The dry formulations of agrochemicals reduce the difficulties related to transport and exposure of users. Nevertheless, these products do not exclude drawbacks and their use requires a deeper knowledge of their toxicological and ecotoxicological effects. The purpose of this work was to study the acute toxicity and reproductive toxicity of glyphosate-based RAPID MAX 750 WG and TAKO-KELE 757 SG on the earthworm Eudrilus eugeniae, ubiquitous in tropical area. Lethality tests were conducted according to EPS1/RM/43, MA.500-VTL1.0, and OECD guideline 207 Methods. LC50 of RAPID MAX were (1687.56±50.53 mg of glyphosate (a.e.) /kg of soil (DW) for adult earthworms and 1416,99±53,06 mg of glyphosate (a.e.) /kg of soil (DW) for juvenile earthworms. LC50 of TAKO-KELE 757 SG were 2215.66±61.83 mg of glyphosate (a.e.) /kg of soil (DW) and 1658.62±38.72 mg of glyphosate (a.e.) /kg of soil (DW), respectively for adult and juvenile earthworms. Juvenile and adult earthworms were more sensitive to RAPID MAX 750 WG compared with TAKO-KELE 757 SG, as LC50 related to RAPID MAX 750 WG were lower than those of SG TAKO-KELE 757 SG. The acute toxicity (lethality) of both herbicides was more severe on juvenile earthworms.

The observation of the coast on the level of Vridi Ako lets appear several old barriers of beach. Four (4) wells were dug on one of these barriers of beach in order to know its lithology and the grain size of sediments. Moreover, a mineralogical and morphoscopy analysis of sands was made. The lithology is characterized by an alternation of layers of color yellowish gray and olive gray with the appearance of a surface of white color. These layers consist of sands whose average of sizes varies between 0.470 and 1.269 mm. these are essentially of coarse sands, good enough classified at very well classified. The mode (Mo) indicates that the shape of the graph is bimodal. This shows that there are two sources suppliers of sediments (hinterland and continental shelf). There is also the following mineral: the sphene, the rutile, the anastase, tourmaline, and unspecified minerals. The quartz grains are primarily very round to sub-angulous with as a whole a shining blunted aspect.