Au Burkina Faso, l’un des soucis majeurs demeure la gestion des eaux résiduaires dans les villes. Notre objectif a été d’étudier des procédés biologiques alternatifs destinés aux petites et moyennes collectivités et particulièrement adaptés aux conditions climatiques tropicales. Nous avons examiné les performances épuratoires de deux matériaux de filtration que sont le sable et un substrat de coco concassé (fibres de coco), sur des systèmes pilotes recevant des effluents issus d’un bassin anaérobie de lagunage. Les résultats montrent des performances croissantes de 93 % à 95 % sur la DCO (Demande Chimique en Oxygène) et un abattement moyen sur la DBO5 (Demande Biochimique en Oxygène) atteignant 99 %, avec la colonisation progressive du massif de sable par la biomasse. Avec le substrat de coco les rendements moyens sur la DCO passent successivement de 15 % à 51 % lorsque les charges hydrauliques varient de 20 à 60 L•m-2•j-1, du fait de l’extraction de composés phénoliques du substrat. Cependant, il présente la même efficacité que le sable pour l’élimination de la pollution biodégradable. Les rendements en azote Kjeldahl sont de 75 % et 84 % pour le substrat de coco et le sable respectivement, alors que le filtrat issu du substrat de coco n’a donné que 7 mg•L-1 en moyenne de nitrates. Dans le même temps, les concentrations en nitrates atteignent 40 mg•L-1 pour le massif de sable. Ce comportement du substrat de coco pourrait être attribué à la formation de complexes entre composés azotés et les tanins issus de ce matériau.

Pour optimiser les rendements (agricoles), l'agriculture intensive necessite une utilisation massive d'intrants agricoles dont les engrais chimiques, potentiellement sources de pollution des ressources en eau. La region du Sud - Ouest du Burkina, dont font partie les zones concernees par la presente etude, connait une agriculture intensive du coton. Il est fait usage dans les champs de coton, d'engrais a base essentiellement d'azote, de phosphate, de potassium, mais egalement d'uree, de chlorure de potassium et de nitrate d'ammonium. Un total de 42 echantillons d'eau de surface, de puits et de forages ont fait l'objet d'analyses, afin d'evaluer l'impact de ces engrais sur la qualite des ressources en eau de consommation des populations sur une annee. Eu egard a la nature des fertilisants utilises, les parametres essentiels suivants ont ete cibles : Nitrates, nitrites, ortho-phosphates, ammonium, potassium, conductivite electrique et durete totale. Il ressort de ces investigations que les eaux de puits, pendant la saison hivernale, presentent des teneurs plus importantes en nitrates et potassium avec des valeurs maximales respectives de 178 mg/L (plus de 3 fois la valeur limite admise par l'OMS pour les eaux de consommation) et 55 mg/L pour une norme admise par l'OMS de 10 mg/L en potassium. Les ortho-phosphates, forme soluble du phosphore et les nitrites, presentent des teneurs inferieures aux normes admises. S'agissant des ions ammonium, un seul puits par sa position en aval d'un WC et d'un parc d'animaux, a donne des valeurs superieures a la norme qui est fixee a 1,5 mg/L, atteignant ainsi 20 mg/L de N-NH+4. Les echantillons d'eau de forages sont exempts de toute contamination, alors que 33% des prelevements d'eau de surface ont donne des teneurs depassant la valeur limite admise seulement en potassium. Globalement, 61% des echantillons d'eau de puits sont contamines par les nitrates, 67% par le potassium et 17% donnent des teneurs superieures a la norme en ammonium. Ce qui permet d'en deduire qu'il y a une infiltration de pollution dans la nappe superficielle qui alimente les puits. La conductivite electrique et la durete totale sans etre excessives presentent les valeurs les plus importantes pour les memes sites que sont les puits, avec des valeurs maximales respectives de 1252 μS/cm et 202 mg/L de CaCO3.

