Utilization of long duration high-volume sampling coupled to SPME-GC-MS/MS for the assessment of airborne pesticides variability in an urban area (Strasbourg,France) during agricultural application

Atmospheric samples have been collected between 14 March and 12 September 2012 on a 2-week basis (15 days of sampling and exchange of traps each 7 days) in Strasbourg (east of France) for the analysis of 43 pesticides. Samples (particle and gas phases) were separately extracted using Accelerated Solvent Extraction (ASE) and pre-concentrated by Solid Phase Micro-Extraction (SPME) before analysis by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). Four SPME consecutive injections at distinct temperatures were made in order to increase the sensitivity of detection for the all monitored pesticides. Currently used detected pesticides can be grouped in four classes; those used in maize crops (acetochlor, benoxacor, dicamba, s-metolachlor, pendimethalin, and bromoxynil), in cereal crops (benoxacor, chlorothalonil, fenpropimorph, and propiconazole), in vineyards (tebuconazole), and as herbicides for orchards, meadows of green spaces (2,4-MCPA, trichlopyr). This is in accordance with the diversity of crops found in the Alsace region and trends observed are in accordance with the period of application of these pesticides. Variations observed permit also to demonstrate that the long time sampling duration used in this study is efficient to visualize temporal variations of airborne pesticides concentrations. Then, long time high-volume sampling could be a simple method permitting atmospheric survey of atmospheric contamination without any long analysis time and consequently low cost.     

Nitrate causes deleterious effects on the behaviour and reproduction of the aquatic snail Potamopyrgus antipodarum (Hydrobiidae, Mollusca)

Nitrate (NO₃ ^?) is present in aquatic ecosystems as a natural component of the nitrogen cycle. However, in the last decades, several human activities are the causes of the rising amounts of organic matter and inorganic nitrogen nutrients in aquatic ecosystems, causing notable increase of nitrate above background natural levels. In spite of the toxicity of nitrate to aquatic animals, there are relatively few studies on the chronic toxicity of this compound to invertebrates. The aim of our study is to assess the effect of chronic (35 days) exposure to nitrate on the behaviour (velocity of movement) and reproduction (number of newborns) of the aquatic snail Potamopyrgus antipodarum. Four actual concentrations of nitrate were used (21.4, 44.9, 81.8 and 156.1 mg?N-NO₃ ^?/L). In each treatment, 12 animals were individually monitored for velocity (weekly) and newborn production (every 3–4 days). Velocity was recorded using quantitative video monitoring. Our results showed that nitrate did not cause mortality, but it reduced the velocity of movement (at 44.9, 81.8 and 156.1 mg?N-NO₃ ^?/L) and number of live newborns (in all tested concentrations). Reproductive impairment was caused at realistic nitrate concentrations which is relevant to the risk assessment of this compound. Our study contributes to the knowledge of the chronic effects of nitrate on the behaviour and reproduction of an aquatic snail.     

Effect of Fe (III) on acid degradation of methylparathion

A study was undertaken to determine the transformation kinetic of methylparathion (O, O, -dimethyl O-4 nitrophenylphosphorotioate) in the presence of Fe(III) between pH 2 and 7. The Fe(III) was not electroactive under the conditions used in this study, and polarographic signals were exhibited by methylparathion and main degradation product only. Data suggest that hydrolysis of methylparathion in an acid medium is catalyzed by Fe(III) and the pesticide did not degrade in this medium without this cation. Methylparathion degradation was observed at all the pHs studied and was independent of the predominant chemical form of Fe(III) in the aqueous medium. The reaction was first-order with pH-dependent rate constant (k) values ranging from 3.3 × 10^{? 3} h^{? 1} to 7.0 × 10^{? 3} h^{? 1}. The k values increased as pH decreased, suggesting that Fe(III) acted as an electrophile in the reaction mechanism.     

