Realistic approach of pesticide residues and French consumer exposure within fruit & vegetable intake

The increase of fruit and vegetable (F&V) intake contributes to the prevention of chronic diseases, but could also significantly increase pesticide exposure and may thus be of health concern. Following a previous pesticide exposure assessment study, the present study was carried out to determine actual levels of pesticides within 400 g of F&V intake and to evaluate consumer risk. Forty-three Active Substances (AS) exceeding 10 % of the Acceptable Daily Intake (ADI) in balanced menus established for our previous theoretical study were considered. Fifty-six pooled food samples were analyzed: 28 fruit samples and 28 vegetable samples. Pesticide values were compared to Maximum Residue Levels (MRL) and to the “toxicological credit” derived from ADI. It was observed that 23 out of the 43 retained AS were never detected, 5 were detected both in F&V samples, 12 only in fruits and 3 only in vegetables. The most frequently detected AS were carbendazim, iprodione and dithiocarbamates. When detected, AS were more frequently found in fruit samples (74 %) than in vegetable samples (26 %). A maximum of 3 AS were detected at once in a given sample. Overall, we observed 8 and 14 overruns of the MRL in 1204 measures in pooled vegetable and fruit samples, respectively (0.7 % and 1.2 % of cases, respectively). Chronic exposure for adults was the highest for dithiocarbamates but did not exceed 23.7 % of the ADI in F&V. It was concluded that raising both F&V consumption up to 400 g/day (～5 F&V/day) according to recommendations of the national health and nutrition plan, does not induce pesticide overexposure and should not represent a risk for the consumer.     

Allium cepa L. as a bioindicator to measure cytotoxicity of surface water of the Quatorze River,located in Francisco Beltrão,Paraná, Brazil

Due to an increase in water consumption in the industrial sector and within the Brazilian population, surface water that receives wastewater from industries, domestic sewage, agricultural industries, and sewage treatment stations can pollute water bodies when not properly treated. The water quality has been linked to catchment characteristics and intensity of agricultural activities. Thus, the aim of this study was to monitor the cytotoxic potential of the water of the Quatorze River, located in the town of Francisco Beltrão, Paraná, Brazil, along its route in the rural area, using the root meristematic cells of Allium cepa L. as a bioindicator. The results showed that the water at points 2, 3, and 4 were not cytotoxic because the rates of A. cepa cell division were unaltered. Point 1 had presented a mitotic index that was statistically larger than the negative control, indicating that this water contained substances with mitogenic capacity, as demonstrated by elevated values in chemical oxygen demand (COD) and biochemical oxygen demand (BOD). However, the mitotic index values decreased along the route of the river (point 1 to point 4), possibly indicating a mechanism of self-purification, despite having received other sources of pollution. Thus, the results of this study show that the water of the Quatorze River should undergo periodic environmental monitoring at different times of the year, including cytotoxicity analysis, to evaluate the principal sources of contamination to maintain the quality of the river water and, consequently, to maintain human health and equilibrium of the entire ecosystem.     

Quantitative evaluation of collagen type VI and SOD gene expression in the nuchal skin of human fetuses with trisomy 21

Objective To investigate the involvement of the genes encoding for COL6A1, COLA2 and super-oxide dismutase (SOD) in the mechanism for the retention of subcutaneous fluid in fetuses with trisomy 21. Methods During a 7-month period (November 2004–May 2005), human fetal skin from the nuchal region was obtained from euploid fetuses and from fetuses with trisomy 21 following abortions and terminations of pregnancy. Cell cultures were performed from nuchal skin. Quantification of COL6A1, COL6A2, COL6A3 and SOD mRNAs were performed using real-time quantitative RT-PCR. Results Twelve fetuses were studied between 13–15 and 19–20 weeks of gestation including 7 cases of trisomy 21. A significant overexpression of genes of interest was demonstrated in trisomy 21 fetuses when compared with euploid fetuses, in the first and in the second trimester of pregnancy (p < 0.0001). Conclusion This study demonstrates a homogeneous overexpression of the genes encoding for α1 and α2 chains of Collagen type VI, and SOD in nuchal skin of human trisomy 21 fetuses. Persistence of this overexpression in the second trimester of pregnancy, despite the absence of an enlarged nuchal translucency (NT), may characterize some compensatory mechanisms. Copyright © 2007 John Wiley & Sons, Ltd.     

Plant Bioavailability of “natural” and “model” Humic acid‐bound [14c] Atrazine residues

The release of bound [14C] atrazine residues and their uptake by maize plants was investigated.

“Natural”; humic acids, extracted from a brown soil, and “model”; humic acids, prepared from catechol, both containing bound [14C] atrazine residues were incubated with plants in soil. After 21 days, the maize plants contained 0.7% (plants grown in soil mixed with “natural”; humic acids) to 1.7% (plants grown in soil mixed with “model”; humic acids) of the radioactivity originally introduced.

The roots contained 55 to 70% of the [14C] residues whereas the remainder was present in the shoots. A significant amount of the total [14C] residues (29 to 53%) became again bound in plant tissues, whereas the, majority of extractable [14C] residues was present in the form of conjugates.

The behaviour of “model”; humic acid‐bound residues was comparable to that of “natural”; humic acid‐bound residues or soil‐bound residues.     

