Lemoine, S.

Ramdine, G.

Aquatic Commons

Anthropogenic contaminations in the mangrove of Guadeloupe (Lesser Antilles): use of a biomarker of genotoxicity for monitoring

Anthropogenic Contaminations in the mangrove of Guadeloupe (Lesser Antilles): Use of a 
Biomarker of Genotoxicity for Monitoring 
 
GAËLLE RAMDINE and SOAZIG LEMOINE 
Laboratoire de Biologie Marine, DYNECAR EA 926, Université des Antilles et de la Guyane, Campus de Fouillole, BP 592, 
97159 Pointe-à-Pitre cedex Guadeloupe, F.W.I. 
 
ABSTRACT 
Mangroves are hotspots of primary production which act as a buffer between marine and terrestrial environment. They shelter 
a unique ecosystem characterized by an exceptional biodiversity.  In Guadeloupe, mangroves spread over 3000 hectares.  Presently 
the mangrove ecosystem of Guadeloupe is under serious threat because many anthropogenic activities are concentrated on the 
coastline and contribute to the contamination of the whole coastal ecosystems by polluting substances.  
Biomarkers have become valuable ecotoxicological tools to assess the toxicity and bioavailability of pollutants. In this study, 
two approaches are used to evaluate the importance of damage caused to mangroves ecosystem.  The first one is the quantification of 
the pollutants (heavy metals, polyaromatics hydrocarbons and pesticides) notably in sentinel species (Crassostrea rhizophorae) and 
the second one is the measure of the impact on natural populations by using a biomarker of genotoxicity.  Here we present an 
adaptation of this biomarker to assess DNA damage in different species as mangrove oysters (Crassostrea rhizophorae) and fishes 
(Ocyurus chrysurus).  The quantification of DNA single strand breaks (SSB) by the comet assay can be used as a rapid and sensitive 
indicator of genotoxicant exposure.  The xenobiotic concentrations should be correlated to comet assay results in order to locate risk 
zone. At present, complementary monitoring studies targeting other biomarkers of oxidative stress (catalase, GST, TBARS) are 
carried out to assess more precisely the impact of contamination of guadeloupean mangroves by human activities.  
 
KEY WORDS:  Mangrove,  pollution, genotoxicity 
 
Contaminaciones Antropogénicas en los Manglares de Guadalupe (Las Antillas Menores): 
Biomonitoreo por la Utilización de un Maracador Biológico de Genotoxicidad 
 
Los mangles son lugares de producción primaria que actúan como tampon entre el ambiente marino y terrestre. Abrigan un 
ecosistema único caracterizado por un excepcional biodiversidad.  En Guadalupe, el manglar se extiende sobre cerca de 3000 
hectáreas.  Actualmente los manglares de Guadalupe están bajo seria amenaza porque muchas de las actividades antropogénicas 
están concentradas en la línea de la costa y contribuyen a la contaminación de los ecosistemas costeros por sustancias contaminantes.  
Los marcadores biológicos son instrumentos preciosos para la evaluación de la toxicidad y la biodisponibilidad de los agentes 
contaminantes.  
En este estudio, dos enfoques fueron abordados para evaluar la importancia de los daños causados a los manglares. El primero 
fue la cuantificación de los agentes contaminantes (metales pesados, pesticidas) en sedimentos y en la especie centinela (Crassostrea 
rhizophorae).  El segundo fue la evaluación del impacto a nivel de las poblaciones naturales utilizando un marcador biológico de 
genotoxicidad.  Este marcador biológico  fue adaptado para evaluar el daño de ADN en varias especies como son : ostras de mangle 
(Crassostrea rhizophorae), pesces (Ocyurus chrysurus).  La cuantificación de las roturas simples de las ramas del ADN por la 
prueba cometa puede ser utilizada como un indicador rápido y sensible a la exposición a sustancias con genotoxicidad. Las 
concentraciones de las sustancias xenobióticas pueden ser correlacionadas con los resultados de las pruebas cometas con el fin de 
localizar las zonas de riesgo. 
Actualmente, se conducen estudios complementarios que se dirigen a otros contaminantes (HAPs).  Estos emplean tambien  
marcadores biológicos de estrés oxydativo (catalasa, Glutathion-S-Transférasa, TBARS) con el fin de evaluar más precisamente la 
importancia de la contaminación de los manglares Guadalupeños por las actividades antropológénicas. 
 