Effect of Liquefied Petroleum Gas on Ozone Formation in Guadalajara and Mexico City

Abstract

Leakages of liquefied petroleum gas (LPG) are suspected to contribute greatly to ozone (O₃) formation in Mexico City. We tested such a hypothesis by outdoor captive-air irradiation (CAI) experiments in the two largest Mexican metropolitan areas: Guadalajara (GMA) in 1997 and Mexico City (MCMA) in 2000. O₃ was monitored in each city for 20 days (8:00 a.m.–6:00 p.m.) in smog chambers containing unaltered morning air or morning air enriched with either commercial LPG or LPG synthetic mixture 60/40 (propane and butane). Tested additions of both components were 35% (by volume) in GMA and 60% (by volume) in MCMA. The addition effects on O₃ (max) were compared with effects from diluting LPG components or total nonmethane hydrocarbons (tNMHCs) by 50%. Diluting tNMHCs had the greatest absolute effect at both cities: it lowered O₃ (max) by 24% in GMA and 55% in MCMA. Adding commercial LPG increased O₃ (max) by 6% in GMA and 28% in MCMA; whereas adding LPG synthetic mixture 60/40 caused a similar increase in O₃ (max), 4 and 21% in GMA and MCMA, respectively. Compared with dilution of tNMHCs, dilution of LPG-associated compounds had a smaller decreasing effect on O₃ (max), only 4% in GMA and 15% in MCMA. These results show that commercial LPG and LPG synthetic mixture 60/40 affect O₃ formation to a lesser extent than estimated previously.     

Characterization of ²⁴¹ Am and ¹³⁴Cs bioaccumulation in the king scallop Pecten maximus: investigation via three exposure pathways

In order to understand the bioaccumulation of ²⁴¹Am and ¹³⁴Cs in scallops living in sediments, the uptake and depuration kinetics of these two elements were investigated in the king scallop Pecten maximus exposed via seawater, food, or sediment under laboratory conditions. Generally, ²⁴¹Am accumulation was higher and its retention was stronger than ¹³⁴Cs. This was especially obvious when considering whole animals exposed through seawater with whole-body concentration factors (CF_7d) of 62 vs. 1, absorption efficiencies (A_0l) of 78 vs. 45 for seawater and biological half-lives (T_b½l) of 892 d vs. 22 d for ²⁴¹Am and ¹³⁴Cs, respectively. In contrast, following a single feeding with radiolabelled phytoplankton, the assimilation efficiency (AE) and T_b½l of ¹³⁴Cs were higher than those of ²⁴¹Am (AE: 28% vs. 20%; T_b½l: 14 d vs. 9 d). Among scallop tissues, the shells always contained the higher proportion of the total body burden of ²⁴¹Am whatever the exposure pathway. In contrast, the whole soft parts presented the major fraction of whole-body burden of ¹³⁴Cs, which was generally associated with muscular tissues. Our results showed that the two radionuclides have contrasting behaviors in scallops, in relation to their physico-chemical properties.     

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.     

Arabica-coffee and teobroma-cocoa agro-industrial waste biosorbents,for Pb(II) removal in aqueous solutions

Environmental Science and Pollution Research - Agro-industrial waste biosorbents of arabica–coffee (WCA) and theobroma–cocoa (WCT) have been characterized and tested to remove Pb(II)...     

Hydrogeological study of an anti-tank range

The Arnhem Anti-Tank Range (Canadian Forces Base [CFB] Valcartier, Canada, in operation since the 1970s) has been characterized, including the drilling, installation, and characterization of 25 wells and a ground-penetrating radar survey. The observed particular features of this site include highly variable flow velocities (from < 3 to 1200 m/yr) and transient flow regime in the regional aquifer below the contaminant source zone of the impact area, sharp flow direction shifts, discontinuous stratigraphy and a local perched aquifer. A transient ground water flow model permitted us to understand how the complex hydrogeological setting shapes contaminant transport in the regional aquifer. The model explains the highly variable energetic material (EM) concentrations measured in the plume with peaks associated to spring and to a lesser extent to fall recharge events. As a conclusion from this work, the authors suggest that the characterization of contaminant sources on slopes should extend over all seasons to be sure to detect potential transient flow conditions and variable contaminant concentrations.