Water-quality issues in the Niger Delta of Nigeria: a look at heavy metal levels and some physicochemical properties

Water contamination: A culprit of serum heavy metals concentration, oxidative stress and health risk among residents of a Nigerian crude oil-producing community

Niger Delta has become popular for crude oil extraction for the past few decades. This uncoordinated activity has made it a hotspot for xenobiotics exposure and water bodies remain the environmental matrix significantly affected. One of the most deleterious components of crude oil is heavy metals (HMs). This study investigates HMs concentration in water and serum of humans residing in an oil-host community with the consideration of systemic effects, pollution status, carcinogenic and non-carcinogenic health risks and comparison made with residents from a non-oil-producing community. Heavy metal analysis, serum electrolytes, Urea, Creatinine, and liver enzymes were assessed using standard procedures; malondialdehyde, catalase, SOD, glutathione reductase, GPx and total antioxidant capacity (TAC) by spectrophotometry and TNF-α and 8-OHdG assessed via ELISA method. We found altered serum electrolytes; increased serum Pb and Cd levels; increased AST, ALT, ALP and lipid peroxidation; and decreased enzymes antioxidants including TAC among Ugbegugun community residents compared with control. We observed an association between environmental crude oil contamination, ecological and health risks in the community. We concluded that protracted exposure to HMs induces multi-systemic toxicities characterized by DNA damage, depletion of the antioxidant system, and increased free radical generation culminating lipo-peroxidation with significant ecological, carcinogenic, and non-carcinogenic risks characterize crude oil water contamination.

Grain size analysis and ecological risk assessment of metals in the sediments of Konsin River and Igboho dam reservoir, Oyo State, Nigeria, under agricultural disturbances

A large amount of agrochemicals and organic manures are applied on agricultural lands which is one of the major pathways of metal contamination in sediments. The present study was an attempt to appraise the grain-size of sediments and metal status of the Konsin River and Igboho dam reservoir sediments using several indexes as contamination factor (CF), degree of contamination (DC), geo-accumulation index (I_geo), enrichment factor (EF), potential ecological risk index (PERI), pollution load index (PLI), and statistical analysis. A total of seven sampling sites were chosen based on prevalent anthropogenic features and analyzed for the concentration of metals, viz., Cd, Cr, Pb, Mn, Fe, Cu, and Zn. The finding from this study showed high presence of very rough grains at the upstream and sand particles at the downstream. The average values of Cd, Cr, Pb, Mn, Fe, Cu, and Zn range from 0.00 - 2.00, 19.50 - 49.90, 20.80 - 65.30, 593.90 - 2532.90, 22,133.60 - 46,058.60, 19.60 - 66.10, and 81.60 - 191.30 mg/kg, respectively. The concentrations of metals in the sediments followed the increasing order of Cd < Cu < Cr < Pb < Zn < Mn < Fe. The observation from this study showed higher affinity of metals to less particle size. The mean concentrations of Cd, Cr, Pb, Mn, Fe, Cu, and Zn were above the toxicity reference value. The I_geo and EF indicated that most of the sites were moderately to strongly polluted due to Cd while the calculated PLI showed progressive deterioration of the environment in most sites. The Pearson's correlation analysis revealed that the presence of metals in the sediments were from anthropogenic and unidentified sources. The status of metals in the study area portends a serious ecological threat to the sediment biota and occupants of the agrarian communities that depend on the water and its produce for survival.

Chemometric and risk assessment of nitrogen composition of atmospheric rainwater from diverse surfaces in Rivers State, Nigeria

Organic and inorganic nitrogen ions in the environment play important role across environmental matrices. Rainwater samples collected from ambient and different roofing surfaces (zinc, aluminium, asbestos and stone-coated roofing sheets) from selected locations at Ogale, Rumuodomaya/Rumuodome, Diobu and Chokocho within Rivers State, Niger Delta, Nigeria, from April to June, July to August and September to October depicting three regiments of early, mid and late rains. The samples were analysed for Kjeldahl nitrogen, ammonium, nitrate and nitrite using APHA methodology. Quantitative assessment showed that Kjeldahl nitrogen were in range of 0.11 to 28.05 mg/L; ammonium 0.50 to 20.22 mg/L, nitrate from 0.12 to 22.69 mg/L and nitrite from 0.15 to 3.90 mg/L. Parameters decreased from early to late rain, which can be attributed to rain dilution factor potential, wind pattern and emission from anthropogenic sources that influenced the rainwater quality across surfaces. Nitrogen results showed that dry and wet deposition has great impact; atmospheric aerosols and biogeochemical interactions can affect water quality. Monthly variation showed that Ogale had high regression compared to other locations due to close proximity to oil and gas emission and marine contribution. Neutralization factor showed that nitrate-nitrite compounds have strong correlation with ammonium ion. Non-carcinogenic risk assessment using US EPA model showed hazard index less than one (1), thus no associated health effect of nitrate and nitrite in rainwater. In conclusion, it is evident that nitrate/nitrite levels and other nitrogen derivatives in rainwater in crude oil-producing Niger Delta and its continuous consumption can cause negative health outcome.

