Bull Environ Contam Toxicol (2013) 91:278–282 DOI 10.1007/s00128-013-1054-z Influence of Fishing Technique on Organochlorine Pesticide Accumulation in Fish and its Possible Human Health Risk in the Republic of Be´nin Elisabeth Yehouenou A. Pazou • Judicae¨l P. Azehoun • Theodora Ahoyo • Patrick Edorh Ale´odjrodo • Nico M. van Straalen • Cornelis A. M. van Gestel Received: 31 January 2013 / Accepted: 29 June 2013 / Published online: 10 July 2013 Ó Springer Science+Business Media New York 2013 Abstract In Be´nin different techniques are used for In the Republic of Be´nin, rivers and estuaries serve as an large-scale commercial fishing, Acadjas (enclosures con- important source of income for fishermen. Fishing in the structed in the river) and Whe´dos (holes made in the river Oue´me´ valley is a major activity during the year and per- banks). This study aimed at assessing the extent of con- formed by all age categories of the population. Over 4,250 tamination related to these fishing techniques. Fish con- fishermen are full-time working in this area together with tained residues of DDT and its metabolites, a-endosulfan, an additional 13,000 seasonal fishermen. Fishermen dieldrin, aldrin, endrin and lindane. Pesticide levels were exploiting the Oue´me´ River use a diversity of techniques, similar in fish from Acadjas and Whe´dos, except for higher such as nets, sieving nets, and sparrow nets. a-endosulfan levels in fish from the Whe´dos. Comparing In Be´nin, particular fishing techniques are used to cul- pesticide intake levels through fish consumption with tol- tivate fish in the river, including Acadjas and Whe´dos. erable daily intake levels showed that in all cases risk for Acadjas are enclosures constructed with wood or branches human health is low. submersed in the river, sometimes surrounded by nets (Lale`ye` 2000; Lale`ye` et al. 2001). They may have different Keywords Human health risk Á Organochlorine forms, square, rectangular or circular, and fish are kept in pesticides Á Fish culture techniques Á Human exposure the Acadjas for 6 months–1 year. Fish in the Acadjas sometimes are fed and may gain considerable weight. Whe´dos consist of a hole made in the river bank when the E. Yehouenou A. Pazou Laboratoire de Recherche en Biologie Applique´e (LARBA), water level is low. Whe´dos also have irregular shapes. Fish De´partement de Ge´nie de l’Environnement, Ecole Polytechnique enter the Whe´dos when the water level rises. After with- d’Abomey-Calavi, Universite´ d’Abomey-Calavi, drawal of the water, fish are trapped in the Whe´dos and 01 BP, 2009 Cotonou, Benin may be kept there for 6–7 months to be collected before the J. P. Azehoun water rises again. Institut National des Recherches Agricoles du Benin, Acadjas and Whe´dos are constructed without consider- 07 BP, 0265 Cotonou, Benin ation of water quality. They may, however, be exposed to waste material dumped into the river, or to run off from T. Ahoyo Laboratoire de Recherche en Biologie Applique´e (LARBA), agricultural land. As a consequence, fish in these systems Universite´ d’Abomey-Calavi, 01 BP, 2009 Cotonou, Benin may get exposed to chemicals, especially to agricultural pesticides. Considering the difference in the way the fish P. E. Ale´odjrodo are kept, it is likely that their exposure to pesticides may De´partement de Biochimie et de Biologie Cellulaire, Universite´ d’Abomey-Calavi, 01 BP, 526 Cotonou, Benin also be different. Differences may be related to the level of pesticide residues in water and sediment, frequency of N. M. van Straalen Á C. A. M. van Gestel (&) exposure or duration of exposure. Department of Ecological Science, Faculty of Earth and Life The purpose of this study was to investigate the pesti- Sciences, VU University, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands cide levels in fish collected from the same river area but e-mail: [email protected] using different fishing (and cultivation) techniques on the 123 Bull Environ Contam Toxicol (2013) 91:278–282 279 one hand and on the other hand to compare them with fish For clean-up, the extract was placed on an aluminium collected from the same river. For that purpose four dif- oxide column and eluted with petroleum ether followed by ferent fish species were collected from Acadjas, Whe´dos elution over a column of deactivated silica gel, also with and from the Oue´me´ River at Lowe´ in Be´nin. The main petroleum ether. The extracts were concentrated to 2.0 mL objective of the present study was to quantify the extent of under a gentle stream of nitrogen gas. Analysis took place contamination of Acadja and Whe´do fish with organo- by GC (Hewlett Packard 6890) with ECD, equipped with