SOUTHERN JOURNAL OF SCIENCES

Background: Dams are one of the biggest threats to aquatic biodiversity. They restrict the movement of migratory fish. The construction of barriers can cause the complete extinction of some species from the rivers. When a dam can no longer perform its function or research will determine the need to demolish it, dams are often removed. In the lower part of the Enguri River, Georgia, an irrigation weir is currently non-functional. Aims: This research aims to prove the need to demolish the dam construction on the 44th km of the Enguri River, as it negatively impacts biodiversity and creates an artificial barrier in the river. Methods: Visual inspection was used as a method to assess the morphology and habitat of the dam where it is located. The conversation method was used with Engurhesi LTD representatives to understand the current function of the dam. The Questions were related to the current function of the dam. Results: Based on the conservation with Engurhesi LTD representatives, the study has shown that there is no reason that an irrigation weir might be left in its current state on the Enguri River. Based on the studies, the damage to biodiversity is real and disturbing. Discussion: The irrigation weir on the Enguri River was left untended because of the construction of the Enguri dam. Currently, there is no reason to divert the river Enguri with the help of an irrigation weir as there is no excess water in this river. Conclusions: In conclusion, it can be said that it is necessary to remove the irrigation weir on the Enguri River to restore habitat and mitigate the threats to biodiversity.

Background: Antibiotic resistance is currently one of the biggest problems in public health. Infectious diseases are the second human death cause, and the emergence of antimicrobial-resistant bacteria increases mortality and morbidity rates. There is a growing clinical need for the development of new antibiotics. In this line, WHO issued an alert about 12 bacteria with an urgent need to develop new antibiotics. Aims: This review aims to analyze the current knowledge of their antibacterial activity against the gram-positive pathogens listed by WHO and their extraction techniques. Methods: We systematically reviewed the literature in PubMed, searching publications describing the use of natural extracts as antibiotics over bacteria. The exclusion criteria consisted of limiting papers on natural extracts tested over the bacteria culture related to eleven selected bacteria, according to an alert issued by WHO in 2017, and seven plant extracts. Results: All the gram-positive bacteria present in the WHO alert have been treated, with different degrees of advance, with some of the plant extracts and plant-based compounds reviewed. Currently, they are in the preclinical stage. Edible herbs are more often used, as well as artemisia and wine byproducts. Discussion: Natural products based on plants have shown to be efficient in inhibiting bacterial growth, even in antibiotic-resistant strains. The classical extraction methods are still in use and have been improved with the available technology to improve efficiency and yield. Conclusions: Ongoing evidence shows that plant extracts and plant-based compounds are effective as antibacterial, with minimal effects on the host cell, a promising antibiotic source. Furthermore, they are sustainable, environmentally friendly, and renewable.

Background: Industrial wastewater contains pollutants that are detrimental to human health in varied proportions. Among the pollutants are heavy metals, including Zn2+, Pb2+, and Cu2+ found in a characterized pharmaceutical wastewater. Several techniques have been proposed for the heavy metal sequester. However, they are with attendant challenges. The adsorption techniques using clay-metal oxide modified adsorbent/composite such as silver-clay adsorbent is considered suitable for an effective sequestering process. Aims: To develop and characterize Ag/clay adsorbent for pharmaceutical wastewater treatment. Methods: The Ag nanoparticles were synthesized using Parkia biglobossa aqueous leaves extract in an optimization study. The raw clay was beneficiated and doped with silver nanoparticles via the wet impregnation method. The silver-clay adsorbent was characterized using FTIR, XRD, SEM, and EDS characterization tools. The developed adsorbent was used for the batch adsorption process of the heavy metal ion removal from the wastewater. Results and Discussion: The phytochemical analysis and FTIR results of the P. biglobosa showed that the leaf contains phenol, tannin, and flavonoids which acts as reducing, capping, and stabilizing agent required for synthesizing the silver nanoparticles. The prepared silver nanoparticles modified clay adsorbent Ag/clay, have evenly distributed stacks of pseudo-hexagonal plates, are rich in silica, possess silver nanoparticles in the frameworks, and contain functional groups suitable for binding heavy metals. The adsorptions of Zn2+, Pb2+, and Cu2+ from pharmaceutical wastewater onto the silver-modified clay were studied as a function of adsorbent dosage and contact time. The percentage removal results obtained showed that the adsorbent had up to 99.96%, 99.5%, and 99.44% removal efficiency for Zn2+, Pb2+, and Cu2+, respectively, which are better compared with previous studies. The adsorption process was feasible, spontaneous, and exothermic, with Langmuir and Pseudo-second-order models as best fits for the process. Conclusions: The adsorption of selected heavy metal ions onto the green synthesized silver-modified clay adsorbent (Ag/clay) was feasible, spontaneous, and exothermic in the order Zn2+>Pb2+>Cu2+ with Langmuir and Pseudo-second-order model best fitted for the process. These show that the synthesized silver oxide nanoparticles supported on local clay can be used as a potentially low-cost adsorbent to remove heavy metal ions from industrial wastewater.