Ouverture Commerciale, Croissance Economique et Environnement au Cameroun : Une Etude Empirique de la Courbe Environnementale de Kuznets

The objective of this paper is to examine the effects of economic growth and the trade openness on the quality of the environment. Pesaran’s et al (2001) Auto-Regressive Distributed Lags (ARDL) was applied on the macroeconomic data of Cameroon dating from 1971 to 2011. The results reveal that: the economic growth induces a deterioration of the environment in the short-term but improves it in the long-term while the trade openness deteriorates the environment in Cameroon.L’objet de ce papier est de déterminer les effets de la croissance économique et de l’ouverture commerciale sur la qualité de l’environnement. La méthode de cointégration par les retards échelonnés ou Auto Regressive Distributed Lags (ARDL) développée par Pesaran et al. (2001) a été appliquée sur les données macroéconomiques du Cameroun sur la période allant de 1971 à 2011. Les résultats révèlent que : la croissance économique induit la détérioration de l’environnement à court terme, mais l’améliore à long terme tandis que l’ouverture commerciale détériore l’environnement au Cameroun

Evaluation of 99 pesticide residues in major agricultural products from the Western Highlands Zone of Cameroon using QuEChERS method extraction and LC-MS/MS and GC-ECD analyses

There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p'-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysis

Calcium platinum aluminium, CaPtAl

A preliminary X-ray study of CaPtAl has been reported previously by Hulliger [J. Alloys Compd (1993), 196, 225–228] based on X-ray powder diffraction data without structure refinement. With the present single-crystal X-ray study, we confirm the assignment of the TiNiSi type for CaPtAl, in a fully ordered inverse structure. All three atoms of the asymmetric unit have .m. site symmetry. The structure features a ∞ 3[AlPt] open framework with a fourfold coordination of Pt by Al atoms and vice versa. The Ca atoms are located in the large channels of the structure

Monitoring and dietary risk assessment of 81 pesticide residues in 11 local agricultural products from the 3 largest cities of Cameroon

This study monitored 81 pesticides residues in 160 samples of 11 dry agricultural products collected in the 3 largest cities of Cameroon, extracted using QuEChERS method and analysed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Residues of 58 (71.6%) compounds were found in the samples, the most distributed pesticides were Imazalil, Triadimenol and Pyrimethanil, and those with the highest average concentrations were Cymoxanil, Thiamethoxam and Thifensulfuron. Half of the positive pesticides were above their European Union maximum residue limits (MRLs) among which Carbaryl, Carbofuran, Malathion, Metalaxyl and Propoxur are pesticides banned in the country. All the 11 food items contained pesticides, the highest contamination rates (12.8%–5.0%) were found in white pepper, maize, Egusi seeds and groundnuts, while groundnuts, Egusi seeds, maize and soybeans showed the highest residue concentrations (1.46–1.37 mg/kg). Pesticide contamination rates were similar in the 3 sampling cities, but Bafoussam and Yaounde had more samples above the MRLs than Douala. Using the food consumption data for Cameroon from the recent Sub-Saharan Africa Total Diet Study, dietary exposure was calculated and potential health risk of Cameroonian consumers was evaluated. Hazard quotient of Carbofuran in groundnuts was 22% above the safe value, the remaining food items could be considered safe for individual pesticide residues, although Triazophos and Metribuzin in maize were of concern. Groundnuts (0.531) and maize (0.443) showed high hazard index, with 17 highly contributing compounds, but there is no reason to be concerned about cumulative exposure to residues from the food items. While the food items are in general safe to eat, to minimize the increasing human health risk of consumers and ensure approval of Cameroon export produces on international market, this study suggests that authorities must regulate the usage of agrochemicals, strengthen the controls for effective implementation of the pesticide bans and implement strong control of obsolete pesticide stocks in the country