chlorinated pesticides. In addition, we made an attempt to an autosampler (Hewlett Packard injector 7673) and a assess the potential human health risk from fish Chrompack 8753 CP-Sil-8 CB column. Helium was used consumption. as the carrier gas, and organochlorine pesticides were identified by comparing their retention times with those of a standard mixture of PCBs and organochlorine pesticides. Materials and Methods For calibration purposes, PCB155, mirex and tetrachloro- benzene were used as internal standards. The Lowe´ area is situated in the lower basin of the Oue´me´ The limits of detection for all pesticides including River between 6°22 and 7°16 N and between 2° and 1°50 E RDDT (pp’-DDE, op’-DDD, pp’-DDD’ op’-DDT, pp’- (see for a map of the area: Yehouenou A. Pazou et al. 2006). DDT) was 0.1 ng/g lipid, the limit of quantification was The lower valley of the Oue´me´ River is bordered in the East 0.3 ng/g lipid. by the basin of Yema in Nigeria, in the west by the basin of Quality assurance measures included rigorous contami- Couffo, in the North by the rocky outcrops situated to the nation control procedures (strict washing and cleaning North of Bohicon (road to Zagnanado) and in the South by procedures), monitoring of blank levels of solvents, Cotonou Lagoon (Colombani et al. 1972). The lower valley equipment and other materials, analysis of procedural of the Oue´me´ River has a sedimentary soil (marble covered blanks, recovery of spiked standards, monitoring of by clayey sands) with an alluvial plain, and is 5 km wide at detector response and linearity, and analysis of a reference Sagon and Gangban, 10 km at Bonou and 20 km at Hozin. material (dried sewage sludge). For each series of 6–8 The valley is flooded in periods of high water. samples, one blank and a sample of the reference material In 2004, fishes belonging to the species Clarias gari- were included. Recoveries of chlorinated pesticides in the epinus, Protopterus annectens, Polypterus senegalensis reference material were between 80 % and 110 % of cer- senegalensis and Parachanna obscura were caught with tified concentrations. sparrow nets from the river and collected from Acadjas and To assess the risk of pesticide intake by fish consump- Whe´dos near Lowe´. Only one fish of each species was tion from Acadjas and Whe´dos by the local population, it caught. The fish were washed and stored in an ice-chest at was assumed that local people would eat one fish per day. 4°C and transported to the laboratory. Muscle tissues of On the basis of that and using the pesticide concentrations each fish were collected, weighted, frozen, lyophilized and measured, for each pesticide the daily intake was esti- stored at -20°C before analysis. mated. Next, daily intake was normalized to an average All fish samples were analysed by the certified chemi- human, weighing 60 kg. The resulting intake values were cal-analytical laboratory of the Hoogheemraadschap Hol- compared with the tolerable daily intake (TDI) values lands Noorderkwartier (HHNK) in Edam. All solvents and reported by the WHO (2004). Assuming all pesticides have other chemicals used were of analytical grade quality the same mode of action, the toxic unit approach was (Merck, J.T. Baker) to ensure purity. adopted to enable summing the risk of the different pesti- Dissected and lyophilized fish flesh (edible muscle tis- cides detected (Van Gestel et al. 2011). For that purpose, a sue) were ground to fine powder using a ceramic pestle and toxic unit (TU) was defined as the estimated daily intake of mortar. Two grams of fish powder were extracted with a pesticide by fish consumption divided by its TDI. If the 200 mL acetone by shaking for 10 min, after which 20 mL sum of the toxic units approach or exceed the value of 1, of a saturated sodium sulphite solution and 100 mL this would indicate a risk for the local population. petroleum ether were added. After shaking for 10 min, the suspension was filtered over a paper filter and washed two times with 500 mL deionized water to which 20 mL Results and Discussion sodium chloride solution was added. The petroleum ether fraction was subsequently dried with sodium sulphate and The organochlorine pesticides pp’-DDE, op’-DDD, pp’- volume reduced evaporation in a Kuderna-Danish rotava- DDD, op’-DDT, pp’-DDT, a-endosulfan, dieldrin, aldrin por at 75–80°C. and lindane were detected at varying concentrations in fish Lipid contents of the fish were obtained by weighing and from both Whe´dos and Acadjas (Table 1). In general, the drying 1 mL of the extract. highest pesticide levels were found in P. obscura and the 123 280 Bull Environ Contam Toxicol (2013) 91:278–282 lowest ones in P.