Residues behavior of some fungicides applied on two greenhouse tomato varieties different in shape and weight

The degradation of 12 fungicides (azoxystrobin, cymoxanil, cyproconazole, cyprodinil, fenarimol, fludioxonil, iprovalicarb, mepanipyrim, penconazole, pyrimethanil, tolclofos-methyl, triadimenol), commonly used in pest management strategies on Sardinian greenhouse tomato crops was studied. A different residue behaviour was observed between the studied cultivar. On the smaller, a “cherry” type tomato, field data showed an initial residue mostly higher than the “beefsteak” tomato. In any case, except for penconazole, all pesticide residues were below their maximum residue levels (MRLs) reaching the pre-harvest interval (PHI). On both cultivar, triadimenol and cymoxanil residues completely disappeared reaching their PHI, while iprovalicarb, fenarimol, and fludioxonil disappeared in a time of 17 to 24 days. On the contrary, azoxystrobin, cyproconazole, cyprodinil, penconazole, tolclofos-methyl, mepanipyrim, and pyrimethanil showed a long persistence on both tested cultivar and may have residual problems due to an accumulation effect if repeated field treatments will be performed. The first group of molecules according to their rapid degradation could be used in low pesticide-input management in order to obtain tomatoes with low or no detectable residues.     

Phyt'Eaux Cités: application and validation of a programme to reduce surface water contamination with urban pesticides

This paper presents first results of Phyt’Eaux Cités, a program put in place by the local water supply agency, the SEDIF (Syndicat des Eaux d’Ile-de-France), in collaboration with 73 local authorities, private societies and institutional offices (365 km²). The challenges included: measurement of the previous surface water contamination, control of urban pesticide applications, prevention of pesticide hazard on users and finally a overall reduction of surface water contamination. An inquiry on urban total pesticide amount was coupled with a surface water bi-weekly monitoring to establish the impact of more than 200 molecules upon the Orge River. For 2007, at least 4400 kg and 92 type of pesticides (essentially herbicides) were quantified for all urban users in the Phyt’Eaux Cités perimeter. At the outlet of the Orge River (bi-weekly sampling in 2007), 11 molecules were always detected above 0.1 μg L⁻¹. They displayed the mainly urban origin of pesticide surface water contamination. Amitrole, AMPA (Aminomethyl Phosphonic Acid), demethyldiuron, diuron, glyphosate and atrazine were quantified with a 100% of frequency in 2007 and 2008 at the Orge River outlet. During the year, peaks of contamination were also registered for MCCP, 2,4 MCPA, 2,4 D, triclopyr, dichlorprop, diflufènican, active substances used in large amount in the urban area. However, some other urban molecules, such as isoxaben or flazasulfuron, were detected with low frequency. During late spring and summer, contamination patterns and load were dominated by glyphosate, amitrole and diuron, essentially applied by cities and urban users. Both isoproturon and chlortoluron were quantified during autumn and winter months according to upstream agricultural practices. In conclusion, 3 years after the beginning of this programme, the cities reduced the use of 68% of the total pesticide amount. An improvement on surface water quality was found from 2008 and during 2009 for all pesticides. In particular, glyphosate showed a decrease of the load above 60% in 2008, partly related to the Phyt’Eaux Cités action.     

PCDD/Fs atmospheric deposition fluxes and soil contamination close to a municipal solid waste incinerator

Bulk depositions and surface soil were collected in a suburban area, near the Adriatic Sea, in order to assess the contribution of a municipal solid waste incinerator to the area’s total contamination with polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs and PCDFs). Samples were collected at two sites, situated in the area most affected by plant emissions (according to the results of the Calpuff air dispersion model), and at an external site, considered as a reference. Results show that the studied area is subject to low contamination, as far as these compounds are concerned. Deposition fluxes range from 14.3 pg m⁻² d⁻¹ to 89.9 pg m⁻² d⁻¹ (0.75 pg-TEQ m⁻² d⁻¹ to 3.73 pg-TEQ m⁻² d⁻¹) and no significant flow differences are observed among the three monitored sites. Total soil concentration amounts to 93.8 ng kg⁻¹ d.w. and 1.35 ng-TEQ kg⁻¹ d.w, on average, and confirms a strong homogeneity in the studied area. Furthermore, from 2006 to 2009, no PCDD/Fs enrichment in the soil was noticed. Comparing the relative congener distributions in environmental samples with those found in stack emissions from the incineration plant, significant differences are observed in the PCDD:PCDF ratio and in the contribution of the most chlorinated congeners. From this study we can conclude that the incineration plant is not the main source of PCDD/Fs in the studied area, which is apparently characterized by a homogeneous and widespread contamination situation, typical of an urban area.     