PALABRAS CLAVES:  Manglar, polución, genotoxicidad 
 
Contaminations D’origine Anthropique des Mangroves de Guadeloupe (Petites Antilles): Biosur-
veillane par L’utilisation d’un Biomarquer de Génotoxicité 
 
Les mangroves sont de hauts lieux de productivité primaire qui jouent un rôle de tampon entre les milieux marin et terrestre.  Elles 
abritent un écosystème unique caractérisé par une exceptionnelle biodiversité.  En Guadeloupe, la mangrove s’étend sur environ 
3000 hectares. Actuellement, les mangroves de Guadeloupe sont sérieusement menacées, car de nombreuses activités anthropiques 
se concentrent sur les zones côtières, contribuant ainsi à la pollution de l’ensemble des écosystèmes côtiers. Les biomarqueurs sont 
de précieux outils permettant d’évaluer la toxicité et la biodisponibilité des contaminants.  Dans cette étude, deux approches ont été 
utilisées afin de déterminer l’importance des dommages causés aux mangroves.  La première est la quantification des polluants 
(métaux lourds, pesticides) au sein du sédiment et d’une espèce sentinelle (Crassostrea rhizophorae).  La deuxième est l’évaluation 
de l’impact au niveau des populations naturelles en utilisant un biomarqueur de génotoxicité.  Ce biomarqueur a été adapté à 
différentes espèces : l’huître de palétuvier (Crassostrea rhizophorae), des poissons (Diapterus rhombeus ; Ocyurus chrysurus) et des 
plantes (Rhizophorae mangle), pour évaluer les dommages causés à l’ADN.  La quantification des cassures simples brins de l’ADN 
réalisée grâce au test comète, peut être utilisée comme un indicateur rapide et sensible de l’exposition des organismes à des 
substances génotoxiques. Les concentrations des contaminants peuvent être corrélées avec les résultats des tests comètes afin de 
localiser les zones à risque. Actuellement, des études complémentaires ciblant d’autres contaminants (HAPs) et employant des 
biomarqueurs de stress oxydatif (catalase, Glutathion-S-Transférase, TBARS) sont conduites afin d’évaluer plus précisément 
Proceedings of the 61st  Gulf and Caribbean Fisheries Institute     November 10 - 14, 2008   Gosier, Guadeloupe, French West Indies 
 Ramdine, G. and S. Lemoine    GCFI:61   (2009)     Page 247 
 
l’importance de la contamination des mangroves 
guadeloupéennes par les activités anthropiques.  
 
MOTS CLÉS: mangrove, pollution, Crassostrea 
rhizophorae  
 
INTRODUCTION 
In Guadeloupe, mangroves are well developed along 
the shore.  This exceptional ecosystem spreads over 3000 
hectares of Guadeloupe’s coastline.  Mangroves are a 
hotspot of primary production (Imbert and Rollet 1989) 
which act as a buffer between terrestrial and marine 
ecosystems.  They are characterized by an exceptional 
biodiversity.  In Guadeloupe, industrial, agricultural, and 
urban developments coupled with the small size of the 
island contribute to concentrate the anthropogenic activities 
on the coastlines where most of the discharges of the island 
occur. 
The main goal of this study is to establish a measure of 
anthropogenic pressure gradient, through an assessment of 
heavy metals, poly aromatic hydrocarbons (PAHs) and 
pesticides contaminations.  It attempts to measure effects 
induced by pollution on organisms.  To establish this 
gradient, bioaccumulation of contaminants was mainly 
assessed by studying a sentinel species, the mangrove 
oyster (Crassostrea rhizophorae).  The effects induced by 
pollution were measured by using a biomarker of genotox-
icity.  
 
