Anne-Claire Martel

A Survey of Pesticide Residues in Pollen Loads Collected by Honey Bees in France

In 2002, a field survey was initiated on French apiaries to monitor weakness of honey bee, Apis mellifera L., colonies. Apiaries were evenly distributed in five sites located on continental France. Five colonies were randomly selected in each apiary, leading to a total of 125 studied honey bee colonies. For 3 yr (starting in autumn 2002), colonies were visited four times per year: after winter, before summer, during summer, and before winter. Pollen loads from traps were collected at each visit. Multiresidue analyses were performed in pollen to search residues of 36 different molecules. Specific analyses were conducted to search fipronil and metabolites and also imidacloprid and metabolites. Residues of 19 searched compounds were found in samples. Contamination by pesticides ranged from 50 to 0%. Coumaphos and tau-fluvalinate residues were the most concentrated of all residues (mean concentrations were 925.0 and 487.2 microg/kg, respectively). Fipronil and metabolite contents were superior to the limit of detection in 16 samples. Residues of fipronil were found in 10 samples. Nine samples contained the sulfone compound, and three samples contained the desulfinyl compound. Residues of imidacloprid and 6-chloronicotinic acid were found in 69% of samples. Imidacloprid contents were quantified in 11 samples with values ranging from 1.1 to 5.7 microg/kg. 6-Chloronicotinic acid content was superior to the limit of quantification in 28 samples with values ranging from 0.6 to 9.3 microg/kg. Statistical tests showed no difference between places of sampling with the exception of fipronil. Possible origins of these contaminations, concentration and toxicity of pesticides, and the possible consequences for bees are discussed.

Influence of Pesticide Residues on Honey Bee (Hymenoptera: Apidae) Colony Health in France

ABSTRACT A 3-yr field survey was carried out in France, from 2002 to 2005, to study honey bee (Apis mellifera L.) colony health in relation to pesticide residues found in the colonies. This study was motivated by recent massive losses of honey bee colonies, and our objective was to examine the possible relationship between low levels of pesticide residues in apicultural matrices (honey, pollen collected by honey bees, beeswax) and colony health as measured by colony mortality and adult and brood population abundance. When all apicultural matrices were pooled together, the number of pesticide residue detected per sampling period (four sampling periods per year) and per apiary ranged from 0 to 9, with the most frequent being two (29.6%). No pesticide residues were detected during 12.7% of the sampling periods. Residues of imidacloprid and 6- chloronicotinic acid were the most frequently detected in pollen loads, honey, and honey bee matrices. Several pairs of active ingredients were present concurrently within honey bees and in pollen loads but not in beeswax and honey samples. No statistical relationship was found between colony mortality and pesticide residues. When pesticide residues from all matrices were pooled together, a mixed model analysis did not show a significant relationship between the presence of pesticide residues and the abundance of brood and adults, and no statistical relationship was found between colony mortality and pesticide residues. Thus, although certain pesticide residues were detected in apicultural matrices and occasionally with another pesticide residual, more work is needed to determine the role these residues play in affecting colony health.

An assessment of honeybee colony matrices, Apis mellifera (Hymenoptera: Apidae) to monitor pesticide presence in continental France

The frequency of occurrence and relative concentration of 44 pesticides in apicultural (Apis mellifera) matrices collected from five French locations (24 apiaries) were assessed from 2002 to 2005. The number and nature of the pesticides investigated varied with the matrices examined-living honeybees, pollen loads, honey, and beeswax. Pollen loads and beeswax had the highest frequency of pesticide occurrence among the apiary matrices examined in the present study, whereas honey samples had the lowest. The imidacloprid group and the fipronil group were detected in sufficient amounts in all matrices to allow statistical comparisons. Some seasonal variation was shown when residues were identified in pollen loads. Given the results (highest frequency of presence) and practical aspects (easy to collect; matrix with no turnover, unlike with bees that are naturally renewed), pollen loads were the best matrix for assessing the presence of pesticide residues in the environment in our given conditions.

