World Health Organization Limits Research Articles

Characterization of Polycyclic Aromatic Hydrocarbons (PAHs) associated with fine aerosols in ambient atmosphere of high-altitude urban environment in Sikkim Himalaya

Polycyclic Aromatic Hydrocarbons (PAHs) compounds are ubiquitous in ambient air due to their persistence, carcinogenicity, and mutagenicity. Gangtok being one of the cleanest cities in India located in Eastern Himalayan region, witnesses high developmental activities with enhanced urbanization affecting the ambient air quality. The present study aims to measure PM2.5 and PAHs in the ambient atmosphere of the Sikkim Himalaya to understand the influence of natural and anthropogenic activities on aerosol loading and their chemical characteristics. The PM2.5 samples were collected and analysed for the duration from Jan 2020 to Feb 2021.The seasonal mean concentrations of PM2.5 and PAHs were observed to be high during autumn and low during summer season. Overall, the annual mean concentration of PM2.5 was found higher than the prescribed limit of World Health Organization and National Ambient Air Quality Standards. The concentration of the 16 individual PAHs were found to be highest during autumn season (55.26 ± 37.15 ng/m3). Among the different PAHs, the annual mean concentration of fluorene (3.29 ± 4.07 ng/m3) and naphthalene (1.15 ± 3.76 ng/m3) were found to be the highest and lowest, respectively. The Molecular Diagnostic Ratio (MDR) test reveals higher contribution from heavy traffic activities throughout the winter and autumn seasons. The other possible sources identified over the region are fossil fuel combustion, and biomass burning. The multivariate statistical analysis (Multifactor Principal Component Analysis) also indicates a strong association between PM2.5 /PAHs and meteorological variables across the region in different seasons. The precipitation and wind pattern during the study period suggests that major contribution of the PM2.5 and PAHs were from local sources, with minimal contribution from long-range transport. The findings are important for comprehending the trends of PAH accumulation over a high-altitude urban area, and for developing sustainable air quality control methods in the Himalayan region.

Quality Assessment of Borehole Water in-Terms of Selected Physicochemical Parameters in Maiduguri Urban Areas, Borno State, Nigeria

In Nigeria, over 120 million peoples use boreholes as their main source of drinking water and in-view of the increasing volume of solid waste materials in Maiduguri, it has become exigencies to evaluate the quality of borehole waters in the city. The objective of this paper is therefore to evaluate some physicochemical characteristic of borehole water samples in Maiduguri urban areas Borno State, Nigeria using standard methods. Result obtained revealed that the pH of all the water samples was within the range of 6.5 to 8.5 as recommended limit by World Health Organization (WHO). Except for the pH of borehole water at Bulumkutu ward which is acidic (6.2). The pHs of all the water from the three wards were alkaline. The total dissolved solid and the electrical conductivity of water samples from the three wards fall within the limit of WHO, except water samples from Ngarannam (1100 mg/l) and (2220 uS/cm). The concentration of major ions (Na, Mg and K) fall far below the WHO recommended limit and thus the water can said to be excellent in terms of these elements. Except for Cl ion (262 mg/g) at borehole water in Gwange ward fall above the permissible limit by WHO. The study recommends performing regular testing of different water sources within the study area to ensure that commensurate attention given is maintaining a healthy population.

Evaluation of physico-chemical and heavy metals status in irrigation, stagnant, and Indus River water at the trans-Himalayan region

