Bacterial infections remain a serious health issue; hence there is a need for continuous search for improved anti-microbials. In addition, it is important to understand the antibacterial mechanism of prospective antimicrobials to fully harness their benefits. In this study, the antimicrobial action of silver nanoparticles was investigated. The antimicrobial potential of silver nanoparticles against different strains of bacteria was evaluated after which Escherichia coli and Staphylococcus aureus were selected as model for gram-negative and gram-positive bacteria respectively. Additionally, to determine mechanism of action, some biochemical assays including determination of kynurenine level, DNA fragmentation, lipid peroxidation and antioxidant status were carried out. Results showed that silver nanoparticles caused DNA damage and induced oxidative stress as reflected in elevated nitric oxide production and lipid peroxidation level. In contrast silver nanoparticles increased the antioxidant capacity viz-aviz, elevated levels of total thiol, superoxide dismutase (SOD), and total antioxidant capacity (TAC) compared to untreated cells. They also initiated inconsistent alteration to the kynurenine pathway. Taken together, the findings indicate that silver nanoparticles exhibited antimicrobial action through the promotion of oxidative stress.

Identification and development of newer and better antimicrobials from natural products represent ongoing research efforts by many investigators. Curcumin is a polyphenol commonly found in the plant Curcuma longa (better known as turmeric). It has been reported to possess several bioactivities including antioxidant, anti-cancer, anti-inflammatory, anti-diabetic, anti-fibrotic, and antimicrobial properties. However, little is known about the antimicrobial mode of action of curcumin, thus undermining its prospects as an alternative antimicrobial agent. In this study, we investigated the mechanism of antimicrobial action by curcumin. The mechanism of inhibition was evaluated in representatives of Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) bacteria isolates, treated with either curcumin singly or in combination with ascorbic acid (1000 μg/mL). Results showed that curcumin has broad antimicrobial capacity. In addition, curcumin only and/or co-treatment with ascorbic acid caused lipid peroxidation in S. aureus and E. coli, and by extension led to DNA damage, indicative of oxidative stress. It is plausible that the oxidative might be related to the activation of the kynurenine pathway in S. aureus but not in E. coli. Furthermore, curcumin exposure led to elevated total antioxidant capacity (TAC) and level of total thiol, but decreased nitric oxide level in the bacteria isolates. Together, the findings suggest that oxidative stress and DNA damage might be partly responsible for the antimicrobial action of curcumin.

Heavy metal contamination has gradually become a highly significant global issue due to its continual existence in the environment and bioaccumulation in the ecosystems, posing deleterious risks to human health. This review aims to investigate the sources, pathways, and toxicological impacts of heavy metals such as cadmium, lead, mercury, and arsenic, elucidating their health consequences and plausible mitigation strategies. Furthermore, the review explores the dual origins of heavy metal contamination; natural geological processes and anthropogenic activities such as industrial emissions, mining, and agricultural practices. These heavy metals seep into soil, water, and food chains, leading to bioaccumulation, bio-magnification and causing significant health risks, including cardiovascular diseases, neurological disorders, and reproductive toxicity. Additionally, the addition of indigenous case studies from Nigeria, such as lead poisoning in Zamfara State and contamination in the Great Kwa River of Cross Rivers State underscores the disproportionate impact of heavy metal pollution in developing nations. These case studies reveal the socio-economic and environmental dimensions of the issue, providing a contextual understanding of region-specific vulnerabilities and health outcomes. To address these problems, the review evaluates already existing mitigation strategies, including chelation therapy and phytoremediation, while proposing sustainable, cost-effective solutions for reducing exposure and mitigating impacts. It emphasizes the importance of integrative approaches involving policy, community engagement, and technological innovations to fight heavy metal contamination effectively. In conclusion, this seminar contributes to the understanding of heavy metal toxicity, giving and showcasing very much important insights into the sources and health implications of contamination. By integrating theoretical perspectives with practical solutions, this review provides a robust framework for informing policy makers and advancing sustainable environmental management practices.

Heavy metal contamination has gradually become a highly significant global issue due to its continual existence in the environment and bioaccumulation in the ecosystems, posing deleterious risks to human health. The major objectives of the review is to investigate the sources, pathways, and toxicological impacts of heavy metals such as cadmium, lead, mercury, and arsenic, elucidating their health consequences and plausible mitigation strategies. Furthermore, the review explores the dual origins of heavy metal contamination; natural geological processes and anthropogenic activities such as industrial emissions, mining, and agricultural practices. These heavy metals seep into soil, water, and food chains, leading to bioaccumulation, bio-magnification and causing significant health risks, including cardiovascular diseases, neurological disorders, and reproductive toxicity. Additionally, the addition of indigenous case studies from Nigeria, such as lead poisoning in Zamfara State and contamination in the Great Kwa River of Cross Rivers State underscores the disproportionate impact of heavy metal pollution in developing nations. The key findings from this review via the selected case studies revealed the socio-economic and environmental dimensions of the issue, providing a contextual understanding of region-specific vulnerabilities and health outcomes. To address these problems, the review evaluates already existing mitigation strategies, including chelation therapy and phytoremediation, while proposing sustainable, cost-effective solutions for reducing exposure and mitigating impacts. It emphasizes the importance of integrative approaches involving policy, community engagement, and technological innovations to fight heavy metal contamination effectively. In conclusion, this review contributes to the understanding of heavy metal toxicity, giving and showcasing very much important insights into the sources and health implications of contamination. By integrating theoretical perspectives with practical solutions, this review provides a robust framework for informing policy makers and advancing sustainable environmental management practices.

There is the indication that human deaths as a result of water-borne diseases exceed five million people per year, with over half of the diseases being microbial intestinal infections, especially cholera and diarrhea. A number of pathogenic microorganisms, regarded as water pollution indicators have been observed as the agents of such. These water pollution indicators are present in feces, sewage and can survive as long as pathogenic organisms. These pathogenic microorganisms cause several waterborne infections and diseases like bacterial (cholera, salmonellosis, shigellosis and several diseases associated with pathogenic strains of E. coli), viral (ranging from a mild febrile illness to myocarditis, meningoencephalitis, poliomyelitis, herpangina, hand-foot-and mouth disease and neonatal multi-organ failure), protozoan (cryptosporidiosis, diarrhea encaphilitis, giardiasis, amoebiasis) and fungal (candidiasis, blastomycosis, cryptococcusis, aspergilosis). These biological contaminants that cause several water-borne diseases can however be removed from water through physical (ultraviolet radiation, solar radiation and boiling) and chemical disinfection methods (chlorination, chloramination and ozonation). The aim of this paper was to review the microbial indicators and pathogenic microorganisms in water and wastewater. The paper also discussed the treatment strategies for microbial-contaminated water and wastewaters.