Analyzing Factors Affecting Farmers' Safe Pesticide Handling Practices in Southwest of Ethiopia: Implications for Policy.

Background: Pesticides play a crucial role in enhancing agricultural productivity by controlling pests. However, inadequate pesticide handling practices have a considerable adverse impact on human health. Nevertheless, there is limited knowledge regarding the extent of safe pesticide handling practices, particularly in low-income settings like Ethiopia. Hence, this study seeks to evaluate the implementation of safe pesticide handling practices and identify the factors associated with the status of the handling practices in low-income settings in Ethiopia. Methods: A cross-sectional study was undertaken, involving 468 farmers randomly selected for participation. Data collection was carried out through structured questionnaires and face-to-face interviews. The analysis aimed to assess the proportion of safe pesticide handling practices (SPHP) and investigate the factors associated with SPHP was done using binary logistic regression. Explanatory variables with a P-value <0.25 were included in the final analysis. The factors were determined based on adjusted odds ratios and 95% confidence intervals, P-value <.05. Model fit was evaluated using the Hosmer and Lemeshow tests. Results: From the findings of our study, only 45.7% of farmers practiced SPHP, with factors such as education, experience, pesticide usage, and attitude toward safe practices influencing their practices. Farmers with education status primary and above were two times more likely to practice good handling of pesticides than those who didn't attend formal education. Farmers with a maximum of 5 years of experience in vegetable farming were 2.4 times more likely to exhibit good handling practices compared to their counterparts. Furthermore, farmers with favorable attitudes toward pesticide handling were 4.2 times more likely to engage in good pesticide handling practices than those with unfavorable attitudes. Therefore, the agricultural sectors, health sectors, and farmer associations should focus on these factors in order to mitigate the health risks associated with poor pesticide handling.

Adsorption enrichment integrated with paper-based devices for detection of trace levels of hexavalent chromium in water samples.

In the present study, a sensitive microfluidic paper-based analytical device (µ-PADs) integrated with adsorption enrichment procedure was developed to analyze Cr(VI) in water samples. The affecting factors, including pH and amounts of reagents were optimized. The limit of detection of 0.0015 mg L-1 and linear range of 0.005-2 mg L-1 were achieved with good intra- and inter-day precision of 5.1 and 7.6% RSD, respectively. The results obtained by the proposed method were validated by inductively coupled plasma-optical emission spectrometry (ICP-OES). The recoveries of the present method and ICP-OES were ranged from 96.3 to 109.0‬% and 106.0 to 109.7%, respectively. The two sets of (µ-PADs and ICP-OES) results were in a good agreement as paired t-test indicated no significant differences. The proposed method could be utilized for analyzing trace levels of Cr(VI) in water samples in the absence of conventional analytical instruments.

Herd and animal level seroprevalence and associated risk factors of small ruminant brucellosis in the Korahey zone, Somali regional state, eastern Ethiopia.

Introduction: Brucellosis is a zoonosis of major public health and economic importance that is endemic in livestock in Ethiopia with varying levels of seroprevalence. Methods: A cross-sectional study was carried out to determine the individual and herd-level seroprevalence of brucellosis in small ruminants in the Korahey zone of the Ethiopian Somali Region. A total of 324 sera from 63 herds of small ruminants were collected randomly using a multistage sampling technique and the sera were tested using the Rose Bengal Plate Test, and seropositive reactors were confirmed by the Complement Fixation Test. Results and discussion: The seroprevalence of brucellosis at the herds and the individual level was 6.35% (95% CI: 0.0-13%) and 1.23% (95% CI: 0.0-2%), respectively; with 1.4% in goats and 0.9% in sheep. Moreover, predicted variables like age group, parity, history of abortion, fetal membranes, herd size, ownership of other livestock species, contact with wild animals in the past year, the introduction of new animals in the past year, and lending of breeding males in the past year were not significantly associated (p > 0.05) with Brucella seropositivity at individual and herd level seroprevalence during multivariable logistic regression analysis. Pastoral community awareness regarding the public health impact of brucellosis and the promotion of an intersectoral One Health approach for the effective control of brucellosis is recommended.

Dispersive liquid-liquid microextraction coupled with microfluidic paper-based analytical device for the determination of organophosphate and carbamate pesticides in the water sample.

