Browsing by Author "Onwona-Agyeman, S."
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Item Global occurrence of anti-infectives in contaminated surface waters: Impact of income inequality between countries(Environment International, 2015-07) Segura, P.A.; Takada, H.; Correa, J.A.; El Saadi, K.; Koike, T.; Onwona-Agyeman, S.; Ofosu-Anim, J.; Sabi, E.B.; Wasonga, O.V.; Mghalu, J.M.; dos Santos, A.M.; Newman, B.; Weerts, S.; Yargeau, V.The presence anti-infectives in environmental waters is of interest because of their potential role in the dissemination of anti-infective resistance in bacteria and other harmful effects on non-target species such as algae and shellfish. Since no information on global trends regarding the contamination caused by these bioactive substances is yet available, we decided to investigate the impact of income inequality between countries on the occurrence of anti-infectives in surface waters. In order to perform such study, we gathered concentration values reported in the peer-reviewed literature between 1998 and 2014 and built a database. To fill the gap of knowledge on occurrence of anti-infectives in African countries, we also collected 61 surface water samples from Ghana, Kenya, Mozambique and South Africa, and measured concentrations of 19 anti-infectives. A mixed one-way analysis of covariance (ANCOVA) model, followed by Turkey-Kramer post hoc tests was used to identify potential differences in anti-infective occurrence between countries grouped by income level (high, upper-middle and lower-middle and low income) according to the classification by the World Bank. Comparison of occurrence of anti-infectives according to income level revealed that concentrations of these substances in contaminated surface waters were significantly higher in low and lower-middle income countries (p=0.0001) but not in upper-middle income countries (p=0.0515) compared to high-income countries. We explained these results as the consequence of the absence of or limited sewage treatment performed in lower income countries. Furthermore, comparison of concentrations of low cost anti-infectives (sulfonamides and trimethoprim) and the more expensive macrolides between income groups suggest that the cost of these substances may have an impact on their environmental occurrence in lower income countries. Since wastewaters are the most important source of contamination of anti-infectives and other contaminants of emerging concern in the environment, it is expected that deleterious effects to the aquatic biota caused by these substances will be more pronounced in countries with inadequate wastewater and collection infrastructure. With the information currently available, we could not evaluate either the role of the receiving environment or the importance of regulatory frameworks on the occurrence of anti-infectives in surface waters. Future studies should focus on these two factors in order to better evaluate risks to aquatic ecosystems in LM&LICs. We propose that CECs such as anti-infectives could be used as a new class of environmental degradation indicators that could be helpful to assess the state of development of wastewater collection and treatment infrastructure around the world.Item Impact of sugarcane bagasse mulching boards on soil erosion and carrot productivity(Catena, 2021) Yakubu, A.; Sabi, E.B.; Onwona-Agyeman, S.; Takada, H.; Watanabe, H.Sustainable crop production depends primarily on water and nutrients among other inputs. Mulching improves soil moisture and nutrient conservation as well as ameliorates soil erosion. We conducted two different experiments to examine the impact of mulch on soil erosion and the productivity of carrot (Daucus carota L.). Mulch used were sugarcane bagasse boards (SBB) and sugarcane bagasse chips (SBC). Each experiment consisted of three treatments in a completely randomized design with three replications. The first experiment under rainfall simulation consisted of 2 SBB and 4 SBB representing 25 and 50% soil surface coverage and no sugarcane bagasse (NSB) represented the control. Treatments in the second experiment were SBB, SBC, and NSB. The 4 SBB and 2 SBB significantly decreased (p < 0.05) erosion by 1.74 Mg ha 1 and 1.57 Mg ha 1. However, there was no significant difference in mitigating erosion between the 4 SBB and 2 SBB. Compared to NSB, 4 SBB and 2 SBB again decreased runoff rate by 223 and 23%. There was no significant improvement in soil moisture retention, temperature, carrot yield, and water productivity under either mulch. Weed growth was significantly reduced at 104 and 72% by SBB and SBC. The yield gap between SBB and SBC was only 18.75%. Unlike the particulate SBC which is susceptible to erosion during runoff, the bulky SBB cannot easily be eroded by runoff. Hence the SBB was recommended for farmers due to its significant impact on ameliorating runoff and erosion, as well as curtailing weed growth under carrot production.Item Involvement of Carnosic Acid in the Phytotoxicity