Influence of various emission scenarios on ozone in Europe

In this study, we investigated the effect of numerous regulations enforced since 1985 to improve air quality on ozone in Europe with the focus on Switzerland, using the Comprehensive Air Quality Model with Extensions (CAMx) for a specific summer period. Several emission scenarios for the year 2010 were also considered. The model results suggest that the emission reductions of ozone precursors should have been effective to reduce ozone production between 1985 and 2000 in northern Switzerland. However, observations do not indicate any significant change in surface ozone levels since early 1990s, except in the region of Zurich where there is a small negative trend. On the other hand, the model predictions match very well the spatial variability of the trends but the calculated trends are around 0.5 ppb year⁻¹ lower than those observed. This difference is similar to the background ozone increase as suggested by the long-term observations at the high Alpine station Jungfraujoch. These results support the hypothesis that the decrease in local ozone production due to emission reductions might have been partly or completely compensated by the simultaneous increase in the background ozone. In 2010, a strict application of the Gothenburg Protocol in Europe would lead to a decrease in peak ozone concentrations by about 5% in Switzerland under the meteorological conditions applied. Our calculations also indicated that emission controls only in Switzerland would not be very effective to improve the air quality in the future. The further development of the background ozone will in any case be very important for the tropospheric ozone levels.     

Bringing the outside in: Can “external” workers experience insider status?

The current study examines the possibility that agency workers can experience perceived insider status despite their assumed “outsider” category. One hundred ninety‐one agency workers from Canadian financial firms completed surveys assessing agency worker perceptions regarding the level of support from both their supervisors and the client firms' permanent workers, as well as the agency workers' level of perceived insider status and affective commitment toward the client firm. Agency worker supervisors (within the client firm) assessed the agency workers' level of interpersonal facilitation. Results indicate that: (1) Agency workers can experience perceived insider status, regardless of their objective classification as outsiders; (2) perceived support from supervisors and the client firms' permanent workers contribute to agency worker perceptions of insider status; and (3) perceptions of insider status are associated with higher levels of both affective commitment and interpersonal facilitation, even in workers that are considered marginally tied to the organization. Copyright © 2009 John Wiley & Sons, Ltd.     

Bioaccumulation of essential metals (Co,Mn and Zn) in the king scallop <Emphasis Type="Italic">Pecten maximus</Emphasis>: seawater,food and sediment exposures

In order to understand the bioaccumulation of essential metals in filter-feeding mollusks living in soft sediments, the uptake and depuration kinetics of three elements (Co, Mn and Zn) were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment, using radiotracer techniques. The scallops were collected in April 2005 in the Pertuis Breton, France and acclimated to laboratory conditions for 8 weeks prior to the experimental exposures. Dissolved metals were efficiently bioconcentrated with mean concentration factors (CFs) ranging from 65 (Co) to 94 (Mn) after 7 days of exposure. Feeding experiments using microalgae Skeletonema costatum (diatom) or Isochrysis galbana (flagellate) showed that metal assimilation efficiency (AE) and retention (T _b½) were strongly influenced by food source. For Co, AE was higher when ingested with I. galbana (29 vs. 4%), whereas Mn and Zn AE was higher for S. costatum (82 vs. 44% and 86 vs. 68%, respectively). Transfer factors (TFs) in P. maximus exposed to radiolabelled sediment were 3–4 orders of magnitude lower than CFs. Nevertheless, the fraction of sediment-bound metals that was taken up was efficiently absorbed in scallop tissues (>85%). Whatever the exposure pathway, metals were strongly retained in the kidneys of P. maximus. Due to poor determination of Mn biokinetics (and related parameters) in scallops exposed through sediment, the relative contribution of the three different pathways could be determined only for Co and Zn using a biodynamic model. The particulate pathway (i.e. food or sediment) appeared to be the main route for bioaccumulation of both metals in this scallop. In addition, even though P. maximus displayed different AEs for Co and Zn according to the food, results of the model were only slightly affected, if any, by change in the dietary parameters (AE and depuration rate constant, k _e).     

Surface air concentration and deposition of lead-210 in French Guiana: two years of continuous monitoring

To make up for the lack of data on (210)Pb aerosol deposition in tropical regions and to use this radionuclide as an aerosol tracer, a monitoring station was run for two years at Petit-Saut, French Guiana. Lead-210 concentration in air at ground level was monitored continuously together with atmospheric total deposition. The air concentration has a mean value of 0.23+/-0.02 mBq m(-3) during both wet and dry seasons, and it is only weakly affected by the precipitation mechanism. This result was unexpected in a wet tropical region, with a high precipitation rate. In contrast, deposition clearly correlates with precipitation for low/moderate rainfall (<15 cm per 15-day), while this correlation is masked by strong fluctuations at high rainfall. The estimated mean annual deposition over the last ten years is 163+/-75 Bq m(-2) y(-1). This provides a procedure for estimating this mean flux at other sites in French Guiana.     

Do tubificid worms influence organic matter processing and fate of pollutants in stormwater sediments deposited at the surface of infiltration systems?

The purpose of this study was to quantify the influences of tubificid worms on the biogeochemical functioning of an infiltration system impacted by a stormwater sediment deposit. Effects of worms with stormwater sediment deposit were compared with effects of worms with two other natural sediment deposits (one low and one rich-particulate organic matter deposits). We measured the effects of invertebrates on sediment reworking, organic matter processing, solute fluxes, microbial characteristics, and pollutant release from stormwater deposit to water. Our results showed that tubificid worms had slight effects on microbial activities in presence of the stormwater deposit whereas they significantly stimulated microbial activities in columns impacted by the other two deposits. High contents of labile organic matter contained in stormwater sediments probably led to very strong microbial activities that could not be easily stimulated by worm activities. In our experimental conditions, no significant influence of tubificid worms on the fate of pollutants (heavy metals and PAHs) contained in the stormwater deposit was measured. In conclusion, our study demonstrated that the organic matter characteristics of the stormwater sediments limited the efficiency of tubificid worms to stimulate organic matter mineralization in infiltration systems.