The water quality of various resources is changing everywhere, including the high-altitude region, which may have adverse health effects on animals and the human population. So far, not much study has been conducted on high-mountain region water resources. Therefore, this study was conducted at Leh-Ladakh, a high-altitude region, to know the water quality of different sources. For this, water samples were collected from irrigation, stagnant (pond), and Indus river water resources and analyzed different physicochemical parameters as per standard methods and heavy metals using inductively coupled plasma-optical emission spectrometry (Optima 7000 DV, Perkin Elmer) at the laboratory. The results revealed that the total mean values of pH (7.58 ± 0.04), electrical conductivity (EC-243.78 ± 18.05 µS/cm), salinity (0.12 ± 0.01%), total dissolved solids (TDS-121.519.75 mg/L), turbidity (1.17 ± 0.22 NTU) and chemical oxygen demand (COD-31.45 ± 0.73 mg/L) of Indus river water, pH (7.43 ± 0.05), EC (231.86 ± 11.00 µS/cm), salinity (0.11 ± 0.01%), TDS (113.31 ± 5.48 mg/L), turbidity (0.85 ± 0.11 NTU) and COD (29.74 ± 0.49 mg/L) of irrigation water, and pH (7.46 ± 0.03), EC (233.14 ± 11.41 µS/cm), salinity (0.12 ± 0.01%), TDS (115.03 ± 5.78 mg/L), turbidity (0.67 ± 0.13 NTU) and COD (29.65 ± 0.57 mg/L) of pond water were within the prescribed limit by World Health Organization (WHO) for drinking water. However, variances in the range of heavy metals were observed in Indus river water, irrigation water, and in stagnant water at different sites. Our results revealed that the As, Cd, and Pb were above the permissible limit of WHO for drinking water. At the same time, the Ni and Cr levels were observed below the maximum permissible limit. Therefore, these water resources, if used for more extended periods, may pose health-related issues to humans and animals from these elements. So, this study finding will help develop specific mitigation strategies for water management for drinking and other purposes.

Characterizing spatial dependence of boron, arsenic, and other trace elements for Permian groundwater in Northern Anhui plain coal mining area, China, using spatial autocorrelation index and geostatistics.

Anthropogenic and geological factors play an essential role in the variability of groundwater quality, resulting in a weak spatial dependence of groundwater trace elements. Thus, it is an essential study to investigate the factors affecting groundwater quality and its spatial abundance of trace elements (including As, B, and other metalloids). In this study, samples are obtained from a Permian sandstone fracture aquifer in a coal mining area. A multivariate statistical analysis, hydrogeochemistry modeling, and spatial autocorrelation analysis were used to analyze the data. The results showed that Moran index was positive for all trace elements, which had good spatial autocorrelation. The Local indicators of spatial association (LISA) indicated that trace elements were clustered. The hydrogeochemical modeling results indicated that the precipitation and stability of iron-phase minerals, such as rhodochrosite and arsenic (As) absorption on the surface of iron-phase minerals in the aquifer, may limit concentrations in the southern region. The spatial autocorrelations of both As and Boron (B) were positive (high-high) in the western areas, indicating that As contamination occurred from both natural geological causes and human coal mining activities. In contrast, B contamination was mainly linked to the influence of human agricultural or industrial activities. Over 96% of the groundwater concentrations of As (10μg/L) and B (300μg/L) in the study area exceeded World Health Organization (WHO) limits. Overall, the results of this work could help decision-makers involved in regional water quality management visualize disperse zones where specific anthropogenic and geological processes may threaten groundwater quality.

Investigation of Leachate Plume and Groundwater Pollution using Geophysical and Physio-chemical Methods in an Open Dumpsite at Idugosa, Federal Capital Territory (FCT), Abuja, Nigeria

A geophysical study has been carried out using the electrical resistivity method, Very LowFrequency Electromagnetic (VLF-EM) and physiochemical analysis to investigate the effects of groundwater contamination in the vicinity of an open dumpsite at Idugosa. A Vertical Electrical sounding was carried out at 100 m away from the dumpsite and the results revealed an H-type curve with 3- layers, with a low resistivity value of 90.0 Ωm, thickness of 9.8 m and depth of 11.3 m at the weathered basement. The control VES revealed 5 –layers of HK-type curve. The resistivity of the weathered and fractured basement ranged from 241.8 Ωm to 2908.4 Ωm with a thickness range of 3.5 m to 13.6 m and a depth range of 5.6 m to 19.1 m. Results of the horizontal profiling using Wenner profiling revealed a low resistivity value of 1.6 Ωm to 3.8 Ωm at a depth of 15 m to 30 m, concentrated at stations 20 to 100. The bottom of the western part showed that the leachate plume had infiltrated and contaminated the groundwater in the zone. The VLF-EM with the three profiles revealed high current density values on the KarousHjelt filter plot at distances of 20 m to 38 m for profile 1, 25 m to 50 m and 75 m to 95 m for profile 2, revealing the presence of contaminants which is mainly from decayed organic matter from waste bodies and heavy metals from the dumpsite. Profile 3 which is further away from profile 1 revealed that the contamination is reduced as we move further away from the dumpsite at about 10 m to 20 m, 50 m to 60 m and 90 m respectively. The physio-chemical analysis results showed a pH range of 6.73 – 7.17 which is within the World Health Organization (WHO) standard (6.5 - 8.5). The Electrical Conductivity (EC) value of the Idugosa dumpsite was found to be 804.9 μS/cm, which is above the WHO standard for EC values, which should not exceed 400 μS/cm. This high value can be attributed to the infiltration of the leachate plume from the dumpsite. The EC for Idugosa control which is 188.0 μS/cm is within the WHO limit for groundwater, thus its safe for consumption.

