World Health Organization Limits Research Articles

Investigation the Level of Groundwater Pollution with Heavy Metals in Mazar-e-Sharif City

The majority of drinking and consumable water sources for the residents of Mazar-e-Sharif city are supplied from underground water. Climate variations, depletion of underground water, pollution resulting from human activities, agriculture, industrial processes, and urban development have significantly impacted the quality of underground water in this region. In this research, the quality of groundwater in terms of contamination with heavy metals such as manganese, copper, aluminum, iron, cadmium, mercury, lead, and arsenic was investigated. Twenty-four random well samples were collected based on international sampling standards, and temperature and pH parameters were measured on-site. The concentration of heavy metals was measured using an atomic absorption spectrophotometer. Data analysis was performed using Excel and SPSS software, and GIS software was utilized for mapping the sampled points. Laboratory results indicated that the lead concentration in wells W6, W11, W20, and W22 was 0.014, 0.013, 0.02, and 0.012 milligrams per liter, respectively. The aluminum concentration in wells W5, W16, and W17 was 0.6, 0.5, and 0.4 milligrams per liter, respectively, and the cadmium concentration in well W3 was 0.005 milligrams per liter. The concentrations in these wells exceeded the recommended limits set by the World Health Organization (WHO). In the remaining wells, the concentrations of heavy metals were below the WHO limits. Descriptive statistics results showed that copper had the highest average concentration, and arsenic had the lowest concentration. Since underground water is the sole source of drinking and consumable water for the city's residents, it is recommended to conduct a systematic study of heavy metal concentrations in groundwater sources to reduce the adverse effects of contaminated water in certain wells.

Assessment of ground-level ozone pollution in Türkiye according to new WHO limits.

Ground-level ozone is a secondary pollutant and is attributable to respiratory diseases and mortality. For this reason, the World Health Organization (WHO) implemented a new long-term (peak season) limit value for ozone. The previous studies related to ozone in Türkiye were spatially limited to certain locations. In this study, annual mean and peak season ozone concentrations, and limit exceedances were investigated for Türkiye for the year 2021. Moreover, ozone peak seasons were determined for the first time for 126 air quality monitoring stations. The annual mean ozone concentration was determined as 44.3 ± 19.3 µg/m3 whereas the peak season average ozone level was 68.4 ± 27.2 µg/m3. April-September period was the most frequently observed ozone peak season. Among all stations, Erzurum Palandöken was by far the most polluted station in terms of annual mean and limit exceedances of ozone. Ankara Siteler stations have the highest rank in peak season mean. 87 and 83 stations exceeded the short-term and long-term recommendations of WHO, respectively. Four hotspot regions were revealed in terms of peak season exceedance: Adana and surrounding provinces, the surroundings of Burdur and Isparta provinces, and the northeastern and northwestern parts of Türkiye. To protect public health, WHO recommendations for 8-h and peak season limits should be immediately implemented in Turkish regulations.

Spatial health risk assessments of nickel in the groundwater sources of a mining-impacted area

Mining activities have increased the potential risks of metal pollution to the groundwater resources in arid areas across the globe. Therefore, this study aimed to examine the health risk associated with nickel (Ni) in the groundwater sources of a mining-impacted area, South Khorasan, Eastern Iran. A total of 110 stations were included in the study, comprising 62 wells, 40 qanats, and 8 springs in summer, 2020. Initially, the collected samples were tested for temperature, pH, and electrical conductivity (EC). Subsequently, the samples were filtered and treated with nitric acid (HNO3) to measure the concentration of Ni using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Hazard quotient (HQ) and non-carcinogenic risk assessments were employed to evaluate the potential risks of Ni to the inhabitants. The findings revealed that the concentration of Ni ranged from 0.02 to 132.39 μg l−1, and only two stations exhibited Ni concentrations above the WHO standards (20 μg l−1). The results demonstrated that 98.21% of the sampled locations had HQ values below one, indicating negligible risk, while 1.78% of the stations exhibited HQ values of one or higher, representing a high non-carcinogenic risk for water consumers. Overall, the concentration of nickel in the groundwater of South Khorasan exceeded the World Health Organization (WHO) limit solely in the Halvan station, posing a non-carcinogenic risk for the residents in that area, and therefore, additional efforts should be made to provide healthier groundwater to consumers in this region.

