China’s economy has enjoyed a long period of explosive growth, making it one of the world’s largest.
Ce papier analyse l’impact de la croissance économique sur les émissions de dioxyde de carbone (ECO2) dans les pays de la zone de l’Union Économique et Monétaire Ouest Africaine (UEMOA) sur la période 1995 à 2021. Après des tests de racine unitaire et de cointégration, nous avons trouvé qu’il existe une relation de long terme entre le logarithme des émissions de dioxyde de carbone (LECO2) et les variables explicatives. En utilisant l’estimateur Pooled Mean Group sur plusieurs séries de régressions et avec un panel dynamique, nos résultats montrent un impact positif et significatif du Produit Intérieur Brut et de la consommation en énergies fossiles sur les émissions de CO2 et nous obtenons une validité empirique d’une courbe en « U » inversé ou Courbe Environnementale de Kuznets (CEK), lorsque nous considérions l’hétérogénéité entre ces États, la relation reste positive pour la Côte d’Ivoire et négative pour le Mali. Ainsi, pour éviter ou atténuer l’impact de la croissance et de l’utilisation des énergies fossiles sur les ECO2, les gouvernements et les acteurs qui œuvrent pour la préservation de la qualité de l’environnement doivent (i) recourir à des technologies additives dans le processus de production ; (ii) réduire l’utilisation des combustibles fossiles et se tourner vers les énergies renouvelables qui émettent moins de polluants dans l’atmosphère ; et (iii)encourager l’innovation verte avec les subventions pour la recherche-développement (R-D), la facilitation de la substitution entre technologies polluantes et technologies propres et le recours à une taxe carbone.
This study evaluating marine biotoxins contamination level of mussel ( Perna Perna ) in the Mamelles Bay (Ouakam) of Dakar is the first report in Senegal. It took place over one year (from March 2018 to February 2019). Liquid chromatography with mass spectrometry (LC-MS-MS) reference method (Regulation (EC) 15/2011 of 10 January 2011) was used to quantify marine biotoxins. Okadaic acid (OA) and its esters are the most problematic of all the researched biotoxins. They are present throughout most of the year, except September and November, with an average monthly concentration of 163 µg/kg, slightly above the regulatory limit (160 µg/kg). The sanitary status of the mussel shows two peaks of contamination, the first of which occurs in the rainy season (August) and the second in the cold season (December), with values equal to 654 and 802 µg/kg respectively 4 to 5 times higher than the regulatory threshold set by Regulation (EC) No 853/2004 of 29 April 2004 supplemented by Regulation (EU) No 786/2013 amending its Annex III and Senegalese Order No 07951 of 12 May 2017. These two peaks coincide with (i) the wintering period, marked by continental land-based inputs due to rainwater runoff, but also with the temperature rise, or (ii) the cold period with the appearance of upwelling (upwelling of cold water, rich in nutrient salts). In addition to the chemical analyses carried out on the mussel, the research work on phytoplankton and the surveys of physicochemical parameters carried out on the water at the collection site show (i) the existence of toxic algae of the Dinophysis genus and Gambierdiscus , in June, i.e., one to two months before the first peak of contamination of the Perna perna by AO; (ii) also a coincidence between the appearance of these phenomena and variations in surface water temperature and salinity, which are determining factors in the appearance and development of harmful algal blooms. Concerning the other biotoxins investigated, in particular AZA and yessotoxins, it was noted that AZA was absent throughout the year, unlike yessotoxins, which were found in the flesh of Perna perna at concentrations below the regulatory limit set at 3750 µg/kg. The maximum being 51 µg/kg obtained in June, i.e., 73 times lower than the regulatory threshold. In the light of the results obtained, it appears that the periods of high contamination are the winter period and the upwelling period, which could lead to closure measures to guarantee the safety of the mussels. It would be interesting to extend the study to all other bivalve mollusks and gastropods, to carry out an inventory and quantify the toxic microalgae present in the water. To this end, the effectiveness of purification techniques would be tested. Keywords: Mussel ( Perna perna ), Marine biotoxins, Toxic microalgae, Mamelles, Dakar. DOI: 10.7176/FSQM/117-04 Publication date: July 31 st 2022
A research for eight weekswas conducted to evaluate the effect of substituting fish meal with local agricultural products in the diet of Nile Tilapia (Oreochromis niloticus).Three treatment dietaries were prepared. The dietary composition of the tested diets is as follows: A1/plant based-diet (Groundnut cake, sesame cake, millet bran, maize meal and 0% fish meal) A2/fishmeal partial replacement diet (Groundnut cake, sesame cake, millet bran, maize meal, and 10% fish meal) and A3/fishmeal based-diet (Groundnut cake, sesame cake, millet bran, maize meal, and 25% fish meal). All the diets were isoprotein and isolipidic diets. The initial average weight of the fish was 3.45±0.5g. The fishes were fed twice a day in triplicate for eight weeks. After the experiment, the final average weights were 4.97±0.5g, 5.43±0.5g, and 5.86±0.5g for A1, A2, and A3, respectively. There were significant differences (p < 0.05) among the three diets. The Feed Conversion Ratio (FCR) of juveniles fed on the A3 diet (1.77) was significantly better (lower) compared to A1 and A2 (3.41 and 2.59, respectively). The FCR of the fish fed diets A1 and A2 were not significantly different. The Specific Growth Rate (SGR), Individual Daily Growth (IDG), and relative average weight gain of juveniles fed on A3 and A2 diets were not significantly different. However, they were significantly higher (p < 0.05) than those of the A1 diet. There were no significant differences (p > 0.05)among all the diets for average weight gain and survival rate. This study revealed the possibility of partial but not total substitution of fishmeal by plant materials in the diet of 3.45g Oreochromis niloticus fingerlings considering both growth and economic factors.