Assessment of heavy metals in fish and sediments from river Mtakuja in the vicinity of a gold mine in Tanzania

Concentrations of heavy metals namely Cr, Fe, Cu, Zn, As, Cd and Pb in African Sharptooth Catfish (clarias gariepinus) and sediment from river Mtakuja Tanzania were analyzed using the Energy Dispersive X-ray Fluorescence spectrometry technique. 32 samples from fish and sediment were investigated. The results show that the concentration of heavy metals was higher in upstream areas than in the downstream area. The concentration of Fe of 428.5 mg/kg in catfish from the upstream area was about 2 times 243.8 mg/kg obtained from the same fish in the downstream area. Similar cases observed for sediments with Fe concentration of 127626.9 mg/kg from upstream that was about 6 times higher than that of 21460.3 mg/kg from downstream area. The concentration of 44.8 mg/kg for Cu in the upstream area sediment was also about 2 times higher than 23.2 mg/kg in the downstream area sediment, while for as the concentration of 13.2 mg/kg was measured in the upstream, which is which is more than 5 times 2.5 mg/kg measured in downstream. The concentration of Cr in the catfish was 17.6 mg/kg which is higher than the permissible limit values of 0.8 mg/kg set by the European Commission (EC), 0.2 mg/kg set by the Food and Agricultural Organization (FAO) and 0.15 mg/kg the World Health Organization (WHO) limit. Moreover, the concentration of Cd was 3.0 mg/kg, which is above the permissible level of 0.2 mg/kg recommended by the EC and WHO. A positive correlation exists between the Cu, Pb, Fe and Cd concentration found in sediments and fish samples. The results show that the river Mtakuja is polluted by mining waste, domestic and agrochemical activities. This suggest that, there is a need for regular monitoring of heavy metal in river Mtakuja in order to monitor and protect aquatic organisms and health of benefactors of this river.

Drinking water quality monitoring of centralized water storage reservoirs in various zones of the National University

Physico-chemical and microbiological pollutants may compromise quality of drinking water. This study aims to highlight various physico-chemical and microbial parameters of drinking water samples from centralized water storage reservoirs of National University. Major water quality parameters which were examined in this study includes pH, Electrical conductivity (EC), Turbidity, Total suspended solids (TSS), Total dissolved solids (TDS), Dissolved oxygen (DO), Residual chlorine, Hardness, Alkalinity. Moreover, microbial analysis of water samples was also carried out through Most Probable Number technique (MPN). Results show that all the physico-chemical parameters were within prescribed limits of World Health Organization and Pakistan Drinking Water Quality Standards (WHO/PDWQS) in both underground and overhead water storage reservoirs except DO ( 9.05-9.2 and 9.05-9.1 mg/L ), TSS (10-20 and 3.3-10 mg/L) and residual chlorine (0.08-0.14 and 0.19-0.28 mg/L) respectively. The MPN index values for both underground and overhead water storage reservoirs ranges between 16- >23 and 1.1-12 respectively and it shows high microbial contamination in water due to low detection of residual chlorine. The results highlight that water from centralized water storage reservoirs of National University is unfit for drinking purposes. Statistical analysis such as paired t-test also reveals that water quality parameters from underground and overhead storage reservoirs are not significantly different from each other except EC and TDS having P values <0.05. It is necessary to safeguard water contamination in water storage reservoirs by monitoring regular inspections and chemical cleaning of water storage reservoirs otherwise it will cause serious threats to well-being of the community.
 Key words: water storage reservoirs, drinking water, microbial quality of water, physico-chemical parameters, paired t-test

Assessment of Surface Water Quality Using the Water Quality Index (IWQ), Multivariate Statistical Analysis (MSA) and Geographic Information System (GIS) in Oued Laou Mediterranean Watershed, Morocco

