L’étude porte sur l’analyse des pratiques, des attitudes et des connaissances des maraîchers par rapport à l’utilisation des pesticides au Togo. Elle a couvert les cinq (5) régions administratives du pays par une enquête auprès de 297 maraîchers. 98 % des maraîchers interrogés admettent que l’emploi des pesticides permet de réduire les pertes liées aux ravageurs et d’assurer un bon rendement. Cependant, la décision d’effectuer les traitements phytosanitaires et les moments de traitement diffèrent d’un maraîcher à un autre et d’une région à l’autre. Les modes d’utilisation et les délais de carence ne sont pas maîtrisés. Les maraîchers en majorité peu formés (14 %) n’ont pas une bonne connaissance des doses d’application et des fréquences de traitement. Ils sont peu convaincus des risques directs qu’ils encourent et de ce fait se protègent rarement.

About 2.5 million t of sedimentary phosphorite mine tailings, highly enriched with Cd, Cr, Cu, Ni, Fe, F, and Zn, are dumped annually in the coastal waters of Togo without any pre-treatment, causing serious pollution problems in the region. We conducted bioaccumulation investigations on fish and crustaceans sampled from the polluted coastal zone. The highest concentrations of metals in fish and crustacean were found close to the tailings outfall and the values decreased further away from the source of pollution. Compared to the international reference norms for seafood given by the WHO, Cd is enriched 10 to 168 fold, Pb 20 to 107 fold, Cu up to 5 fold, Fe up to 15 fold, and F up to 3 fold.

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Surface sediments of the lagoons of Lomé, Togo, were analyzed for mercury, methylmercury, and trace elements. Concentrations were greater than typical for natural lagoon sediments, and with greater variability within the Eastern lagoon compared to the Western one. The Eastern lagoon is larger and has been dredged in the past, while the Western lagoon, which also receives major waste inputs, has not been dredged and shows less tidal flushing. Accordingly, one naturally believes that the Eastern lagoon is cleaner and probably safe to use due to its natural resources, including fishes to eat. Unexpectedly, we describe here that mercury methylation was greater in the Eastern lagoon, indicating increased bioavailability of mercury, as probably facilitated by past dredging that decreased solidphase retention of inorganic mercury. Urbanization has historically been more developed in the southern part of the lagoons, which is still reflected in contamination levels of sediment despite dredging, probably because sources of contamination are still more important there today. Such urban contamination emphasizes the need to regulate waste discharges and possible airborne contamination in growing cities of developing countries, and implements environmental and public health monitoring, especially in relation to misbelieves systematically associated with the cleansing effect of dredging activity.