Assessment of the Health Risk, Aesthetic and Agricultural Quality of Rainwater, Surface Water and Groundwater in the Shale Bedrock Areas, Southeastern Nigeria

Evaluation of hydro-chemical facies and surface water quality dynamics using multivariate statistical approaches in Southern Nigeria

The geochemical and chemical constituents of river water quality could be influenced by human activities and organic processes like water interacting with the lithogenic structure that the river flows through. Evaluating evidence based primary root of the predominant pollutant ions, their interactions as well as the factors controlling their dominance is crucial in studies regarding water environment and hydrology especially as most studies focus on theoretical methods. In order to understand the water cycle, safeguard surface water resources, and preserve the human environment, this study evaluated surface water hydro-chemical facies, quality dynamics, and portability in southern Nigeria using multivariate statistical approaches by analyzing selected hydro-chemical characteristics as indicators of pollution along the river during wet and dry seasons. Twenty water samples were taken, analyzed, and subjected to mathematical statistics: Gibbs plot, trilinear piper analysis, stiff pattern analysis, ionic scatter analysis, correlation, and principal component analysis. Result of surface water recorded mean pH ranges from 4.8 for wet season and 5.3 for dry season, above the WHO, and during dry season TDS, Mg2+, Pb, and Cd were above the WHO limits, respectively. Abundance of cation and anion in surface water was in a decreasing trend of: HCO3 > Ca2+ > Mg2+ > Cl- > Na+ > SO42- > K + > NO3-. Trilinear plot, stiff pattern, and Gibbs ratio indicated hydrochemical facie of water dominated by calcium bicarbonate (Ca-HCO3) water type. From plots and ionic ratio, the major hydrochemical process of water chemistry during wet and dry seasons was rock-water interaction arising majorly from weathering processes. Ionic ratios of Ca2+ and Mg2+1, Ca2+ and HCO2- [1:2], Ca2+ + Mg2+ and HCO3- + SO42- [1:1], revealed dissolution of dolomite as their common origin, with total cations in wet and dry seasons ranging between 43 and 57% and total anions: 37.3-62.7, with dry season dominance. The overall WQI of the river seemed good quality due to rapid flow and self-purification of the river but may be harmful in the future. It was recommended that constant surveillance and monitoring of human activities along waterways be enforced in order to ensure that undesirable pollution levels don't occur in the river.

Hydrogeochemical assessment and health-related risks due to toxic element ingestion and dermal contact within the Nnewi-Awka urban areas, Nigeria

Awka and Nnewi metropolises are known for intensive socioeconomic activities that could predispose the available groundwater to pollution. In this paper, an integrated investigation of the drinking water quality and associated human health risks of contaminated groundwater was carried out using geochemical models, numerical water quality models, and the HHRISK code. Physicochemical analysis revealed that the groundwater pH is acidic. Predicted results from PHREEQC model showed that most of the major chemical and trace elements occurred as free mobile ions while a few were bounded to their various hydrated, oxides and carbonate phases. This may have limited their concentration in the groundwater; implying that apart from anthropogenic influx, the metals and their species also occur in the groundwater as a result of geogenic processes. The PHREEQC-based insights were also supported by joint multivariate statistical analyses. Groundwater quality index, pollution index of groundwater, heavy metal toxicity load, and heavy metal evaluation index revealed that 60-70% of the groundwater samples within the two metropolises are unsuitable for drinking as a result of anthropogenic influx, with Pb and Cd identified as the priority elements influencing the water quality. The HHRISK code evaluated the ingestion and dermal exposure pathway of the consumption of contaminated water for children and adult. Results revealed that groundwater from both areas poses a very high chronic and carcinogenic risk from ingestion than dermal contact with the children population showing greater vulnerability. Aggregated and cumulative HHRISK coefficients identified Cd, Pb, and Cu, to have the highest health impact on the groundwater quality of both areas; with residents around Awka appearing to be at greater risks. There is, therefore, an urgent need for the adoption of a state-of-the-art waste management and water treatment strategies to ensure safe drinking water for the public.