P-349 Abstract: High concentrations of HCH (hexachlorocyclohe-xane) and DDT (dichlorodiphenyltrichloroethane) were found in moldavian soils. Elevated levels of organochlored pesticides correspond to soils situated near the storehouses. Soil presents great levels of HCH- isomers and DDT-isomers with a prevalence of a-HCH, b-HCH, pp’DDT and pp’DDE. Concentrations of total-DDTs determined in soils from the storehouses ranged from 0,03 to 118 mg/kg and the values of total-HCHs ranged from 0,07 to 1180 mg/kg. We have found the same molecules in agricultural soils situated near the warehouses but with lower concentrations of pesticides. Concentrations of total-DDTs browsed from 0,07 to 0,900 mg/kg and the total-HCHs was from 0,05 to 4,5 mg/kg. These results denote a possible recent input of HCHs and a decomposition of DDTs from “old sources” in soils of the samples areas.

According to heterozygosity, allele number, and Correspondence Analusis, the chub populations of the lentic Saone River were genetically homogeneous while those of the lotic Rhone River (including flowing sections and standing backwaters) were diverse. These two groups of populations were distant by 150 km.

The genetic variability of cultured stocks of common carp (Cyprinus carpio) was studied using two types of genetic markers: allozymes and microsatellites. A comparative analysis was investigated between six strains from extensive aquaculture in two French regions (Dombes and Forez) and five strains from the Czech Republic stemming from artificial selection and maintained in the Research Center of Vodnany. Observed heterozygosity from allozyme data varied from 0.003 to 0.029 for French strains and was significantly lower than that observed for Czech strains, which varied from 0.026 to 0.058. The genetic variability of microsatellites for the whole data set was considerably higher than that for allozymes. The mean number of alleles per microsatellite locus was higher for French strains than for Czech strains (respectively, 6.2 and 4.2). Microsatellites are generally considered to be selectively neutral and the reduction of microsatellite allelic diversity in Czech strains could be related to a possible population bottleneck associated with breeding practice. However, the patterns of genetic variation for the two types of marker are possibly biased by the limited number of sampled individuals and must be confirmed in the future by more extensive studies. Significant differentiation between the strains was shown using F statistics, whatever the tested groupings, and no obvious difference was detected between relationships inferred with the two types of genetic markers. A neighbour-joining analysis of genetic distances (chord distance of Cavalli-Sforza and Edwards [Am. J. Hum. Genet 19 (1967) 233.]) between strains showed that the topologies of the trees for microsatellites and allozymes were globally congruent. However, a more pronounced discrimination between the strains of the two countries was detected by the microsatellite markers which appeared more suitable to infer the effect of the geographical separation of the ancestral strains or different culture histories.

Six populations de carpe commune (Cyprinus carpid) ont été comparées sur la base de quatre critères : morphologie, génétique, rendement de transformation et aspect des filets. Les provenances géographiques des différents lots étudiés correspondent aux principales régions de production piscicole françaises : Dombes, Forez, Brenne, Allier, Lorraine et Poitou-Charentes. Une discrimination géographique des populations est possible mais elle repose sur une approche globale intégrant l'ensemble des paramètres. Les différences semblent essentiellement liées aux conditions environnementales et permettent de distinguer les lots issus des régions où l'élevage est plus intensif et traditionnellement centré sur la carpe (Dombes, Forez, Lorraine) et les lots correspondant à un élevage plus extensif et davantage orienté vers le marché du repeuplement (Allier, Brenne, Poitou-Charentes).

