Seblework Mekonen

Pesticide residue evaluation in major staple food items of Ethiopia using the QuEChERS method: A case study from the Jimma Zone

Samples of maize, teff, red pepper, and coffee (green bean and coffee bean with pulp) were collected from a local market in the Jimma Zone, Ethiopia. Samples were analyzed for the occurrence of cypermethrin, permethrin, deltamethrin, chlorpyrifos ethyl, DTT and its metabolites, and endosulfan (α, β). In the analytical procedure, the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction methodology with dispersive solid phase extraction clean up (d-SPE) technique was applied. Validation of the QuEChERS method was satisfactory. Recovery percentages of most pesticides were in the range of 70% to 120%, with good repeatability (%relative standard deviationu2009<u200920). The limit of detection and limit of quantification varied between 0.001u2009µg/g and 0.092u2009µg/g and between 0.002u2009µg/g and 0.307u2009µg/g, respectively. The main pesticides detected were DDT, endosulfan, cypermethrin, and permethrin. All of the pesticides analyzed were detected in red pepper and green coffee bean. Residues of DDT in coffee pulp significantly differed (pu2009<u20090.01) from other food items except for red pepper. The concentration of pesticides in the food items varied from 0.011u2009mg/kg to 1.115u2009mg/kg. All food items contained 1 or more pesticides. Two-thirds of the samples had residues below corresponding maximum residue limits, and the remaining one-third of samples were above the maximum residue limits. These results indicate the need for a good pesticide monitoring program to evaluate consumer risk for the Ethiopian people.

Pesticide residues in drinking water and associated risk to consumers in Ethiopia

Access to safe and reliable drinking water is vital for a healthy population. However, surface water may be contaminated with pesticides because of the nearby agricultural areas as well as from household application. Water samples were collected from water sources in Jimma zone and Addis Ababa, Ethiopia. The extraction and clean up of the samples were undertaken using liquid-solid and liquid-liquid methods. Human exposure was assessed by calculating the estimated daily intake (EDI) of pesticides in water and compared with the acceptable daily intake (ADI) and the acute reference dose (ARfD). The mean concentrations of 2,4-D, malathion, diazinon and fenpropimorph were 1.59-13.90xa0μg/l and 0.11-138 µg/l in Jimma and Addis Ababa water sources, respectively. The residue level of some of the pesticides were above the European drinking water guide line values, which is an indication of an illegal use of pesticides in the study areas. Concerning human health risk estimation, there was no acute risk (EDIxa0<xa0ARfD). However, chronic risks to human health were observed from exposure to diazinon and fenpropimorph (EDIxa0>xa0ADI) for Jimma and Addis Ababa populations, respectively. A comprehensive monitoring is required to reduce the level of pesticide residues in the water and to minimize particularly the long term human health risks.

The Application of Predictive Modelling for Determining Bio-Environmental Factors Affecting the Distribution of Blackflies (Diptera: Simuliidae) in the Gilgel Gibe Watershed in Southwest Ethiopia

Blackflies are important macroinvertebrate groups from a public health as well as ecological point of view. Determining the biological and environmental factors favouring or inhibiting the existence of blackflies could facilitate biomonitoring of rivers as well as control of disease vectors. The combined use of different predictive modelling techniques is known to improve identification of presence/absence and abundance of taxa in a given habitat. This approach enables better identification of the suitable habitat conditions or environmental constraints of a given taxon. Simuliidae larvae are important biological indicators as they are abundant in tropical aquatic ecosystems. Some of the blackfly groups are also important disease vectors in poor tropical countries. Our investigations aim to establish a combination of models able to identify the environmental factors and macroinvertebrate organisms that are favourable or inhibiting blackfly larvae existence in aquatic ecosystems. The models developed using macroinvertebrate predictors showed better performance than those based on environmental predictors. The identified environmental and macroinvertebrate parameters can be used to determine the distribution of blackflies, which in turn can help control river blindness in endemic tropical places. Through a combination of modelling techniques, a reliable method has been developed that explains environmental and biological relationships with the target organism, and, thus, can serve as a decision support tool for ecological management strategies.