Heavy metal profile of surface and ground water samples from the Niger Delta region of Nigeria: a systematic review and meta-analysis

This systematic review and meta-analysis estimated the pooled mean levels of heavy metals in ground and surface water samples obtained from the Niger Delta region of Nigeria (NDRN). PUBMED and Google Scholar databases were searched for studies published between 2000 and 2019, which assessed the levels of heavy metals in natural water samples obtained from the NDRN. Thirty one (31) studies which had a total of 951 water samples were identified. The pooled mean estimate (PME) from the meta-analysis indicates that the levels of Ni, Cd, Cr, and Pb in the majority of the natural water bodies from the NDRN are higher than the WHO safe permissible limit for drinking water. The contributions of prevailing anthropogenic activities to the observed heavy metal profiles of natural water sources from the NDRN were discussed. Stricter enforcement of safe environmental practices is necessary to protect the lives of the over 30 million inhabitants of this oil rich region.

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.

Oxidative Stress Indices as Markers of Lead and Cadmium Exposure Toxicity in Auto Technicians in Ibadan, Nigeria

Auto technicians (auto mechanics, panel beaters, battery chargers, and auto painters) are among the most valuable work force in the society. Reports on oxidative stress in persons occupationally exposed to mixed chemicals abound; however, few have narrowed down specifically on auto technicians, while even fewer have stratified the exposure in the different subgroups of auto technicians. This study evaluated the antioxidant status in auto technicians routinely exposed to lead and cadmium and stratified the results of exposure by different subgroups of auto technicians in Ibadan, Nigeria. Sixty-five apparently healthy males (aged 18 to 65years) were selected based on specific inclusion criteria using a structured questionnaire. Thirty-four were cases consisting of participants routinely working as auto technicians or apprentices(≥2years) while controls were thirty-one nonoccupationally exposed male members of staff/students of the University College Hospital, Ibadan, Nigeria. Blood was collected from all participants and analyzed for the presence of lead, total antioxidant capacity (TAC), and total plasma peroxides (TPP); oxidative stress index (OSI) was calculated. Urine samples collected from all participants were analyzed for the presence of urinary lead and cadmium using standard laboratory methods. Although values of TAC in cases (22538 ± 8726.54) were not statistically different from what was obtained in controls (26741.87 ± 8696.68), TPP and OSI were statistically higher in cases than in controls (183.88 ± 53.39 and 120.16 ± 70.54, respectively, and 0.93 ± 0.45 and 0.49 ± 0.33, respectively). The blood lead level in cases (10.11 ± 4.47) was significantly higher than in controls (7.72 ± 1.22) while elevated urinary lead and cadmium levels were observed in cases (0.65 ± 0.21 and 0.34 ± 0.11, respectively) compared to controls (0.52 ± 0.19 and 0.27 ± 0.10, respectively). Raised TPP and OSI levels-hallmark of active lipid peroxidation-found to be highest among panel beaters compared to others may be prognostic of membrane-damaging diseases in this subgroup of auto technicians.

Occurrence and Toxicological Risk Assessment of Polycyclic Aromatic Hydrocarbons and Heavy Metals in Drinking Water Resources of Southern China

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals exposure is related to a variety of diseases and cancer development, posing a great health risk to humans. In this study, water samples were collected from nine important water sources in Guangdong, Guangxi and Hainan provinces to determine the degree of PAHs and heavy metals contamination. Overall, the total contents of 16 PAHs and heavy metals were found within the permissible levels. In human health risk assessment, the benzo(a)pyrene equivalent concentration (BaP_eq) presented a much lower level than the guideline values announced by Chinese Environmental Protection Agency (CEPA) and United States Environmental Protection Agency (US EPA), demonstrating that the PAHs contamination level in drinking water was mostly acceptable. For heavy metals, the Chronic daily intake (CDI), hazard quotient (HQ) or hazard index (HI) suggested that the water quality in nine water sources was desirable and did not present a risk to human health.

