Impact of sewage sludge spreading on heavy metal speciation in tropical soils (Réunion, Indian Ocean)

This study was designed to evaluate the impact of sewage sludge spreading on tropical soilborne heavy metal speciation. Sludgeborne heavy metal speciation was also assessed, and the potential mobility of the elements was classified as follows: Zn>Ni>Cu approximately Cr. Two sequential extraction procedures were applied to study Cr, Cu, Ni and Zn speciation in control soils and sludge-amended soils. We demonstrated that sewage sludge spreading over a 2-year period did not have an impact on soilborne heavy metal concentrations but affected speciation of the most mobile fractions of Ni and Zn. Both protocols were consistent for the organic matter fractions, with an increase in Cu, Zn and Cr concentrations in the amended soil as compared to the control soil. In addition, we highlighted that the two protocols characterized different pools of organic matter and that organic compounds remained in the solid matrix after extraction. With respect to the reducible fraction, completely opposite results were obtained with the two protocols and the solid residue study revealed that the two schemes were ineffective in characterizing iron and manganese fractions.     

Devising Local Sustainable Development Indicators: from technical issues to bureaucratic stakes. The Greater Lyons experience

The paper will draw on the experience of Greater Lyons (France) in the development and implementation of air quality indicators in the framework of an environmental monitoring body, created in 1992. The analysis shows a patent discrepancy between the strength of the political support enjoyed by the monitoring body at its creation and its gradual confinement within the administrative structure of Greater Lyons. In fact, developing and using indicators raises not only technical issues but also political and bureaucratic stakes. The experience provides food for thought as regards the emergence of sustainable development issues within large and complex structures such as that of Greater Lyons. The paper points out that if indicators are hybrid objects, monitoring bodies, which are supposed to devise and promote them, are hybrid as well: their management, in terms of aims, means and position within the administrative body, is at least as important as their so-called 'technical' function.     

Maternal serum leptin concentration during the second trimester of pregnancy: association with fetal chromosomal abnormalities

Recent studies suggest that leptin, the product of the obese gene, is produced by the placenta during pregnancy. The present study addressed the question whether second trimester maternal serum leptin could be altered by fetal Down syndrome or Edwards syndrome. Maternal serum leptin concentrations were measured in 18 pregnancies complicated with Down syndrome, six pregnancies complicated with Edwards syndrome and 183 uncomplicated pregnancies during the second trimester of pregnancy. The present results demonstrate that leptin concentrations in uncomplicated pregnancies slightly decrease from the 16th week of pregnancy, reaching a minimum of 18.8 ng/ml around the 20th week, and then rapidly increase to 28.2 ng/ml by the 24th week. Leptin correlation with maternal body weight decreases from r=0.695 at 16–17 week of gestation to r=0.544 at >22 weeks of gestation. There was no significant difference between the mean MoMs of Down syndrome- (0.926) or Edwards syndrome- (0.960) affected pregnancies and normal pregnancies (1.002). A weak correlation (r=0.18, p<0.02) was observed between corrected leptin MoMs and human chorionic gonadotrophin (hCG) MoMs in normal pregnancies. It is assumed that around the 20th week of pregnancy placental leptin production is activated or at least is accelerated and it is added to the amount of leptin produced by maternal adipose tissue. Fetal Down syndrome or Edwards syndrome does not seem to alter maternal leptin concentration and therefore leptin cannot be used as a marker for these chromosomal abnormalities in the early second trimester of pregnancy. Copyright © 2002 John Wiley & Sons, Ltd.     