MATERIALS AND METHODS 
 
Study Area 
In this study, seven stations located in the shoreline 
mangrove were selected according to the location of the 
main streams and of the others most important sites of 
human activities (Figure 1).  The Fajou Islet was defined as 
a control station because of its relative distance from the 
coastline.  
 
Collection and Analytical Methods 
On each station, oysters were hand sampling in order 
to the measure heavy metals (cadmium, mercury, lead) and 
polycyclic aromatic hydrocarbons (PAHs) concentrations 
with the help of respectively atomic absorption spectrome-
try and gas chromatography.  For pesticides, organisms 
were collected with fish net and fish trap before being 
analyzed with the help of liquid chromatography. 
 
Genotoxicity Analysis: The Comet Assay 
The comet assay is a technique developed to detect 
DNA strand breaks which permits to identify genotoxicity 
of xenobiotic substances.  Cells are included in agarose gel 
and then lysed in an alkaline solution prior to be submitted 
to electrophoresis.  After neutralization, DNA is stained 
with ethidium bromide and then observed with a micro-
scope.  DNA damage is assessed according to a visual 
classification method.  Comets are classified into four 
categories based on the length of migration and/or the 
perceived relative proportion of the DNA in the tail 
(Figure 2).  A numerical value is assigned to each 
category: A (for an undamaged nucleus) to D (for a 
severely damaged nucleus).  The numerical value permits 
to calculate a mean score for each station studied.  For each 
individual, a hundred cells were observed.  The mean score 
can fluctuate between 0 and 300.  In this study, the comet 
assay was applied on gill cells of mangrove oysters 
(Crassostrea rhizophorae) (n = 10) and liver cells of 
yellowtail snapper (Ocyurus chrysurus) (n = 5). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 1.  The study zone. Seven stations: Des Rotours 
Channel (DRC); Perrin Channel (PC); Belle Plaine Channel 
(BPC); Grande Rivière à Goyave (GRG) ; Raizet Channel 
(RC); Bas-du-Fort Marina (BFM). 
Figure 2.  The different cell damage stages (A-D) used for 
scoring the comet assay (visual approach). 
Page 248  61st Gulf and Caribbean Fisheries Institute  
 
 
RESULTS 
 
Metals, Pesticides and Polycyclic Aromatic  
Hydrocarbons Concentrations 
Table 1 presents the mean heavy metals and PAHs 
(particularly Benzo(α)Pyrene:BαP) concentrations.  Grande 
Rivière à Goyave shows the highest concentration of 
cadmium (0.55 mg/kg).  Moreover, at this station, high 
concentrations of chlordecone, a very persistent pesticide, 
were recorded in crabs (Callinectes exasperates) (0.03 mg/
kg) and shrimps (Penaeus schmitti) (0.079 mg/kg) 
(Bouchon and Lemoine 2007).  Perrin Channel shows the 
highest concentration of mercury (0.25 mg/kg).  High 
concentrations of dithiocarbamate were detected as well 
into fishes (Archosargus rhomboidalis) (0.40 mg/kg) and 
moray (Gymnothorax funebris) (0.39 mg/kg) (Bouchon and 
Lemoine 2007).  The highest concentrations of lead were 
recorded at Raizet Channel (0.80 mg/kg) and Bas-du-Fort 
Marina (0.81 mg/kg).  At this last one, very high concen-
trations of PAHs and Benzo(α)Pyrene were found 
(respectively 961.16 and 65.4 ng/g).  It is important to 
underline that these values exceed the limit values 
determined by European legislation.  
 
