Soil quality and heavy metal contamination in an open dumpsite in Navrongo, Ghana.

The increasing proximity of the Dudumbia dumpsite, an open dumpsite in Navrongo, Ghana, to human settlements necessitates an investigation of the soil quality to safeguard the environment from heavy metal toxicity. This study examined the impact of waste dumping activities on the physicochemical properties of the soil, as well as the level of heavy metal (Pb, Cd, Ni, Cr, As, Hg, Cu, Mn, and Zn) contamination and associated risks. Various contamination and risk assessment tools were used, including the geoaccumulation index (Igeo), pollution load index (PLI), potential ecological risk (Er), and potential ecological risk index (PERI). The study found significant improvements in notable soil attributes such as phosphorus (P), organic carbon (C), total nitrogen (N), calcium (Ca), magnesium (Mg), potassium (K), sodium (Na), and effective cation exchange capacity, with percentage increases ranging from 50.8 to 2078.3%. Igeo values ranged from 2.07 to 6.20, indicating contamination levels from moderate to extreme. The PLI and PERI values were 16.241 and 1810, respectively. The Er values for the heavy metals ranged from 36 to 607, indicating ecological risk levels from low to very high, with Cd and Hg posing very high risks. These results suggest that while the dumpsite soil shows improvements in some characteristics favourable for plant cultivation, waste dumping significantly contributes to heavy metal contamination. The soil at the dumpsite is deteriorated and poses significant health risks, particularly due to Cd and Hg. Therefore, remediation efforts should prioritise mitigating the risks posed by Cd and Hg.

Combination therapy: synergism among three plant extracts against selected pathogens.

OBJECTIVE: The synergism among extracts of Senna alata, Ricinus communis, and Lannea barteri, and their anti-infective activities were investigated. The data collected for the antimicrobial activity of the extracts combinations were interpreted to be one of the following categories: synergy; indifferent; additive; or antagonistic. The interpretation was made based on the fractional inhibitory concentration index (FICI) results. FICI of ≤ 0.5 indicates synergism, > 0.5 to 1 indicates additive effects, > 1 to ≤ 4 indifference, and > 4 is considered to be antagonism. RESULTS: Compared with the data of the individual extracts, the MIC values of the extract-extract combinations against all strains of the tested microorganisms were significantly lower, ranging from 0.97 to 1.17, 0.97 to 4.69, 0.50 to 1.17, 1.17 to 3.12 and 2.34 to 4.69 mg/mL for Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia and Candida albicans respectively. L. bateri aqueous-S. alata ethanol extracts and S. alata aqueous-R. cummunis ethanol extracts combinations showed a synergy effect against all the test microorganisms. The other combinations exhibited at least one additive effect. Neither antagonism nor indifference activity was observed. This study validates the relevance of combining these plants in treating infections by traditional medicine practitioners.

Antibacterial and antifungal activities and phytochemical profile of leaf extract from different extractants of Ricinus communis against selected pathogens.

OBJECTIVES: Ricinus communis leaves are used in herbal preparations for treating candidiasis, skin and wound infections in Ghana. This study aimed at comparing the phytochemical profile of aqueous, methanol, petroleum ether, ethyl acetate and ethanolic extracts of the leaves of Ricinus communis and determine the growth inhibitory activities, bactericidal, bacteriostatic and fungicidal effects of the respective extracts on Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonaie and Candida albicans. RESULTS: The aqueous, methanol and ethanol extracts were shown to contain most of the phytochemicals analyzed. All solvents extracts exhibited inhibitory activity against the growth of all microorganisms under study. The methanol extract showed highest zones of inhibition and was found to be statistically significant (P < 0.05) compared to other solvents extracts. All solvents extracts exhibited both bacteriostatic and bactericidal effects on the test organisms at varying concentration, with MIC values ranging from 3.13 to 25.0 mg/ml and MBCs were from 200 to 400 mg/ml. MFCs of Candida albicans was between 200 and 400 mg/l. Our data confirm the anti-bacterial and anti-fungal properties of R. communis and showed that the biologically relevant phytochemicals from the leaves of this plant can be extracted with the solvents aqueous, methanol and ethanol.