Metallic elements have various origins: natural and anthropogenic sources as geochemical, marine and atmospheric sources resulting from the fallout of pollutants emitted or dust raised and which are transported by wat...Metallic elements have various origins: natural and anthropogenic sources as geochemical, marine and atmospheric sources resulting from the fallout of pollutants emitted or dust raised and which are transported by water and air currents. Thus marine, brackish and fresh continental waters may have high metal concentrations. In addition, some essential metals can become toxic above certain concentration values in aquatic environments. The aquatic ecosystems of Cotonou channel and lake Nokoué receive the pollutants charges from the town cities of Cotonou, Abomey-Calavi and town hall of So Ava. The aim of this study is to analyze waters from Eighteen (18) stations identified in the two ecosystems (nine by ecosystem). The concentrations of magnesium (Mg), calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), beryllium (Be), aluminum (Al), strontium (Sr), molybdenum (Mo), silver (Ag), tin (Sn), barium (Ba), platinum (Pt), mercury (Hg), thallium (Tl), lead (Pb), thorium (Th) and uranium (U) were measured after acid digestion of the water samples using the inductively coupled plasma source mass spectrometer (ICP-MS). The results of the analyses indicate an unequal distribution of metals in the different ecosystems. However, atypical concentrations were observed at some stations of the lake and the channel. Magnesium, calcium and manganese have very high values in Lake Nokoué respectively at Ganvié market station GAN_M (2990 ± 105 mg/L), Ganvié center, station GAN_C (4991 ± 177 mg/L) and Lake middle station MLak4 (10662 ± 17.03 μg/L). On the other hand, iron, aluminum and strontium have very high concentrations in the Cotonou Channel respectively at Agbato station AGB (5236 ± 103 and 8289 ± 519 μg/L) and at the estuary station EST (6118 ± 68 μg/L). The concentrations were compared to wells and cborehole waters in sixth neighborhood of Cotonou. We have used statistical analyzers such as MANOVA which have made it possible to classify the waters and metals in the ecosystems studied compared to groundwater and Well water waters. We use hierarchical clustering on principal components to identify similarities between stations based on metal concentration with R software packages “FactoMineR” and “factoextra”. In general, we can conclude that most of the metals have an anthropogenic source except strontium and major elements (Ca and Mg) which could respectively provide from marine waters and geochemical sources.展开更多
This study focuses on air quality in southern Benin in order to show public authorities what the Beninese populations are exposed to for efficient decision-making. Two sampling campaigns were carried out, one in the w...This study focuses on air quality in southern Benin in order to show public authorities what the Beninese populations are exposed to for efficient decision-making. Two sampling campaigns were carried out, one in the wet period and the other in the dry season. The measurements were taken using a monitor called an “Air Quality Monitor”. For data processing, the multiple comparison methods of Dun (1961) and the Wilcoxon test were used. To maintain legitimacy, all spatial data were included in the official cartographic repository of Benin: WGS 1984, Transverse Mercator Universe Projection (UTM), Zone 31 North. The Moran statistic was used to measure the levels of spatial autocorrelation of the variables studied and to test the significance. In order to locate the spatial subsets, the local spatial association indices of Anselin Local Moran and Getis-Ord, Gi* were used. In terms of results, on the 13 monitoring sites and the 8 parameters chosen to determine air quality, we do not note any significant inter-seasonal difference. Of the eight parameters, only three parameters present spatial autocorrelation leading to predictions of ambient air quality over the entire study area based on the distance separating the points, namely, PM<sub>2.5</sub>, PM<sub>10</sub> and ambient air quality index (AQI). The localities affected by atmospheric pollution in South Benin are located in the south-western part of Benin, headed by Cotonou, which is heavily polluted by CO<sub>2</sub>, TCOV, PM<sub>10</sub> and PM<sub>2.5</sub>.展开更多
The present study focused on the chemical characterization of the watercourse of the Togbadji Lake wildlife ranch. The methodological approach followed is as follows: Bibliography review, Sampling campaign. The result...The present study focused on the chemical characterization of the watercourse of the Togbadji Lake wildlife ranch. The methodological approach followed is as follows: Bibliography review, Sampling campaign. The results obtained were the subject of descriptive statistics, the two-sample Wilcoxon test to determine the impact of different localities on the abundance of microbiological contaminants, a Principal Component Analysis (PCA) with the software R version 3.5.0, in order to group the pollution parameters according to the different levels and sources of contamination. From our results, it is found that the respective average values in dry and rainy seasons for ammonium ions are 0.38 ± 0.16 mg/L and 0.22 ± 0.03 mg/L;for nitrite ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for nitrate ions 3.72 ± 2.52 mg/L and 7.84 ± 4.91 mg/L;for total Kjeldahl nitrogen 1.27 ± 1.44 mg/L and 1.19 ± 1.49 mg/L;for orthophosphate ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for total phosphorus 0.04 ± 0.01 mg/L and 0.11 ± 0.23 mg/L;the chemical oxygen demand 93.36 ± 61.73 mg/L of O2 and 89.93 ± 66.11 mg/L of O2 and the biochemical oxygen demand over 5 days 25.50 ± 18.22 mg/L of O2 and 37 ± 33.15 of O2. It emerged that the main sources of pollution in Lake Togbadji are runoff water, discharges of various wastewater from artisanal activities, livestock farming and open defecation.展开更多
