Les hydrocarbures aromatiques polycycliques : les abeilles, le miel et le pollen, sentinelles des

Cette partie a fait l’objet d’un article publié dans la revue Chemosphere 86: 98-104 (Lambert

et al., 2012b).

Polycyclic aromatic hydrocarbons: Bees, honey and pollen as sentinels for

environmental chemical contaminants

Olivier Lambert^a,*, Bruno Veyrand^b, Sophie Durand^b, Philippe Marchand^b, Bruno Le Bizec^b, Mélanie Piroux^a, Sophie Puyo^a, Chantal Thorin^c, Frédéric Delbac^d,e, Hervé Pouliquen^a

aLUNAM Université, ONIRIS, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes-Atlantique, Plateforme Environnementale Vétérinaire, Centre Vétérinaire de la Faune Sauvage et des Ecosystèmes des Pays de la Loire (CVFSE), Atlanpole-La Chantrerie, BP40706, Nantes, F-44307, France bLUNAM Université, ONIRIS, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes-Atlantique, Laboratoire d’Etude des Résidus et Contaminants dans les Aliments (LABERCA), Atlanpole-La Chantrerie, BP40706, Nantes, F-44307, France

cLUNAM Université, ONIRIS, Ecole Nationale Vétérinaire, Agroalimentaire et de l’Alimentation Nantes-Atlantique, Unité de Statistiques, Atlanpole-La Chantrerie, BP40706, Nantes, F-44307, France

d

Clermont Université, Université Blaise Pascal, Laboratoire « Microorganismes : Génome et Environnement », BP 10448, Clermont-Ferrand, F-63000, France

eCNRS, UMR 6023, LMGE, Aubière, F-63177, France

*Corresponding author. Tel.: +33 (0)2 40 68 77 76; fax: +33 (0)2 40 68 77 51. E-mail address: olivier.lambert@oniris-nantes.fr (O. Lambert).

Résumé

Trois matrices apicoles échantillonnées dans six ruchers différents de l’Ouest de la France ont été analysées pour doser les hydrocarbures aromatiques polycycliques (4HAPs : benzo[a]pyrène, benzo[a]anthracène, benzo[b]fluoranthène et chrysène). Les échantillons ont été collectés lors de quatre périodes différentes pour les années 2008 et 2009. Les échantillons

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de miel ont montré les niveaux de contamination en 4HAPs les plus faibles (minimum = 0,03 µg.kg^-1 ; maximum = 5,80 µg.kg^-1 ; moyenne = 0,82 µg.kg^-1 ; écart type = 1,17). Les échantillons d’abeilles ont montré les niveaux de contamination en 4HAPs les plus élevés (minimum = 0,32 µg.kg^-1 ; maximum = 73,83 µg.kg^-1 ; moyenne = 7,03 µg.kg^-1 ; écart type = 17,83) avec une dispersion importante des concentrations due à quatre pics principaux de concentrations élevées. Les échantillons de pollen ont montré seulement un épisode majeur présentant les concentrations les plus élevées retrouvées en 4HAPs (minimum = 0,33 µg.kg^-1 ; maximum = 129,41 µg.kg^-1 ; moyenne = 7,10 µg.kg^-1 ; écart type = 22,28). Les concentrations retrouvées en 4HAPs ont été significativement influencées par le contexte paysager pour tous les échantillons apicoles prélevés.

Abstract

Three beehive matrices, sampled in six different apiaries from West France, were analyzed for the presence of four polycyclic aromatic hydrocarbons (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene). Samples were collected during four different periods in both 2008 and 2009. Honey samples showed the lowest levels of PAH4 contamination (min = 0.03 µg kg^-1; max = 5.80 µg kg^-1; mean = 0.82 µg kg^-1; Sd = 1.17). Bee samples exhibited higher levels of PAH4 contamination (min= 0.32 µg kg^-1; max = 73.83 µg kg^-1; mean = 7.03 µg kg^-1; Sd = 17.83) with a great dispersion of the concentrations due to four main events of high concentrations. Pollen samples showed only one major episode with the highest PAH4 concentration found (min = 0.33 µg kg^-1; max = 129.41 µg kg^-1; mean = 7.10 µg kg^-1; Sd = 22.28). The PAH4 concentrations found were significantly influenced by the landscape context for all beehive samples.

Keywords: Polycyclic aromatic hydrocarbons; Bees; Honey; pollen; PAHs

1. Introduction

The assessment of environmental health may be investigated with sentinel species (Lagadic et al., 1998; van der Schalie et al., 1999; Basu et al., 2007). Honeybee (Apis

mellifera L.) was in particular commonly presented as an appropriate sentinel to monitor the

environmental pollution (Kevan, 1999; Porrini et al., 2003; Perugini et al., 2009) due to its biological characteristics: (i) a widespread distribution, (ii) bred for its beehive matrices

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(pollen, honey and propolis) resulting in a quite easily capture and in sufficient numbers for studies, (iii) behavior as a wild pollinator species, (iv) a restricted home range, and (v) sensitivity to environmental pollutants.

