Impact De L’exploitation Artisanale De La Sabliere De Toutsang Sur La Structure Des Communautes De Macroinvertebres Du Cours D’eau Doulahang A Dschang (Ouest Cameroun)

The impact of wastewaters from the Toutsang sandpit (Dschang), both on water parameters and on benthic macro-invertebrate community structure of the Doulahang stream was studied from March 2015 to February 2016 on a monthly basis in three sampling stations named TS1, TS2 and TS3. The physico-chemical analysis were carried out according to standard protocols while the benthic macro-fauna was harvested using a haze net of 30 cm side and 400 μm mesh size. The analysis of physico-chemical parameters revealed that the introduction of wastewater from the sandpit at the TS2 station led to an increase of the temperature, conductivity, total dissolved solids, salinity, suspended matter, turbidity and colour. The wildlife inventory identified 63 taxa divided into 4 phyla, 6 classes, 13 orders and 31 families. The lowest values of the taxonomic richness (18 taxa, against 46 taxa and 47 taxa respectively to stations TS1 and TS3), the Shannon diversity index (2.48 bits / ind.) and the Pielou's evenness (0.62) were observed at station TS2 which received wastewaters from the sandpit. Similarly, the low values of the richness and abundance of the pollutionsensitive groups (Ephemeroptera-Trichoptera-Odonata) were recorded in this station. Significant negative correlations were found between some metrics (total taxonomic richness, taxonomic richness of the Diptera, Richness of Ephemeroptera-Trichoptera-Odonata, Taxonomic richness of insects, Relative abundance of Ephemeroptera-Trichoptera-Odonata, Shannon Weaver diversity index, Pielou's evenness) descriptors of the structure of benthic macro-fauna communities and physico-chemical parameters indicative of physical pollution such as turbidity, suspended matter and colour

Bioévaluation De La Qualité Des Eaux Du Cours D’eau Menoua En Zone Périurbaine De Dschang, Ouest Cameroun

We conducted a study to assess the impact of peri-urban agricultural activities of the city of Dschang on the water quality and macroinvertebrate structure of the Menoua stream. This study covered 3 stations (one reference station at the upstream of the peri-urban agricultural activities and two downstream) with a monthly sampling frequency from March 2015 to February 2016. The physico-chemical analysis were carried out according to standard protocols while the benthic macro-fauna was harvested using a haze net of 30 cm side and 400 μm mesh size. Physico-chemical parameters such as temperature, pH, conductivity, TDS (Total Dissolved Solids), salinity, turbidity, colour, SS (Suspended Solids), nitrate, ammonium and orthophosphate were analyzed. The inventory of benthic macroinvertebrates revealed a taxonomic richness of 42 families and 77 taxa and a gross abundance of 1833 individuals. Spatio-temporal monitoring of physicochemical and biological parameters provided the image of relatively low pollution. Metrics such as total taxonomic richness, richness of ETO (Ephemeroptera-Trichoptera-Odonata), relative abundance of Ephemeroptera-Trichoptera-Odonate (% ETO), diversity of Shannon and Weaver and Pielou's equitability were determined at each of the three stations. These indices, unlike several other studies, increased downstream of anthropogenic activities. Low agricultural activity in the watershed has resulted in habitat diversification and availability of resources for benthic macroinvertebrates, resulting in increased abundance and diversit

Environmental and Human Health Assessment in Relation to Pesticide Use by Local Farmers and the Cameroon Development Corporation (CDC), Fako Division, South-West Cameroon

Pesticides are widely used to reduce crop losses due to pests. This study (an initial part of a project on risk assessment and biomonitoring) deals with pesticide use patterns in the South-West, Cameroon. This descriptive and cross-sectional study was done using questionnaires randomly administered to 137 respondents. Twenty-one crops were recorded in the area with a total of 107 pesticides (60 active ingredients) used. Three illegally used pesticides were recorded (lindane, dimethoate and malathion). Application of pesticides in combination was quite common (42.3%). Pesticide application was mainly manual using a sprayer (96.4%) with 54% of users experiencing health problems post-application. Because of the lack of funding and training, 19.7% sprayed pesticides without protection. For the Restricted Entry Interval (REI), 43.1% entered the field in less than 12h after pesticide application. The correlation between the REI and the number of symptoms was negative and non-significant (R=-0.07, p≥0.05). The main place to store pesticides was the house (57.7%) with the exception of CDC where pesticides were kept in a pesticide store. Some respondents (54.7%) said they hadn’t received any training on pesticide application while 20.4 % of respondents failed to follow recommended doses. Surface water around farms was used by 62.1% of pesticides users for domestic purposes. Some farmers (46.7%) have once heard about pesticide related accident while 14.6% suffered from pesticide intoxication, the prevalence being significantly higher in males (p<0.05). Therefore, there is a need to regulate the pesticides sector, assess ecological risk and the bioaccumulation potential of these pesticides as well as their ability to hindrance water quality and biota