Phylogenetic relationships among Greek populations of the chub, Leuciscus cephalus, were investigated using 600 bp of the cytochrome b gene. The aim of this study was to test the assumption that the main difference in ichthyological composition between both sides of the Balkan Peninsula is directly linked to differences in the dispersion mechanisms used by fish in order to extend their distribution range. Phylogenetic and nested clade analyses clearly showed that populations in Greece are significantly differentiated. Greek populations were found to descend from three lineages in three geographical provinces: Western, Central, and Eastern Greece. The chub reached Western Greece at the beginning of the Pleistocene and Eastern Greece during the mid-Pleistocene. Chub dispersion occurred mainly by river confluence due to sea level lowering and river capture in Western Greece and sea dispersal with low-salinity conditions within the Aegean Sea in Eastern Greece. However, in Central Greece, the original mtDNA lineage has presumably been lost owing to a genetic introgression following a second invasion from the Danube during the final stage of the last glaciation. This study provides new elements for a better understanding of the composition of the contemporary ichthyofauna in Greece and highlights possible evolutionary mechanisms responsible for the high endemism rate in the Western Greek biogeographic province.

Carp (Cyprinus carpio) were tested for cadmium accumulation and elimination during and after a simulated pollution exposure. Fish were distributed in two 1000-l indoor concrete aquaria supplied with a continuous flow (8 l min(-1)) of well water. The cadmium concentration was maintained at 53 microg l(-1) in one aquarium and 443 microg l(-1) in the other aquarium for 127 days. The exposure phase was followed by a 43-day depuration period. The cadmium accumulation in liver, kidney and muscle was measured by means of ICP-MS. The data showed that cadmium exposure produces significant cadmium uptake in tissues. Cadmium concentrations increased sharply in kidney and liver, whereas the pollutant level in muscle was only significant after 106 days. After 127 days of Cd exposure (53 microg l(-1)), the cadmium concentration in kidney was 4-fold higher than in liver and 50-fold higher than in muscle for a toxic level of 53 microg l(-1). At a Cd of 443 microg l(-1), kidney cadmium content was 2-fold higher than in liver and 100-fold higher than in muscle. In kidney and liver, the toxic concentration increased as the concentration of pollutant in water increased. During the 43 depuration days, the loss of accumulated cadmium was rapid and immediate in muscle. Conversely, no loss of cadmium was observed in kidney and liver.

Geographical variation of cytochromebmitochondrial DNA (mtDNA) in chub (Leuciscus cephalusL.) was analysed in 31 samples from 20 different river basins in the Balkan Peninsula and Danube catchment. Multivariate methods of ordination were used to analyse variation of the data sets. The results were interpreted in the context of the proposed ichthyogeographic districts separating the Balkan Peninsula into two main ichthyogeographic divisions (Eastern Greece/Ponto-Aegean and Western Greece/South Adriatic-Ionian). Boundary detection supported these two ichthyogeographic districts forL. cephalus, revealing a boundary that ran from north to south through the Balkan Peninsula and the middle of Greece. The results also revealed the existence of a third division in Central Greece. The results of ordination techniques on homogeneous zones and analysis of the molecular variance confirmed the results obtained in studying local variability (boundaries). They also allowed us to test the existence of possible subdivisions proposed by different authors inside the two main ichthyogeographic districts. These subdivisions were not supported. The multivariate methods used in this study allowed us to propose a coherent picture of chub ichthyogeographic districts in terms of boundary detection and maximal autocorrelation between populations and to explain the patterns of chub mtDNA variation. A complete interpretation of results concerningL. cephalusrequires careful consideration of both boundary analysis and autocorrelative approach. Results from an the autocorrelative approach alone could lead to substantial misinterpretations.