Modified Rice Husk Waste‐Based Filter for Wastewater Treatment: Pilot Study and Reuse Potential

AbstractThis study investigates a rice husk waste‐based filter (RHW‐BF) for the treatment of graywater (GW) and primary treated wastewater (PTW). The RHW‐BF comprises three layers: coarse sand, chemically modified rice husk (MRH), and gravel. Continuous runs (Run I, II, III) assessed chemical oxygen demand, total suspended solids, total dissolved solids, and turbidity removal. Run (I) for GW achieved high removal: 73.7 %, 73.4 %, 74.6 %, and 92.6 %. Subsequent runs showed decreasing efficiencies due to media saturation. Similar trends occurred for PTW, with Run (I) achieving significant removal: 70.3 %, 69.0 %, 44.2 %, and 90.2 %. MRH particles played a crucial role in sustainable pollutant removal. The study compares treated wastewater with the World Health Organization and Egyptian limits, demonstrating its suitability for reuse in irrigation, agriculture, or sewer discharge.

Pollution, spatial distribution, and health risks assessment of nutrient concentration in surface water resources of Maroon-Jarahi Basin in southwestern Iran.

Nowadays, the introduction of nutrients caused by human activities is considered an environmental issue and a significant problem in river basins and coastal ecosystems. In this study, the concentration of nutrients ( and ) in the surface water sources of the Maroon-Jarahi watershed in the southwest of Iran was determined, and the pollution status and health risk assessment were done. The average concentration of nitrate and phosphate in Ludab, Maroon, Zard, Allah, Jarahi rivers, and Shadegan wetland were obtained at 2.25-0.59, 4.59-1.84, 4.07-2.02, 5.40-2.81, 11.51-4.67, 21.63 and 6.20 (mg/l), respectively. A comparison of the results with the World Health Organization (WHO) limit showed that nitrate was lower than in all stations, but phosphate was higher than the limit in some stations of the Maroon, Allah, Jarahi rivers, and Shadegan wetland. Calculation of linear regression analysis showed significant positive relationships between nitrate and phosphate in all surface water sources (except Ludab) and based on the N/P ratio, nitrogen was estimated as the limiting factor in phytoplankton growth (N/P < 16). The evaluation of the status of the Nutrient pollution index (NPI) was observed as: Shadegan > Jarahi > Allah > Maroon > Zard > Ludab that the Jarahi River and Shadegan wetland were in the medium pollution class (1 < NPI ≤ 3) and other waterbodies were in the non-polluted to low pollution state (NPI < 1). Calculation of the chronic daily intake (CDI) showed that water body nutrients cause more non-carcinogenic health risks through the oral route than dermal exposure, and according to HI, children's health is more at risk than adults. Findings showed that surface water resources especially downstream of the Maroon-Jarahi watershed are at eutrophication risk, and to control the nearby human activities and as a result increase the nutrients in these water resources, measures should be taken.

Risk assessment of four toxic heavy metals in terrestrial and aquatic ecosystems around BSCIC tannery industrial estate of Savar, Dhaka,Bangladesh.

