241 research outputs found
Les leçons d'un échec : la culture attelée en pays Mossi (Haute-Volta)
Rémy Gérard. Les leçons d'un échec : la culture attelée en pays Mossi (Haute-Volta).. In: Cahiers d'études africaines, vol. 12, n°47, 1972. SystÚmes agraires africains. pp. 512-519
L'enquĂȘte dĂ©mographique Ă passages rĂ©pĂ©tĂ©s
RĂ©my GĂ©rard. L'enquĂȘte dĂ©mographique Ă passages rĂ©pĂ©tĂ©s.. In: Cahiers d'Ă©tudes africaines, vol. 12, n°47, 1972. SystĂšmes agraires africains. pp. 520-523
Une étude de terroir en Afrique noire : méthodes et techniques
Rémy Gérard. Une étude de terroir en Afrique Noire. Méthodes et techniques. In: Cahiers d'études africaines, vol. 6, n°21, 1966. pp. 121-129
Total mercury concentrations in an industrialized catchment, the Thur River basin (north-eastern France): geochemical background level and contamination factors
River bottom sediments and soils were collected from the industrialized Thur River basin (north-eastern France) to assess mercury contamination. The regional geochemical background level of total mercury was evaluated to calculate mercury contamination factors (Fc) in soils and river bottom sediments. Our estimate of the mean background mercury levels in river sediments and soils, not affected by human activities, was 232 ng g1 (range: 27â406 ng g1). Sediments contaminated by the effluent from a chlor-alkali plant yielded the highest contamination factors (FcÂŒ1784). Contamination factors of surficial soils within 1 km of the industrial site range from 6.3 to 43.6. This contamination is attributed to diffuse atmospheric deposition from this local plant. However, even upstream from this industrial area elevated contamination factors were recorded for river bottom sediments (FcÂŒ3.2 to 26.4) and for one alluvial soil profile (FcÂŒ10). This is possibly due to past pollution resulting from waste water discharges. Mercury contamination in the different horizons of alluvial soils is not correlated with soil organic carbon content, but may be the result of occasional accidental pollution arising from the introduction of contaminated suspended particulate matter by the Thur River during periods of flooding
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