A microfluidic paper-based analytical device (µ-PAD) is a promising new technology platform for the development of extremely low-cost sensing devices. However, it has low sensitivity that might not enable to measure maximum allowable concentration of various pollutants in the environment. In this study, a dispersive liquid-liquid microextraction (DLLME) was developed as a preconcentration method to enhance the sensitivity of the µ-PAD for trace analysis of selected pesticides. Four critical parameters (volume of n-hexane and acetone, extraction time, NaCl amount) that affect the efficiency of DLLME have been optimized using response surface methodology. An acceptable mean recovery of 79-97% and 83-93% was observed at 1 µg L-1 and 5 µg L-1 fortification level, respectively, with very good repeatability (2.2-6.01% RSD) and reproducibility (5.60-10.41% RSD). Very high enrichment factors ranging from 317 to 1471 were obtained. The limits of detection for the studied analytes were in the range of 0.18-0.41 µg L-1 which is much lower than the WHO limits of 5-50 µg L-1 for similar category of analytes. Therefore, by coupling DLLME with µ-PAD, a sensitivity that allows to detect environmental threat and also that surpassed most of the previous reports have been achieved in this study. This implies that the preconcentration step has a paramount contribution to address the sensitivity problem associated with µ-PAD.

Microfluidic Paper Based Analytical Devices for the Detection of Carbamate Pesticides.

Microfluidic paper-based analytical devices (µ-PADs) are a new technology platform for the development of extremely low-cost sensing applications. In this study, µ-PADs has been developed for quantitative determination of carbamate pesticides. Key experimental parameters including concentration and volume of acetylcholinesterase, acetylthiocholine iodide and 5,5'-dithiobis-(2-nitrobenzoic acid), incubation time and image capturing time were systematically optimized. Under optimal conditions, the method showed wide range of linearity (0.25-16 mg/L), repeatability (4%-5% RSD) and intermediate precision (7%-10% RSD). Limit of detection was observed to be 0.4, 0.24 and 0.46 mg/L for carbaryl, carbosulfan and furathiocarb, respectively. An acceptable mean recovery (87% to 94%) was observed for the three pesticides at 1 mg/L fortification level. The results reveal that the developed method requires minimal reagents, simple and is easy to handle. It can be used for the quantification of carbamate pesticides in resource limited laboratories without the need for the conventional analytical instruments.

Microfluidic paper-based analytical devices coupled with coprecipitation enrichment show improved trace analysis of copper ions in water samples.

The present study focused on improving sensitivity to trace levels of Cu(II) by subjecting microfluidic paper-based analytical devices (µ-PADs) to a preconcentration process via coprecipitation using aluminum hydroxide. The experimental conditions were optimized for the pH of the coprecipitation, centrifugation, and amounts of reagents that were deposited onto µ-PADs for the Cu(II) assay. The resultant limit of detection reached as low as 0.003 mg L-1 with a linear range of 0.01-2.00 mg L-1. The relative standard deviations for intra- and inter-day precision were 3.2 and 4.6%, respectively (n = 9). Spiked water samples were analyzed using the µ-PADs after coprecipitation preconcentration. The results were verified by comparing them with those of inductively coupled plasma-optical emission spectrometry (ICP-OES). Recoveries ranged from 97.1 to 104% and from 98.7 to 105% using the present method and ICP-OES, respectively. These results suggest that the simple, highly sensitive, and inexpensive proposed method would be helpful for analyzing trace levels of Cu(II) in water samples in poorly equipped laboratories.

Case Report: Khat Chewing and Acute Myocardial Infarction in Two Young Men without Underlying Risk Factors.

Khat (Catha edulis) chewing is linked to several social, psychological, and health-related problems. Studies show that khat is associated with gastrointestinal and nervous system diseases. However, little is known about khat's effect on the cardiovascular system. This case report describes acute myocardial infarction (AMI) among two young adults who chew khat frequently, but who do not have underlying cardiovascular disease (CVD) risk factors. Case 1 is a 29-year-old apparently healthy man who presented with severe, squeezing, left-side chest pain after consumption of khat. Most of the laboratory results were within the normal range except for his serum troponin level, which was 400 times more than the normal limit. The patient was diagnosed with Killip class IV, ST-segment elevation, anteroseptal AMI. Case 2 is a 25-year-old man who is a frequent khat chewer. He presented with sudden-onset, severe, squeezing, retrosternal chest pain after khat chewing and vigorous activity. The patient was diagnosed with (Killip class III) acute ST-elevation myocardial infarction with cardiogenic pulmonary edema. These case reports describe two young adult male patients who were confirmed of having AMI with no known risk factors. Both cases had a similar history of frequent khat chewing and the onset of AMI after it, implying that khat could be an important CVD risk factor among young adults. Hence, it is essential to explore further the epidemiology and association between khat use and AMI. Both molecular and population-level studies could help to establish the causal relationship of khat and CVD.

