Prevalence and Associated Factors of Work-Related Injury Among Municipal Solid Waste Collectors in Hawassa City, Southern Ethiopia: A Cross-Sectional Study.

Introduction: Municipal solid waste collectors are at risk of experiencing work-related health problems due to the waste they handle and the physical effort they put in. Work-related injuries among domestic waste collectors have been the subject of scant research in developing nations. Therefore, it is necessary to describe work-related injuries in these subpopulation groups. Objective: This study aimed to determine the prevalence and associated factors of work-related injury among municipal solid waste collectors in Hawassa city, Southern Ethiopia. Methodology: A cross-sectional study was conducted from January 11 to 30, 2022, with all the registered municipal solid waste collectors (411). Three diploma environmental health professionals assisted in collecting data using a pretested structured interviewer-administered questionnaire; 1 Bachelor of Science environmental health professional served as a supervisor. Statistical Package for the Social Sciences (SPSS) version 20.0 was used to enter, clean, code, and analyze the data. Associations between independent and dependent variables were assessed, and the strength of the associations was presented by using Adjusted Odds Ratio (AOR) and 95% confidence intervals (CI). According to the bivariable analysis, all independent variables associated with a P-value <.25 were entered into a multivariable logistic regression model. Variables in the multivariable regression analysis were considered significant if their P-value was less than 0.05. Results: In this study, the prevalence of work-related injuries within the last 30 days was 12.9% (95% CI: 9.5, 16.3), while the prevalence over the last 12 months was 59.4% (95% CI: 54.7, 64.0). After adjusting for possible confounding factors, age 18 to 24 years [AOR = 1.72;95% CI: (1.07, 2.76)], lack of personal protective equipment (PPE) utilization [AOR = 2.30; 95% CI: (1.44, 3.68)], chewing khat (yes) [AOR = 2.32;95% CI: (1.32, 4.08)], drinking alcohol (yes) [AOR = 1.80; 95% CI: (1.003, 3.24)] and job dissatisfaction [AOR = 2.26, 95% CI: (1.44, 3.54)] were shown to be significantly associated with work-related injury. Conclusion: The prevalence of work-related injuries was high. Age 18 to 24 years, chewing khat, drinking alcohol, lack of PPE utilization, and job dissatisfaction were significantly associated with work-related injury. Based on the findings of this study, we suggest that addressing these risk factors could help to reduce work-related injuries.

Level of Heavy Metals in Fish and Associated Human Health Risk From the Omo Delta in Southern Ethiopia: A First-Hand Report.

This study was the first to investigate the levels of heavy metals in commercially important fish species (Lates niloticus and Oreochromis niloticus) and the human health risk in Southern Ethiopia. Sixty fish samples were collected from the Omo delta. The target hazard quotient (THQ), hazard index (HI), and target cancer risk (TCR) were used to estimate the human health risks. The mean levels of heavy metals detected in the liver and muscle of Lates niloticus generally occurred in the order of Fe> Zn > Pb > Cu >Mn> Cr > Co > Ni and Fe > Pb > Zn >Mn > Cu > Co > Cr >Ni, respectively. Similarly, the mean levels of iron in the muscle and liver tissues of Oreochromis niloticus were in the order of Fe > Pb > Zn >Mn> Cu > Cr > Co > Ni and Pb > Fe > Zn >Mn> Co > Cu > Ni, respectively. The THQs in the muscle of L. niloticus and O. niloticus decreased in the order Pb > Cr > Cu >Mn> Co > Zn > Fe> Ni and Pb >Mn> Co > Cu > Zn > Ni> Fe respectively. Pb had the highest THQ value in L. niloticus and O. niloticus, which were 0.61 and 0.409, respectively in adult. Similarly, Pb had noted that, L. niloticus and O. niloticus had the highest THQ values, at 0.87 and 0.58, respectively in children. The HI values due to consumption of L. niloticus muscle were 0.668 for adults and 0.942 for children. The mean concentrations of Pb and Cr in the tissues of L. niloticus and O. niloticus were above the FAO/WHO permissible limits. Consequently, investigating heavy metal pollution levels in fish and human health risks from the Omo delta is imperative for addressing environmental and public health concerns.

The contents of essential and toxic metals in coffee beans and soil in Dale Woreda, Sidama Regional State, Southern Ethiopia.

