A simple multi-residue method for the determination of pesticides in fruits and vegetables using a methanolic extraction and ultra-high-performance liquid chromatography-tandem mass spectrometry: optimization and extension of scope.

In 2004, a new multi-residue pesticides method had been published using methanol as extraction solvent. Our goal for this study was to optimize the analytical scheme while extending the compound scope from 19 to 200 pesticides. The main changes from the original method take place at the sample extraction and processing with a special attention to make the overall method fit for routine analysis with minimal cost. Hence, after a quick Ultra-Turrax homogenization with a methanolic solution, the sample is simply diluted before the separation and detection by ultra-high-performance liquid chromatography and MS/MS detection for quantitative and confirmatory purposes. The performance of the method including limits of quantification (LOQs), linearity, matrix effect, precision was evaluated during validation in accordance with the European Union SANCO/12571/2013 regulatory guidelines. Two representative matrices, lettuce and orange, were selected and fortified at two concentration levels for these experiments. At the LOQ and ten times the LOQ, recoveries of the analytes were mostly within 70-120%, with coefficients of variation lower than 25% in intra-day repeatability conditions. In addition to being simple and fast, these results demonstrate the suitability of the optimized method for the analysis of large scope pesticides in routine laboratories.

HS-GC-MS method for the analysis of fragrance allergens in complex cosmetic matrices.

Potential allergenic fragrances are part of the Cosmetic Regulation with labelling and concentration restrictions. This means that they have to be declared on the ingredients list, when their concentration exceeds the labelling limit of 10 ppm or 100 ppm for leave-on or rinse-off cosmetics, respectively. Labelling is important regarding consumer safety. In this way, sensitised people towards fragrances might select their products based on the ingredients list to prevent elicitation of an allergic reaction. It is therefore important to quantify potential allergenic ingredients in cosmetic products. An easy to perform liquid extraction was developed, combined with a new headspace GC-MS method. The latter was capable of analysing 24 volatile allergenic fragrances in complex cosmetic formulations, such as hydrophilic (O/W) and lipophilic (W/O) creams, lotions and gels. This method was successfully validated using the total error approach. The trueness deviations for all components were smaller than 8%, and the expectation tolerance limits did not exceed the acceptance limits of ± 20% at the labelling limit. The current methodology was used to analyse 18 cosmetic samples that were already identified as being illegal on the EU market for containing forbidden skin whitening substances. Our results showed that these cosmetic products also contained undeclared fragrances above the limit value for labelling, which imposes an additional health risk for the consumer.

Effect of household and industrial processing on the levels of pesticide residues and degradation products in melons.

Two varieties of melons (Cucumis melo) were treated with two fungicides (carbendazim and maneb) and four insecticides (acetamiprid, cyromazin, imazalil and thiamethoxam) to quantify the effect of household processing on the pesticide residues. To ensure sufficiently high levels of residues in flesh and peel, the most concentrated formulations were applied observing good agricultural practice. The peeling step decreased the concentration of pesticide residues for maneb, imazalil and acetamiprid by more than 90%. Cyromazin, carbendazim and thiamethoxam were reduced by approximately 50%. The reduction of the pesticides could not be fully explained by the systemic character of the pesticides. However, the agricultural practices (time of application), solubility and mode of action (systemic versus contact pesticide) of the pesticides could be used to explain the difference in processing factors for the studied pesticides. Degradation products (melamine and ethylenethiourea) were also investigated in this study, but were not detected.

Dietary intake of PCDD/Fs and dioxin-like PCBs of the Belgian population.

The World Health Organization recommends assessing human exposure to contaminants on a regular basis. In order to assess the current dietary exposure of the Belgian adult population to PCDD/Fs and dioxin-like PCBs and to update exposure estimates of 2000-2001, a total diet study was designed. The mean dietary intake of PCDD/Fs and dioxin-like PCBs in the Belgian adult population in 2008 was estimated to be 0.72pgTEQkgbw(-1)d(-1) (middle bound concentrations, TEF of 1998) based on occurrence data of 2008 and national food consumption data of 2004. This value is clearly below the Tolerable Weekly Intake (TWI) of 14pgTEQkgbw(-1)week(-1) set by the Scientific Committee on Food of the European Commission and below the provisional tolerable monthly intake of 70pgTEQkgbw(-1)month(-1) set by the Joint FAO/WHO Expert Committee on Food Additives. Considering the cumulative distribution, the intake was less than 1pgTEQkgbw(-1)d(-1) for more than 80% of the population, and less than 2pgTEQkgbw(-1)d(-1) for the entire population. When using the 2005 TEF instead of the 1998 TEF, the mean dietary intake in the Belgian adult population was estimated to be 0.61pgTEQkgbw(-1)d(-1).

PCB and organochlorine pesticides in home-produced eggs in Belgium.

The level of polychlorinated biphenyls (PCB) and persistent organochlorinated pesticides (OC) in home-produced eggs was investigated in Belgium. The concentration of dichlorodiphenytrichloroethane (DDT) is above the norm for 17% of the eggs collected during the spring on 58 different locations. For PCB, aldrin, dieldrin, and chlordane, 3-5% of the samples are above the norm too. These levels are surprisingly high for compounds banned for about 30 years. Higher concentrations in home-produced eggs are expected compared to battery eggs because of contact with the environment and especially the soil. For ten selected locations, the concentration in soils, excreta and feed was measured, but no simple correlation between egg and feed or soil level could be established. Hexachlorohexane, endosulfan, endrin, methoxychlor and nitrofen were not detected in any sample.