Comparison of metal bioaccumulation in crop types and consumable parts between two growth periods

A high proportion of populations in most developing countries live below the poverty line and those near refuse grounds resort to dumpsite farming to grow food. Consequently, high levels of waste‐derived contaminants are found in crops consumed by these people. This study investigates the extent to which crops cultivated on the Mbale dumpsite (Uganda) were contaminated by 11 metals and 2 non‐metals: iron (Fe), aluminum (Al), zinc (Zn), manganese (Mn), copper (Cu), mercury (Hg), lead (Pb), nickel (Ni), cobalt (Co), cadmium (Cd), selenium (Se), chromium (Cr), and arsenic (As). We investigated how element bioaccumulation in crops was influenced by the growth period (short‐ and long‐term crop maturity). The short‐term crops were Zea mays and Amaranthus cruentus, whereas the long‐term crops were Manihot esculenta, Colocasia esculenta, Musa acuminata, Carica papaya, Coffea arabica, and Saccharum officinarum. Results showed that nine metals were present at concentrations above World Health Organization/Food and Agriculture Organization (WHO/FAO) food safety recommendations and hence may pose health risks to consumers. In this study, leaves contained higher metal concentrations than other analyzed consumable parts. Pb and Co were found at higher concentrations in leaves of short‐term crops than in long‐term crops. Among short‐term crops, only Z. mays seeds contained permissible metal concentrations by WHO/FAO standards. The growth period was also found to influence metal bioaccumulation in crop types. Pb, Co, Fe, Al, and Cu concentrations were significantly higher in the short‐term crops than in long‐term crops, while Mn, Ni, and Cr concentrations were higher in long‐term crops than in short‐term crops. Overall, public awareness about the health risks associated with consuming short‐term leafy crops grown on dumpsites should be improved to reduce toxic metal exposure. While implementing such a campaign, the food supply of individuals whose survival depends on such crops should not be jeopardized. Therefore, farmers need alternative farming areas outside dumpsites. Integr Environ Assess Manag 2022;18:1056–1071. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC)

Assessment of Chemical Pollution With Routine Pesticides Using PRIMET, a Pesticide Risk Model in the Benoe Stream in the South-West Region of Cameroon

Widespread extensive and improper application of pesticides may pose risk to aquatic ecosystem and affect non-target organisms. This study aimed at assessing chemical pollution with pesticides using the PRIMET (Pesticides Risks in the tropics to Man, Environment and Trade) model in the Benoe stream. Ecotoxicological data on pesticides, pesticide and water physico-chemistry were used as input parameters. Water parameters were measured monthly for 06 months in 08 sampling points along the stream. Pesticide characteristics were obtained from the Pesticides Properties Data Base (PPDB) and the PRIMET software. The risk assessment was done for 44 active ingredients used in the area and whose ecotoxicological and physico-chemical data were available. Water parameters significantly (p<0.05) varied across seasons. Based on the Exposure Toxicity Ratio (ETR) and the Predicted Exposure Concentration (PEC), the model predicted 09 pesticides to pose a definite acute risk (ETR>100), seven to pose an acute possible risk (1≤ETR≤100) and 28 to pose no risk (ETR<1). Cadusafos (ETR=5200, PEC=39µg/l) was the most risky pesticide while imazalil (ETR=0.0002, PEC=0.0053µg/l) was the least risky compound. Cypermethrin was predicted to pose both definite acute risk to water and possible chronic risk to fish, water and Daphnia. Seven active ingredients were predicted to pose possible chronic risk to Daphnia. Pesticide used in plantations near water bodies is a threat to the aquatic ecosystem augmented in case of misuse. Bioaccumulation potential and impact of these compounds on water quality and biota community structure should be examined