Risk of DDT residue in maize consumed by infants as complementary diet in southwest Ethiopia

Infants in Ethiopia are consuming food items such as maize as a complementary diet. However, this may expose infants to toxic contaminants like DDT. Maize samples were collected from the households visited during a consumption survey and from markets in Jimma zone, southwestern Ethiopia. The residues of total DDT and its metabolites were analyzed using the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) method combined with dispersive solid phase extraction cleanup (d-SPE). Deterministic and probabilistic methods of analysis were applied to determine the consumer exposure of infants to total DDT. The results from the exposure assessment were compared with the health based guidance value in this case the provisional tolerable daily intake (PTDI). All maize samples (n=127) were contaminated by DDT, with a mean concentration of 1.770 mg/kg, which was far above the maximum residue limit (MRL). The mean and 97.5 percentile (P 97.5) estimated daily intake of total DDT for consumers were respectively 0.011 and 0.309 mg/kg bw/day for deterministic and 0.011 and 0.083 mg/kg bw/day for probabilistic exposure assessment. For total infant population (consumers and non-consumers), the 97.5 percentile estimated daily intake were 0.265 and 0.032 mg/kg bw/day from the deterministic and probabilistic exposure assessments, respectively. Health risk estimation revealed that, the mean and 97.5 percentile for consumers, and 97.5 percentile estimated daily intake of total DDT for total population were above the PTDI. Therefore, in Ethiopia, the use of maize as complementary food for infants may pose a health risk due to DDT residue.

Effect of Household Coffee Processing on Pesticide Residues as a Means of Ensuring Consumers’ Safety

Coffee is a highly consumed and popular beverage all over the world; however, coffee beans used for daily consumption may contain pesticide residues that may cause adverse health effects to consumers. In this monitoring study, the effect of household coffee processing on pesticide residues in coffee beans was investigated. Twelve pesticides, including metabolites and isomers (endosulfan α, endosulfan β, cypermethrin, permethrin, deltamethrin, chlorpyrifos ethyl, heptachlor epoxide, hexachlorobenzene, pp-DDE, pp-DDD, op-DDT, and pp-DDT) were spiked in coffee beans collected from a local market in southwestern Ethiopia. The subsequent household coffee processing conditions (washing, roasting, and brewing) were established as closely as possible to the traditional household coffee processing in Ethiopia. Washing of coffee beans showed 14.63-57.69 percent reduction, while the roasting process reduced up to 99.8 percent. Chlorpyrifos ethyl, permethrin, cypermethrin, endosulfan α and β in roasting and all of the 12 pesticides in the coffee brewing processes were not detected. Kruskal-Wallis analysis indicated that the reduction of pesticide residues by washing is significantly different from roasting and brewing (P < 0.0001). However, there was no significant difference between coffee roasting and brewing (P > 0.05). The processing factor (PF) was less than one (PF < 1), which indicates reduction of pesticides under study during processing of the coffee beans. The cumulative effect of the three processing methods has a paramount importance in evaluating the risks associated with ingestion of pesticide residues, particularly in coffee beans.

Physicochemical and Biological Characteristics of Two Ethiopian Wetlands

Wetlands serve as important natural resources and play a major eco-hydrological role in environmental management. However, information about the potential anthropogenic threats to Ethiopian wetlands is lacking; therefore an investigation was conducted to assess the physicochemical and biological characteristics of two Ethiopian wetlands. The results clearly suggest that there is a high level of anthropogenic threats to both the wetlands. The more intense agricultural practices and waste discharge was closely associated with higher phosphate concentration and low level of dissolved oxygen (DO). The biological analysis reveals a notable reduction of the diversity of macroinvertebrates in the downstream direction. Kitto wetland has significantly better MI diversity than Boye (p-valueu2009<u20090.05). Overall, Boye wetland was relatively more polluted than Kitto due to intensive pollutant input mostly from the Jimma Town as well as intensive agriculture related practices around the Boye wetland excepts downstream site B3 which was furthest away from human activity. Protecting wetlands from anthropogenic threats is one of the major concerns in developing countries. This can be achieved by creating awareness among people by employing appropriate communication strategies about the importance of wetlands. In addition, intensive surveillance and monitoring programmes could pave the way to address the current catastrophe in the near future.