Acaricide residues in honey and wax after treatment of honey bee colonies with Apivar® or Asuntol®50

Acaricide residues were assessed in French commercial beeswax using newly developed liquid and gas chromatography methods. Most of the commercial wax samples and all samples taken during the industrial recycling process contained coumaphos and fluvalinate. Amitraz and coumaphos residue levels were also followed in several hives experimentally treated with Asuntol®50 or Apivar®, two products used in France to control varroa infestation. After the Asuntol®50 treatment, coumaphos residues increased in honey and wax combs, persisted more than 30 days in honey and one year or more in comb wax. The half-life of coumaphos was 69 and 115–346 days in honey and comb wax respectively. Following Apivar® treatment, amitraz was not detected in honey nor in wax. These results are consistent with and complete other studies: the use of coumaphos entails wax contamination which persists through commercial recycling. As this may be a threat for bee health, the use of Asuntol®50 should be avoided.ZusammenfassungZur Bekämpfung der Varroamilbe werden in Frankreich die Akarizide Amitraz, Fluvalinat und Coumaphos eingesetzt. Offiziell zugelassen ist dafür Apivar® (Amitraz). Perizin® (Coumaphos) hatte diesen Status bis 2005, wurde aber nie in den Handel gebracht. Seit einigen Jahren verwenden viele Imker Asuntol®50 (Coumaphos). Dieses Tierarzneimittel hat keine Zulassung für die Anwendung in Bienenvölkern. Diese Bestandsaufnahme soll eine Übersicht über die Akarizid-Belastung von Handelswachs in Frankreich geben. In Zusammenarbeit mit der Bienenwachs verarbeitenden Industrie wurden auch Proben vor und nach dem Umarbeitungsprozess von Altwaben untersucht.Bei zwei Völkergruppen mit je 5 Bienenvölkern wurde darüber hinaus die Rückstandsentwicklung von Amitraz und Coumaphos in Wachs und Honig nach der Anwendung von Apivar® (2 Streifen pro Volk, Anwendungsdauer 10 Wochen) bzw. Asuntol® (10 g einer Mischung Asuntol®50 / Puderzucker 15:500) verfolgt.Für die geplanten Untersuchungen wurden spezifische HPLC- und GC-Methoden entwickelt. Coumaphos und Fluvalinat konnten in 89 % bzw. 70 % der Handelswachsproben (n = 47) mit Rückstandsgehalten von 0,27–5,81 mg.kg−1 bzw. 0,13–3,62 mg.kg−1 nachgewiesen werden.Sämtliche Proben, die während der Umarbeitungsphase von Altwaben gezogen wurden, waren mit Coumaphos und Fluvalinat belastet.Nach Apivar®—Behandlung wurden Amitraz-Rückstände im zentralen Bereich der beiden Waben gefunden, die 24 Stunden lang Kontakt zu den Streifen hatten. In der Folgezeit konnte der Wirkstoff in keiner anderen Probe des Bienenvolkes (Wachs der peripheren Waben und im Honig) nachgewiesen werden. Nach Asuntol®50-Behandlung nahmen die Coumaphos-Rückstände im Bienenvolk zu. Der Wirkstoff war im Honig mehr als 30 Tage und im Wabenwachs über 1 Jahr lang nachweisbar. Einen Tag nach der letzten Asuntol®50-Anwendung lag die durchschnittliche Coumaphosbelastung im Wachs bei 16,1 mg.kg−1 und erreichte nach 26 Tage einen Wert von 6.9 mg.kg−1. Die Halbwertszeit von Coumaphos lag im Honig bei 69 und im Wachs bei 115–346 Tagen.Diese Ergebnisse bestätigen bzw. vervollständigen die Ergebnisse vorangegangener Studien. Die Verwendung von Coumaphos führt zu einer lang anhaltenden Kontamination des Bienenwachses. Die hohe Persistenz des Wirkstoffs führt im Rahmen der industriellen Umarbeitung von Altwaben zu kontaminierten Mittelwänden, die mitverantwortlich dafür sind, dass Coumaphos-Rückstände auch in Imkereien gefunden werden, in denen der Wirkstoff nicht zum Einsatz gekommen ist.Da eine negative Wirkung dieser Rückstände auf die Gesundheit der Bienenvölker nicht ausgeschlossen werden kann, sollte auf eine Asuntol®50-Anwendung verzichtet werden.

