HEALTH RISK ASSESSMENT OF SOME HEAVY METALS AND PHYSICO-CHEMICAL QUALITY OF SURFACE WATER IN BIBIANI A MINING ENCLAVE IN GHANA

The quality of water is a powerful environmental determinant of health, increased productivity and enhanced economic development. Levels of As, Fe, Pb, Zn, and Cu were determined in both water and sediment samples within ten communities in Bibiani and its environs using the Atomic Absorption Spectroscopy. The results for most of the physiochemical parameters determined were below the WHO permissible limits with the exception of colour and turbidity. Cd, Pb, and Zn in water were below detection whereas As were in the range of 0.006 to 0.047 mg/l and Fe below detection to 2.00 mg/l. Pamuso had the highest As the level of 0.480 mg/l whilst Pataboso recorded the least value of 0.006 mg/l. Fe in two communities were above the limit but Cu was within the WHO limit. The mean levels of heavy metals in sediment obtained were in the range of: As (1.451 to 4.220); Cd (below detection to 1.104 mg/kg); Cu (below detection to 3.951 mg/kg); Fe (46.215 to 549.450 mg/kg); Zn (0.351 to 2.350 mg/kg) whilst Pb was below detection. The HI results in six communities were above the guidance value of 1.0 for adults and in all samples for children which is likely to pose risk to human health. Moreover, the CRing for As was above the USEPA guidance value of 1 x 10-6 in all the communities which imply consumers are likely to be exposed to cancer risk. The concentrations of As, Cd, Cu and Zn in the sediments were lower than the corresponding effect range low (ERL) values in the sediment quality guidelines and could have no adverse effects on aquatic organisms

Hydrochemical characteristics of surface water and ecological risk assessment of sediments from settlements within the Birim River basin in Ghana

Abstract Background Geogenic and anthropogenic activities such as Artisanal and illegal gold mining continue to have negative impacts on the environment and river basins in China. This work studied the hydrogeochemical characteristics of surface water from the Birim River basin and assess the quality of water for human consumption and agricultural activities. In addition, the ecological risk assessment for Cd, Zn, Pb and As in sediment was evaluated using pollution indices. Results The results show that the turbidity, temperature, colour and iron concentration in the water samples were above the World Health Organization guidelines. Multivariate analysis explained five components that accounted for 98.15% of the overall hydrogeochemistry and affected by anthropogenic and geogenic impacts. The surface water was observed to range from neutral to mildly acidic, with the dominance of HCO3 −, Cl−, Ca2+, Mg2+, and Na+ in ionic strength. The Piper diagram reveals five major surface water types: Na–HCO3–Cl, Na–Cl–HCO3, Na–Ca–Mg–HCO3, Na–Ca–Mg–HCO3 and Ca–Na–Mg–HCO3. The Gibbs plot showed that the major ion chemistry of surface water was mostly influenced by atmospheric precipitation and the water quality index showed that the majority of the surface water from settlements within the Birim River basin were of poor quality for drinking and other domestic purposes. However, irrigation suitability calculations with reference to sodium adsorption ratio, residual sodium carbonate, and magnesium ratio values, together with Wilcox and USSL models indicated that the surface water within the area under study was suitable for agriculture. The potential ecological risk for single heavy metals pollution and potential toxicity response indices gave low to considerable ecological risks for the sediments, with greater contributions from Cd, Pb and As. Whilst geo-accumulation indices indicated that the sediments ranged from unpolluted to moderately polluted Modified degree of pollution and Nemerow pollution index calculations which incorporate multi-element effects, however, indicated no pollution. Conclusion There are some levels of both potential ecological risks and health hazards in the study area. Hence continuous monitoring should be undertaken by the relevant agencies and authorities so that various interventions could be put in place to prevent the situation from deteriorating further in order to protect the inhabitants of the settlements within the Birim River basin

Role of BaTiO3 crystal surfaces on the electronic properties, charge separation and visible light–response of the most active (001) surface of LaAlO3: A hybrid density functional study

Surface engineering has been proved as an efficient technique to boost charge separation and visible light absorption of semiconductor photocatalyst materials. Herein, we offer a first insight into the photocatalytic properties and electronic structure of cubic LaAlO3(001) modified with cubic BaTiO3 (001), (011) and (111) surfaces. Compared to the bulk LaAlO3, the BaTiO3/LaAlO3(001) heterostructures showed superior redshift of absorption, work functions and a suitable staggered type–II band alignment to separate the photoinduced carriers. The BaTiO3(001) surface coupled with LaAlO3(001) surface show improved visible light photoactivity owing to the more surface complex and terminal barium atoms forming the main active adsorption sites on its surface. These findings offer new insight into the understanding of preferential exposure of photocatalytic active surfaces, which will aid in designing active heterostructures for photocatalytic reactions, as well as understanding the mechanism of photocatalysis

