Chemical and Microbiological Contamination in Limpet (Patella spp.) of the Portuguese Coast

Coastal production areas can be impacted by anthropogenic contamination from urban, agro-industrial and leisure activities. Some contaminants, such as chemical substances might also have a telluric origin. Non filter feeding univalve mollusks, such as limpets, which are collected in rocky shores either for sale or for auto-consumption, are very appreciated in Portugal, but have been excluded from provisions on the classification of production areas, although can present relevant contamination. Thus, the aim of this study was to assess the microbiological and toxic metal contaminations in limpets (Patella spp) of the Portuguese coast, taking into account the production area and seasonal variation, and comparing their contamination levels with those occurring in bivalve mollusk indicator species, mussel (Mytilus edulis). The risks associated to the consumption of limpet meals were also assessed. For that, microbial total and fecal levels and cadmium, lead and mercury contents in limpets and mussels samples from three coastal areas over several months were analyzed based on standard methodologies. Contents of mercury and lead in limpets from the three areas studied, were always below the limits of 0.50 mg kg-1 and 1.5 mg kg-1 allowed by the EU, respectively. Regarding cadmium, levels in limpet were always above the limit of 1.0 mg kg-1, reaching about 3.0 mg kg-1 in some samples. These values probably indicate contamination from telluric origin (soil or rocks) in the coastal studied areas. Results indicated that microbiological contamination of fecal origin was low and in general below the detection level. Contamination levels did not show a clear seasonal pattern. The two mollusk species, limpets and mussels, differed statistically in all contaminants analyzed, being cadmium the most of concern, and always higher in limpets than in mussel samples. Thus, the potential risk associated with limpet consumption, taking into account the cadmium tolerable weekly intake (TWI), was investigated, being possible to reach a reliable recommendation of less than a monthly meal of 160 g. As recreational picking of limpets is common in Portugal, official 4recommendations of maximum periodic human consumption should be published and enforcement increased in forbidden areasinfo:eu-repo/semantics/acceptedVersio

Integration of time as a description parameter in risk characterisation: Application to methyl mercury

Within the food risk assessment procedure, the characterisation of the risk consists in the comparison of the dietary exposure with a health based guidance value established in a previous step. One of the identified weaknesses of this comparison is that the time is not considered in the description. The aim of this paper is to describe the dietary exposure as a dynamic process determined by the accumulation phenomenon due to successive dietary intakes and by the pharmacokinetics ruling the elimination process in between intakes. Such a process belong to the category of piecewise deterministic Markov processes, which are widely used in a large variety of applications in insurance risk or in operations research, ranging from queuing systems to inventory/storage models. The inputs of the Kinetic Dietary Exposure Model are the probability distributions governing intakes and inter-intake times, as well as the half-life of the contaminant in the human body. In this paper, an application to methyl mercury is considered, with,exponential distributions for both the intakes and the inter-intake times, fitted from the French national consumption survey INCA, and a fixed half-life of 6 weeks for the elimination process. Within this framework, the process settles to a steady-state after approximately 5 years. A "Kinetic Tolerable Intake" (KTI), derived from the "Provisional Tolerable Weekly Intake" (PTWI) of 1.6 mu g/kg bw, is set to 14.6 mu g/kg and the probability of exceeding this threshold in the long run in the French adult female population is 1.22 E-15. (c) 2007 Elsevier Inc. All rights reserved

Dietary exposure of Brazilian consumers to dithiocarbamate pesticides : a probabilistic approach

A probabilistic estimation of the exposure of the Brazilian population to the dithiocarbamate pesticides was performed using the Monte Carlo Risk Assessment program (MCRA 3.5). Residue data, as CS(2), for 3821 samples were obtained from the Brazilian national monitoring program on pesticide residues and from the monitoring program conducted in the Distrito Federal on rice, beans and nine fruits and vegetables. Food consumption data were obtained from a Brazilian household budget survey conducted between 2002 and 2003. Processing factors for washing, peeling or cooking were applied to the residues found in the crops. Daily intakes at the highest percentiles for the general population reached a maximum of 2.0mug CS(2)/kg body weight per day (upper band of the 95% confidence interval at P99.99). Tomato, rice, apple and lettuce were the commodities which contributed most to the intake. Based on the registered uses and the toxicological profile of dithiocarbamates, the risk from exposure was evaluated assuming that all residues came from the use of ethylene-bis-dithiocarbamate (EBDC) or that a fraction of it came from the use of propineb. For this last scenario, a cumulative risk assessment was conducted. In the first scenario, the highest intake reached up to 11.9% EBDC ADI for the general population and up to 31.1% ADI for children. When 30% of the residues were considered as coming from propineb use, the values were 15.2% and 39.7% ADI, respectively