Surface water is used for a variety of purposes, including agriculture, drinking water, and other services. Therefore, its quality is crucial for irrigation, human welfare, and health. Thus, the main objective is to improve surface water quality assessment and geochemical analysis to evaluate anthropogenic activities’ impact on surface water quality in the Oued Laou watershed, Northern Morocco. Thirteen surface water samples were characterized for 26 physicochemical and biological parameters. In this aspect, emerging techniques such as multivariate statistical approaches (MSA), water quality indices (WQI), irrigation water quality (IWQI), and Geographic Information System (GIS) were employed to identify the sources of surface water pollution, their suitability for consumption, and the distribution of surface water quality. The results showed that the major ion concentrations were reported in the following order: Ca2+, Na+, Mg2+, and K+; and HCO3− > CO32− > Cl− > SO42− > NO3− > F− > PO43− > NO2−. It was also demonstrated that almost all parameters had concentrations lower than World Health Organization (WHO) limits, except for bicarbonate ions (HCO3−) and the biochemical oxygen demand for five days (BOD5), which exceeded the WHO limits at 120 mg/L and 3 mg/L, respectively. Furthermore, the types of Ca2+-HCO3− (Calcium-Bicarbonate) and Ca2+-Mg2+-HCO3− (Calcium-Magnesium-Bicarbonate) predominated in surface water. The Principal Component Analysis (PCA) indicates that the Oued Laou river was exposed to two forms of contamination, the first being attributed to anthropogenic activities such as agriculture, while the second reflects the water-sediment interaction. The Hierarchical Cluster Analysis (HCA), reflecting the mineralization in the study area, has classified the samples into four clusters. The Inverse Distance Weighting (IDW) of the WQI indicates that 7.69% and 38.46% of the surface water represent, respectively, excellent and good quality for drinking. At the same time, the IWQI revealed that 92.30% of the water surface is good for irrigation. As a result, the combination of WQIs, PCA, IWQI, and GIS techniques is effective in providing clear information for assessing the suitability of surface water for drinking and its controlling factors and can also support decision-making in susceptible locations such as the Oued Laou river in northern Morocco.

Shallow Groundwater Quality and Human Health Risk Assessment in Holte, a Town in Southern Ethiopia

Groundwater quality and human health risk assessment are critical for the long-term usage of household water supplies. The purpose of this study was to evaluate groundwater quality and human health risk in Holte, a town in the Derashe Special Woreda in southern Ethiopia. Water samples from seven shallow groundwater wells were taken and examined for hydrogeochemical properties. The Water Quality Index (WQI) was developed to assess the suitabilityof groundwater for drinking. Groundwater hydrochemistry types and evolutionary processes were investigated. The results suggested that the typical pH of groundwater samples had an average pH of 7.99. The values of electrical conductivity (EC), bicarbonate (HCO3) and total dissolved solid (TDS) in all samples were above the recommended upper limit of World Health Organization (WHO) for drinking water. Based on the hydrochemical findings, the orders of cationic abundance and anionic abundance in the groundwater were Ca²⁺ < Mg²⁺ < K⁺ < Na⁺ and F⁻ < SO₄²⁻ < Cl⁻< HCO₃⁻, respectively. According to the Piper Tri-linear Diagram, the majority of groundwater samples were found to have Mixed Ca-Na-HCO3. The Gibbs fields results showed that evaporation dominated groundwater quality, whereas chemical weathering of rock-forming minerals dominated the remaining samples. The calculated WQI result showed that 57.1% (4 handpumps) of groundwater samples from the town had acceptable water quality, but 42.9% (3 handpumps) had poor water quality. The finding of this study suggests that groundwater quality parameters should be tested and monitored on handpumps at sample locations 1, 2, and 3 in the town to minimize human health risks and ensure long-term socioeconomic development.