Tetracycline residues in honey after hive treatment

Tetracyclines are used to control bacterial diseases such as European and American foulbrood, which may cause severe losses in the honey bee population and honey production. By using 24 hives randomly distributed into four groups of six hives, this study was performed to measure the occurrence of tetracycline hydrochloride (TC) residues in honey following two types of TC application. Two groups of colonies were treated three times with 0.5 g TC in 1 litre syrup (group S) or in 10 g powdered sugar (group P). Six hives of a first control group (C) fed with untreated syrup were installed at 20 and 45 m from groups S and P, respectively. A second control group (DC) was set up 3 km away. Honey was sampled at different times from all hives, and honey artificially contaminated with TC was stored in the laboratory at 4, 20 and 35°C; all samples were analysed by ELISA and HPLC methods. One day after the last application, the mean TC concentration in brood chamber honey was ten times higher in group S (40.7 mg kg−1) than in group P (4.34 mg kg−1). After 8 days, TC residues were detected in all hives of group C. After 146 days, the mean TC concentration in harvested honey was 1.54, 0.35 and 0.15 mg kg−1 for groups S, P and C, respectively. The control group C had been contaminated with TC by drifting. In all hives of group DC, no residues were detected at any time during the study. The honey collected at day 504 did not contain any detectable TC residues, except in one super from group C (0.026 mg kg−1). The half-life of TC in honey from supers was similar in groups C, S and P: 65 days. This duration was twice lower than in honey stored in laboratory in similar conditions: at 35°C in the dark (t ½ = 121 days). In honey stored at 20°C, TC was quite stable and its half-life was 242 days. The data from these experiments indicate levels of TC residues in honey after a treatment in hives, their persistence and diffusion into the apiary. These results show that the TC must be used with precaution in honey production.

A case control study and a survey on mortalities of honey bee colonies (Apis mellifera) in France during the winter of 2005-6.

Summary Several cases of mortality of honey bee colonies (varying from 38 to 100%) were observed in France during the winter of 2005–6. In order to explain the causes of these mortalities, a case control study was conducted on a limited area, together with a larger survey in 18 other apiaries located in 13 sites over the entire country. Both studies included diagnosis of the main honey bee diseases, assessment of the colony management measures taken by beekeepers and the determination of pesticide residues in apicultural matrices. Pollen analysis was carried out on beebread samples to identify which floral species were used for forage before colony death. Poor Varroa destructor treatments together with Nosema disease and brood diseases were frequent in apiaries with high colony mortalities. The absence of any preventive treatment against V. destructorwas the main risk factor.

A case report of a honey bee colony poisoning incident in France

A case report of a honey bee colony poisoning incident in France Marie-Pierre Chauzat, Anne-Claire Martel, Philippe Blanchard, Marie-Claude Clément, Frank Schurr, Cosette Lair, Magali Ribière, Klaus Wallner, Peter Rosenkranz and Jean-Paul Faucon Agence Française de Sécurité Sanitaire des Aliments, Unit of honey bee Pathology, 105 route des Chappes, BP 111, 06 902 Sophia Antipolis cedex, France. Apicultural State Institute, University of Hohenheim, August-von-Hartmannstrasse 13, D-70599 Stuttgart, Germany.

HPLC Determination of Sulfathiazole in French Honeys

Abstract A rapid reversed‐phase high‐performance liquid chromatographic method, with fluorimetric detection, is described for routine analysis of sulfathiazole (STZ) residues in honey. Samples were dissolved in 1 M hydrochloric acid and submitted to pre‐column derivatization with fluorescamine. Liquid chromatographic analysis of the fluorescent derivative is performed on a C18 column using a mobile phase of 2% acetic acid/ acetonitrile (60:40, v/v). The quantification limit obtained for STZ in honey was 10 µg/kg.

PESTICIDE RESIDUES IN RASPBERRIES AND LETTUCE: EXTRACTION AND COMPARISON OF THREE CHROMATOGRAPHIC METHODS: HPLC, HPTLC AND GC

The determination of iprodione, vinclozolin, and cymoxanil fungicide residues in raspberries and lettuce has been carried out by HPLC with an UV detector, by HPTLC with an densitometric detection, and by GC with an electron capture detector (ECD). In all cases, fungicide residues were extracted with acetone and liquid-liquid partitioning process and finally purified on silica gel. Recoveries are always higher than 70%. For iprodione, vinclozolin, and cymoxanil, respectively, the limits of detection were 0.01 ppm, 0.013 ppm, and 0.08 ppm for the HPLC method, 0.2 ppm, 0.43 ppm, and 0.5 ppm for the HPTLC method, and 0.025 ppm, 0.004 ppm, and 0.03 ppm for the GC method.