of Rosmarinus officinalis Leaves(Toxins, 2018-11) Appiah, K.S.; Mardani, H.K.; Omari, R.A.; Eziah, V.Y.; Ofosu-Anim, J.; Onwona-Agyeman, S.; Amoatey, C.A.; Kawada, K.; Oikawa, Y.; Fujii, Y.Weeds are rapidly developing resistance to synthetic herbicides, and this can pose a threat to the ecosystem. Exploring allelopathic species as an alternative weed control measure can help minimize the ecological threat posed by herbicide-resistant weeds. In this study, we aimed to evaluate the contribution of some polyphenols to the allelopathy of rosemary (Rosmarinus officinalis L.). The phytotoxic effects of rosemary (leaves, roots, inflorescences, and stems) crude extracts were tested on lettuce (Lactuca sativa L.). Soils incorporated with dried rosemary leaves were also tested on test plants. Reversed-phase high-performance liquid chromatography (HPLC) analysis was used to determine the content of some polyphenols (caffeic, ferulic, gallic, rosmarinic, carnosic, and chlorogenic acids) in rosemary. The specific activity and total activity of crude extracts and individual compounds were evaluated using lettuce. The crude extract of rosemary leaves showed the highest growth inhibitory effect among the rosemary organs tested. Soil amended with rosemary leaf debris reduced the dry matter and seed emergence of lettuce. Carnosic acid was the main compound detected in rosemary leaves and had a high specific activity when tested on lettuce. During the seed germination period, there was observed filter paper coloration among the test plants treated with carnosic acid (250 µg/mL). The high concentration and strong inhibitory effect of carnosic acid could explain the inhibitory activity of the rosemary leaf extract. Hence, we conclude based on the total activity estimation that carnosic acid among the other tested compounds is the major allelochemical in rosemary leaves. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.Item Monitoring of organic micropollutants in Ghana by combination of pellet watch with sediment analysis: E-waste as a source of PCBs(Marine Pollution Bulletin, 2014-09) Hosoda, J.; Ofosu-Anim, J.; Sabi, E.B.; Akita, L.G.; Onwona-Agyeman, S.; Yamashita, R.; Takada, H.Plastic resin pellets collected at 11 beaches covering the whole Ghanaian coastline were analyzed for polychlorinated biphenyls (PCBs). PCB concentrations (∑13 congeners) were higher in Accra, capital city, and Tema (39-69. ng/g-pellets) than those in rural coastal towns (1-15. ng/g-pellets) which are close to global background, indicating local inputs of PCBs. River sediments were also analyzed for PCBs together with molecular markers. Sedimentary PCBs concentrations were highest at a site (AR02) downstream of an electronic waste (e-waste) scrapyard. At the site (AR02), concentration of linear alkylbenzenes (LABs), a marker of municipal wastewater, was lower than another site (AR03) which is located at the downstream of downtown Accra. This result suggests that PCBs are introduced more to the river from the e-waste site than from activities in downtown Accra. PAHs concentrations were relatively higher in urban areas with strong petrogenic signature. Abundance of triphenylbenzenes suggested plastic combustion near e-waste scrapyard. © 2014 Elsevier Ltd.Item Seasonal Changes in the Plant Growth-Inhibitory Effects of Rosemary Leaves on Lettuce Seedlings(Plants, 2022) Appiah, K.S.; Omari, R.A.; Onwona-Agyeman, S.; Amoatey, C.A.; Ofosu-Anim, J.; Smaoui, A.; Arfa, A.B.; Suzuki, Y.; Oikawa, Y.; Okazaki, S.; Katsura, K.; Isoda, H.; Kawada, K.; Fujii, Y.Plant biodiversity has been studied to explore allelopathic species for the sustainable management of weeds to reduce the reliance on synthetic herbicides. Rosemary (Rosmarinus officinalis L., syn Salvia rosmarinus Spenn.), was found to have plant growth-inhibitory effects, and carnosic acid was reported as an allelochemical in the plant. In this study, the effects of seasonal variation (2011–2012) on the carnosic acid concentration and phytotoxicity of rosemary leaves from two locations in Tunisia (Fahs and Matmata) were investigated. The carnosic acid concentration in rosemary leaves was determined by HPLC, and lettuce (Lactuca sativa L.) was used as the receptor plant in the phytotoxicity bioassay. The highest carnosic acid concentration was found in rosemary samples collected in June 2011, which also had the highest inhibitory activity. Furthermore, a significant inverse correlation (r = 0.529; p < 0.01) was found between the inhibitory activity on lettuce hypocotyl and the carnosic acid concentration in rosemary leaves. Both temperature and elevation had a significant positive correlation with carnosic acid concentration, while rainfall showed a negative correlation. The results showed that the inhibitory effects of rosemary leaf samples collected in summer was highest due to their high carnosic acid concentration. The phytotoxicity of rosemary needs to be studied over time to determine if it varies by season under field conditions.