The shifting of tannery industries from Hazaribagh to Savar adjacent to Dhaleshwari River might have inevitable adverse impacts, especially the heavy metal contamination of both terrestrial and aquatic ecosystems. The study was carried out to investigate the concentrations of four heavy metals in the soil, water, and plant samples collected from around Dhaleshwari River adjacent to the Bangladesh Small & Cottage Industries Corporation Tannery Industrial Estate, Dhaka. This study revealed that average concentrations of cadmium and chromium in soil exceeded the maximum permissible limit of World Health Organization (1996) and average concentrations of lead, cadmium, and chromium in water exceeded the maximum permissible limit of World Health Organization (2011) and Environmental Conservation Rules (1997). The average concentrations of lead, cadmium, and chromium in the roots and shoots of both Eichhornia crassipes and Cynodon dactylon exceeded the maximum permissible limit of Food and Agriculture Organization/ World Health Organization (2016). Ecological risk assessment using indices model for soil pollution indicated that soil is mostly contaminated with cadmium and chromium which can pose strong ecological risk Health risk assessment using indices model for water pollution revealed the high degree of contamination and unacceptable non-carcinogenic risk and carcinogenic risk for adults as well as children through ingestion of water. Average bioconcentration factor and bioaccumulation factor were higher in Eichhornia crassipes than Cynodon dactylon for lead, cadmium, and chromium. Average translocation factor was also higher in Eichhornia crassipes for all the metals except cadmium. It is suggested remedial and mitigation measures be instituted to control environmental degradation of the newly established Tannery Industrial Estate.

Diagnosis of Crude Oil Impacted Soil in Eleme Local Government Area, Rivers State, Nigeria

This study assessed the potential effects of crude oil on soil quality in Eleme Local Government Area of Rivers State. Soil samples were collected from 10 geopolitical wards of the Eleme Local Government Area of Rivers State, Nigeria. The soil and water samples were subjected to physicochemical and microbial analyses to test for pH, heavy metal content (Cadmium, Iron, Lead, Copper, and Chromium), Total Petroleum Hydrocarbon (TPH), Benzene, Toluene, Ethylbenzene and Xylene (BTEX) contents and Total Viable Count (TVC). Parameters of the soil were determined and compared to the control site and the permissible World Health Organization (WHO) limits. The soil pH varied across location, ranging from 5.5-7. TPH varied in across the different communities studied, ranging from 1.275-4889.29 mg/kg, and exceeding the WHO limit of 10mg/kg in all polluted soils. The result for the heavy metals showed that the soil samples of the studied sites showed increases in all heavy metals, when compared to the control. Cd values ranged from 0.01 - 0.32 mg/kg; Fe from 1325.23 - 9364.76 mg/kg, Pb from 0.001 mg/kg to 0.93 mg/kg and Cr from 0.001 - 5.08 mg/kg, all with WHO limits. The result for the microbial showed increases in TVC content in polluted soil. Results indicate that crude oil spillage has led to significant contamination of soil in the study area which could affect soil fertility.

ASSESSMENT OF HEAVY METAL CONTAMINATION IN FISH AND WATER SAMPLES FROM BABBAN WUYA MADACHI RIVER: IMPLICATIONS FOR HUMAN HEALTH AND ENVIRONMENTAL SUSTAINABILITY

This manuscript investigates the presence and concentration of heavy metals, namely zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd), in water and two commonly consumed fish species (Tilapia and Catfish) from the Babban Wuya Madachi River. Heavy metal contamination poses significant risks to both human health and environmental sustainability. The study employs Atomic Absorption Spectroscopy (AAS) to analyze heavy metal concentrations in water and fish samples collected from ten different points along the river. The mean concentration of Zn, Cu, Pb, and Cd in the Tilapia fish, Catfish and water are 50.85 ± 0.22, 2.84 ± 0.27, 7.89 ± 0.78, 0.80 ± 0.02 mg/kg; 33.87 ± 1.08, 1.49 ± 0.10, 3.74 ± 0.42, 0.33 ± 0.01mg/kg; and 0.07 ± 0.00, 0.09 ± 0.00, 0.05 ± 0.02, BDL mg/L respectively. Results indicate that water concentrations generally fall below World Health Organization (WHO) standards, while the concentrations of certain heavy metals in fish samples exceed WHO limits, notably Zn, Pb, and Cd. Moreover, concentration of Cu in fish samples is within the standard WHO limit of 2.25 mg/kg and in water its concentration is below the standard limit of 2mg/L. It has been reported that, heavy metals such as Zinc, Cd and Pb has a unique behavior that once absorbed by man it retained in the body system for long and accumulate to cause kidney problems and born demineralization through direct bone damage or indirect through renal dysfunction. The findings underscore the necessity of continued monitoring...