Carbon and nitrogen losses by surface runoff following changes in vegetation

Rainfall simulation experiments were conducted on annual grassland and coastal sage scrub hillslopes to determine the quantities of C and N removed by surface runoff in sediment and solution. Undisturbed coastal sage scrub soils have very high infiltration capacities (> 140 mm h(-1)), preventing the generation of surface runoff. Trampling disturbance to the sage scrub plots dramatically reduced infiltration capacities, increasing the potential for surface runoff and associated nutrient loss. Infiltration capacities in the grassland plots (30-50 mm h(-1)) were lower than in the sage scrub plots. Loss rates of dissolved C and N in surface runoff from grasslands were 0.5 and 0.025 mg m(-2) s(-1) respectively, with organic N accounting for more than 50% of the dissolved N. Total dissolved losses with simulated rainfall were higher than losses in simulations with just surface runoff, demonstrating the importance of raindrop impact in transferring solutes into the flow. Experimental data were incorporated into a numerical model of runoff and sediment transport to estimate hillslope-scale sediment-bound nutrient losses from grasslands. According to the model results, sediment-bound nutrient losses are sensitive to the density of vegetation cover and rainfall intensity. The model estimates annual losses in surface runoff of 0.2 and 0.02 g m(-2) for sediment-hound C and N, respectively. The results of this study suggest that conversion of coastal sage scrub to annual grasslands increases hillslope nutrient losses and may affect stream water quality in the region.     

Risk of Public Disclosure in Environmental Farm Plan Programs: Characteristics and Mitigating Legal and Policy Strategies

Although various studies have shown thatfarmers believe there is the need for a producer-ledinitiative to address the environmental problems fromagriculture, farmers in several Canadian provinceshave been reluctant to widely participate inEnvironmental Farm Plan (EFP) programs. Few studieshave examined the key issues associated with adoptingEFP programs based on farmers', as opposed to policymakers', perspectives on why producers are reluctantto participate in the program. A study adapting VanRaaij's (1981) conceptual model of the decision-makingenvironment of the firm, and prospect theory on valuefunctions associated with the gains and losses fromrisky choices can be used to characterize how farmersperceive potential risks in environmental farmplanning. This framework can be used to assert thatfarmers are concerned about risks of public disclosureof potentially incriminating environmental informationfrom farms because the EFP program requirements foridentification and extensive documentation of farminformation is perceived by farmers as facilitatingthe accessibility of environmental information to thepublic, and public investigative efforts. Although theEFP program does not explicitly generate informationabout the environmental conditions of a farm nor thedisclosure of such information to the public, itcreates the possibility of generating and divulgingpotentially incriminating information that the farmermay want to treat as confidential. Yet, alone, theserisks of public disclosure concerns should not preventfarmers from participating in the EFP. Awareness ofand participation in environmental farm planning canbe increased if farmers and policy makers understandwhat the risks are, and how they arise. Aspects of theEFP process that have the potential to generate riskof public disclosure concerns relate to farm reviews,documentation and record keeping, and correctiveaction plans. There are legal and policy instrumentsthat can offer various forms of protection and helpminimize such risks, and these need to be assessed.     

Effect of Nutrient Management Planning on Crop Yield, Nitrate Leaching and Sediment Loading in Thomas Brook Watershed

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10–25 %, for grain crop production, to significantly lower ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching while balancing impacts on crop yields within the watershed.     

Sustainable forestry management in developing countries

The central message of this paper is that natural forests have multiple uses and multiple users. The paper describes the crisis in Asian forestry and four failures which lie behind the crisis. The first failure is related to economic policy which has consistently underpriced timber, not accounting for the true cost of replacing the felled trees or the value of non-timber goods and services (including environmental services). The second failure stems from the lack of community involvement in managing forests. The third failure is that of forestry institutions which have not been able to adapt to changes required to meet new challenges — away from timber extraction towards environmental services and social forestry. The fourth failure arises from technological constraints, including difficulties in carrying out long-term research (to cover the 20–40 year time horizon in the forestry sector) and ineffective application of research results. A number of specific suggestions for moving toward sustained yield management in Asia are presented. The sustainable management of forests in Asia is crucial not only for indigenous peoples, the environment and economies of the countries of Asia, but also for the biodiversity and health of the global environment.