Probabilistic assessment of the cumulative acute exposure to organophosphorus and carbamate insecticides in the Brazilian diet

In the present study, the cumulative exposure of 25 acetylcholinesterase (AChE) inhibiting pesticides through the consumption of nine fruits and vegetables by the Brazilian population was assessed. Food consumption data were obtained from a household budget survey conducted in all Brazilian states from July 2002 to June 2003. Residue data from 4001 samples were obtained from the Brazilian national monitoring program on pesticide residues. Relative potency factors (RPF) were calculated with methamidophos or acephate as index compounds (IC), using BMD10 or NOAEL for AChE inhibition, mostly in rat brain, obtained from national and international pesticide evaluations. Monocrotophos and triazophos, in addition to aldicarb, had the highest calculated RPF in any scenario. The exposure to AChE inhibiting pesticides for the general population at P99.9, represented 33.6% of the ARfD as methamidophos and 70.2% ARfD as acephate. The exposure calculated as acephate could exceed the ARfD at the upper bound of the 95% confidence interval for this percentile. Exposure for children aged up to 6 years were, on average, 2.4 times higher than the exposure for the general population. Tomato represented about 67% of the total intake of AChE inhibiting pesticides. The highest calculated equivalent residues in tomato, which drove most of the estimated intakes at the high percentiles, were related to the illegal use of monocrotophos and triazophos in this cro

Pseudo-regenerative block-bootstrap for hidden Markov chains

International audienc

Bootstrapping Robust Statistics for Markovian Data Applications to Regenerative R- and L-Statistics

International audienc

Some recent advances in modelling dietary exposure to ochratoxin A

Workshop on Ochratoxin A in Food - Recent Developments and SignificanceBaden, AUSTRIAJUN 29-JUL 01, 2005One of the key questions when assessing the exposure to contaminants is the choice of the method and the impact of this choice on the result to be compared with the toxicological reference value. This problem is particularly significant in the case of ochratoxin A (OTA) for which the use of crude estimates can provide results close to the current provisional tolerable weekly intake (PTWI). This paper compares different exposure assessment models for OTA using the same data set for food consumption (i.e. French INCA survey 1999) for the same groups of the population (i.e. adults excluding under-reporters and children 3-14 years-old) but with various ways of handling the occurrence of OTA in food. The consumption and contamination data were combined through 11 different scenarios based on parametric and non-parametric modelling and on the use of analytical results obtained on raw commodities or on foodstuffs ready-to-eat. In order to assess exposure to OTA using data on consumption of processed and composite foods it was necessary to use recipe information in order to utilize available contamination data which only exists for raw materials. The impact of such an adjustment appears to be essential to avoid an overestimation of the exposure. The impact of the other assumptions and the choice of mathematical models influence the results less but should be considered and detailed carefully in future dietary exposure assessments

A minimum-volume set approach to dietary risk-benefit analysis

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Identification of the main pesticide residue mixtures to which the French population is exposed

Owing to the intensive use of pesticides and their potential persistence in the environment, various pesticide residues can be found in the diet. Consumers are therefore exposed to complex pesticide mixtures which may have combined adverse effects on human health. By modelling food exposure to multiple pesticides, this paper aims to determine the main mixtures to which the general population is exposed in France. Dietary exposure of 3337 individuals from the INCA2 French national consumption survey was assessed for 79 pesticide residues, based on results of the 2006 French food monitoring programmes. Individuals were divided into groups with similar patterns of co-exposure using the clustering ability of a Bayesian nonparametric model. In the 5 groups of individuals with the highest exposure, mixtures are formed by pairs of pesticides with correlations above 0.7. Seven mixtures of 2-6 pesticides each were characterised. We identified the commodities that contributed the most to exposure. Pesticide mixtures can either be components of a single plant protection product applied together on the same crop or be from separate products that are consumed together during a meal. Of the 25 pesticides forming the mixtures, two-DDT and Dieldrin are known persistent organic pollutants. The approach developed is generic and can be applied to all types of substances found in the diet in order to characterise the mixtures that should be studied first because of their adverse effects on health. (C) 2013 Elsevier Inc. All rights reserved