Oxidative stress and DNA damage in zebrafish liver due to hydroxyapatite nanoparticles-loaded cadmium

This study investigated the acute and sub-acute toxicity responses in zebrafish following their exposure to hydroxyapatite-loaded cadmium nanoparticles (nHAP-Cd). The results indicate that cadmium chloride (Cd²⁺), 20 nm nHAP-Cd (nHAP₂₀-Cd), and 40 nm nHAP-Cd (nHAP₄₀-Cd) caused toxicity in zebrafish; the toxicity levels were in the following order: Cd²⁺ > nHAP₂₀-Cd > nHAP₄₀-Cd. Furthermore, nHAP-Cd showed level II grade of acute toxicity in zebrafish; the gradation was done on the guidelines of the Organization for Economic Co-operation and Development 203. We also found that Cd²⁺ ions and nHAP-Cd affected the malondialdehyde (MDA) levels and membrane permeability of zebrafish livers; these effects were compliant with the changes in antioxidant levels. The results of enzyme assays indicate the following notion: following the exposure of zebrafish to 0.12-0.93 mg/L nHAP-Cd, the activities of peroxidase, superoxide dismutase, and catalase enzymes increased significantly. Moreover, the content of anti-superoxide anion also increased substantially. This increasing trend of enzymatic activity was observed until the concentration of nHAP-Cd reached 1.86 mg/L nHAP-Cd. By increasing the concentration of both Cd²⁺ and nHAP-Cd, we found that levels of DNA damage had increased substantially in zebrafish liver; this effect was visualized by performing comet assay.

Seasonal variation of heavy metals in water and sediments in the Halda River, Chittagong, Bangladesh

The present study was carried out to assess the contamination levels of heavy metals (Pb, Cd, Cr, Cu, Hg, Al, Ni, Co, Zn, Mn) in surface water and sediment of the Halda River. The observed order of heavy metal concentration in water for Al > Ni > Zn > Mn > Cu > Cd > Pb > Cr > Co > Hg (mg/l) and for sediments Al > Mn > Zn > Ni > Cr > Pb > Cu > Co > Cd > Hg (mg/kg), respectively. The concentrations of Pb, Cd, Cr, Cu, Hg, Al, Ni, Co, Zn, and Mn in water, whereas in sediment Pb, Cu, Al, Ni, Co, Zn, and Mn were found above the permissible limit (WHO 2004; USEPA 2006; EPA 1986, 2002 and ECR 1997). Significant variations in the concentrations of Al and Ni were found in water (p < 0.05) while Cr, Cu, Pb, Co, Mn, and Ni showed substantial changes in sediment (p < 0.05). Principal component analysis (PCA) and correlation matrix revealed anthropogenic intrusions of Pb, Cd, Cr, Cu, Hg, Al, Ni, Co, Zn, and Mn in water and sediment. In case of water, very strong linear relationship was found in Hg vs Pb (0.941), Mn vs Zn (0.939), and Ni vs Cu (0.922) at the significance level 0.01. In sediment, very strong linear relationships were found in Mn vs Cr (0.999), Co vs Ni (0.999), Ni vs Cu (0.994), Zn vs Pb (0.993), Co vs Cu (0.992), Cu vs Cr (0.990), Mn vs Cu (0.989), Mn vs Ni (0.975), Mn vs Co (0.975), Ni vs Cr (0.974), Co vs Cr (0.972), Mn vs Pb (0.951), Cr vs Pb (0.948), Zn vs Cr (0.944), and Mn vs Zn (0.941) at the significance level 0.01 which direct that their common origin entirely from industrial effluents, municipal wastes, and agricultural activities. The study shows that seasonal water flows/water discharge (pre-monsoon, monsoon, and post-monsoon) have an impact on the mobility of metals. Elevated levels of metals were detected during monsoon in sediments (Pb, Cr, Cu, Al, Ni, Co, Zn, Mn) and post-monsoon in water (Cd, Hg, Ni, Co, Mn). The detection of high-risk metals in the Halda River may demonstrate that metals can cause significant effects on fry and fingerlings of the Gangetic carp fishery and prawn fishery (via sub-lethal and lethal effects and bioaccumulation or secondary poisoning of metals to fish and prawn).

Conflicts - Oil Exploration and Water

Water resources and water quality are closely related to oil exploration, refining and distribution. Since oil products provide over 90% of transport energy in almost all countries it is apparent that any oil operation is an inherent risk for water resources. Since water supplies will be increasingly stressed as a consequence of climate change and population increase the environmental risks associated with oil exploration may intensify. Thus, there are more reasons than CO2 emissions and climate change to cut down on oil production and consumption. In this paper water related risks are discussed from two aspects: (1) water use and water pollution as a result of normal exploration, refining and distribution, (2) water and marine life contamination caused by accidents. It will be exemplified by some major oil accidents, too often caused by human errors or negligence. Ecological effects of oil contamination for seawaters and freshwaters are discussed. Some aspects of social and economic consequences are examined. Some possibilities for mitigating oil leakage risks are highlighted.