A parent-school initiative to assess and predict air quality around a heavily trafficked school

Many primary schools in the UK are situated in close proximity to heavily-trafficked roads, yet long-term air pollution monitoring around such schools to establish factors affecting the variability of exposure is limited. We co-designed a study to monitor particulate matter in different size fractions (PM1, PM2.5, PM10), gaseous pollutants (NO2, O3 and CO) and meteorological parameters (ambient temperature, relative humidity) over a period of one year. The period included phases of national COVID-19 lockdown and its subsequent easing and removal. Statistical analysis was used to assess the diurnal patterns, pollution hotspots and underlying factors driving changes. A pollution episode was observed early in January 2021, owing to new year celebration fireworks, when the daily average PM2.5 was around three-times the World Health Organisation limit. PM2.5 and NO2 exceeded the threshold limits on 15 and 10 days, respectively, as the lockdown eased and the school reopened, despite the predominant wind direction often being away from the school towards the roads. The peak concentration levels for all pollutants occurred during morning drop-off hours; however, some weekends showed higher or comparable concentrations to those during weekdays. The strong disproportional Pearson correlation between CO and temperature demonstrated the possible contribution of local sources through biomass burning. The impact of lifting restrictions after removing the weather impact showed that the average pollution levels were low in the beginning and increased by up to 22.7 % and 4.2 % for PM2.5 and NO2, respectively, with complete easing of lockdown. The Prophet algorithm was implemented to develop a prediction model using an NO2 dataset that performed moderately (R2, 0.48) for a new monthly dataset. This study was able to build a local air pollution database at a school gate, which enabled an understanding of the air pollution variability across the year and allowed evidence-based mitigation strategies to be devised.

The comparison between in-situ monitored data and modelled results of nitrogen dioxide (NO2): case-study, road networks of Kigali city, Rwanda

The incomplete combustion of fossil fuels from petrol, natural gas, and fuel oil in the engine of vehicles contributes to air quality degradation through traffic-related air pollutant emissions. The Real-time affordable multi-pollutant (RAMPs) monitors were installed in Kigali, the capital of Rwanda, to fill the gap in air quality datasets. Using RAMPs, this is the first air quality modelling research in Rwanda aiming to report the concentration of NO2 by comparing In-situ monitored data and modelled results. We targeted NO2 emissions from 27 road networks of Kigali to address the impacts of traffic emissions on air quality over 2021. The American Meteorological Society and Environmental Protection Agency regulatory models (AERMOD and ISCST3) were used for simulation. Statistical indexes include fractional bias (FB), the fraction of the prediction within the factor of two of the observations (FAC2), normalized mean square error (NMSE), geometric mean bias (MG), and geometric variance (VG) used to assess models' reliability. Monitoring shows the annual mean of 16.07 μg/m3, 20.35 μg/m3, and 15.46 μg/m3 at Mont-Kigali, Gacuriro, and Gikondo-Mburabuturo stations, respectively. Modelling shows the daily mean of 111.77 μg/m3 and annually mean of 50.42 μg/m3 with AERMOD and daily mean of 200.26 μg/m3 and annually mean of 72.26 μg/m3 with ISCST3. The FB, NMSE, and FAC2 showed good agreement, while MG and VG showed moderate agreement with AERMOD. The FB, NMSE, and MG showed moderate agreement, while FAC2 and VG disagreed with ISCST3. Traffic and urban residential emissions were identified as potential sources of NO2. Results indicated that Kigali residents are exposed to a significant level of NO2 exceeding World Health Organisation limits. Findings will help track the effectiveness of Rwanda’s recently executed pollution-control policy, suggest evidence based on the recommendations to reduce NO2, and use further dispersion models to support ground-based observations to improve public health.

Air Quality Assessment along China-Pakistan Economic Corridor at the Confluence of Himalaya-Karakoram-Hindukush