Are cosmetics used in developing countries safe? Use and dermal irritation of body care products in Jimma town, southwestern Ethiopia

Background. Rabbit skin model was used to test skin irritation of the most commonly used cosmetic products in Jimma town, southwestern Ethiopia. The most commonly used cosmetics were Dove, Glysolid, College, Top Society, Fair and Lovely, Nivea, Lux, Magic fruit world, Solea, Body talk, Kris, Holly, Victoria, and Sweet Heart. Methods. Intact and abraded rabbit skins were tested for erythema and edema under shade and under sun exposure. Draize Primary Irritation Index (PII) was used to calculate skin irritation of each cosmetic. Cosmetic ingredients were analyzed from the labels. Results and Discussion. Only Dove cream caused no skin irritation except for an abraded skin under sun exposure for five consecutive days. It has been identified that application of cosmetics on abraded skin under sunny condition worsens the irritation. Cosmetic labels revealed that most ingredients used in all products were those restricted chemicals due to their adverse health effects. Conclusion. This study has concluded that use of cosmetics under sunshine and also on abraded skin increases skin irritation. Hence, those users who have abraded skin are advised not to apply those cosmetics on continuous basis specifically under sun exposure.

Exposure to DDT and its metabolites from khat (Catha edulis) chewing: Consumers risk assessment from southwestern Ethiopia

ABSTRACT Khat (Catha edulis) is one of the most consumed plant in the horn of African countries. However, it is a stimulant plant that has several side effects on the health of consumers. On top of that, the khat leaves used for human consumption are often contain contaminants such as pesticide residues. The present study aims to investigate the level of DDT residue and its metabolites (pp‐DDE, pp‐DDD, op‐DDT and pp‐DDT) in khat samples and to undertake exposure assessment to consumers. The khat samples were collected from local markets in southwestern Ethiopia. Consumption survey was undertaken using 24 h recall method for both male and female khat consumers. The finding showed that 80% of the khat samples contained DDT and its metabolites. Some of the residues were above the maximum residue limit (MRL) set by Food and Agricultural Organization (FAO). The concentration of pp‐DDE and pp‐DDT in khat were in the range of 0.033–0.113 and 0.010–0.026 mg/kg, respectively. High concentration of the metabolite (pp‐DDE) compared to the parent compound (pp‐DDT) revealed the historical use of DDT in the study area. Probabilistic exposure analysis indicated that the mean and 97.5 percentile (P97.5), of the estimated daily intake of total DDT were 0.002 and 0.006 mg/kg bw/day, respectively. The study concluded that khat consumers are exposed to the stimulant effect of the plant as well as DDT and its metabolites in Jimma zone. HIGHLIGHTSAbout 80% of the khat samples were contaminated with DDT and its metabolites.Some of the residue levels were above the maximum residue limit set by FAO and WHO.The maximum concentration of pp‐DDE and pp‐DDT in khat were 0.113 and 0.026 mg/kg, respectively.The mean and 97.5 percentile estimated daily intake of total DDT were 0.002 and 0.006 mg/kg bw/day.

Exposure and Health Risk Assessment of Lead in Communities of Jimma Town, Southwestern Ethiopia

AbstractnHuman beings could be exposed to lead arising from different environmental sources, such as air, water and soil. Tap water, air and soil samples were collected from four quadrants of Jimma town in southwestern Ethiopia. Eighty samples from each environmental source: water, air and soil samples were collected and analyzed for lead concentration. Prediction of the blood lead level and risk characterization was made using integrated exposure uptake biokinetic model and lead risk was calculated using USEPA guideline. Average concentration of lead in water, air and soils were 24.55xa0±xa010.01, 1.01xa0±xa00.41xa0µg/m3, and 220.08xa0±xa0135.95xa0µg/g respectively. Uptake of lead by children is significantly higher than the adults. The total risk value was 1.41 for children and 0.37 for adults. The finding revealed that children are more at risk than adults.n