Genotoxicity Analysis 
Six stations were selected to carry out the comet assay 
on mangrove oysters (Figure 3).  During the rainy season 
2005, the highest level of DNA damage (193.75) is 
obtained at Bas-du-Fort Marina (BFM).  During the 
following dry season 2006, the whole mean scores 
increased except for Grande Rivière à Goyave (GRG).  The 
highest ones were recorded at BFM (253.80) and Raizet 
Channel (RC) (237.30).  Conversely, during the dry season 
2007, about one year later, the whole mean scores de-
creased.  During this season, the level of DNA damage is 
the most important (196.90) at Raizet Channel (RC). 
 
 
 
Figure 4 presents the results of comet assay applied on 
yellowtail snapper (Ocyurus chrysurus) (Quistin 2007).  In 
this study two stations were selected.  One supposed to be 
free from pollution and the other one located near an 
industrial zone.  The comet assay did not show significant 
differences between the stations. 
 
  
Table 1.  Mean heavy metal and PAH concentrations at 
selected stations. 
  Heavy metals (mg/kg) 
Hydrocarbons 
(ng/g) 
Stations 
Cad-
mium 
Mer-
cury Lead 
Σ 
PAHs BαP 
Des Rotours  
Channel (DRC) 0,14 0,1 0,15 66,86 2,03 
Fajou Islet (FI) 0,27 0,06 0,2 117,2 3,1 
Grande Rivière à 
Goyave (GRG) 0,55 0,09 0,16 142,56 12,9 
Raizet Channel (RC) 0,19 0,11 0,8 163,03 2,6 
Bas-du-Fort Marina 
(BFM) 0,17 0,06 0,81 961,16 65,4 
Perrin Channel (PC) 0,21 0,25 0,14 - - 
Belle Plaine Channel 
(BPC) 0,17 0,06 0,11 - - 
Figure 3.  Levels of DNA damage recorded in mangrove 
oysters (Crassostrea rhizophorae) gill cells at six stations at 
different seasons. Mean scores (n=10 oysters per station, 
100 cells per oyster) calculated using points assigned to 
four different comet classes (0, 1, 2 and 3). 
Figure 4.  Levels of DNA damage recorded in yellowtail 
snapper (Ocyurus chrysurus) gill cells at six stations at dif-
ferent seasons.  Mean scores (n = 10 oysters per station, 
100 cells per oyster) calculated using points assigned to 
four different comet classes (0, 1, 2 and 3). 
 Ramdine, G. and S. Lemoine    GCFI:61   (2009)     Page 249 
 
DISCUSSION 
Table 2 presents a comparison of results between 
Guadeloupe and other Caribbean and South American 
countries.  Concerning non essential metals cadmium, 
mercury and lead the concentrations are lower in Guade-
loupe.  Cadmium bioaccumulated in oysters coming from 
Grande Rivière à Goyave probably originate from an-
thropic sources, namely a rum distillery and illegal dumps. 
Moreover, heavy metal dispersion is probably enhanced at 
this station by the large amount of suspended materials and 
organic matter present in the stream.  Lead is a metal 
commonly used in batteries.  High concentrations of this 
metal recorded at Raizet Channel (RC) could partially 
originate from wrecked cars found in Grand-Camp’s dump. 
Indeed, RC collects rain runoff from Pointe-à-Pitre, one of 
the main Guadeloupean towns and receives Grand-Camp’s 
dump (31 hectares) lixiviation products.  In the last few 
years, the frequentation of the Bas-du-Fort Marina (BFM) 
has considerably increased, generating higher heavy metal 
and hydrocarbons pollution levels (wastes from boat 
careening, car park and gas station drained into the stream). 
Cadmium, like mercury and lead, are highly toxic non-
essential metal (Depledge and Rainbow, 1990; Pruski and 
Dixon, 2002).  Bihari and Fafandel (2004) show that 
Benzo(α)Pyrene is a genotoxic substance.  The relative 
proportions of the different levels of DNA damage varies 
according to the station and the season.  Between 2005 and 
2006, RC and BFM were stations where high concentra-
tions of genotoxic substances (heavy metal, PAHs) were 
recorded.  The comet assay is very sensitive and shows that 
a high level of genotoxicity occurs where the anthropo-
genic activities are important.  
The biomarker of genotoxicity used in these studies is 
a good diagnostic tool which permits complementary 
studies to be carried out: the use of biomarkers of oxidative 
stress (Catalase, Glutathion-S-Transferase, Thiobarbituric 
Acid Reaction Species) and accurate researches of 
pollutants.  This study asks the question of the choice of 
the biological models.  Even if the yellowtail snapper 
(Ocyurus chrysurus) gives responses concerning the level 
of DNA damages, it is a non-sedentary organism, con-
versely to the mangrove oyster which is a good sentinel 
specie for this kind of study. 
 