Recently, analyses of the air quality in Pakistan have received significant interest, especially regarding the impact of air pollutant concentrations on human health. The Atlas of Baseline Environmental Profiling along the China-Pakistan Economic Corridor (CPEC) at five locations in Gilgit-Baltistan (GB) is a major landmark in this regard due to the presence of massive glaciers in the region, which are considered as water reserves for the country. Using various statistical measurements, the air quality was analyzed at the studied geographic locations. Further, air quality was evaluated based on air pollutant data acquired from ambient air monitoring laboratories. For example, 24 h concentrations of particulate matter (PM2.5) were found to range from 25.4 to 60.1 µg/m3, with peaks in the winter season at Gilgit. It was found that PM2.5 values were 1.7 and 1.3 times greater than National Environmental Quality Standards (NEQS) standards only at Gilgit and Chilas, respectively, and 1.5 to 4 times greater than the World Health Organization (WHO) standards at all locations. Similarly, PM2.5 concentrations were found to range from 31.4 to 63.9 µg/m3, peaking at Chilas in summer 2020. The observed values were 1.1 to 1.8 times and 2 to 4.2 times greater than the NEQS and WHO standards, respectively, at all locations. In addition, the average peaks of black carbon (BC) were measured at Gilgit, both in winter (16.21 µg/m3) and summer (7.83 µg/m3). These elevated levels could be attributed to the use of heavy diesel vehicles, various road activities and different meteorological conditions. Pollutants such as carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOX) and ozone (O3) were found to be within NEQS and WHO limits. Based on air quality metrics, the effect of PM2.5 on air quality was found to be moderate in Sost, Hunza and Jaglot, while it was at unhealthy levels at Gilgit and Chilas in the winter of 2019; moderate levels were observed at Sost while unhealthy levels were detected at the remaining locations in the summer of 2020. There are no specific guidelines for BC. However, it is associated with PM2.5, which was found to be a major pollutant at all locations. The concentrations of CO, SO2 and O3 were found to be at safe levels at all locations. The major fraction of air masses is received either locally or from transboundary emissions. This study demonstrates that PM2.5 and BC are the major and prevailing air pollutants within the study region, while other air pollutants were found to be within the permissible limits of the WHO and NEQS.

Heavy Metals, Pesticide, Plasticizers Contamination and Risk Analysis of Drinking Water Quality in the Newly Developed Housing Societies of Gujranwala, Pakistan

The supply of clean drinking water is essential for a healthy life, but access to safe and healthy drinking water has become a key issue worldwide, especially in developing nations such as Pakistan. This research work focused on investigating the suitability of groundwater by measuring quality parameters, identification of pesticide pollutants, and health risk analysis in adults and children due to the consumption of groundwater in recently developed housing societies of the Gujranwala district, Punjab, Pakistan. Drinking water samples (n = 200) were collected from electric water pumps and analyzed by in situ testings following the Standard American Public Health Association (APHA) methods. Pesticides and plasticizers detection was carried out using gas chromatography-mass spectrometry (GC/MS). Results showed that the concentrations of dissolved Cr and Pb at more than 20% of sampling sites exceeded the allowable limit of the World Health Organization (WHO). However, the measured physico-chemical attributes and concentrations of Fe and Zn did not exceed their respective permissible limits. The most abundant pollutants detected were plasticizers (30); followed by herbicides (21); fungicides, acaricides, and insecticides (16); and various types of plant growth regulators (7). Differential patterns for the hazard quotient (HQ) and hazard indices (HI) were observed, of which were above the WHO limits. The decreasing order of the hazard quotient was Cl > Zn > Mg > Cr > Pb for both adults and children. In crux, the quality of water is poor for drinking purposes and the safety and well-being of residents in the recently developed housing societies of the study area may be at risk. Hence, it is important to implement a plan for water quality management, and the regular monitoring (periodic testing of qualitative and quantitative attributes) of the water quality to overcome health-related issues.

Evaluation of Noise Generated by Train Movement at Rail Near to Residential Areas – Case Study at Kluang, Johor.

Rail transportation is one of the largest transportations that is widely used in Malaysia. Therefore, many railways have been built in urban and rural areas to improve interstate connectivityin Malaysia. However, train noise generated from train movement can disturb the comfort of nearby residents that live near railways.This studywas conducted nearbythe residential area between the Kluang –Renggam rail line to investigate the noise leveland compare the existing noise level with the guideline from the Department of Environment (DOE) and World Health Organization (WHO) limits. Besides, the impact of this urban pollution to the residents nearby were evaluated by the noise index of noise pollution level (LNP). The results showed that the A-weighted noise levels (LAeq) at all locations exceeded WHO limit while the LAeqat 2 locations (20m and 30m from the rail track) were exceeded the noise limit that set by DOE. Besides, the noise levels captured at the location which 55m away from sound source were nearly approximated to 60 dBA. Theresidents nearby were affected by this urbannoise pollutionwhere the LNP values obtained from this study were approximately to the LNP limits. Thus, alternative strategiesshould be carried out in this area in order to make sure that the community in this area free from the noise disturbance. Further studysuch as developed noise mapping and the questionnaire of annoyance level for the residential area can be implemented to improve the findings on the effect of train noise in the future.

