Pesticide residues in food is a public health concern. This study aimed to evaluate health risk and benefit associated with chronic consumption of fruits and vegetables (F&V) containing residual pesticides in the province of Quebec, Canada. Based on a representative sample of Quebecers (n = 4727, aged 1–79) enrolled in the Canadian nutrition survey, population's mean chronic dietary exposure through consumption of F&V was evaluated for 169 different pesticide active ingredients (PAI), including 135 for which toxicological reference values (TRV) were available in the literature. Total lifetime cancer risk was estimated to be 3.3 × 10− 4 considering the 28 substances for which an oral slope factor was also available. Non-cancer risk quotients greater than 1 were obtained at the 95th percentile of children's exposure for 10 of the 135 PAIs, and considering the most severe pesticide-specific TRV. Dithiocarbamates and imazalil are the authorized PAI that contribute the most to cancer and non cancer risk; they are therefore identified as “priority” PAI. For each estimated case of cancer triggered by PAI exposure, at least 88 cases were deemed prevented by the consumed F&V, based on the population's etiological fraction of the cancer risk that F&V prevent. Concluding, chronic health risks investigated are low and health benefits of F&V consumption by far outweigh the PAI-related risk. However, risk estimates are not negligeable and uncertainties remain. Thus, reducing PAI exposure through F&V consumption with a particular focus on “priority” PAI mentionned above, while maintaining an abundant and varied F&V diet, is desirable.

The recent emergence of West Nile virus (WNV) in North America highlights vulnerability to climate sensitive diseases and stresses the importance of preventive efforts to reduce their public health impact. Effective prevention involves reducing environmental risk of exposure and increasing adoption of preventive behaviours, both of which depend on knowledge and acceptance of such measures. When making operational decisions about disease prevention and control, public health must take into account a wide range of operational, environmental, social and economic considerations in addition to intervention effectiveness. The current study aimed to identify, assess and rank possible risk reduction measures taking into account a broad set of criteria and perspectives applicable to the management of WNV in Quebec under increasing transmission risk scenarios, some of which may be related to ongoing warming in higher-latitude regions. A participatory approach was used to collect information on categories of concern to relevant stakeholders with respect to WNV prevention and control. Multi-criteria decision analysis was applied to examine stakeholder perspectives and their effect on strategy rankings under increasing transmission risk scenarios. Twenty-three preventive interventions were retained for evaluation using eighteen criteria identified by stakeholders. Combined evaluations revealed that, at an individual-level, inspecting window screen integrity, wearing light colored, long clothing, eliminating peridomestic larval sites and reducing outdoor activities at peak times were top interventions under six WNV transmission scenarios. At a regional-level, the use of larvicides was a preferred strategy in five out of six scenarios, while use of adulticides and dissemination of sterile male mosquitoes were found to be among the least favoured interventions in almost all scenarios. Our findings suggest that continued public health efforts aimed at reinforcing individual-level preventive behaviours combined with the application of larvicides to manage the risk of WNV infection are the interventions most acceptable and effective at reaching current management objectives now and under future theoretical transmission risk.

A study on the use of pesticides in market-gardening production was carried out on 108 market-gardeners in the rural city of Tori-Bossito in Southern Benin. The objective of the study was to characterize the potential risks of pesticides usage by farmers and the impacts on their health and on the environment. Two risk indexes were calculated for each pesticide: an environmental risk index (ERI) and a health risk index (HRI). First stage larva of the mosquito Aedes aegypti were used as bio-indicator for detecting insecticide residue in vegetable before their harvesting on the farms. The highest ERI were obtained for carbofuran, chlorpyriphos ethyl and endosulfan. Pesticide residues were found in 42% of the samples of leaves of eggplant, cucumber, amaranth and solanum. Vegetables growers used pesticides that may be highly hazardous and which were not registered in most cases. These situations could have unexpected consequences including the exposure of consumers to health hazards.

ABSTRACT The arrival of West Nile Virus in North America prompted public health authorities to develop intervention plans in order to prevent the propagation of this mosquito-transmitted pathogen. The last-resort measure proposed by the Government of Quebec (Canada) is the large-scale application of insecticides by aerial or ground Ultra Low Volume (ULV) treatment. This article presents an assessment of the exposure to malathion and its metabolite, malaoxon, for a population where an eventual application of malathion would occur. Each exposure pathway is detailed by describing the equation and every conservative assumption. This methodological framework was then used with the aim of assessing the toxicological risk based on a probabilistic approach (see companion article, this issue). In the current study, a daily absorbed dose of the mixture of malathion and malaoxon was estimated in terms of “malathion equivalent dose.” Each exposure pathway following a single event of ground or aerial ULV spraying of malathion was investigated for the population, classified into five age groups. Dermal exposure to dislodgeable residues on turf, foliage, and hard surfaces was estimated to be the most important source of exposure compared to any other pathways; it accounts for 63% to 98% of the estimated cumulative absorbed doses. The hand-to-mouth behavior of toddlers may also contribute considerably to their “malathion-equivalent” exposure (i.e., approximately 15% of the cumulative dose). Otherwise, the current study shows that ground ULV spraying is the type of treatment that may induce lower exposure, because the predicted concentration of malathion on turf and foliar surfaces is less than the one predicted for aerial ULV spraying.