Background: For developing countries such as Ethiopia, coffee is a commodity of great economic, social, and environmental importance. No detailed investigations have been performed on the contents of essential and toxic metals in coffee beans and soil in this study area. Methods: The levels of essential metals (Na, K, Ca, Zn, Mn, Cu, Co, Cr, Ni) and toxic elements (Pb and Cd) were investigated in coffee beans (coffee growing farmland and coffee washed plants) and soil samples (from farmland) using flame atomic absorption spectrometry (FAAS) and flame emission atomic spectroscopy. We selected six (20%) administrative units (kebele) with purposive sampling techniques based on their coffee production capacity in Dale Woreda for soil testing. After coffee sample preparation in a microwave system with HNO3and H2O2 reagents, the accuracy of the optimized procedure was evaluated by analysing the digest of the spiked samples. Soil samples were abridged with a slight revision of the EPA 3050B acid digesting method. ANOVA was used to determine the significant differences in the mean concentration of metal within coffee beans from farmland at the various sampled sites at the p < 0.05 significance level. To correlate the effect of one metal concentration on other metals in the coffee bean samples, Pearson correlation matrices were used. Results: Calcium had the highest concentration (1,355 ± 18.02 mg kg-1) of macroelements in soil samples, followed by K (681.43 ± 1.52 mg kg-1). Similarly, Na (111.63 ± 0.35 mg kg-1), Cu (49.96 ± 0.99 mg kg-1), Co (5.43 ± 0.31 mg kg-1), Mn (0.62 ± 0.238 mg kg-1), Ni (0.194 ± 0.01 mg kg-1), and Zn (0.163 ± 0.007 mg kg-1) were detected among the microelements in the soil samples. Pb and Cr were not detected in all soil samples. Potassium (K) was found to have the highest concentration (99.93 ± 0.037 mg kg-1), followed by Ca (17.23 ± 0.36 mg kg-1), among the macroelements in coffee beans from farmers' farms. Similar to coffee beans from farmland, samples from washed plants also contained the highest K (77.93 ± 0.115 mg kg-1), followed by Ca (4.33 ± 0.035 mg kg-1). Metal levels in coffee bean samples from farmland are in the following order: K>Na>Ca >Mn>Cu> Ni>Zn. Metal levels were found to be K>Na>Ca >Mn>Cu> Zn>Ni in coffee beans from the washed plants. Co, Cr, Pb and Cd were no detected in all coffee bean samples. Except for calcium, potassium and manganese, the levels of metals in coffee beans from farmland and washed plants were not significantly different at the 95% confidence level within a kebele. Conclusions: We observed permitted levels of macro- and trace elements in coffee beans from farmlands and washed plants. Only in the soil samples are cadmium concentrations higher than those permitted for agricultural soil recommended by the WHO and FAO. Overall, there is no health danger linked with the use of coffee beans due to detrimental and trace heavy metals.

Treatment Performance Assessment of Natural and Constructed Wetlands on Wastewater From Kege Wet Coffee Processing Plant in Dale Woreda, Sidama Regional State, Ethiopia.

Constructed wetlands are engineered systems built to use natural processes and remove pollutants from contaminated water in a more controlled environment. The research was an experimental research carried out to assess the effectiveness of natural and constructed wetland systems in the treatment of coffee wastewater. The 2 vertical flow constructed wetland was built. The first wetland covered an area of 132 m2. It has 12 m width and 11 m length. Open space is constructed between 2 constructed wetlands with a dimension of 11 m × 3 m × 1 m. The second wetland was constructed and its function is similar to the first one, from this wetland water is discharged to the river. The construction of the wetland is accomplished by constructing 20 cm wide furrows with a spacing of 30 cm. Vetiver grasses have planted with a spacing of 20 cm intervals. The physicochemical data were recorded, organized, and analyzed using R software (version 4.1) and Microsoft Excel. Data were processed using parametric (one-way ANOVA) and nonparametric (Mann-Whitney's U test) statistical tests of homogeneity. One-way analysis of Variance (ANOVA) was used to determine the significance of differences in variations in physicochemical variables within the constructed wetland sites. Tukey's multiple comparisons for differences between means were also assessed. Findings indicated that a natural wetland had a mean influent and effluent of total suspended solids (TSS) of 2190.78 ± 448.46 mg/l and 972.67 ± 234.312 mg/l, respectively. A Mann-Whitney U test revealed that TSS were significantly higher in natural wetland (median = 1551.50) compared to constructed wetland (median = 922.5), U = 676.5, z = -2.435, P = .015, r = .257. Natural wetlands had a mean influent of biological oxygen demand (BOD) was 4277.94 ± 157.02 mg/l, while in the effluent of BOD it was 326.83 ± 112.24 mg/l. While in constructed wetland it was 4192.4 ± 191.3 mg/l, 782.72 ± 507.6 mg/l, and 88.28 ± 20.08 mg/l in influent, middle, and effluent respectively. Average chemical oxygen demand (COD) value at influent in natural wetlands was 8085.61 ± 536.99 mg/l and in the effluent it was 675.33 ± 201.4 mg/l. In constructed wetland, it was found to be 8409.8 ± 592.9, 1372.6 ± 387.94, and 249.0 ± 7.68 for influent, middle, and effluent respectively. Comparatively, the purification efficiency of organic pollutants (TSS, BOD, and COD) of constructed wetlands was better than natural wetlands, whereas natural wetlands had better purification efficiency of nitrogen compounds such as ammonium, nitrite, and nitrate. On average, removal rates for nitrogen compounds were 39.53% and -24.41% for ammonium, 79.44% and 55.4% for nitrite, and 68.90% and 60.6% for nitrate in natural and constructed wetlands respectively, while the phosphate removal rate was 43.17% and 58.7% in natural and constructed wetlands, respectively. A Mann-Whitney U test revealed that there is no significance difference in nitrite, nitrate, ammonium, and phosphate concentration between natural and constructed wetlands(P > .05). Based on these results, both systems of treatment were effective in treating the coffee effluent since most of the values obtained were below the permissible EEPA limits. Even though the constructed wetland treatment plant performed better overall, in comparison, the natural wetlands had better purification efficiency for nitrogen compounds like ammonium, nitrite, and nitrate and the constructed wetlands had better purification efficiency for organic pollutants (TSS, BOD, and COD).