Physico-chemical analysis of Obizi River in Awka South Local Government Area of Anambra State, Nigeria for domestic purposes

Physico-chemical properties of obizi river in awka south local government area of anambra state were analyzed for its pollution level and determined if it will be fit for domestic purposes. It is significant for cooking, drinking, fishing, recreational and other uses. It flows via a channel that may be contaminated by industrial, agricultural, and other anthropogenic activities, limiting its normal uses for cooking, drinking, fishing, recreational and other uses. The parameters analyzed includes temperature (°C), pH, turbidity (NTUb), conductivity μs/cm, resistivity mg/l, chloride mg/l. Temperature(°C), pH, turbidity (NTUb) resistivity mg/l and conductivity μs/cm was measured in-situ using mercury thermometer with a range of 100C -350C, pH meter (HANNA H1991002), turbidimeter (Hl 88703, WAGTECH), conductivity and resistivity multi-meter (HI 991300, Hanna Instruments, Romania) and chloride was determined by titration. The results of the analysis were equivalence with world health organization (WHO) limit for domestic drinking water and other purposes. From the results obtained, it showed that all the parameters analyzed were above WHO permissible limit except resistivity and chloride which is within the world health organization (WHO) limit for domestic drinking water. As much, it is not recommended for human consumption and is recommended that the state government put in place a treatment plant which can be used to treat the obizi river water before being used by the community that depends solely on it for domestic purposes.

Evaluation and environmental risk assessment of heavy metals in the soil released from e-waste management activities in Lahore, Pakistan.

In developing regions, electronic waste either gets recycled by using crude and primitive techniques in recycling centers or dumped in dumping grounds that result in the leaching of heavy metals into the ambient environment. The objective of this study is to determine the concentration of heavy metals (Cu, Pb, Zn, Cd, Mn, and Fe) in the surface soil of recycling centers and dumping sites in Lahore, Pakistan, and to quantify and compare the environmental risk. The mean concentration (mg/kg) of Cu, Pb, Zn, and Cd was 722.96, 446.81, 378.76, and 4.11, respectively in the surface soil of recycling centers,and only the mean concentration of Cu (214.09mg/kg) from dumping sites were above permissible limits of World Health Organization. Results of the geo-accumulation index (Igeo) and contamination factor (Cf) revealed that the surface soil is highly contaminated with Cu, Pb, and Cd. The Cd content (701.24) caused a very high potential ecological risk (Er) (> 320) to nearby biological communities. The noncarcinogenic risk was only expected from Pb to children (1.70) living near recycling centers, whereas no risk was observed for adults living either near recycling centers (0.23) or dumping sites (0.01). There is a high probability of carcinogenic health risks to children (1.085 × 10-2) and adults (1.195 × 10-3) from Cu. Hence, all the results suggest that e-waste recycling and dumping activities were a significant source of heavy metals to the surrounding environment, children, and adults, so it is strongly recommended to take action for sustainable management of e-waste.

Chemical quality assessment of major brands of bottled mineral water available in the Ethiopian market

Assessing bottled mineral water with drinking water guidelines set by the World Health Organization (WHO) and the Ethiopian Standard Agency (ESA) are highly relevant for practitioners, bottling companies, managers, regulators, and policymakers regarding water supply particularly bottled water. The present study was carried out to report the physicochemical quality of six branded bottled mineral water widely available in the Ethiopian market and compare them with drinking water standards. The investigated physicochemical parameters were pH, electrical conductivity (EC), total dissolved solids (TDS), chloride ion (CL - ), nitrate ion (NO3 - ), potassium (K+ ), sodium (Na+ ), zinc (Zn+ ), iron (Fe3+), calcium (Ca2+) and magnesium ion (Mg2+) using standard analytical techniques. Flame Atomic Absorption Spectroscopy (FAAS) was used to determine the number of metal elements. The Ultra Violet-Visible Spectrophotometer (UV-VIS) analysis was used to determine the amount of NO- in the bottled mineral water. The TDS and CL-values were determined by using gravimetric and volumetric methods. The study results revealed that the values of the quality parameter concentrations measured experimentally were slightly varied from the labeled values on the bottle. However, all brands were within EAS and WHO limit values for drinking water. The calculated correlation coefficient between the bottled water and the soil sample, between some dissolved solids and the TDS concentration in bottled mineral water, and between TDS and the pH concentration in bottled mineral waters was 0.99, 0.77 and 0.94, respectively. The study also verified that all the studied bottled water brands are safe for human consumption.

