Oryzalin fate and transport in runoff water in Mediterranean vineyards

An experimental study was conducted in a 91.4-ha Mediterranean vineyard catchment in southern France to characterize the fate and transport of oryzalin in runoff water and thus to assess the risk of contamination of surface waters. Oryzalin concentrations in soil were monitored on two fields, one no-till and one tilled from March 1998 to March 2000. Concentrations in solution and on solid phase of runoff water were measured at the outlets of both fields and the catchment. The droughts in the two summer periods reduced the dissipation of oryzalin and increased its field half-life up to 35 days. Consequently, oryzalin was detected throughout the year in runoff water, with maximum dissolved concentrations > 600 microg l(-1) at the field scale. Oryzalin transport essentially occurred in solution. At the no-till field, seasonal losses were 2.29% and 1.89% of the applied amount in 1998 and 1999, respectively. The corresponding values at the tilled field were 1.56% and 0.29%, since tillage reduced total losses by reducing surface runoff. At the catchment scale, oryzalin concentrations were smaller than those at the field scale, due to dilution effects and staggering of application. Large part of the overland flow from the fields reinfiltrated in the ditches before reaching the outlet of the catchment. As a result, seasonal oryzalin losses were <0.2% of the applied amount.     

Assessment of polychlorinated biphenyls (PCBs) in cheese from Rio Grande do Sul, Brazil

Polychlorinated biphenyls (PCBs) are among the most toxic environmental pollutants. Food, especially animal based, has been described as the major source for human exposure to PCBs. We investigated PCB levels (congeners 10, 28, 52, 153, 138, and 180) in cheese from 14 cities of Rio Grande do Sul, Brazil. The fat was extracted using sodium sulfate and petroleum ether, and PCBs purification was conducted using florisil and hexane. The identification and quantification were made in a gas chromatograph with microelectron capture detector (GC-microECD). PCB congeners were found (lower bound data as ngg(-1) fat) in the following rank: 52 (15.75)>180 (4.91)>28 (3.43)>153 (3.00)>10 (2.38)>138 (1.37). Summation operatorPCB contamination ranged from 0 to 78.32 ngg(-1) fat. Differences in PCB levels between industrialized (33.32 ngg(-1) fat) and homemade (26.58 ngg(-1) fat) cheese and between two different regions (36.19 vs. 26.95 ngg(-1) fat) were not statistically significant. For university students, the estimated daily intake (EDI) of PCBs from cheese ranged from 0 to 3.13 pgkg(-1) b.w. EDI was significantly higher for industrialized than homemade cheese, and for cheese from Mountain/Porto Alegre region than from Santa Maria/South/Western region. No sample exceeded maximum level of PCBs allowed in dairy products in the European Community.     

Identifying areas of high herpetofauna diversity that are threatened by planned infrastructure projects in Spain

A major task related to conservation is to predict if planned infrastructure projects are likely to threaten biodiversity. In this study we investigated the potential impact of planned infrastructure in Spain on amphibian and reptile species, two highly vulnerable groups given their limited dispersal and current situation of population decline. We used distribution data of both groups to identify areas of high herpetofauna diversity, and compared the locations of these areas with the locations of the planned road, high-speed train railway and water reservoir network. Four criteria were used for this identification: species richness, rarity, vulnerability, and a combined index of the three criteria. From a total of 1441 cells of 20 x 20 km, areas of high diversity were defined as those cells whose ranked values for the different criteria included either all species or all threatened species. The combined index provided the smallest number of cells needed to retain all threatened species (1.7 and 2.6% of the cells for amphibian and reptile species, respectively). Coincidences between these high diversity areas and cells including planned infrastructures-denominated 'alert planning units'-were 35.4% for amphibians and 31.2% for reptiles. Mitigation of the potential impacts would include actions such as barriers to animal access to roads and railways and ecoducts under these constructions. Our approach provides conservation authorities information that can be used to make decisions on habitat protection. A technique that identifies threats to herpetofauna before they occur is also likely to improve the chance of herpetofauna being protected.     

Carbon and nitrogen stocks and nitrogen mineralization in organically managed soils amended with composted manures

The use of composted manures and of legumes in crop rotations may control the quality and quantity of soil organic matter and may affect nutrient retention and recycling. We studied soil organic C and N stocks and N mineralization in organically and conventionally managed dryland arable soils. We selected 13 extensive organic fields managed organically for 10 yr or more as well as adjacent fields managed conventionally. Organic farmers applied composted manures ranging from 0 to 1380 kg C ha yr and incorporated legumes in crop rotations. In contrast, conventional farmers applied fresh manures combined with slurries and/or mineral fertilizers ranging from 200 to 1900 kg C ha yr and practiced a cereal monoculture. Despite the fact that the application of organic C was similar in both farming systems, organically managed soils showed higher C and similar N content and lower bulk density than conventionally managed soils. Moreover, organic C stocks responded to the inputs of organic C in manures and to the presence of legumes only in organically managed soils. In contrast, stocks of organic N increased with the inputs of N or C in both farming systems. In organically managed soils, organic N stocks were less mineralizable than in conventional soils. However, N mineralization in organic soils was sensitive to the N fixation rates of legumes and to application rate and C/N ratio of the organic fertilizers.     

Home composting versus industrial composting: Influence of composting system on compost quality with focus on compost stability

Stability is one of the most important properties of compost obtained from the organic fraction of municipal solid wastes. This property is essential for the application of compost to land to avoid further field degradation and emissions of odors, among others. In this study, a massive characterization of compost samples from both home producers and industrial facilities is presented. Results are analyzed in terms of chemical and respiration characterizations, the latter representing the stability of the compost. Results are also analyzed in terms of statistical validation. The main conclusion from this work is that home composting, when properly conducted, can achieve excellent levels of stability, whereas industrial compost produced in the studied facilities can also present a high stability, although an important dispersion is found in these composts. The study also highlights the importance of respiration techniques to have a reliable characterization of compost quality, while the chemical characterization does not provide enough information to have a complete picture of a compost sample.     

Long-term disruption of growth,reproduction, and behavior after embryonic exposure of zebrafish to PAH-spiked sediment

A natural sediment spiked with three individual polycyclic aromatic hydrocarbons (PAHs; pyrene, phenanthrene and benzo[a]pyrene) was used to expose zebrafish embryos and larvae during 4 days. The total PAH concentration was 4.4 μg g^?1 which is in the range found in sediment from contaminated areas. Quantification of metabolites in the larvae after exposure confirmed the actual contamination of the larvae and indicated an active metabolism especially for pyrene and benzo[a]pyrene. After a transfer in a clean medium, the larvae were reared to adulthood and evaluated for survival, growth, reproduction, and behavior. Measured endpoints revealed a late disruption of growth (appearing at 5 months) and a trend toward a lower reproductive ability. Adults of embryos exposed to sediment spiked with PAHs displayed lethargic and/or anxiety-like behaviors. This latter behavior was also identified in offspring at larval stage. All together, these effects could have detrimental consequences on fish performances and contribution to recruitment.