Beehive matrices can be used as bioindicators of the presence and the levels of pesticides (Rissato et al., 2007; Balayiannis and Balayiannis, 2008; Chauzat et al., 2011), heavy metals (Leita et al., 1996; Tuzen et al., 2007) and other environmental pollutants (Ponikvar et al., 2005). However, few studies concerned the contamination by polycyclic aromatic hydrocarbons (PAHs). PAHs are a large group of organic compounds containing two or more aromatic rings and belonging to the food and environment contaminants. They are produced by natural and anthropogenic processes. PAHs are ubiquist environmental pollutants produced during the incomplete combustion of organic matter and during human or industrial activities such as vehicle exhaust, gas-fired or oil-fired heating, incinerators, industrial emissions, (Hodgeson, 1990; Wang et al. 2001; Dong and Lee, 2009).

Most of research papers have been published on PAH levels in air, soil, plants or edibles matrices due to their carcinogenic properties and to their concern in food safety (Tao et al., 2004; Dobrinas et al., 2008; Moret et al., 2010). To our knowledge our study is the first to assess and compare the contamination of three apicultural matrices, namely bees, honey and pollen.

PAHs generally occur in complex mixtures which may consist of hundreds of compounds. Among these compounds, fifteen were identified in 2005 (Commission Regulation, 2005/108/EC) as a priority because they show clear evidence of mutagenicity and genotoxicity in somatic cells, in experimental animals and in vivo. Morever, they have also shown clear carcinogenic effects, excepted for benzo[ghi]perylene, for various types of bioassays in experimental animals (EC, 2002). The Scientific Committee on Food think that these compounds may be regarded as potentially genotoxic and carcinogenic to humans. Thus, this committee suggested to use benzo[a]pyrene as a marker of occurrence and effect of the carcinogenic PAHs in food. In 2008, the scientific Opinion of the Panel on Contaminants in the Food Chain (EFSA, 2008) indicated that the sum of four PAHs (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene respectively) can be used as alternatives to benzo[a]pyrene alone as markers of the carcinogenicity of the genotoxic and carcinogenic PAHs, and would be equally effective.

In this context, the aim of the present study was to investigate the contamination of various apiaries to PAHs through analyses on foraging bees, honey and trap pollen over 2 years. Furthermore, the results of this study was expected to provide valuable information

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regarding (i) the PAH contamination and level differences between apiaries located in France with particular landscape context (island, specific road network, …), (ii) the evolution in time of the apiary matrices contamination and (iii) the relevant matrices of choice for monitoring environmental PAH contamination.

2. Materials and methods

2.1. Study area, sampling sites and biological matrices of hive sampling

Six apiaries owned by six different volunteer beekeepers were selected to participate in this study. Two apiaries (apiary A and apiary F) are represented in Fig. 1 and were located in a hedgerow landscape of Loire Atlantique (44, France), one apiary (apiary G) was located in a cultivated landscape of Maine et Loire (49, France), one apiary (apiary M) was located in a hedgerow landscape of Mayenne (53, France), two apiaries were located on islands, one (apiary IO) in the Isle of Ouessant of Finistère (29, France) and one (apiary IY) in the Isle of Yeu of Vendée (85, France) (Fig. 1).

Three different types of biological matrice (foraging bees, honey and trap pollen) were taken from eight colonies in each apiary. At the first time of sampling, eight colonies per apiaries were selected. Then, all the samples collected during the all lenght of the study from one apiary were always taken from the eight same selected colonies. Samples were collected at four different periods during two beekeeping seasons: (i) at the end of April and at the beginning of May 2008 (period 1) and 2009 (period 5), (ii) at the end of June and at the beginning of July 2008 (period 2) and 2009 (period 6), (iii) at the end of July and at the beginning of August 2008 (period 3) and 2009 (period 7), and (iv) at the end of September and at the beginning of October 2008 (period 4) and 2009 (period 8). At each sampling sessions, samples were taken from the eight colonies chosen and then pooled by biological matrice. In total, 432 samplings were collected: 144 bees samples, 144 honey samples and 144 trap pollen samples.

The samples of foraging bees were removed with a hand dryer Dyson^® on the hive’s flight board, excluding the bees with pollen sac. The honey samples were removed directly from several honeycombs on each colony with a cutter. The pollen samples were collected in pollen trap set up by the beekeepers 3 d before the sampling. Field collected samples were

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placed immediately on ice after sampling and stored in a standard freezer at −20 °C until analysis.