A phylogeographic analysis of mitochondrial DNA variation was performed in order to test the hypothesis of a postglacial recolonization of mid‐ and north‐European rivers from a Danubian refuge. Over 345 chub specimens from European rivers covering most of the species’ native range were investigated using 600 bp of the cytochrome b gene. Chub in European rivers belong to four highly divergent mitochondrial groups (lineages) differing by mean divergence estimates from 5.2% to 7.89%. These four lineages have a largely allopatric distribution, implying four geographical sets: two Mediterranean, and two north‐European sets. This pattern provided strong evidence for: (i) the eradication of this species from most of Europe during maximum ice extent; (ii) its survival in four refugia (Adriatic side of the Balkans, eastern Greece (Aegean Rivers), southern tributaries of the Danube, and periphery of Black and Caspian Seas); (iii) a differential postglacial recolonization of mid‐ and northern Europe from the last two refugia only; (iv) the occurrence of this recolonization in two steps for the Danubian (western) lineage that entered western Europe (Rhine–Rhone–Loire drainages) during the Riss–Würm interglacial period and survived the last glaciation there before colonizing Garonne, UK and German drainages up to the Elbe during the Holocene; and (v) the occurrence of this recolonization in a single step for the Ponto‐Caspian (eastern) lineage that entered the Baltic area as far as the Oder in the Holocene. Both lineages came into contact in the River Elbe without evident mixing.

The aim of this investigation was to compare the genetic responses of two common cyprinids, chub (Leuciscus cephalus) and roach (Rutilus rutilus), to various habitat and pollution regimes within the same river basin, the Rhone, using allozyme data. Over the three main portions of the River Rhone, lower genetic polymorphism and lower heterozygosity were detected for the chub in the Saone, which is characterized by lower environmental diversity than in the Lower and Upper Rhone. On a local scale, no detectable decrease in polymorphism or heterozygosity was observed in populations of both species living in heavily polluted sites of the Rhone's Chemical Corridor. Significant differentiation was detected between populations of both chub and roach localized upstream and downstream from the dams of Donzère Mondragon, which were erected 45 years ago. The F statistics and neighbor-joining analysis of genetic distances suggested that the Upper Rhone populations were unique in comparison with the other populations for both species; this situation could be the result of historical factors and (or) a selective pressure in a variable environment. Isolation by distance was observed for chub in the less perturbed river system over a range of 100 km. By contrast, there was no relationship between geographic distance and genetic distance for roach, whatever the subsystem tested.

The phylogenetic and systematic relationships among 12 populations of Greek chub (Leuciscus cephalusL.) were investigated using RFLP analysis of two PCR-amplified mtDNA segments (D-loop and cytochrome b). Three out of eight, and nine out of ten restriction enzymes were polymorphic for D-loop and cytochrome b, respectively. Twenty-one different haplotypes were detected. Estimated nucleotide sequence divergence among the 21 genotypes ranged from 0.313 to 6.79%; the mean value of sequence divergence among populations was 3.421±0.00%. The calculated NST value of 0.94, indicates high interpopulation diversity. Dendrograms based on haplotypes as well as those of populations, support the previous recognition of different subspecies, but these mtDNA data are not concordant with previous allozyme data among these fish. Our results suggest that to clarify phylogenetic relationships multiple genetic systems need to be examined.

Phylogenetic relationships between European cyprinids (Teleostei:Cypriniformes:Cyprinidae) were investigated by comparing cytochrome b gene sequences from 29 species, among which 20 were newly sequenced. Results were in general agreement with previous morphologically-based studies, but new interesting relationships were found. The classical barbelled/lacking barbels split is dubious. Genus Leuciscus appears paraphyletic. The phylogenetic location of some American cyprinid species was recovered; at least two distinct invasions of the New World are likely. Finally, the problem of intergeneric cyprinid hybrids is addressed. The genus rank for these interbreeding entities is supported and hybrids are seen as the consequence of a high genetic flexibility. This is the first molecularly based study of cyprinid diversity. It sheds light on the evolution and taxonomy of this major freshwater fish family.

Populations of cyprinid fishes from several rivers in Portugal - Chondrostoma polylepis, France - European chub Leuciscus cephalus, roach Rutilus, rutilus, Austria - nase Chondrostoma nasus, R, rutilus and Greece - L. cephalus were investigated by allozyme electrophoresis to assess the effects of river engineering on their genetic diversity. No effects of dams on genetic variability were apparent in most places; this may be explained either by the permeability of dams to fish dispersal, by recent dates of isolation, and/or by the fact that the populations were large enough for genetic drift not to take place. However, a change in genotype structure caused by the darns may be suspected in the Lower Rhone. The chub and roach populations of the reservoirs and residual flow stretches show affinity with upstream lentic populations and not with upstream lotic populations as would be expected according to the mean gradient of their habitats. They are unstable populations in which extinction and colonisation from lentic upstream habitats presumably determine genetic structure.