EVALUATION OF HEAVY METALS' CONCENTRATION AND PHYSICOCHEMICAL PARAMETERS OF GROUNDWATER WITHIN JOS METROPOLIS OF PLATEAU STATE, NIGERIA

This paper studied the quality of drinking water from borehole sources in Jos and its environs. The level of heavy metal concentrations and some physicochemical parameters were determined using standard methods. The result of heavy metal concentrations analyzed within the ten (10) sampling points shows that JS1 sampling point had a significantly high (p&lt;0.05) concentration of copper (0.0064 mg/L) and lowest in JS1 sampling point (0.001 mg/L). Chromium had a significantly high (p&lt;0.05) concentration in JS10 sampling point (0.718 mg/L) and lowest in JS1 (0.153 mg/L). Manganese had significantly high (p&lt;0.05) concentration in JS4 sampling point (0.198 mg/L) and lowest in (JS6 0.020 mg/L). Iron was significantly high (p&lt;0.05) in JS4 sampling point with the concentration of 1.388 mg/L and lowest value of 0.020 mg/L in JS5. Zinc had a significantly high (p&lt;0.05) in JS4 sampling point with the concentration of 0.085 mg/L. Lead had significantly high (p&lt;0.05) in JS8 sampling point with a concentration of 0.005 mg/L. Cadmium and nickel were not detected in all ten (10) sampling points. The electrical conductivity and pH and were found to be in the range of (0.000 - 350 µSv/cm) and (4.81 – 6.70), respectively. This research findings suggest that continued water quality monitoring should be carried out to check the concentration levels of copper, zinc, manganese, cadmium, nickel, lead and physicochemical parameters electrical conductivity and pH in those ten (10) sampling points to prevent them from been above the limit of World Health Organization (WHO) permissible limit and also creating...

Generation of PM10 Map with Sentinel-2 Satellite Images: The Case of Çankırı Province

Air pollution, which is characterized as a global environmental problem, negatively affects life in Turkey as a result of the increase in the amount of energy needed and uncontrolled construction. In order to minimize the health impacts of air pollution, air quality should be monitored regularly and necessary steps should be taken to improve it. With the innovations in satellite technologies, the air quality of large areas can be monitored with the help of satellite images and effective solutions can be produced in many areas such as the detection of air pollutant parameters and the creation of thematic maps. The main objective of the research is to investigate the relationship between in-situ measured PM10 parameters and Sentinel-2 satellite data and to map PM10 based on this relationship. In this context, PM10 parameters measured in the field on two different dates and Sentinel-2 satellite images dated 22.11.2021 and 16.04.2022 were used as data sources. The relationship between the data used was established by multiple regression analysis. The coefficients obtained from the analysis results were applied to the relevant bands and thematic maps were created using satellite images. The correlation coefficients of 0.80 and 0.79 calculated by regression analyses indicate that sufficient accuracy was achieved in the research. The results of the study show that satellite imagery provides accurate data for PM10 estimate and that pollution exceeds World Health Organization limits in the road transportation network and industrial areas.

Long-term exposure to ambient air pollution and risk of microvascular complications among patients with type 2 diabetes: a prospective study.

