Insecticide residues cross-contamination of oilseeds during storage

Abstract

Abstract:Pesticide residues are found in oilseeds and crude oils: they are mainly organophosphate insecticides (pirimiphos-methyl, dichlorvos, malathion) Key words: oilseeds, insecticide, pesticide residues, storage, cross-contaminationPost-harvest insecticide residues are frequently found on oilseeds, at low levels. But, no insecticide is allowed to be applied directly to oilseeds during storage. Consequently, maximum residue levels (MRLs) allowed by European regulation are very low (mostly at the lower limit of analytical determination): 0,01 mg/kg for dichlorvos (still authorised during this study, but forbidden now), and 0,05 mg/kg for pirimiphos-methyl. No MRL exists for malathion, so it shouldn't be found beyond the analytical limit of quantification. These insecticide treatments are authorised on stored cereals and corn as a grain protectant, and on empty storage and handling equipment as a control agent for residual insect populations in empty granaries. Dichlorvos, malathion and pirimiphos-methyl were the substances most employed during this study (storage season 2006-2007, regulation changed later). So, we can hypothesise that crosscontamination phenomena can exist, between these various kind of seeds, cereals and oilseeds, sharing the same grain handling and storage system. This phenomena has already been demonstrated in Canada on rapeseed [1][2][3], when empty bins are treated with organophosphorous insecticides (bromophos, malathion, fenitrothion). Canadian storers were warned that treating before storing rapeseed could lead to residues above the maximum allowable limits.Uptake of pirimiphos-methyl by a single-layer of rapeseed or wheat on galvanized-steel surfaces was demonstrated and quantified in a laboratory study [4,5]. It was shown that, for small bins (less than 50 tons), it could lead to residues quantities above regulatory limits. But in big elevators, insecticide uptakes by seeds can also occur at other stages: conveying belts, handling of oilseeds after cereals had been treated in the same circuits, outloading bin, etc. so we cannot rule out either risk for grain storage companies.In order to improve our knowledge about this post-harvest insecticide cross-contamination, especially in big elevators, an investigation was carried out with the collaboration of several French grain storage companies. Real cases were observed, with an accurate traceability of sunflower seeds lots all along their route inside storage facilities (from receipt to outloading) to find where the insecticides were taken up by the oilseeds. Results presented in this article concern the first year of the investigation, concentrating on sunflower seeds during the storage season [2006][2007]. This investigation will continue on rapeseed during the next storage season. Materials and methodsThe process adopted for this survey was: -Identifying with storage operators sunflower lots that could be "traced" (recording of each step from receipt to outloading): 11 grain storage companies agreed to collaborate, and allowed us t...

The difference in dissipation of clomazone and metazachlor in soil under field and laboratory conditions and their uptake by plants

“…Information on the presence of pesticide residues in rapeseed plants or the dissipation of these substances is very limited, and only a few literature references concern the content of pesticides in oilseed rape or oil seeds [31][32][33][34] . For this reason, focusing our research on this area seems to be justified.…”

Prospects for Use of Biological Control of Insect and Mites for the Food Industry in North America

“…Beside pest resistance, other aspects make the use of insecticides and fumigants decreasingly appealing such as the risk of residues in food products, even when the pesticides are not used directly onto the products [35,36], the risk of exposure to applicators, possible issues with metal corrosion and self-ignition of phosphine gas, and the continuous increase in organic farming production and increasing demand in North America for organic products throughout the supply chain [37]; i.e., the number of certified organic farms increased by 50% in USA between 2008 and 2019 and by 45% in Canada between 2009 and 2019 [38], which is in great need of non-chemical alternatives.…”

Les enseignements de 7 années de plan de surveillance des oléagineux

“…Ainsi, le sujet des r esidus d'insecticides post-r ecolte est apparu important et mobilisateur, ce qui a pouss e les professionnels de la fili ere a mener des actions sp ecifiques pour identifier les sources de contaminations des graines ol eagineuses par ces r esidus dans les installations de stockage. Les enquêtes men ees en collaboration avec les entreprises du secteur ont permis l'identification des situations menant a ces contaminations crois ees, ce qui a fait l'objet de publications (Dauguet, 2007 ;Dauguet, 2009), et de recommandations relay ees par les f ed erations des organismes de collectestockage. Selon les derniers r esultats du PSO, les teneurs en ces r esidus ont tendance a baisser, ce qui montre une prise en compte de cette probl ematique par les professionnels grâce a la communication qui a et e faite autour du sujet.…”

“…Results of this monitoring plan were transmitted to the French government and the European Commission in cases of revisions of regulatory thresholds. (Dauguet, 2007 ;Dauguet, 2009). Ces mol ecules sont ensuite elimin ees aux diff erentes etapes du raffinage de l'huile, et donc absentes des huiles raffin ees commercialis ees.…”