Assessment of the chemical contamination in home-produced eggs in Belgium: general overview of the CONTEGG study.

This overview paper describes a study conducted for the Belgian Federal Public Service of Health, Food Chain Safety and Environment during 2006-2007. Home-produced eggs from Belgian private owners of hens were included in a large study aiming to determine concentration levels of various environmental contaminants. By means of the analyses of soil samples and of kitchen waste samples, obtained from the same locations, an investigation towards the possible sources of contaminants was possible. Eggs, soils, faeces and kitchen waste samples were checked for the presence of dioxins, PCBs (including dioxin-like PCBs), organochlorine pesticides, trace elements, PAHs, brominated flame retardants and mycotoxins. The study design, sampling methodology and primary conclusions of the study are given. It was found that in some cases dioxin-like compounds were present at levels that are of concern for the health of the egg consumers. Therefore, measures to limit their contamination in eggs, produced by hens of private owners, were proposed and deserve further attention.

Validation of the analysis of the 15+1 European-priority polycyclic aromatic hydrocarbons by donnor-acceptor complex chromatography and high-performance liquid chromatography-ultraviolet/fluorescence detection.

The European Commission recommends to monitor the 16 polycyclic aromatic hydrocarbons (PAHs) possessing both genotoxic and carcinogenic properties. Since robust analytical methods specific for this set of European PAH are lacking, a new method for their analysis in food is proposed. The donnor-acceptor complex chromatography (DACC) is used as clean-up step and high-performance liquid chromatography-ultraviolet/fluorescence detection (HPLC-UV/FLD) is used for detection and quantification. The method has been validated for analysis of PAH in oil and in dried plants and bears very good results for all compounds.

PCBs and PCDD/FS in fish and fish products and their impact on the human body burden in Belgium.

The concentrations of marker PCBs (28, 52, 101, 118, 138, 153, 180) in fish have been assessed with GC-MS: an average concentration of 540 ng-PCB g(-1) fat (5.02 ng-PCB g(-1) wet weight) was observed. The average concentration of PCDD/Fs, assessed with the CALUX bioassay, amounted to 64 pg-CALUX-TEQ g(-1) fat (0.58 pg-CALUX-TEQ g(-1) wet weight) and that of PCDD/Fs + dioxin-like PCBs amounted to 131 pg-CALUX-TEQ g(-1) fat (1.18 pg-CALUX-TEQ g(-1) wet weight). Results of the PCB congeners analyses show that PCB-153 is the most abundant congener in almost all samples, with also main contributions of the 138- and 180-congeners. For some species such as the sand sole and lemon sole, a fairly constant PCB content, independent of the fat percentage, was observed. For a second group of species such as whelks, cod, and whiting, a positive correlation was observed between their PCB concentration (ng g(-1) fat) and their % of fat. The relationship between marker PCBs and PCDD/Fs concentrations, when plotted on a log scale, fits a straight line (correlation coefficient r = 0.83). With our results on fish and literature data for other food products, intake of marker PCBs and PCDD/Fs could be calculated for the adult population in Belgium (19-60 years old). The Total Daily Intake (TDI) of marker PCBs (ng-PCB day(-1)) ranges between 1690 and 2210. The TDI of PCDD/Fs (pg-CALUX day(-1)) ranges between 80.5 and 122, that of PCDD/Fs + dioxin-like PCBs amounts to 151. When PCDD/Fs in fish are assessed with GC-HRMS, the TDI can be lower. The relative importance of fish regarding marker PCB intake amounts to 15-19%, while regarding PCDD/Fs intake it amounts to 34-51%. Using TDI, the body burden evolution of marker PCBs and PCDD/Fs, with age has been calculated.

Chemical contamination of free-range eggs from Belgium.

The elements manganese, cobalt, nickel, copper, zinc, arsenic, selenium, molybdenum, cadmium, antimony, thallium, lead and mercury, and selected persistent organochlorine compounds (dioxins, marker and dioxin-like polychlorinated biphenyls, dichlorodiphenyltricholroethane (DDT) and metabolites as well as other chlorinated pesticides) were analysed in Belgian free-range eggs obtained from hens of private owners and of commercial farms. It was found that eggs from private owners were more contaminated than eggs from commercial farms. The ratios of levels in eggs from private owners to the levels in eggs from commercial farms ranged from 2 to 8 for the toxic contaminants lead, mercury, thallium, dioxins, polychlorinated biphenyls and the group of DDT. DDT contamination was marked by the substantial presence of p,p'-DDT in eggs from private owners in addition to dichlorodiphenyldichloroethylene (p,p-DDE) and dichlorodiphenyl-dichloroethane (p,p'-DDD). It is postulated that environmental pollution is at the origin of the higher contamination of eggs from private owners. Extensive consumption of eggs from private owners is likely to result in toxic equivalent quantity intake levels exceeding the tolerable weekly intake.