Remediation of contaminated lands in the Niger Delta, Nigeria: Prospects and challenges

Contamination of the total environment (air, soil, water and biota) by crude oil has become a paramount interest in the Niger Delta region of Nigeria. Studies have revealed variable impacts of oil toxicity on the environment and exposed populations. The revelation gained much international attention in 2011 with the release of Environmental Assessment of Ogoniland report by the United Nations Environment Programme (UNEP). This has up scaled local and international pressures for urgent clean-up and restoration of degraded bio-resource rich environments of the Niger Delta, starting from Ogoniland. Previous remediation attempts in the area had failed due to erroneous operational conclusions (such as conclusions by oil industry operators that the Niger Delta soil is covered by a layer of clay and as such oil percolation remains within the top soil and makes remediation by enhanced natural attenuation (RENA) suitable for the region) and the adoption of incompatible and ineffective approaches (i.e. RENA) for the complex and dynamic environments. Perennial conflicts, poor regulatory oversights and incoherent standards are also challenges. Following UNEP recommendations, the Federal Government of Nigeria recently commissioned the clean-up and remediation of Ogoniland project; it would be novel and trend setting. While UNEP outlined some measures of contaminated land remediation, no specific approach was identified to be most effective for the Niger Delta region. Resolving the technical dilemma and identified social impediments is the key success driver of the above project. In this paper, we reviewed the socio-economic and ecological impacts of contaminated land in the Niger Delta region and the global state-of-the-art remediation approaches. We use coastal environment clean-up case studies to demonstrate the effectiveness of bioremediation (sometimes in combination with other technologies) for remediating most of the polluted sites in the Niger Delta. Bioremediation should primarily be the preferred option considering its low greenhouse gas and environmental footprints, and low-cost burden on the weak and overstretched economy of Nigeria.

Concentrations of some heavy metals in underground water samples from a Nigerian crude oil producing community

Pollution due to oil exploration activities in the Niger Delta region of Nigeria and government under-investments in potable water infrastructure has led to the dependence of the population on personal boreholes. Yet, there are little quality or surveillance reports on such waters. The concentrations of heavy metals in underground water samples from an oil producing area, Umuebulu, in the Niger Delta were therefore investigated. Water samples were collected from three test points, each approximately 300 m from (1) wellhead area (WHA), (2) flare area (FA) and (3) effluent discharge area (EDA), and one control point located 10 km away from any oil-related activity. The concentrations of lead, arsenic and cadmium were determined in the samples using atomic absorption spectrophotometry. All three heavy metals were present in the test, and control water samples at concentrations significantly (P < 0.05) exceeding the maximum contaminant levels recommended by the World Health Organization. The total hazard index of the water samples showed that their consumption constituted significant health risks in the order EDA > FA > WHA > Control. Appropriate water treatment and surveillance is warranted and therefore recommended for underground water resources of the studied community.

Assessment of Concentrations of Heavy Metals and Phthalates in Two Urban Rivers of the Northeast of Puerto Rico

Urbanization adjacent to rivers has increased in recent years and is considered a source of environmental contamination. The resulting increase in number of urban rivers in highly populated areas, such as the Caribbean island of Puerto Rico, has led to the appearance of synthetic as well as naturally occurring chemicals not previously observed nor regularly monitored in freshwater habitats. Some of these chemicals, such as heavy metals and plasticizers, have been shown to affect endocrine, respiratory, and nervous system function in animals and humans, even at relatively low concentrations. The purpose of this study was to measure concentrations of such emergent contaminants on rivers of urbanized areas on the northeast of Puerto Rico, as one element in the assessment of the impact of urbanism on water quality in these communities. To accomplish this, we used Inductively Coupled Plasma and Gas Chromatography Mass Spectrometry to measure amounts of heavy metals and phthalates, respectively, in superficial water of three rivers of Puerto Rico: Mameyes (non-urban), Río Piedras (urban river without a dam), and La Plata (urban river with a dam). The urban rivers had significantly higher concentrations of heavy metals arsenic, barium, cadmium, manganese, and antimony, when compared with the reference non-urban river. Manganese was the only metal found in concentrations higher than limits established by the EPA for drinking water. Of eight phthalates amenable to measurement with the chosen protocol and instrumentation, only dibutyl phthalate was detected, only in the La Plata river, and at concentrations ranging from 3 to 8 parts-per-billion. These findings suggest that urbanism close to rivers of Puerto Rico is likely having an impact on water quality and thus further study to identify the potential sources, as well as the inclusion of these emergent contaminants on the list of chemicals regularly monitored by government agencies is justified.