This study focuses on monitoring the exposure of populations in South Benin to atmospheric pollution. Thirteen (13) monitoring points were identified where the Air quality measurements were taken using autonomous elec...This study focuses on monitoring the exposure of populations in South Benin to atmospheric pollution. Thirteen (13) monitoring points were identified where the Air quality measurements were taken using autonomous electronic devices called “Air Quality Monitor”. Calibrated and turned on, the measuring device automatically determines the concentrations of carbon dioxide CO<sub>2</sub>, Total Organic Compounds, methanal (HCHO), particulate matter PM<sub>2.5</sub> and PM<sub>10</sub>, temperature in degrees Fahrenheit and relative humidity (RH). Per site, air pollution levels are recorded for 5 minutes every 30 minutes from 7 a.m. to 6 p.m. After the analyses, it appears that the carbon dioxide CO<sub>2</sub> contents vary from 400 to 1444 ppm with an average of 486.80 ± 184.3 ppm, the daily contents of Total Volatile Organic Compounds from 0.01 to 6 .91 mg/m<sup>3</sup> with a daily average of 0.36 ± 0.65 mg/m<sup>3</sup>, aldehydes from 0.005 to 3 mg/m<sup>3</sup> with an average of 0.05 ± 0.17 mg/m<sup>3</sup>, for particulate matter of diameters less than or equal to 2.5 μm (PM<sub>2.5</sub>) pollution levels vary between 5 and 173.8 μg/m<sup>3</sup> with an average of 21.5 ± 17.62 μg/m<sup>3</sup>. On the other hand, for PM<sub>10</sub>, the contents vary from 5 to 449.6 μg/m<sup>3</sup> with an average of 28.17 ± 31.74 μg/m<sup>3</sup>, the Air Quality Index (AQI) varies from 0, 3 to 243 with an average of 39 ± 33.16. From the results observed, it appears that the south-western part of South Benin is heavily polluted by CO<sub>2</sub>, Total Volatile Organic Compounds, PM<sub>10</sub> and especially PM<sub>2.5</sub> with the city of Cotonou at its head, in particular the Red Star crossroads, the Toyota crossroads and the crossroads after the friendship stadium. The impacts of this pollution could be significant on sensitive people such as the elderly, newborns and patients with acute and chronic respiratory illnesses.展开更多
文摘Metallic elements have various origins: natural and anthropogenic sources as geochemical, marine and atmospheric sources resulting from the fallout of pollutants emitted or dust raised and which are transported by water and air currents. Thus marine, brackish and fresh continental waters may have high metal concentrations. In addition, some essential metals can become toxic above certain concentration values in aquatic environments. The aquatic ecosystems of Cotonou channel and lake Nokoué receive the pollutants charges from the town cities of Cotonou, Abomey-Calavi and town hall of So Ava. The aim of this study is to analyze waters from Eighteen (18) stations identified in the two ecosystems (nine by ecosystem). The concentrations of magnesium (Mg), calcium (Ca), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), beryllium (Be), aluminum (Al), strontium (Sr), molybdenum (Mo), silver (Ag), tin (Sn), barium (Ba), platinum (Pt), mercury (Hg), thallium (Tl), lead (Pb), thorium (Th) and uranium (U) were measured after acid digestion of the water samples using the inductively coupled plasma source mass spectrometer (ICP-MS). The results of the analyses indicate an unequal distribution of metals in the different ecosystems. However, atypical concentrations were observed at some stations of the lake and the channel. Magnesium, calcium and manganese have very high values in Lake Nokoué respectively at Ganvié market station GAN_M (2990 ± 105 mg/L), Ganvié center, station GAN_C (4991 ± 177 mg/L) and Lake middle station MLak4 (10662 ± 17.03 μg/L). On the other hand, iron, aluminum and strontium have very high concentrations in the Cotonou Channel respectively at Agbato station AGB (5236 ± 103 and 8289 ± 519 μg/L) and at the estuary station EST (6118 ± 68 μg/L). The concentrations were compared to wells and cborehole waters in sixth neighborhood of Cotonou. We have used statistical analyzers such as MANOVA which have made it possible to classify the waters and metals in the ecosystems studied compared to groundwater and Well water waters. We use hierarchical clustering on principal components to identify similarities between stations based on metal concentration with R software packages “FactoMineR” and “factoextra”. In general, we can conclude that most of the metals have an anthropogenic source except strontium and major elements (Ca and Mg) which could respectively provide from marine waters and geochemical sources.