Occurrence and risk assessment of volatile organic compounds in multiple drinking water sources in the Yangtze River Delta region, China

Volatile organic compounds (VOCs) are widely present in water environment, which can threaten ecological sustainability and human health. The concentrations of VOCs and their ecological risks in drinking water are of great concern to human beings. Therefore, 54 kinds of VOCs were investigated from 58 locations of the Yangtze River Delta Region (Yangtze River, Qiantang River, Huangpu River, Taihu Lake and Jiaxing Urban River). Out of 54 target compounds, only 31 VOCs were detected, with total concentrations ranging from 0.570 to 46.820 μg/L from 58 locations of all drinking water sources. Among all detected VOCs compounds, only toluene and styrene can cause high-level ecological risk at location TH-2 of Taihu Lake. According to the carcinogenic and non-carcinogenic risk index, compounds such as 1,2-dichloroethane, bromodichloromethane and 1,1,2-trichloroethane posed a higher carcinogenic risk, and 1,2-dichloroethane, trichloroethylene and toluene posed a higher non-carcinogenic risk. Olfactory risks of water bodies in the Yangtze River Delta region are negligible. Although the concentrations of VOCs in the Yangtze River Delta region did not exceed national standards in China and guidelines of the World Health Organization (WHO) for drinking water, the presence of some ecological and health risks indicated that future monitoring studies and control practices are important to ensure ecological safety of drinking water sources.

An appraisal of data collection, analysis, and reporting adopted for water quality assessment: A case of Nigeria water quality research

The appropriate acquisition and processing of water quality data are crucial for water resource management. As such, published articles on water quality monitoring and assessment are meant to convey essential and reliable information to water quality experts, decision-makers, researchers, students, and the public. The implication is that such information must emanate from data obtained and analysed in an up-to-date, scientifically sound manner. Thus, inappropriate data analysis and reporting techniques could yield misleading results and mar the endeavours of achieving error-free conclusions. This study utilises the findings on water quality assessment in Nigeria over the last 20 years to reveal the likely trends in water quality research regarding data collection, data analysis, and reporting for physicochemical, bacteriological parameters, and trace organics. A total of 123 Web of Science and quartile ranked (Q1-Q4) published articles involving water quality assessment in Nigeria were analysed. Results indicated shortcomings in various aspects of data analysis and reporting. Consequently, we use simulated heatmaps and graphs to illustrate preferred ways of analysing, reporting, and visualising some regularly used descriptive and inferential statistics of water quality variables. Finally, we highlight alternative approaches to the customarily applied water quality assessment methods in Nigeria and emphasise other areas of deficiency that need attention for improved water quality research.

A comprehensive review of water quality monitoring and assessment in Nigeria

Nigeria is the most populated black nation in the world with about 199 million people. About 66.3 million Nigerians do not have access to safe drinking water. In this study, research findings on water quality monitoring and assessment in Nigeria over the past two decades were systematically reviewed. There are still grave enforcement issues in Nigeria as quality guidelines are still being contravened at no cost to the infringer due to the corrupt socio-political circumstances of the country. The quality of surface water, groundwater, rainwater and commercially available water was discussed in line with their pollution sources. The quality of surface water was generally poor. Groundwater pollution has come due to landfill leachate, oil and gas exploration and production, sewage and hydrogeological interactions of the groundwater with the base rock. The hydrogeological effect has led to the observation of lead and barium in groundwater in many locations across the country. The main issue with rainwater in Nigeria is the low pH but it was observed to be fairly clean. Commercially available water (bottled or sachet) is currently the best source of drinking water for the Nigerian populace. Bottled water quality is higher than for sachet water and the latter largely influenced by microbe contamination. Future perspectives in water quality monitoring and assessment are suggested in the evaluation of emerging contaminants and micro-pollutants and the utilisation of internet-enabled technologies.