Patients with type 2 diabetes (T2D) may disproportionately suffer the adverse cardiovascular effects of air pollution, but relevant evidence on microvascular outcome is lacking. We aimed to examine the association between air pollution exposure and the risk of microvascular complications among patients with T2D. This prospective study included 17 995 participants with T2D who were free of macro- and micro-vascular complications at baseline from the UK Biobank. Annual average concentrations of particulate matter (PM) with diameters <2.5 μm (PM2.5), <10 μm (PM10), nitrogen dioxide (NO2) and nitrogen oxides (NOx) were assessed using land use regression models. Cox proportional hazards regression was used to estimate the associations of air pollution exposure with incident diabetic microvascular complications. The joint effects of the air pollutant mixture were examined using quantile-based g-computation in a survival setting. In single-pollutant models, the adjusted hazard ratios (95% confidence intervals) for composite diabetic microvascular complications per interquartile range increase in PM2.5, PM10, NO2 and NOx were 1.09 (1.04-1.14), 1.06 (1.01-1.11), 1.07 (1.02-1.12) and 1.04 (1.00-1.08), respectively. Similar significant results were found for diabetic nephropathy and diabetic neuropathy, but not for diabetic retinopathy. The associations of certain air pollutants with composite microvascular complications and diabetic nephropathy were present even at concentrations below the World Health Organization limit values. Multi-pollutant analyses demonstrated that PM2.5 contributed most to the elevated risk associated with the air pollutant mixture. In addition, we found no interactions between air pollution and metabolic risk factor control on the risk of diabetic microvascular complications. Long-term individual and joint exposure to PM2.5, PM10, NO2 and NOx, even at low levels, was associated with an increased risk of diabetic microvascular complications, with PM2.5 potentially being the main contributor.

Spatial Trends and Distribution Patterns of Toxic Heavy Metal Contamination in an Urbanized Watershed

Rapid urban growth in developing nations exacerbates pressures on water resources through increased pollution loading if management practices cannot adapt efficiently. This study evaluated industrial effluent impacts on river systems in Nigeria contaminated by discharge from beverage, oil and biscuit manufacturing plants. Physicochemical parameters and heavy metal concentrations were monitored at sites upstream and downstream from waste outfalls during wet and dry seasons. Results demonstrated exceedances of national water quality standards for indicators of organic pollution like biochemical oxygen demand and chemical oxygen demand. Notably, highly toxic heavy metals exceeded World Health Organization limits by over 100 times, posing serious public health concerns through various exposure pathways. Seasonal variations reflected changes in pollution inputs. Spatial trends showed metal levels decreasing with distance, though remaining well above safe levels 100m downstream. A predictive transport model was formulated based on field measurements incorporated into the advection-dispersion equation. Key coefficients for the dispersion rate and velocity/dispersion ratio were quantified, allowing simulation of concentration changes under differing scenarios. Model predictions closely aligned with observed metal distribution patterns. Findings highlight the need for upgraded wastewater treatment and emissions controls to mitigate pollution over-burdening natural assimilative capacity. Continuous monitoring programs should track remediation effectiveness. This study provides insights to help authorities balance rapid industrialization, environmental protection and sustainable development goals through evidence-based regulatory strategies ensuring public health.

Microbiological quality of irrigation water on highly diverse fresh produce smallholder farms: elucidating environmental routes of contamination.

To evaluate the microbiological safety, potential multidrug-resistant bacterial presence and genetic relatedness (DNA fingerprints) of Escherichia coli isolated from the water-soil-plant nexus on highly diverse fresh produce smallholder farms. Irrigation water (n=44), soil (n=85), and fresh produce (n=95) samples from six smallholder farms with different production systems were analysed for hygiene indicator bacterial counts and the presence of shigatoxigenic E. coli and Salmonella spp. using standard microbiological methods. Identities of isolates were confirmed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), and the genetic relatedness of the E. coli isolates determined using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) analysis. Irrigation water E. coli levels ranged between 0 and 3.45 log MPN/100 ml-1 with five farms having acceptable levels according to the World Health Organization limit (3 log MPN/100 ml-1). Fresh produce samples on four farms (n=65) harboured E. coli at low levels (<1 log CFU/g-1) except for one sample from kale, spring onion, green pepper, onion, and two tomato samples, which exceeded international acceptable limits (100 CFU/g-1). Only one baby carrot fresh produce sample tested positive for Salmonella spp. Of the 224 samples, E. coli isolates were identified in 40% (n=90) of all water, soil, and fresh produce types after enrichment. Additionally, the DNA fingerprints of E. coli isolates from the water-soil-plant nexus of each respective farm clustered together at high similarity values (>90%), with all phenotypically characterized as multidrug-resistant. The clustering of E. coli isolated throughout the water-soil-plant nexus, implicated irrigation water in fresh produce contamination. Highlighting the importance of complying with irrigation water microbiological quality guidelines to limit the spread of potential foodborne pathogens throughout the fresh produce supply chain.

