemical analyses may not be representative of Cu bioavailability, defined as the soil Cu fraction that plants can actually absorb (i.e. Cu fraction which is not strongly adsorbed to soil components). Lipid peroxidation caused by Cu in plants was investigated as a relevant bioassay of toxicity. Seven-day-old rapeseed plantlets were grown on Cu-supplemented medium in controlled conditions. Lipid-peroxidation was assessed by measuring: (1) the 2-thiobarbituric acid (TBA)-reactive substances; (2) the hydroperoxy acids by HPLC analysis; and (3) the alkane outputs by gas chromatography. We first verified the correlation between the results obtained by each method and then discussed their advantages and disadvantages within the context of a bioassay, showing that the volatile alkane output measurement is the most precise and easy to perform method for this purpose.     

Development of a loading dock safety evaluation tool

INTRODUCTION: Companies that use forklifts to load and unload trucks at loading docks are well aware of the main danger associated with this type of activity (i.e., the possibility of the forklift falling or tipping over when the truck suddenly moves away from the dock). Even if various truck restraint measures can be implemented to reduce the possibility of this type of accident, a number of hazardous incidents that result in a forklift tipping over from a loading dock still do occur regularly in day-to-day activities. This situation has brought experts to examine and evaluate the effectiveness of different measures and systems depending on the context in which they are used. METHODS: The present study touched upon both the technical and the organizational aspects of the restraint measures that could have an impact on safety. Certain elements were examined very closely, especially the failure of mechanical devices and their relation to the environment in which they are used, as well as the systemic interaction between people and the various restraint measures in use in a given context. CONCLUSION: This article presents a safety evaluation tool regarding restraint measures or systems for trucks docked at loading platforms - a tool that, of course, would take into consideration both the specific contextual aspects related to the docking bay itself, and to the plant. IMPACT ON INDUSTRY: This tool is designed to help companies choose the optimal safety measures to implement, while remaining realistic in terms of the technical and economic aspects of any given situation.     

Quantifying sources of climate uncertainty to inform risk analysis for climate change decision-making

Quantitative estimates of future climate change and its various impacts are often based on complex climate models which incorporate a number of physical processes. As these models continue to become more sophisticated, it is commonly assumed that the latest generation of climate models will provide us with better estimates of climate change. Here, we quantify the uncertainty in future climate change projections using two multi-model ensembles of climate model simulations and divide it into different components: internal, scenario and model. The contributions of these sources of uncertainty changes as a function of variable, temporal and spatial scale and especially lead time in the future. In the new models, uncertainty intervals for each of the components have increased. For temperature, importance of scenario uncertainty is the largest over low latitudes and increases nonlinearly after the mid-century. It has a small importance for precipitation simulations on all time scales, which hampers estimating the effect which any mitigation efforts might have. In line with current state-of-the-art adaptation approaches, we argue that despite these uncertainties climate models can provide useful information to support adaptation decision-making. Moreover, adaptation decisions should not be postponed in the hope that future improved scientific understanding will result in more accurate predictions of future climate change. Such simulations might not become available. On the contrary, while planning adaptation initiatives, a rational framework for decision-making under uncertainty should be employed. We suggest that there is an urgent need for continued development and use of improved risk analysis methods for climate change adaptation.