Public health challenges as a result of contaminated water sources in Kumba, Cameroon

Kumba, the largest city in the Southwest Region of Cameroon, is characterized by the prevalence of waterborne diseases due to ingestion of contaminated water. Sixty-four water samples were collected from different sources including pipe-borne (PW), surface/stream (SW) and groundwater (HDW) sources as well as the catchment area (CW) in Kumba metropolis. These water samples were analyzed for physicochemical and microbiological parameters and the results compared with international standards. The results of physiochemical parameters showed that the water samples were mildly acidic, not saline and soft. The levels of some trace elements (Al, Fe, As, Cd, Co, Cu, Fe, Mn, Pb) in some water samples were higher than permissible limits. Water Quality Index, Contamination Index (C_d) and Trace Element Toxicity Index were used to evaluate the water samples. Results showed that most of the water sources are poor and unsafe for consumption due to high concentrations of Al, Fe, Mn and Pb. Microbiological parameters revealed that 74% of the water samples are in the class of high risk to grossly polluted. Pollution associated with the catchment area was probably the main factor controlling the quality of pipe-borne water, while that of the surface and groundwater may be attributed to geogenic and anthropogenic sources including unlined pit latrines. Water sources, especially those ingested by humans in Kumba, should be properly managed including regular treatment so as to protect the health of humans and improve the quality of life.

Lithium in drinking water sources in rural and urban communities in Southeastern Nigeria

There is a dearth of data on lithium content of domestic water sources in Nigeria. This study reported the lithium concentration in ground and surface water sources used for drinking in Southeastern Nigeria. Thirteen (13) natural springs, 24 streams, 7 hand-dug wells and 80 boreholes, making a total of 124 water samples were collected from strategic locations and analysed by ICP-OES. The distribution of lithium according to water sources and lithostratigraphic units as well as dietary contribution of lithium through drinking water was investigated. Average lithium concentrations in water samples from all sources were between 0.09 and 1.54 μg/L (overall mean ± SEM: 1.0 ± 0.2 μg/L). Results according to the geological formations of the areas studied indicated that only water sources located within the Benin Formation and Bende-Ameki Formation contained lithium in the range of <0.21-7.24 and < 0.21-1.97 μg/L respectively, whereas lithium was not detected in samples located within the Nsukka and Mamu lithostratigraphic units. Total intakes of lithium from water consumption (0.64 L for children and 2 L for adults) for all water sources were 79 and 247 μg/day for children and adults respectively, while the average daily intake of lithium from the water sources ranged from 0.004 to 0.066 and 0.002-0.044 μg/kg body weight for children (15 kg) and adults (70 kg) respectively. Drinking water in the study areas contributes only about 0.02-0.47% of the U.S. EPA estimated daily intake (9.3-44.3 μg/kg) of Lithium.

Multivariate statistical approach and water quality assessment of natural springs and other drinking water sources in Southeastern Nigeria

This baseline study investigated the physico-chemical and trace elements (including potentially toxic elements, PTEs) contents of ground and surface water sources used for domestic purposes in some districts within the shale bedrock terrain of Southeastern Nigeria. A total of 124 water samples from 13 natural springs, 24 streams, 80 boreholes and 7 hand-dug wells were collected from rural and urban areas and analysed by ICP-OES, GF-AAS and CV-AFS for 21 elements. The distribution pattern, sources of contamination, health risk of potentially toxic elements (PTEs), together with water quality index were investigated. The results were compared with national and international guidelines for drinking water. Al and Fe were implicated as the dominant pollutants in the water bodies. Water quality index (WQI) indicated that all the water sources had either excellent or good water quality (WQ) with the exception of a borehole, which had poor WQ. Different multivariate statistical approaches applied to evaluate the origins of the elements in the water bodies identified six source types that accounted for 70.88% of the total variance. Anthropogenic activities were considered to contribute much of Cu, Pb, Cd, Cr, Li and P, while Al, As, Co, Fe, Se, Ni, Y and V were likely from crustal materials, minerals and ores, and natural environments. Both anthropogenic and natural sources accounted for the Hg, Mn and Zn. Cluster analysis (CA) was adopted to classify 124 sample points into two groups of water pollution, reflecting influences from crustal materials and anthropogenic sources. From the result of hazard quotient and index (HQ/HI), there is little or no health risks arising from PTEs in using water from the region.