OBJECTIVE:This study was undertaken to assess the exposure to organophosphate (OP) pesticides in children from peri-urban areas of the Province of Quebec, Canada, through measurements of semi-specific alkylphosphate (AP) metabolites.METHODS:Eighty-nine children aged between 3 and 7 years were recruited via pamphlets sent to day-care centers. A first morning urine void was collected early in the spring of 2003 prior to summertime, which is the usual period of outdoor pesticide use. During summertime, up to five more first morning voids were repeatedly collected, at 72-h intervals, over a 13-day period. The potential determinants of exposure were assessed by a questionnaire at the time of urine collection.RESULTS:Methylphosphate metabolites were detectable in 98.2% of the 442 samples analyzed while ethylphosphates were detected in 86.7% of the samples. The geometric mean concentration (GM) of the total AP metabolites was 61.7 mug/g creatinine (range: 2.7-1967.3 mug/g creatinine). The difference in urinary AP concentrations between samples collected during spring and summer was non-significant (P=0.08). There was also no significant difference in the mean AP concentrations between summer samples of individuals living in municipalities where outdoor pesticide use is or is not restricted (P=0.25). However, the presence of a pet in the house was associated with an increase in AP concentrations during spraying season (P=0.02). Pesticides were seldom used, as reported by the questionnaire. A significant correlation was also observed (P<0.001) between the urinary AP concentrations in samples provided by siblings at the same time period.CONCLUSIONS:Mean concentrations of AP were generally higher than those reported in other studies. The observed exposure apparently occurred mainly through the dietary ingestion of OP residues. These data raise questions on the levels of OP residues in Quebec food and the possibility that our participants consumed more fruits and vegetables than those in other studies.

Les employés du Jardin botanique et des serres Louis Dupire de la ville de Montréal sont régulièrement en contact avec des pesticides dans le cadre de leurs activités. L’inquiétude soulevée, en regard des risques à la santé qui pourraient découler de l’exposition aux pesticides dans un milieu fermé comme les serres, justifiait d’entreprendre une étude dans le but de répondre aux interrogations des travailleurs et des responsables du service de santé. Les résultats de cette recherche devaient permettre, le cas échéant, d’améliorer certaines pratiques de travail dans les entreprises concernées. C’est pour cette raison que la Direction de la toxicologie humaine de l’Institut national de santé publique du Québec, de concert avec le CLSC des Faubourgs qui gère le programme de santé au travail de ces entreprises, a initié une étude d'exposition professionnelle. Diverses études indiquent que les risques pour la santé pourraient être plus importants dans un complexe serricole qu’à l’extérieur, car un milieu fermé favorise des niveaux d’exposition plus importants. En effet, certains facteurs, tels que les conditions de température et d’humidité, pourraient contribuer à une plus grande absorption cutanée des pesticides. De plus, une ventilation restreinte pourrait favoriser les risques d’atteintes respiratoires au cours de la période suivant immédiatement une application de pesticides. Enfin, ce type de milieu serait moins propice à la dégradation des produits antiparasitaires. Plusieurs auteurs ont décrit des risques d’effets aigus et chroniques pour les travailleurs exposés aux pesticides en milieu serricole. Ils pourraient être d’ordre respiratoire, cutanée, neurologique, reproductif, développemental ou autres. Plusieurs méthodes ont été utilisées pour évaluer le potentiel d’exposition des travailleurs. Tout d’abord, le comportement des résidus foliaires délogeables a été évalué, pour certains produits représentatifs, entre l’application des pesticides et le retour des travailleurs à des activités dans les serres. Le but était de vérifier si les résidus diminuaient rapidement à l’intérieur du délai de réentrée usuellement respecté par les travailleurs tel que déjà observé en milieu extérieur. Les risques d’exposition cutanée des travailleurs ont aussi été évalués par une technique de lavage des mains, laquelle devait également servir à documenter l’efficacité du port des gants. Une approche qualitative d’évaluation de l’exposition externe utilisant un marqueur fluorescent a également été utilisée. L’exposition totale des travailleurs, pour les produits à l’étude, a été déterminée par la mesure de métabolites urinaires excrétés sur une période post-exposition de 24 heures et des mesures des variations de l’activité des cholinestérases ont été effectuées lors de l’utilisation d’insecticides organophosphorés. Finalement, la contamination potentielle des locaux adjacents aux serres ainsi que les différentes pratiques de travail ont été évaluées. Les résultats de l’étude indiquent que les travailleurs sont toujours exposés lors du retour dans la serre le lendemain suivant l’application des pesticides. D’une part, à l’encontre des observations effectuées dans des environnements extérieurs, il apparaît que les résidus délogeables possèdent une plus grande stabilité dans un milieu fermé tel que les serres. D’autre part, quelque soit le pesticide utilisé, il a été possible de retrouver et quantifier les pesticides dans les solutions de lavage de mains des travailleurs. Finalement, il a été possible de détecter des métabolites urinaires des pesticides étudiés chez une majorité de travailleurs. Toutefois, probablement en raison des courtes périodes d’exposition et des faibles contacts avec les plantes traitées, les niveaux d’exposition mesurés étaient généralement faibles pour la majorité de ceux-ci. Il apparaît que les types de tâches impliquant un contact plus important avec les plantes traitées favoriseraient des niveaux d’exposition plus importants. Cependant, certaines pratiques de travail, comme le port de gants, permettraient de diminuer considérablement l’exposition des travailleurs. Plusieurs autres mesures correctives ont été proposées dans ce sens.