Phylogenetic relationships between European cyprinids (Teleostei:Cypriniformes:Cyprinidae) were investigated by comparing cytochrome b gene sequences from 29 species, among which 20 were newly sequenced. Results were in general agreement with previous morphologically-based studies, but new interesting relationships were found. The classical barbelled/lacking barbels split is dubious. Genus Leuciscus appears paraphyletic. The phylogenetic location of some American cyprinid species was recovered; at least two distinct invasions of the New World are likely. Finally, the problem of intergeneric cyprinid hybrids is addressed. The genus rank for these interbreeding entities is supported and hybrids are seen as the consequence of a high genetic flexibility. This is the first molecularly based study of cyprinid diversity. It sheds light on the evolution and taxonomy of this major freshwater fish family.

Allozyme variation in Chondrostoma from Austrian, French and northern Creek rivers was investigated. Populations of C. nasus from the upper Danube catchment are genetically very similar and apparently connected by high levels of gene flow. Chondrostoma nasus has conserved all major allozyme polymorphisms during its recent range expansion into the Rhone basin. Chondrostoma vardarense from the Aries and Aliakmonas rivers share most of their allozymes with C. nasus from the upper Danube catchment, but have less genetic variation, a possible consequence of a genetic bottleneck following river capture.

To investigate phylogenetic relationships amongLeuciscusspecies occurring in Portuguese inland waters, the cytochromebgene was sequenced from representatives of the main rivers. This study supports the recognition of the species level forL. pyrenaicus,including populations from the southern Portuguese drainages (Tejo, Sado, and Guadiana drainages), and forL. carolitertii,including populations from the northern Portuguese drainages. The existence of two new species occurring in the extreme southwestern drainages of Mira and Arade is also suggested. The present results support the monophyly of the Mira and the Arade populations, as well as an early divergence of these two lineages. The present-day distribution ofLeuciscusspecies is seen as a consequence of Pliocene and Pleistocene events, such as river disjunctions and posterior confluence in epicontinental seas and river captures. A mixture of haplotypes was observed in the Mondego and the Tejo drainages, which could be a consequence of ancient river captures, with a possible mitochondrial DNA introgression in the Tejo drainage and a recent introduction by man in the Mondego drainage. The pattern of differentiation among mtDNA haplotypes and their geographic distribution is discussed in terms of evolutionary aspects.

Starch‐gel electrophoresis was used to examine genetic differentiation at four polymorphic loci in the European chub Leuciscus cephalus from 27 samples and three main areas of the Rhone River basin in France. The Upper Rhone samples appeared to be genetically distinct at locus PGM‐2* from the Lower Rhone and Saone‐Grosne samples according to the constant row total‐multiple correspondence analysis (CRT‐MCA), which allowed the estimation of multivariate Fst equivalents. No difference between Lower Rhone and Saone‐Grosne samples was revealed by the global analysis considering the three areas. However, distinct local analyses in the three areas showed that the spatial structure of genetic variability was dissimilar in these last two areas, suggesting a non‐equilibrium process under the influence of dams in the Lower Rhone, and isolation by distance in Saone system. Isolation by distance was also suggested for the Upper Rhone samples.

Overall heterozygosity was high in all roach populations, and so was gene flow between them. However, genetic diversity was greater in the fast-flowing and more diverse French Upper Rhone than in the uniformly lentic River Saone. Rhone backwaters may be considered as ecotones and reservoirs of genetic diversity, but such is not the case in the Saone owing to the uniformity of the environment.