Optimization of microwave-assisted carbohydrate extraction from indigenous Scenedesmus sp. grown in brewery effluent using response surface methodology.

The use of wastewater as a nutrient source for microalgae cultivation is considered as a cost-effective approach for algal biomass and biofuel production. The microalgal biomass contains carbohydrates that can be processed into bioethanol through different extraction methods. The objective of this study is to optimize the microwave-assisted extraction (MAE) of carbohydrates from the indigenous Scenedesmus sp. grown on brewery effluent. Optimization of independent variables, such as acid concentration (0.1-5 N), microwave power (800-1200 W), temperature (80-180 °C) and extraction time (5-30 min) performed by response surface methodology. It was found that all independent variables had a significant and positive effect on microwave-assisted carbohydrate extraction. The quadratic model developed on the basis of carbohydrate yield had F value of 112.05 with P < 0.05, indicating that the model was significant to predict the carbohydrate yield. The model had a high value of R2 (0.9899) and adjusted R2 (0.9811), indicating that the fitted model displayed a good agreement between the predicted and actual carbohydrate yield. An optimum carbohydrate yield obtained was 260.54 mg g-1 under the optimum conditions of acid concentration (2.8 N), microwave power (1075 W), temperature (151 °C) and extraction time (22 min). The validation test showed that the model has adequately described the microwave-assisted extraction (MAE) of carbohydrates from microalgal biomass. This study demonstrated that the indigenous Scenedesmus sp. grown on brewery effluent provides a promising result in carbohydrate production for bioethanol feedstock.

Speciation of chromium in water samples using microfluidic paper-based analytical devices with online oxidation of trivalent chromium.

Speciation of chromium (Cr) was demonstrated using microfluidic paper-based analytical devices (µ-PADs) that permit the colorimetric determination of hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)) via online oxidation. The µ-PADs consist of left and right channels that allow the simultaneous measurements of Cr(VI) and total Cr based on the colorimetric reaction of Cr(VI) with 1,5-diphenylcarbazide (DPC). For the determination of Cr(VI), a sample solution was directly reacted with DPC in the left channels whereas total Cr was determined in the right channels, which permitted online oxidation in the pretreatment zone containing cerium (IV) (Ce(IV)) followed by a colorimetric reaction with DPC. We found that the online oxidation of Cr(III) proceeded 100% whereas Ce(IV) inhibited the reaction of Cr(VI) with DPC. Therefore, speciation can be achieved by measuring the Cr(VI) and total Cr in the left and right channels followed by the subtraction of Cr(VI) from total Cr. The limits of detection and quantification were 0.008 and 0.02 mg L-1 for Cr(VI) and 0.07 and 0.1 mg L-1 for Cr(III) or total Cr, respectively. The linear dynamic ranges were 0.02-100 mg L-1 and 0.1-60 mg L-1 for Cr(VI) and Cr(III), respectively. The RSDs were less than 7.5%. The results obtained using µ-PADs were in good agreement with those obtained via ICP-OES with recoveries of 92-108% for Cr(III) and 108-110% for Cr (VI) using µ-PADs, and 106-110% for total Cr using ICP-OES. Thus, the µ-PADs could potentially be utilized for the speciation of chromium in developing countries where environmental pollution and the availability of sophisticated instruments are significant problems.

Remote Investigation of Total Chromium Determination in Environmental Samples of the Kombolcha Industrial Zone, Ethiopia, Using Microfluidic Paper-based Analytical Devices.

Microfluidic paper-based analytical devices (µ-PADs) fabricated in Japan were employed for the determination of total chromium (Cr) in water, soil, and lettuce irrigated with wastewater in Ethiopia. The µ-PADs, which were printed by wax printing in Japan, were transported to Ethiopia and prepared for the determination of total Cr by adding appropriate reagents to the pretreatment and detection zones. Soil and lettuce samples were determined by the µ-PADs and a UV-Vis spectrophotometer in Ethiopia. A paired t-test showed that the mean total Cr concentrations determined in the soil and lettuce samples were not significantly different between µ-PADs and UV-Vis spectrophotometric analysis at the 5% level of significance. This implies that the µ-PADs have good accuracy and reliability, and could be employed to monitor Cr in environmental samples. We found that the total Cr concentrations in all soil and lettuce samples were above the permissible limit. Moreover, evaluating Cr contamination level using the geo-accumulation index indicated that the soils were contaminated with Cr moderately to heavily. Thus, the present work successfully demonstrated the potential of remote investigations of pollution in a less-equipped laboratory by transporting the µ-PADs fabricated in another laboratory.