 
CONCLUSION 
Human activities release pollutants into the biotope. 
Among these pollutants, genotoxins are bioaccumulated 
and are responsible of disturbances at the individual scale, 
notably genotoxicity.  Accumulation of unrepaired DNA 
lesion could explain the embryotoxicity of certain chemical 
pollutants.  As embryotoxicity exerts a direct impact on 
recruitment rate, genotoxicity could be closely related to 
modifications of the structure of marine communities and 
then in long-term could produce a possible impact upon 
ecosystems. 
 
ACKNOWLEDGEMENT 
The authors gratefully acknowledge the staff of La Rochelle’s 
Centre de Recherches des Littoraux Anthropisés and Centre Commun 
d’Analyses, as well as the Marine Biology Laboratory of the Antilles-
Guyane University of Guadeloupe technicians, for their support and 
assistance.  
 
LITERATURE CITED 
Bihari, N. and M. Fafandel.  2004.  Interspecies differences in DNA single 
strand breaks caused by benzo(α)pyrene and marine environment. 
Mutation Research 552: 209-217. 
Bouchon, C. and S. Lemoine.  2007.  Contamination par les pesticides des 
organismes marins de la baie du Grand Cul-de-Sac Marin (île de la 
Guadeloupe). Rapport final. 36 pp. 
Depledge, M.H. and P.S. Rainbow.  1990.  Models of regulation and 
accumulation of trace metals in marine invertebrate. Comparative 
Biochemistry Physiology C 97:1-7. 
Imbert, D., and B. Rollet.  1989.  Phytomasse et production primaire dans 
la mangrove du Grand Cul-de-Sac Marin (Guadeloupe). Oecologica 
Plant. 7 21 (4):379-396.  
Pruski, A.M. and D.R. Dixon.  2002.  Effects of cadmium on nuclear 
integrity and DNA repair efficiency in the gill cells of Mytilus 
edulis. Aquatic Toxicology 57:127-137.  
Quistin, R.  2007.  Mise au point de la technique du “test comet” sur les 
poisons. Rapport. 18 pp. 
Sbriz, L., R.A. Margarita, N.M Alberto de Rodriguez, S.W. Fowlers, and 
J.L. Sericano.  1998.  Levels of chlorinated hydrocarbons and trace 
metals in bivalves and nearshore sediment from the Dominican 
Republic. Marine Pollution Bulletin 36:971-979.  
Silva, C.A.R., P.S Rainbow, B.D. Smith, and Z.L. Santos. 2001. 
Biomonitoring of trace metal contamination in the Potengi estuary, 
Natal (Brazil), using the oyster Crassostrea rhizophorae, a local 
food source. Water Ressources 35:4072–4078.  
 
 
 
 
 
 Table 2.  A comparison of heavy metal concentrations (mg/
kg) from Guadeloupe and other Caribbean and South 
American countries. 
Stations Cd Hg Pb References 
Guadeloupe 0.14-0.55 0.05-0.11 0.16-0.81 this study 
Dominican 
Republic 0.35-2.57 0.49-7.02 0.08-1.46 
Sbriz et al., 
1998 
Brazil 0.8-1.9 - 1.8-7.8 
Silva et al., 
2001 


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Anthropogenic contaminations in the mangrove of Guadeloupe (Lesser Antilles): use of a biomarker of genotoxicity for monitoring

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