Study of the levels of some heavy metals present in the cement dust of Al-Mergib factory

In this study, the concentrations of heavy metals (lead, nickel, and copper) in the cement dust of a factory were estimated using an Atomic Absorption Spectrophotometer technique. Three samples were taken from the factory chimney at different locations and times. The first sample revealed the highest concentration of elements during examination (on the upper part of the chimney) is lead (about 30.7 mg/l), nickel (6.9 mg/l), and copper (1.697 mg/l). The lead concentration decreased slightly in the second sample (mid-chimney), but it is still the most abundant element in this sample (30.1 mg/l). And in the third sample (below the chimney), the lead concentration decreased slightly (29.7 mg/l), then Cooper, and Nickel. All the metals studied were within the World Health Organization (WHO) limit nickel (200 mg/l) and copper (100 mg/l), except for lead (5 mg/l), higher than the permissible limit Keywords: Cement factory, Cement dust, Wet digestion, Heavy metals

Potentially toxic elements in soil-plant-water-animal continuum in a mining area from Northwestern Mexico: animal exposure pathways and health risks for children.

Mining increases environmental concentrations of potentially toxic elements (PTEs) accumulating in organisms and spreading in the human food chain-their presence in milk is of great human health concern. Pathways were identified by which these elements reach raw milk from farms within a mining area in Northwestern Mexico; health risks for dairy cattle and children were also evaluated. Water from river and cattle waterers, as well as, soils showed that PTE concentrations generally below the Mexican and international limits; cattle forage concentrations were above the World Health Organization limits. Al, Mg, Mo, Ni and Zn were recorded in raw milk samples from the mining area, showing that Cd, Co, Cr, Cu, Pb and V are transferred from soil to plants but not accumulated in raw milk. Zn concentrations in raw milk exceeded the permissible limit; milk from farms without mining operations (comparison site) showed the presence of Al, Cr and Cu. In cattle tail hair, PTE did not correlate with raw milk concentrations. Metal accumulation in milk was higher through water consumption than that accumulated through forage consumption. Daily intakes (DI) of Al, Mg and Zn in cows could represent a risk for their health. The observed biotransference was higher than in other parts of Mexico, and the calculated DI and hazard quotients indicate no adverse health effects for children. However, the hazard Index values indicate that exposure to multiple PTE represents a risk for children. Management measures should be performed to control the cumulative risks to protect young children's health.

Assessment of Groundwater Quality around Amaenyi and State Secretariat Dumpsites in Awka, Southeastern Nigeria

The effects of two dumpsites located at Amaenyi and State Secretariat Awka on groundwater resources was investigated using hydrochemical parameters. A total of eighteen (18) groundwater samples were collected from areas in the vicinity of the dumpsites and analysed for various hydrochemical and biological parameters using standard methods. The results of the analysis were subjected to interpretations using various methods such as spatial distribution maps, water quality indices (WQI, HPI, Cd and MEI), comparing with international and local standards and statistical analysis. The results indicate that parameters such as Ec, TDS, Na+, K+, Ca2+, Cl-, NO3- and SO42- were in compliance with the acceptable limits of World Health Organization and Nigerian Drinking Water Standard. However, HCO3-, total hardness, COD, BOD, DO1, DO5, Pb, Fe, Cd and Hg exceeded the permissible guidelines in some samples. WQI rated 20% of the samples in Amaenyi as excellent, 30% (good), 10% (poor), 20% (very poor) and the remaining 20% is unfit for consumption while in State Secretariat area, 37.5% was very poor and the remaining 62.5% was unfit for consumption. HPI rated groundwater as highly contaminated while Cd classified most of the water samples to indicate low contamination except for sample A1 which was highly contaminated. Also, MEI indicated that groundwater has low heavy metal pollution. The correlation analysis indicates strong positive relationship between BOD, COD, DO1, DO5, total hardness, bicarbonate, calcium and sulphate, lead, magnesium and chloride. It was concluded that groundwater in the study area is mostly contaminated and the contaminants is attributed to be from the waste dumpsites and other anthropogenic activities.