Toxicity of Millettia ferruginea darasana (family: Fabaceae) against the larvae and adult ticks of Amblyomma variegatum Fabricius a three-host tick in cattle.

The in vitro toxicity of Millettia ferruginea darasana (family: Fabaceae) was tested against the larvae adult male and female of a three-host tick, Amblyomma variegatum Fabricius (family: Ixodidae or hard tick), known as 'tropical bont tick' parasitic mainly to cattle found in Ethiopia and other equatorial Africa. The 20, 40, 60, 80 and 100 % concentrations of the seed oil extracted with petroleum ether were found to kill all (100 % mortality) larvae after 12, 9, 6, 3 and 1.5 h respectively. The results summarized in the Table 1 was found to be statistically significant at the probability level of p = 0.05. The 100 % concentration of the oil caused 100 % mortality of adult male, adult female and fully engorged female tick after 5, 7 and 12 h respectively. The root and root bark showed less toxicity. The leaves did not show any toxicity. [Table: see text].

Determination of organochlorine pesticide residue levels in chewable parts of the khat (Catha edulis) plant.

In this study, the levels of DDT and its metabolite residues were determined in chewable parts of Catha edulis plants grown in the southern part of Ethiopia. The levels of p,p'-DDT and p,p'-DDE were found to be in the range of 10.8-19.7 and 3.5-18.6 µg/kg, respectively. These data revealed that the residue being detected is from recent applications. The estimated daily intake of total DDT from C. edulis consumption was calculated to be in the range between 0.0278 and 0.0747 µg/kg, which is significantly lower than the FAO/WHO guideline. However, this may not guarantee safety, as the application of DDT extends to vegetables as well. Even though the use of DDT was banned in Ethiopia for agriculture purposes, detectable levels are still being observed. The results of the study necessitate the need for awareness creation among the people in the community.

Removal of nitrite from aqueous solution using sugarcane bagasse and wheat straw.

Sugarcane bagasse and wheat straw were applied for the removal of nitrite ions from water samples. Batch experiments were conducted to establish optimum pH (5), initial nitrite concentration (5 mg/L), adsorbent dose (3 mg/L) and contact time (90 min). Under the optimized conditions, raw sugarcane bagasse was found to be a more effective (removal efficiency 90 %) adsorbent in removing nitrite ions than wheat straw (removal efficiency 63 %). Adsorption isotherms and kinetic parameters were also studied. The correlation coefficient values for Langmuir and Freundlich isotherm models were 0.9625 and 0.9590, respectively. The results showed that the adsorption of nitrite fairly fits both Langmuir and Freundlich adsorption isotherms for both adsorbents. The kinetics of the adsorption process follows the pseudo second-order kinetic model.

Assessment of organochlorine pesticide pollution in Upper Awash Ethiopian state farm soils using selective pressurised liquid extraction.

Upper Awash Agro Industry Enterprises (UAAIE) is one of the major state farms in Ethiopia with known large-scale pesticide use. Although organochlorine pesticides (OCPs) have been applied for about three decades, no studies have been carried out on levels of residue in the region. In this work a fast selective pressurised liquid extraction (SPLE) methodology has successfully been applied for screening of 13 OCPs in 12 soil samples from different fields in UAAIE, which further strengthen this methodology. Quantitative and qualitative analyses were done using a dual column gas chromatography-electron capture detection system (GC-ECD) and a GC equipped with a mass spectrometer (MS), respectively. The main contaminants identified comprised of previously used persistent organic pollutants (POPs) and currently used insecticides. Low concentrations or non-detectable levels of certain OCPs (aldrin, dieldrin, endrin, and heptachlor) indicate a positive phasing out of these persistent organic pollutants (POPs). Similarly HCHs were found in few soils and at low concentrations. Endosulfans and DDTs were detected in substantial amounts in the soils with Sigmaendosulfans up to 56000 and SigmaDDTs up to 230 ng g(-1) dry weight, which is a threat to the surrounding and downstream ecosystems, especially considering that the investigated OCPs constituted 29000 l of the 63000 l of pesticide applied annually on the fields. Additional concerns must be raised concerning synergistic effects of all pesticides added.

Selective pressurized liquid extraction for multi-residue analysis of organochlorine pesticides in soil.