Humic acid formation in artificial soils amended with compost at different stages of organic matter evolution

A composting process was conducted under optimal conditions for 150 d, obtaining three biomasses at different levels of maturity: raw material (RM), fresh compost obtained after 11 d of composting (FC), and evolved compost (EC) obtained after 150 d of composting. During the composting process, HAs were extracted and fully characterized by mass balance, DRIFT, and 1H and 13C-nuclear magnetic resonance spectroscopy. Each compost sample was incubated for 180 d in an artificial soil, after which HA extraction was repeated and characterized. To compare composts containing different amounts of labile organic matter (OM), an equal amount of unhydrolyzable OM was added to the soils. Our results indicated that compost HAs consist of a biologically and chemically stable fraction (i.e., the unhydrolyzable HA [U-HA]) and a labile fraction, whose relative contents depended on the composting duration. Humic acid from more EC contained a higher amount of recalcitrant fraction (aromatic carbon) and a lesser amount of labile fraction (aliphatic carbon) than HA from RM and FC. These results suggest that the humification process during composting preserves the more recalcitrant fraction of the compost-alkali soluble/acid insoluble fraction (HA-fraction). Incubation of composts in soil showed that due to the higher labile fraction content, HAs from raw material were more degraded than those from EC. The abundance of labile carbon of soil amended with less-evolved compost (RM and FC) allowed the more recalcitrant fractions of U-HA to be more preserved than in EC. These results suggest that less-evolved compost could contribute more than well evolved compost to the stable soil OM.     

Studying soil organic matter using 13C CP-MAS NMR: the effect of soil chemical pre-treatments on spectra quality and representativity

¹³C CP-MAS NMR spectroscopy is a technique that has proved to be useful in studying soil organic matter (SOM). Nevertheless, NMR spectra exhibit a weak signal and have very low resolution due to: the low natural abundance of ¹³C (1.1 % of C) in SOM, the generally low SOM content of soils, and the presence of paramagnetic impurities. This paper studies the effects of soil chemical pre-treatments on ¹³CP-MAS NMR spectra quality and spectra representativity i.e. soil C mass balance.

After chemical pre-treatment to increase total organic carbon (TOC) content and C/Fe ratio, eight soils characterized by different levels of organic carbon content and C/Fe ratios were studied using ¹³CP-MAS NMR. Moreover, where chemical treatments were not applicable due to high carbon losses, the number of ¹³CP-MAS NMR scans was increased in order to obtain satisfactory spectra.

Results show that chemical pre-treatment of soils with C/Fe > 1 caused high C losses. Bulk soils were therefore studied by increasing the number of ¹³CP-MAS NMR scans. Acceptable spectra were obtained from 8K scans (1K = 1024 transient). On the other hand, even when a large number of scan (32K) are used, soil with C/Fe < 1 cannot be studied. As these soils are characterized by low C losses after HCl treatments (range of 2.9–25.4%), a pre-treatment of at least 1.39 mol l⁻¹ HCl removes excess Fe and at the same time increases C/Fe ratio resulting in 32K scans providing good spectra.     