Scenedesmus sp. MN738556 as a whole cell biosensor for sub-part per billion detections of Cd2+ cations in freshwater sources

Recent increases in human activity and contamination of the marine environment have led to the advent of biosensors as sensitive, easy-to-operate, and rapid devices for water pollution screening. In the present study, a whole-cell electrochemical biosensor based on the native green microalgae Scenedesmus sp. MN738556 was developed, for the first time, to assess the biotoxicity of Cd2+ ions in freshwater. This electrochemical biosensor was constructed by immobilization of microalgae-BSA film on a glassy carbon electrode surface. The biosensor responses were based on chronoamperometric currents generated by alkaline phosphatase (ALP) activity. Since Cd2+ ions have an inhibition effect on ALP, the reduction in the general current can be used to determine the toxicity degree of these ions. The feasibility was evaluated and the application of the biosensor was optimized for parameters such as pH and cell density. The sensitivity of the biosensor was verified through the IC50 value of 0.26 ppb for Cd2+cation with the LOD of 0.1 ppb at pH 8.5 and 107 cells/mL. These values are practical for natural water environment monitoring based on the World Health Organization limit (3 ppb for Cd2+ ions in drinking water). The selectivity of the fabricated biosensor was investigated in binary mixtures of other divalent cations such as Zn2+, Ni2+, Cu2±, and Hg2+ at 1:1 and 1:10 ratios. The results indicated that the fabricated Scenedesmus biosensor is highly sensitive with a good selectivity at a 1:1 ratio for measuring the concentration of Cd2+ cations except in the presence of Hg2+. Moreover, this biosensor could respond with only one drop of an analyte (50 μL of 1000 ppb Cd2+ ions), resulting in suitability for simple and on-site water toxicity testing. Finally, two real freshwater samples were selected to prove the reliability, reproducibility, and performance of the Scenedesmus biosensor for the detection of Cd2+ cations discharges in the aquatic environment.

Analysis of the Concentration of Heavy Metals in Khat Grown in Meru County and the Assessment of Their Associated Health Risks

Contamination of farm produce by toxic heavy metals has become a serious global health concern. These metals can bioaccumulate in plant tissues and are precursors for major public health problems such as cancer and neural impairment. Khat (Catha edulis) also referred to as miraa has the potential to sequester and accumulate both micronutrients and potentially toxic heavy metals in its consumable parts—tender leaves and soft barks of young shoots which are known to possess psychoactive properties when consumed. Therefore, the motivation behind this contribution is to determine the levels of six heavy metals, namely, cadmium (Cd), copper (Cu), chromium (Cr), lead (Pb), iron (Fe), and nickel (Ni) in consumable Meru khat samples, compare these levels with the permissible limits of World Health Organization (WHO) in order to predict associated health risks, and to estimate the noncarcinogenic risks of these metals by total health quotient (THQ) and health index (HI) on khat consumers. 1.0 g of dry ground khat samples was digested in 0.05 M HCl and allowed to stand for 5 hours before being analyzed for heavy metals using inductively coupled plasma atomic emission spectroscopy (ICP-AES). The mean heavy metal concentrations (mg/kg) in dry khat samples of six toxic heavy metals were Cd (7.81 ± 1.56), Cr (15.98 ± 2.22), Cu (15.81 ± 2.84), Fe (97.35 ± 32.67), Ni (0.37 ± 0.02), and Pb (32.36 ± 9.95). Based on the results, the mean levels of Pb, Cd, and Cr exceeded WHO permissible limits. In addition, the Pb and Cd THQ values and the HI of the six heavy metals investigated in the khat samples exceeded the threshold value of 1.0. Furthermore, the THQ and HI values showed that Pb and Cd were potentially the major contributors to noncarcinogenic risks on regular khat consumers. This is a matter of concern on the excessive consumption of Meru khat-based products, which over time may cause a toxicological response. Based on the findings of this study, the use of agrochemicals should significantly be minimized in khat farming. Accordingly, the Meru khat farmers should be sensitized on alternative farming practices that do not potentially cause heavy metal contamination in khat.