Measurement of volatile organic compounds and associated risk assessments through ingestion and dermal routes in Dongjiang Lake, China

This study aims to investigate the occurrence, distribution and risk assessment of volatile organic compounds (VOCs) in Dongjiang Lake of China. Twenty two kinds of VOCs were detected, and the major VOCs were alkene compounds. The total concentration of VOCs (∑VOCs) ranged from 2.93 to 4.69 µg/L, and none of the VOCs detected in Dongjiang Lake exceeded the concentration limits set in the National Drinking Water Quality Standards (GB5749-2006) or the National Environmental Quality Standards for Surface Water (GB3838-2002) of China. Risk quotients (RQ) model, Multimedia Environment Pollutant Assessment System (MEPAS) and value of odor hazard index (OHI) were used to assess the ecological risk, lifetime carcinogenic risk and olfactory risk of VOCs in Dongjiang Lake, respectively. The RQ_total values varied from 3.95 × 10^-3 to 0.34 and the RQ values for all the 22 detected VOCs in 12 sample locations of Dongjiang Lake were below 0.01, which means negligible risk to aquatic organisms. The cancerous and non-cancerous risk indices were in the range of 2.31 × 10^-9-5.16 × 10^-7 and 1.68 × 10^-7-1.45 × 10^-2, respectively. Bromodichloromethane and 1,1-dichloroethene were associated with the highest and lowest carcinogenic risks in all 12 sample locations. Results also demonstrated that the olfactory risk in Dongjiang Lake is negligible. These data suggest that the VOCs in Dongjiang Lake may not lead great ecological and health risks for organism and human.

Atmospheric Arsenic Deposition in the Pearl River Delta Region, South China: Influencing Factors and Speciation

This is a comprehensive study on mobilization/speciation and temporal/spatial variation of atmospheric arsenic (As) deposition in the Pearl River Delta (PRD) region. A set of experimental procedures was established for measuring the deposition fluxes of individual As species. The deposition carrying inorganic As^III % was significantly higher than that contained in atmospheric particles. Compared with dry deposition, wet deposition was much more harmful to the regional ecosystem, as it contributed the majority of bulk deposition (>75%) and carried most of the mobilized iAs^III compounds. A stepwise linear regression model was utilized to identify the factors influencing total As deposition (wet: precipitation and PM_2.5, dry: relative humidity, wind speed, and PM₁₀, bulk: precipitation, PM_2.5, and wind speed). By examining the representativeness of the study sites and comparison with the literature data, the statistic models were verified to explain the temporal/spatial variation of total As deposition in the entire PRD region, where significant seasonal variation was only found for wet deposition (wet season > dry season). The annual As load contributed from regional atmospheric deposition increased from 2013 to 2015, when the contributions of individual cities varied annually.

Simultaneous assessments of occurrence, ecological, human health, and organoleptic hazards for 77 VOCs in typical drinking water sources from 5 major river basins, China

Owing to the growing public awareness on the safety and aesthetics in water sources, more attention has been given to the adverse effects of volatile organic compounds (VOCs) on aquatic organisms and human beings. In this study, 77 target VOCs (including 54 common VOCs, 13 carbonyl compounds, and 10 taste and odor compounds) were detected in typical drinking water sources from 5 major river basins (the Yangtze, the Huaihe, the Yellow, the Haihe and the Liaohe River basins) and their occurrences were characterized. The ecological, human health, and olfactory assessments were performed to assess the major hazards in source water. The investigation showed that there existed potential ecological risks (1.30 × 10 ≤ RQtotals ≤ 8.99 × 10) but little human health risks (6.84 × 10(-7) ≤ RQtotals ≤ 4.24 × 10(-4)) by VOCs, while that odor problems occurred extensively. The priority contaminants in drinking water sources of China were also listed based on the present assessment criteria.