APPLIED CHEMICAL SCIENCE LABORATORY TECHNOLOGY

Point-of-sale (POS) machines are widely used for cashless transactions in Nigeria, but frequent handling by multiple users makes their keypads potential fomites for microbial transmission. This research aimed to determine the microbial load, public health risk and antimicrobial resistance patterns present on POS keypads sampled from twenty locations between Five Junction and First East Circular Junction, Benin City. 20 Swab samples were used to swab on the screen or button of the POS machines to collect isolates. The bacterial isolates were identified using morphological, microscopic and biochemical techniques. Antibiotic susceptibility testing was conducted to determine resistance profiles of the bacterial isolates. Analysis of bacterial counts revealed considerable contamination, ranging from 1.5 × 10³ cfu/ml to 6.55 × 10 4cfu/ml. Four bacterial species were identified which were Staphylococcus spp. (34.15 %), Pseudomonas spp. (26.83 %), Aeromonas spp. (24.40 %) and Enterococcus spp. (14.63 %). Antibiogram results demonstrated multidrug resistance, particularly in Pseudomonas sp. which showed resistance to several antibiotics including streptomycin and chloramphenicol. The presence of pathogenic and multidrug-resistant bacteria on POS keypads indicates their potential role in the transmission of infectious diseases and antimicrobial resistance within the community. Nevertheless, further research is needed to establish effective disinfection practices, determine the frequency of contamination and evaluate the impact of hyg

This study evaluated the non-carcinogenic health risks associated with dermal exposure to heavy metals chromium (Cr), lead (Pb) and zinc (Zn) in groundwater from Ikpeshi, Edo State, Nigeria. The research aimed to quantify metal concentrations, assess health risks across population groups, identify contamination sources and propose mitigation strategies. Groundwater samples were analyzed and risk assessment models were applied using Chronic Daily Intake (CDI), Hazard Quotient (HQ) and Hazard Index (HI) frameworks as outlined by the United States Environmental Protection Agency (USEPA, 2004). Results revealed that chromium exhibited the highest mean concentration (0.177 mg/L), followed by zinc (0.257 mg/L) and lead (0.016 mg/L). Both Cr and Pb levels exceeded the permissible limits set by the World Health Organization (WHO, 2017) and USEPA, primarily due to artisanal and small-scale mining, mine tailings leaching and oxidation of metal-bearing minerals within the Igarra schist belt. Risk assessment outcomes indicated that children are more vulnerable to dermal exposure than adults, given their higher skin surface area-to-body weight ratio and frequent water contact. Chromium was identified as the dominant contributor to non-carcinogenic risks, followed by lead, while zinc
showed minimal contribution. Some HI values for children exceeded unity, indicating potential chronic health effects and the mean carcinogenic risk (CR) for Cr approached the USEPA threshold of 1 × 10⁻⁴. The study concludes that chromium and lead pose significant public health
concerns in Ikpeshi groundwater. The findings emphasize the need for effective groundwater monitoring, regulation of mining effluents and community-based mitigation strategies such as the use of affordable household filtration systems, rainwater harvesting and public health education to reduce dermal exposure risks and safeguard water quality.

Heavy metal content was determined by analyzing water samples taken from Ebira camp, Akoko Edo Local Government, Edo state. In all, ten samples were taken at ten distinct Ebira camp sampling sites. With the aid of the Atomic Absorption Spectrometer (AAS), the samples were
examined and tested for five distinct heavy metals: iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), and nickel (Ni). The average concentrations of these heavy metals are 1.0384, 0.5362, 0.2975, 0.0376, and 0.0244 mg/l for Fe, Zn, Cu, Mn, and Ni, respectively. The acquired results
were compared to the 2011 WHO standard, which corresponds to Fe, Zn, Cu, Mn, and Ni values of 0.3, 1.0, 2.0, 0.1, and 0.1, respectively. With the exception of iron, which has a mean iron content higher than the WHO guideline, the results indicated that the concentration of heavy metals in the area was generally lower than levels permitted by the WHO. The possibility exists that an excessive amount of iron in the groundwater could promote the growth of bacteria responsible for the foul smell. Geospatial analysis of the gathered data was done using geographic information system (GIS) software. Maps showing pollution concentrations and patterns of spatial distribution were produced using spatial interpolation techniques (kringing or inverse distance weighting).
According to the heavy metals' spatial distribution map, manganese (Mn) levels varied greatly throughout the region, with the eastern and northeastern regions exhibiting the highest values. According to the nickel concentration map, the region's southwest is where the concentration of
nickel increases most unevenly. The zinc content of the water rose non-uniformly from the community center to the boundary, according to the spatial distribution map of zinc. The spatial distribution map of copper reveals that the amount of copper in groundwater rose unevenly from
the region's center to its borders, with the community's center having the lowest level of copper and the region's northeastern regions having the highest copper value. The spatial distribution map of iron indicates that there was also a non-uniform increase in the iron content of the water.
Anthropogenic factors, such as factories or industries, agricultural practices, or geogenic processes, such as variations in the composition of the underlying rock or soil, are to blame for the irregularities in the geographical distribution maps. It may also be connected to the metallic ion
concentration and volume at each site. The groundwater in the study area, is generally less contaminated by heavy metal pollution, with little to no contamination index.Heavy metal content was determined by analyzing water samples taken from Ebira camp, Akoko Edo Local Government, Edo state. In all, ten samples were taken at ten distinct Ebira camp sampling sites. With the aid of the Atomic Absorption Spectrometer (AAS), the samples were examined and tested for five distinct heavy metals: iron (Fe), zinc (Zn), copper (Cu), manganese
(Mn), and nickel (Ni). The average concentrations of these heavy metals are 1.0384, 0.5362, 0.2975, 0.0376, and 0.0244 mg/l for Fe, Zn, Cu, Mn, and Ni, respectively. The acquired results were compared to the 2011 WHO standard, which corresponds to Fe, Zn, Cu, Mn, and Ni values
of 0.3, 1.0, 2.0, 0.1, and 0.1, respectively. With the exception of iron, which has a mean iron content higher than the WHO guideline, the results indicated that the concentration of heavy metals in the
area was generally lower than levels permitted by the WHO. The possibility exists that an excessive amount of iron in the groundwater could promote the growth of bacteria responsible for the foul smell. Geospatial analysis of the gathered data was done using geographic information system (GIS) software. Maps showing pollution concentrations and patterns of spatial distribution were produced using spatial interpolation techniques (kringing or inverse distance weighting).
According to the heavy metals' spatial distribution map, manganese (Mn) levels varied greatly throughout the region, with the eastern and northeastern regions exhibiting the highest values. According to the nickel concentration map, the region's southwest is where the concentration of
nickel increases most unevenly. The zinc content of the water rose non-uniformly from the community center to the boundary, according to the spatial distribution map of zinc. The spatial distribution map of copper reveals that the amount of copper in groundwater rose unevenly from
the region's center to its borders, with the community's center having the lowest level of copper and the region's northeastern regions having the highest copper value. The spatial distribution map of iron indicates that there was also a non-uniform increase in the iron content of the water. Anthropogenic factors, such as factories or industries, agricultural practices, or geogenic processes, such as variations in the composition of the underlying rock or soil, are to blame for the irregularities in the geographical distribution maps. It may also be connected to the metallic ion concentration and volume at each site. The groundwater in the study area, is generally less contaminated by heavy metal pollution, with little to no contamination index.