Southern mullets (Chelon richardsonii) as a potential biological indicator for mercury pollution in the Walvis Bay lagoon, Namibia

Southern mullet Chelon richardsonii is one of the important fish species found in the Walvis Bay lagoon (WBL) that is commercially exploited for local consumption. The southern mullet is, however, exposed to mercury (Hg) found in sediments, which forms part of its diet. This study evaluated the Hg concentration in muscles, stomach content, liver, and gills of C. richardsonii over two years. The Hg concentration was higher in the liver (0.005 mg kg−1) and relatively lower in the gills (0.001 mg kg−1). There were temporal variations in Hg concentration among the tissues; a positive correlation between mean Hg concentration and fish sizes (total length and total weight) was documented in the gills; and a negative correlation for size versus Hg concentration was recorded in the livers, stomach contents, and the muscles of southern mullets. The Hg concentrations of all tissues were below the World Health Organisation (WHO) limit for fish (0.5 mg kg−1), which indicates that it does not pose a human health risk at the current levels. This study’s findings form a baseline for using southern mullets as biological indicators of Hg pollution in WBL. The study also highlights the need for regular monitoring programmes to protect and maintain the ecological characteristics of WBL as per Namibia’s mandates under the Ramsar Convention.

DISTRIBUTION OF HEAVY METALS IN SOILS WITHIN THE VICINITY OF THE OYIGBO GAS FLARE SITE IN RIVER STATE, NIGERIA

Six heavy metals were determined in soils to assess the impact gas flaring had on the micronutrient status of the soils. Soils were collected from the gas flaring site at Oyigbo in Rivers State Nigeria at 10m, 50m and 100m distance to the flare stack, from surface and subsurface depths. The soils were analysed for heavy metals using GBC-Avanta PM SN A6600 Atomic Absorption Spectrophotometer (AAS). Alterations in the micronutrient levels measured evidently point to the impact of the Oyigbo gas flare. However, concentrations of all the heavy metals were found to be within the target benchmark limits of Nigeria’s Department of Petroleum Resources (DPR) and the World Health Organization (WHO), except for Cd which recorded a concentration of 0.34 0.08 mg/kg at 0-10cm depth, 100m away from the flare and 1.18 mg/kg at 10-20cm depth, 10m away from the flare; these 10m results exceeded the 0.8mg/kg limit of DPR and WHO. One way analysis of variance (ANOVA) showed that the differences in the concentrations of the other metals (Fe, Pb, Zn, Cr and Ni) were statistically significant (P<0.05); this was validated by a complimentary post-hoc analysis using the Turkey’s Multiple Comparison Test. The trend in the concentrations was Cr > Ni > Fe > Pb > Zn > Cd. A geographically similar control soils collected from Choba, a community outside the vicinity of the gas flaring, had significantly lower concentrations of metals. Given the tendency of heavy metals to bio-accumulate and bio-magnify, it is recommended that periodic human health risk assessment be carried out in the study area to ascertain the toxic potency of these metals to the agricultural community.

The influence of water level fluctuations on the migration and enrichment of phosphorus in an agricultural groundwater system, Jianghan Plain.

The enrichment of phosphorus (P) in groundwater (GW) has been regarded as one of the most important sources of water eutrophication, but its sources and mechanisms have remained unclear. This study focused on hydraulic change show that drove the migration of P in an agricultural groundwater system, Jianghan Plain, Central China. Based on four rounds of field investigation over different seasons and across two consecutive years. Seasonable water table fluctuations (WLFs) reached 1.6m and 3.8m in GW and surface water (SW), respectively. Moreover, the concentrations of P in GW were obviously higher than those in SW where 54.1% of all GW samples presented higher content of P than the World Health Organization (WHO) limit of 0.4mg/L with the highest one arriving to 1.97mg/L. Although the trends and amplitudes varied at different points and depths, the spatial and temporal distribution of P corresponded with the local WLFs that were responsible for the enrichment of GW P. On the one hand, WLFs changed hydraulic conditions to enhance the migration of soluble P in the unsaturated zone into the aquifer. On the other hand, WLFs resulted in changes to the redox conditions or to the GW hydrochemical compositions, which promoted the dissolution of Fe or Mn containing P. These caused the release and enrichment of P in GW. Therefore, this study helps understand the geochemical cycling of P and improves GW management in the local GW system, Jianghan Plain.