Assessment of water quality parameters using multivariate analysis for Klang River basin, Malaysia

This case study uses several univariate and multivariate statistical techniques to evaluate and interpret a water quality data set obtained from the Klang River basin located within the state of Selangor and the Federal Territory of Kuala Lumpur, Malaysia. The river drains an area of 1,288 km(2), from the steep mountain rainforests of the main Central Range along Peninsular Malaysia to the river mouth in Port Klang, into the Straits of Malacca. Water quality was monitored at 20 stations, nine of which are situated along the main river and 11 along six tributaries. Data was collected from 1997 to 2007 for seven parameters used to evaluate the status of the water quality, namely dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, suspended solids, ammoniacal nitrogen, pH, and temperature. The data were first investigated using descriptive statistical tools, followed by two practical multivariate analyses that reduced the data dimensions for better interpretation. The analyses employed were factor analysis and principal component analysis, which explain 60 and 81.6% of the total variation in the data, respectively. We found that the resulting latent variables from the factor analysis are interpretable and beneficial for describing the water quality in the Klang River. This study presents the usefulness of several statistical methods in evaluating and interpreting water quality data for the purpose of monitoring the effectiveness of water resource management. The results should provide more straightforward data interpretation as well as valuable insight for managers to conceive optimum action plans for controlling pollution in river water.

Water quality associated public health risk in Bo, Sierra Leone

Human health depends on reliable access to safe drinking water, but in many developing countries only a limited number of wells and boreholes are available. Many of these water resources are contaminated with biological or chemical pollutants. The goal of this study was to examine water access and quality in urban Bo, Sierra Leone. A health census and community mapping project in one neighborhood in Bo identified the 36 water sources used by the community. A water sample was taken from each water source and tested for a variety of microbiological and physicochemical substances. Only 38.9% of the water sources met World Health Organization (WHO) microbial safety requirements based on fecal coliform levels. Physiochemical analysis indicated that the majority (91.7%) of the water sources met the requirements set by the WHO. In combination, 25% of these water resources met safe drinking water criteria. No variables associated with wells were statistically significant predictors of contamination. This study indicated that fecal contamination is the greatest health risk associated with drinking water. There is a need to raise hygiene awareness and implement inexpensive methods to reduce fecal contamination and improve drinking water safety in Bo, Sierra Leone.

Heavy metal contaminations in the groundwater of Brahmaputra flood plain: an assessment of water quality in Barpeta District, Assam (India)

A study was conducted to evaluate the heavy metal contamination status of groundwater in Brahmaputra flood plain Barpeta District, Assam, India. The Brahmaputra River flows from the southern part of the district and its many tributaries flow from north to south. Cd, Fe, Mn, Pb, and Zn are estimated by using atomic absorption spectrometer, Perkin Elmer AA 200. The quantity of heavy metals in drinking water should be checked time to time; as heavy metal accumulation will cause numerous problems to living being. Forty groundwater samples were collected mainly from tube wells from the flood plain area. As there is very little information available about the heavy metal contamination status in the heavily populated study area, the present work will help to be acquainted with the suitability of groundwater for drinking applications as well as it will enhance the database. The concentration of iron exceeds the WHO recommended levels of 0.3 mg/L in about 80% of the samples, manganese values exceed 0.4 mg/L in about 22.5% of the samples, and lead values also exceed limit in 22.5% of the samples. Cd is reported in only four sampling locations and three of them exceed the WHO permissible limit (0.003 mg/L). Zinc concentrations were found to be within the prescribed WHO limits. Therefore, pressing awareness is needed for the betterment of water quality; for the sake of safe drinking water. Statistical analysis of the data was carried out using Special Package for Social Sciences (SPSS 16).

Metal concentrations in the water of Chah nimeh reservoirs in Zabol, Iran

The main objectives of this article were to monitor the metal concentrations of Fe, Cu, Pb, B, Ni, V, Cd, Se, As, and Cr in the water of Chah nimeh reservoirs in Zabol, south-eastern Iran; and to identify any relationships between metals. Metal concentrations in the water samples were analyzed using ICP-OES. The results indicated that there were a highly positive correlation between Cr and Se, Ni (p < 0.01), and, between As and Ni (p < 0.01). Also, there were significant differences between Cr, Ni, Pb, and Se in the water of Chah nimeh reservoirs.