In this study, the non-edible part of oyster mushroom was utilized for quantitative removal of the most commonly used s-triazine herbicide; atrazine and its breakdown products including deethylatrazine (DEA), hydroxyatrazine (ATOH) and deisopropylatrazine (DIA) from aqueous samples. The functional groups available on the oyster mushroom were studied applying FTIR before and after adsorption. Experimental parameters influencing the uptake process including acidity, sorbent mass, sorption time, initial analyte quantities, and agitation speed were analysed and the maximum removal was found at 4, 0.3 g, 120 min, 0.5 mg L^-1, and 150 rpm, respectively. Accordingly, the adsorption capacities of 0.994, 1.113, 0.991 and 1.016 mg g^-1 were obtained for DIA, DEA, ATOH and atrazine, respectively. The adsorption characteristics were discussed utilizing Langmuir and Freundlich isotherm models. The fundamental characteristic of the Langmuir isotherm, which can be elaborated using separation factor or equilibrium parameter, R_L, and coefficient of variation, R², were (0.761, 0.996), (0.884, 0.975), (0.908, 0.983) and (0.799, 0.984) for DIA, DEA, ATOH and Atrazine, respectively. These findings showed that all analytes' adsorption processes were fitted well to the Langmuir adsorption isotherm, indicating that the adsorbent surface was covered in a monolayer. The kinetics was also evaluated using the pseudo-first and pseudo-second order models. The coefficient of determination, r², were found to be 0.09703, 0.9989, 0.9967 and 0.9998 for DIA DEA, ATOH and atrazine, respectively, for pseudo-second order, signifying that, all analytes were found to follow the pseudo-second order rate model showing that the rate limiting step is chemisorption in the sorption process. Based on these findings, the non-edible and disposable part of the oyster mushrooms can be utilized as a preferred alternative biosorbent for the uptake of the target compounds analysed and other pollutants possessing comparable physicochemical characteristics occurring in various water bodies.

Plant derived bioactive molecules are always in demand and are the main focus of research. Despite the growing market demand for herbal medicines, safety of medicinal plants is still a concern. The present work aimed at generating preliminary phytochemical and biosafety information of crude methanolic and chloroform extracts of Cissus quadrangularis L. (aerial parts) and Solunumincanum L. (fruit). Both plants are extensively used by traditional healers among the agro-pastoralist communities of Fafan Zone in Eastern Ethiopia. The investigation employed standard phytochemical screening procedures and acute (2000mg/kg single dose) and sub-acute (200 and 400mg/kg repeated doses) oral toxicity studies in Swiss albino mice. Changes in body weight, packed cell volume (PCV), Hb level and mortality were recorded to evaluate the toxicity profile of the crude extracts. The phytochemical study revealed the presence of several secondary metabolites in both plants. The acute toxicity study did not show extracts related mortality and body weight reduction at 2000 mg/kg of methanol and chloroform extracts of both plants. However, the sub-acute toxicity study exhibited that crude extract of fruit of S. incanum(400 mg/kg) showed relatively higher toxic effects of causing a more pronounced (p<0.05) mortality, body weight loss, and reduction in PCV and Hb levels, compared to negative control. Extracts of C. quadrangularis revealed low mortality and a marginal increase of the hematological parameters. A detailed experimental analysis of these herbs extensively used by the agro-pastoralists of the area is essential to establish their therapeutic value and safety in use. Key words: Cissus quadrangularis, Solunum incanum, phytochemical, toxicity.

High-density dispersive liquid-liquid microextraction method coupled with high-performance liquid chromatography with a diode array detector (HD-DLLME-HPLC-DAD) was developed for extraction and determination of six commonly used sulfonylurea herbicides in matrices of environmental waters. For simultaneous extraction of the target herbicides, the optimum experimental parameters that 024influence extraction efficiency were investigated. Under optimized conditions, the limit of detection (LOD) and quantification (LOQ) were 0.8-1.5 and 1.9-5.1 ng mL−1, respectively. The precisions in terms of relative standard deviations (% RSDs) of both intra-day and inter-day precisions (n = 6) were found to be 2.92 to 7.08 and 3.01 to 8.13, respectively. Furthermore, applicability of the developed method was investigated by analyzing spiked tap, lake, river and underground water samples and satisfactory recoveries were obtained in the range of 84.3–101.7% with RSDs < 9.8% (n = 6) and the target analytes were not detected in real samples. The proposed method offered several attractive features including fast analysis time, simplicity, sensitivity, and selectivity. Therefore, the trace level enrichment and assessment of sulfonylurea herbicides residues from environmental water matrices using HD-DLLME-HPLC-DAD could be utilized as a reliable alternative in routine laboratory analysis of contaminated environmental waters. KEY WORDS: Environmental water, High-density dispersive liquid-liquid microextraction, HPLC-DAD, Miniaturization analytical technique, Sulfonylurea herbicides, Trace level enrichment Bull. Chem. Soc. Ethiop. 2024, 38(5), 1189-1204. DOI: https://dx.doi.org/10.4314/bcse.v38i5.1