A selective pressurized liquid extraction (SPLE) procedure capable of performing simultaneous extraction and clean-up has been demonstrated for multi-residue analysis of organochlorine pesticides (OCPs) in soil. The final method was performed at 100 degrees C for 3 x 10 min using acetone/n-heptane (1:1, v/v). Florisil was placed inside the extraction cell downstream the sample to remove interfering compounds. Extraction of two soil samples by SPLE gave a recovery which was over 80% for beta-endosulfan, endosulfan sulfate, p,p'-DDT and p,p'-DDE compared to PLE with off-line clean-up. The same trend was observed when applying the SPLE method to a certified reference soil sample (CRM 811-050) containing 13 OCPs, where the SPLE method gave 80-90% recovery vis-à-vis the PLE method with off-line clean-up. Feasibility of the SPLE method was further demonstrated by applying it to five real soil samples collected in Ethiopia.

Optimisation of pressurised liquid extraction for the determination of p,p'-DDT and p,p'-DDE in aged contaminated Ethiopian soils.

The effectiveness of extracting p,p'-DDT and p,p'-DDE from aged contaminated soil samples by means of pressurized liquid extraction (PLE) was evaluated. Two soil samples, which were contaminated more than 10 years ago, were used in the investigation. The static extraction time was optimised and then validated against the total sum of target analytes obtained from multiple sequential extractions. The PLE results were also compared with Soxhlet extraction (SOX). PLE for 3x10 min at 100 degrees C was proven to be more exhaustive than SOX in the determination of p,p'-DDE from both soil samples. In the case of p,p'-DDT, PLE was found to be equally as exhaustive as SOX. Additionally, most of the previous PLE investigations used hazardous organic solvents such as n-hexane, toluene and dichloromethane mixed with acetone, whereas in this investigation the less toxic solvent combination n-heptane/acetone has been employed.

Extracting Syringe for determination of organochlorine pesticides in leachate water and soil-water slurry: a novel technology for environmental analysis.

The Extracting Syringe (ESy), a novel membrane-based sample preparation technique directly coupled as an autosampler to gas chromatography, has been employed for the analysis of organochlorine pesticides (OCPs) in raw leachate water. The ESy has also been applied for extraction of OCPs from contaminated soil samples and its performance has been compared to liquid-solid extraction (LSE) and accelerated solvent extraction (ASE). Extraction of 3-mL leachate sample at the optimised conditions resulted in enrichment factors from 32 (Endrin aldehyde) to 242 (Endrin) and detection limits from 1 to 20 ng/L. The inter-day and intra-day repeatability (% RSD) at 100 and 500 ng/L were <6% and <24%, respectively. The relative recovery at 100 and 500 ng/L ranged from 68% (Aldrin) to 116% (Endrin aldehyde); except Heptachlor that showed 51 and 60%, respectively. The ESy extraction of the slurry-made soil samples revealed occurrence of Endosulfan I (18.2 microg/g soil), 4,4'-DDE (2.6 ng/g soil), Endosulfan II (8.7 microg/g soil) and Endosulfan sulfate (1.1 microg/g soil); showing good agreement with LSE results. The total ESy consumption of organic solvents was 4.2 mL from which only 0.6 mL n-undecane was used during the extraction step (7 microL for the extraction per se), while in the LSE and ASE, it was 420 and 18.1 mL, respectively. The ESy extraction time (0.5 h) was comparable to the ASE time (0.6 h); and the time required for the LSE was 3.75 h. To sum up, the ESy has shown its competency to LSE and ASE technologies, demonstrating its applicability for environmental analysis of organic pollutants, towards green techniques for green environment.

Development of a pressurized liquid extraction and clean-up procedure for the determination of alpha-endosulfan, beta-endosulfan and endosulfan sulfate in aged contaminated Ethiopian soils.

Pressurized liquid extraction (PLE) was investigated for the extraction of two endosulfan isomers and their metabolite from two real contaminated soil samples. PLE for 3x10min at 100 degrees C was proven to be more exhaustive than Soxhlet extraction (SOX) in one soil sample. On the other soil sample investigated the method was found to be equally exhaustive as SOX. The use of hazardous organic solvents such as n-hexane, toluene, and diethyl ether has been avoided in PLE and clean-up. Instead less toxic solvents have been used both at the extraction step (acetone/n-heptane) and clean-up step (ethyl acetate/n-heptane). A column Florisil clean-up procedure that consumes relatively low solvent volumes has been optimized and applied to purify soil extracts. The developed analytical procedure was validated by applying it to a certified reference soil material (CRM811-050). A recovery of 103% total endosulfan residue was obtained versus certified values.