Formaldehyde Exposure and Its Potential Health Risk in Some Beauty Salons in Kumasi Metropolis

Cosmetologists may be potentially exposed to high levels of formaldehyde as a result of their exposure to formaldehyde released from the various cosmetic products used in the beauty salons. In order to assess the exposure of cosmetologists to formaldehyde, the indoor air in sixty beauty salons across the ten submetros in Kumasi were sampled to determine the formaldehyde levels and the associated noncarcinogenic human health risks. Sampling was done using System Service Innovation Incorporation air sampler model 1000i, and the MBTH spectrophotometric method was used for analysis. The mean levels of formaldehyde concentrations ranged from 88.67 to 170.67 µg/m3. Out of the sixty salons sampled, 36 salons had formaldehyde levels above the WHO permissible limit of 100 µg/m3 for an eight-hour working period and also exceeded the 55 and 9 µg/m3 for chronic and acute reference exposure limit, respectively, set by the Office of Environmental Health Hazard Assessment. The results of this study revealed that the number of customers that visit the salon in a week, number of salon services offered, and age of salon had a positive significant correlation with the level of formaldehyde determined in each salon. The health risk study also revealed that about 50% of the salons had hazard quotient (HQ) above the safety limit (HQ = 1) and may, therefore, pose health risks to cosmetologists in these salons. Results from the analysis of the questionnaire revealed that hairdressers in salons that provide the entire range of salon services captured in the study are at higher risk to the effects of formaldehyde

Experimental and ab initio studies of enhance photocatalytic efficiency of La-doped ZnO/g-C3N4 nanocomposites for bromothymol blue dye degradation

The ability of photocatalysis to clean up environmental contamination, notably in the treatment of water and air, has received extensive research. The composite materials synthesized by the coprecipitation method were made of ZnO and graphitic carbon nitride (g-C3N4) with various concentrations of lanthanum doping (La-ZnO). It was discovered that La metal ions were evenly distributed throughout the layered stacking structures of ZnO nanosheet, which had an impact on the band structure and increased the rate of electron-hole separation and visible light absorption. First-principles calculations show that La-doped ZnO-gC3N4 possesses a direct band gap and a type-II band structure with the conduction band minimum and the valence band maximum located in separate layers. A built-in electric field from the gC3N4 to the La-doped ZnO has been established through an analysis of charge density difference, Bader charge, work function, and band alignment. The electron-hole pair becomes spatially separated as a result, which increases the photodegradation activity. High interfacial charge transfer, efficient charge separation and migration, and high visible light optical absorbance were caused by the direct coating of ZnO on an ultra-thin g-C3N4 layer. The 0.6 % La-doped ZnO-gC3N4 degraded 97 % of the bromothymol blue (BB) dye, which was four times higher than the bulk ZnO, which could remove only about 21 % of the dye at the same time. The combined effects of lower photo corrosion, higher solar light usage owing to a hollow structure and heterostructured semiconductor photocatalysis contribute to this increased photocatalytic activity. The capacity of La-doped ZnO/g-C3N4 nanocomposite to effectively break down BB dye via photocatalysis suggests that it has the potential to address the problems associated with dye pollution in water systems

La–doped ZnO–rGO nanocomposites: Synthesis and characterization as photocatalyst for effective degradation of bromothymol blue dye in water

Several techniques for eliminating organic dyes and pesticides present in water and wastewater have been developed to lessen their negative environmental effects. The use of semiconductor photocatalysts to break down organic pollutants like dyes and insecticides has garnered a lot of interest recently. In this work, we have prepared simple, quick, and high–yielding La–doped ZnO–rGO nanoparticles that can be used for photocatalytic degradation. The prepared nanoparticles were characterized by various methods including morphological, optical, and photocatalytic properties using cutting–edge technologies like Transmission electron microscopy, energy dispersive spectroscopy, ultraviolet–visible spectroscopy, X–ray diffraction and scanning electron microscopy. The study investigated the photocatalytic action of La–doped ZnO–rGO nanocomposites under visible light irradiation and bromothymol blue as a module dye. According to the findings, La–doped ZnO–rGO nanoparticles demonstrated discernible photocatalytic performance, with the 0.6% La–doped ZnO–rGO exhibiting the best degradation percentage of 81% in 210 min and a rate constant of 1.158 × 10−3 min−1