Validation of an off line solid phase extraction liquid chromatography-tandem mass spectrometry method for the determination of systemic insecticide residues in honey and pollen samples collected in apiaries from NW Spain.

The use of pesticides to protect crops against plagues and insects is one of the most important ways to assure agricultural quality and productivity. However, bad application practices may cause the contamination of different environmental compartments and animal species, as a consequence of migration or accumulation of those compounds. Fipronil, imidacloprid and thiametoxam are systemic or systemic-like insecticides widely used in maize crops. Their heavy action in the nervous system of target insects also means a high toxicity to non-target pollinator insects such as honey bees which can get in touch with them through pollen and nectar during foraging activities. These insecticides have even been suspected to cause a significant decrease of honeybee colonies that has been observed in many countries since the past decade. Since September 1st 2008, the European Commission set new MRLs in food and feed of plant and animal origin. The pesticides included in this study have MRLs in honey and pollen between 10 and 50 ng g(-1). In the present work, an analytical method was developed with the aim of determining residues of fipronil and some of its metabolites (fipronil sulfone, fipronil sulfide, fipronil desulfinyl and fipronil carboxamide), thiamethoxam and imidacloprid in honey and pollen samples. The extraction optimization was performed using a Doehlert experimental design by studying two factors, the mixture and the ratio of solvents used. Prior to the extraction procedure, raw hive samples containing honey, pollen and wax were centrifuged at 4000 rpm. The upper solid material was removed, and 1 g of the lower phase was mixed with 3 mL of the optimized mixture of methanol/water (10/90). The extract was passed through a florisil cartridge and the target compounds were eluted with methanol and analysed by LC-MS/MS in selective reaction monitoring (SRM) mode. The method was validated according to the guidelines included in the SANCO/10684/2009 document and the ISO 11843 standard for the following parameters: decision limit (CCalpha), detection capability (CCbeta), recovery, repeatability and reproducibility at 0.5, 1 and 1.5 folds the MRLs. Ion suppression/enhancement effects into the ion source were also assessed. The CCbeta values were included between 0.83 and 4.83 ng g(-1), well below the current MRLs. The validated method was applied to the determination of the target pesticides in 91 samples collected in colonies from 73 apiaries of NW Spain (two sampling campaigns during 2008). None of the target insecticides were detected among all the collected samples.

COMPRENDO: Focus and approach.

Tens of thousands of man-made chemicals are in regular use and discharged into the environment. Many of them are known to interfere with the hormonal systems in humans and wildlife. Given the complexity of endocrine systems, there are many ways in which endocrine-disrupting chemicals (EDCs) can affect the body's signaling system, and this makes unraveling the mechanisms of action of these chemicals difficult. A major concern is that some of these EDCs appear to be biologically active at extremely low concentrations. There is growing evidence to indicate that the guiding principle of traditional toxicology that "the dose makes the poison" may not always be the case because some EDCs do not induce the classical dose-response relationships. The European Union project COMPRENDO (Comparative Research on Endocrine Disrupters--Phylogenetic Approach and Common Principles focussing on Androgenic/Antiandrogenic Compounds) therefore aims to develop an understanding of potential health problems posed by androgenic and antiandrogenic compounds (AACs) to wildlife and humans by focusing on the commonalities and differences in responses to AACs across the animal kingdom (from invertebrates to vertebrates) .

European ring exercise on water toxicity using different bioluminescence inhibition tests based on Vibrio fischeri, in support to the implementation of the water framework directive.

An inter-laboratory comparison exercise was conducted under the European Union funded project entitled: Screening Methods for Water Data Information in Support of the Implementation of the Water Framework Directive (SWIFT-WFD) and coordinated by the Consejo Superior de Investigaciones Científicas (CSIC), in order to evaluate the reproducibility of different toxicity tests based on the bioluminescence inhibition of Vibrio fischeri, for the rapid water toxicity assessment. For the first time, this type of exercise has been organized in Europe, and using different tests based on the same principle. In this exercise, 10 laboratories from 8 countries (Austria, Cyprus, Germany, Greece, Italy, Portugal, Romania, and Spain) took place, and a total number of 360 samples were distributed. During the exercise, six series of six samples were analyzed along 5 months. Every batch of samples was composed by three real samples and three standard solutions. The real samples were: a raw influent and the effluent of a wastewater treatment plant (WWTP), and a sample from a first settlement of the WWTP spiked with a mixture of toxicant standards. A final number of 330 (91.7%) samples was analyzed, 3300 values in duplicate were collected, and the results for each sample were expressed as the 50% effective concentration (EC(50)) values calculated through five points of dilution inhibition curves, after 5 and 15min of incubation times. A statistical study was initiated using 660 results. The mean values, standard deviations (sigma), variances (sigma(2)), and upper and lower warning limits (UWL and LWL) were obtained, using the EC(50) values calculated with the result from the participating laboratories. The main objectives of this toxicity ring study were to evaluate the repeatability (r) and reproducibility (R) when different laboratories conduct the test, the influence of complex matrix samples, the variability between different tests based on the same principle, and to determine the rate at which participating laboratories successfully completed tests initiated. In this exercise, the 3.93% toxicity values were outliers according with the Z-score values and the Dixon test. The samples with the greater number of outliers were those with the smallest variability coefficient, corresponding to the greater and the smaller toxicity level. No relation was found through the cluster analysis, between the final results and the different commercial devices involved. Testing by multiple commercial devices did not appear to reduce the precision of the results, and the variability coefficient for the exercise was nearby to the average value for past editions carried out at national level, where the different participants used the same commercial device. Stability of samples was also followed during the exercise. While statistical significance differences were not found for the greater part of samples, for the sample from the WWTP influent, a significant decrease of the toxicity value was found along this study. Nevertheless, this was a type of sample with a high toxicity level during all the exercise. On the other hand, in order to obtain the chemical characterization of real samples, those were analyzed by chromatographic techniques, using different sequential solid phase extraction (SSPE) procedures, followed by liquid chromatography coupled with mass spectrometry (LC-MS), and gas chromatography-mass spectrometry (GC-MS). Good agreement was found between the chemical analysis results and the toxicity level of the samples.