Evaluation of Geology and Hydrochemistry of Nawfia-Agulu Axis of Anambra State, Southeastern Nigeria

The investigation of the geological, hydrochemical, and engineering characteristics of the Nawfia – Agulu area was carried out. The study aimed at mapping the geology through field data collection, outcrop logging, and laboratory analysis. Consequently, eleven soil and ten water samples were collected and analyzed through particle size distribution test; Atterberg limits tests and hydrochemical analysis to provide insights into the lithology, sediment characteristics, and water quality. The results indicated the dominance of the Ameki/Nanka Formation and Imo Formation as the underlying geology of the study area. The grain sizes of the sand samples ranged from medium to coarse grained, moderately to poorly sorted, and strongly positive to positively-skewed. The depositional environment was nearshore/beach, influenced by nearshore waves and turbulent currents. Engineering properties highlighted the prevalence of uniformly to well-graded soil and moderately to highly plastic behavior, as indicated by the mean plasticity index (PI) value of 26%. These findings suggest potential challenges for infrastructural development in some parts of the area. The water quality indicated slightly acidic water. The physical parameters and the major ions were within the permissible limits of World Health Organization (WHO) and the Nigerian Standard for Drinking Water Quality (NSDWQ). However, elevated concentrations of heavy metals, including lead, chromium, mercury, iron, and cadmium, in water sources exceeded the respective permissible limits for drinking water indicating contamination/pollution. The dominant water type was Ca2+ – Mg2+– SO42- – Cl– and the dominant hydrochemical process was simple dissolution or mixing and ion-exchange.

Analyses of the Elemental Content of three Brands of Natron in Four Local Government Areas in Kebbi State

Natron is the second most consumed salt in Nigeria. It is used as a food additive to cook beans, maize, and other palatable foods. Several studies have investigated the elemental content in this salt in Nigeria. However, there is paucity of information on the elemental content of this widely consumed salt in Kebbi State. Thus, this study is focused on the analyses of elemental content in Natron in sold in four Local Government Areas (LGAs) of Kebbi State. Three brands of Natron were collected from markets in Birnin Kebbi, Jega, Kalgo and Bunza local governments. Atomic Absorption Spectroscopy (AAS) was used to analyse the elemental content. Furthermore, the elemental content values were collated for the samples of the different brands of Natron. The sodium content of the Kanwa Jarirai brand in Jega had the lowest sodium content of while the Balma brand in Bunza had the highest sodium content of . All three Natron brands investigated in the four LGAs exceeded the World Health Organization (WHO) permissible limit for potassium, iron and, manganese levels. All the brands of Natron did not satisfy the adult daily calcium intake except for the Kanwa Jarirai from Jega with . Moreso, all the three brands in the selected four LGAs satisfied the sodium permissible WHO limits. The iron, manganese, and potassium WHO permissible limits were not met. In addition, the Natron from the four LGAs did not satisfy the adult daily intake of calcium except the Kanwa Jarirai from Jega. Consumers will need to be cautious of the usage of the analysed Natrons as they contained high levels of sodium which might not be beneficial to cardiovascular health.