文摘This study focuses on air quality in southern Benin in order to show public authorities what the Beninese populations are exposed to for efficient decision-making. Two sampling campaigns were carried out, one in the wet period and the other in the dry season. The measurements were taken using a monitor called an “Air Quality Monitor”. For data processing, the multiple comparison methods of Dun (1961) and the Wilcoxon test were used. To maintain legitimacy, all spatial data were included in the official cartographic repository of Benin: WGS 1984, Transverse Mercator Universe Projection (UTM), Zone 31 North. The Moran statistic was used to measure the levels of spatial autocorrelation of the variables studied and to test the significance. In order to locate the spatial subsets, the local spatial association indices of Anselin Local Moran and Getis-Ord, Gi* were used. In terms of results, on the 13 monitoring sites and the 8 parameters chosen to determine air quality, we do not note any significant inter-seasonal difference. Of the eight parameters, only three parameters present spatial autocorrelation leading to predictions of ambient air quality over the entire study area based on the distance separating the points, namely, PM<sub>2.5</sub>, PM<sub>10</sub> and ambient air quality index (AQI). The localities affected by atmospheric pollution in South Benin are located in the south-western part of Benin, headed by Cotonou, which is heavily polluted by CO<sub>2</sub>, TCOV, PM<sub>10</sub> and PM<sub>2.5</sub>.
文摘The present study focused on the chemical characterization of the watercourse of the Togbadji Lake wildlife ranch. The methodological approach followed is as follows: Bibliography review, Sampling campaign. The results obtained were the subject of descriptive statistics, the two-sample Wilcoxon test to determine the impact of different localities on the abundance of microbiological contaminants, a Principal Component Analysis (PCA) with the software R version 3.5.0, in order to group the pollution parameters according to the different levels and sources of contamination. From our results, it is found that the respective average values in dry and rainy seasons for ammonium ions are 0.38 ± 0.16 mg/L and 0.22 ± 0.03 mg/L;for nitrite ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for nitrate ions 3.72 ± 2.52 mg/L and 7.84 ± 4.91 mg/L;for total Kjeldahl nitrogen 1.27 ± 1.44 mg/L and 1.19 ± 1.49 mg/L;for orthophosphate ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for total phosphorus 0.04 ± 0.01 mg/L and 0.11 ± 0.23 mg/L;the chemical oxygen demand 93.36 ± 61.73 mg/L of O2 and 89.93 ± 66.11 mg/L of O2 and the biochemical oxygen demand over 5 days 25.50 ± 18.22 mg/L of O2 and 37 ± 33.15 of O2. It emerged that the main sources of pollution in Lake Togbadji are runoff water, discharges of various wastewater from artisanal activities, livestock farming and open defecation.
文摘This study focuses on monitoring the exposure of populations in South Benin to atmospheric pollution. Thirteen (13) monitoring points were identified where the Air quality measurements were taken using autonomous electronic devices called “Air Quality Monitor”. Calibrated and turned on, the measuring device automatically determines the concentrations of carbon dioxide CO<sub>2</sub>, Total Organic Compounds, methanal (HCHO), particulate matter PM<sub>2.5</sub> and PM<sub>10</sub>, temperature in degrees Fahrenheit and relative humidity (RH). Per site, air pollution levels are recorded for 5 minutes every 30 minutes from 7 a.m. to 6 p.m. After the analyses, it appears that the carbon dioxide CO<sub>2</sub> contents vary from 400 to 1444 ppm with an average of 486.80 ± 184.3 ppm, the daily contents of Total Volatile Organic Compounds from 0.01 to 6 .91 mg/m<sup>3</sup> with a daily average of 0.36 ± 0.65 mg/m<sup>3</sup>, aldehydes from 0.005 to 3 mg/m<sup>3</sup> with an average of 0.05 ± 0.17 mg/m<sup>3</sup>, for particulate matter of diameters less than or equal to 2.5 μm (PM<sub>2.5</sub>) pollution levels vary between 5 and 173.8 μg/m<sup>3</sup> with an average of 21.5 ± 17.62 μg/m<sup>3</sup>. On the other hand, for PM<sub>10</sub>, the contents vary from 5 to 449.6 μg/m<sup>3</sup> with an average of 28.17 ± 31.74 μg/m<sup>3</sup>, the Air Quality Index (AQI) varies from 0, 3 to 243 with an average of 39 ± 33.16. From the results observed, it appears that the south-western part of South Benin is heavily polluted by CO<sub>2</sub>, Total Volatile Organic Compounds, PM<sub>10</sub> and especially PM<sub>2.5</sub> with the city of Cotonou at its head, in particular the Red Star crossroads, the Toyota crossroads and the crossroads after the friendship stadium. The impacts of this pollution could be significant on sensitive people such as the elderly, newborns and patients with acute and chronic respiratory illnesses.