Genotoxicity of leachates from highly polluted lowland river sediments destined for disposal in landfill

The Matanza-Riachuelo is one of the most polluted rivers of Latin America. The complex chemical mixture of pollutants discharged into the river is accumulated in the river sediments. In this paper, Matanza-Riachuelo river sediment composition and genotoxicity were tested in order to develop a cost-effective, environmentally sound option for disposal and management of contaminated dredged materials. Sampling was performed in a rural area, in a solid waste dumpsite and also in an urban and industrial area. The concentrations of total heavy metals increased from the upper basin to the lower basin. The Ames Salmonella typhimurium test and the Saccharomyces cerevisiae D7 test were performed using toxicity characteristic leachate procedure (TCLP) leachates. The concentrations of copper, lead, and chromium in the leachates exceeded the guide levels for the protection of aquatic life. Low concentrations of organic chlorinated compounds were detected in the leachates. Genotoxic profiles were obtained by testing TCLP leachates from polluted sediment samples with Salmonella typhimurium, Saccharomyces cerevisiae D7, and water sediment suspension with Allium cepa test. No mutagenicity effects on Ames test were observed. Gene conversion and mitotic reversion in Saccharomyces cerevisiae D7 and chromosome aberration in Allium cepa were induced by the sediment samples. Results obtained suggest that dredged sediments could be classified as genotoxic hazardous waste.     

Modification of soil humic matter after 4 years of compost application

Two soil plots, 1 ha each, were amended yearly for 4 years, respectively, with 35.8 and 71.6 Mg ha(-1) yr(-1) of mature compost (CM) obtained from food and vegetable residues. The compost, amended soils, and a control soil plot after 4 years (S4), were analyzed for humin (HUC), humic acid (HAC), fulvic acid (FAC), and non-humic carbon (NHC) content. Compared to S4, the amended soil contained more humified C (HAC, FAC and HUC) and less NHC. Further evidence of the effect of compost on soil organic matter was obtained by the analysis of the humic acid (HA) fractions isolated from both the compost and the soils. These were characterized by elemental analyses and Diffuse Reflectance Infrared Fourier Transformed spectroscopy. The HAs isolated from CM and from S4 were significantly different. The HAs isolated from the amended plots were more similar to HA isolated from CM than to HA isolated from S4. The experimental data of this work indicate that the compost application may affect significantly the soil organic matter composition, and that the approach used in this work allows one to trace the fate of compost organic matter in soil.     

Detection and isolation of fetal cells from maternal blood using the flourescence-activated cell sorter (FACS)

The presence of fetal cells in the maternal circulation during pregnancy has been suggested by repeated observations of small numbers of cells containing Y chromatin or a Y chromosome in the blood of pregnant women. With the fluorescence-activitated cell sorter (FACS), we have used antibodies to a paternal cell surface (HLA) antigen, not present in the mother, to select fetal cells from the lymphocyte fractions of a series of maternal blood samples, collected as early as 15 weeks of gestation. These sorted cells have been examined for a second paternal genetic marker, Y chromatin. Y chromatin-containing cells were found among the sorted cells from prenatal maternal blood specimens in 8 pregnancies subsequently producing male infants whose lymphocytes reacted with the same antibodies to paternal antigen used for sorting with the FACS. In each of 17 pregnancies resulting in male infants who failed to inherit the antigen detected by the antibodies used for cell sorting, Y chromatin-containing cells were not found prenatally. The use of two paternal genetic markers, a cell surface antigen and nuclear Y chromatin, to identify fetal cells in maternal blood permits us to conclude that these cells are present in the mother's circulation, as early as 15 weeks gestation. Further development of the techniques reported here could lead to widespread screening of maternal blood samples during pregnancy for detection of fetal genetic abnormalities.     

Bacterial flora from echinoderm guts and associated sediment in the abyssal Vema Fault

Individuals of the asteroid Solaster sp. and the holothurian Pseudostichopus villosus (Theel) were collected from deep-sea bottom of the Vema fault in the mid-Atlantic ridge during the BIOVEMA cruise (November, 1977) of the R.V. Jean Charcot. Heterotrophic aerobic bacteria of the guts were isolated, identified and compared with bacterial isolates from surface sediment of the same area. Bacterial population structures displayed a predominance of Gram-negative rods in the echinoderm guts and a predominance of Gram-positive bacteria (particularly cocci) in the surface sediment. Investigation of the metabolic potentialities of the isolates suggested that the microflora of echinoderms, and in particular of the Asteroidea, have more specialized orientations in the catabolism of organic compounds. Single-linkage cluster analysis of all the isolates (130 strains) based on 139 phenotypic features revealed that out of 15 identified clusters, only one included both enteric and sediment isolates. The bacteria in this cluster were similar to the genus Micrococcus.