Reliability of stored river water as an alternative for consumption in Ekpoma, Nigeria: a human health risk assessment

With looming global water-related issues, the monitoring of water quality for household and industrial consumption has become more pertinent. Rivers in nearby towns serve as primary water sources for Ekpoma town. 123 samples of stored river water were collected from 41 sampling locations and physical properties - pH, electrical conductivity (EC), salinity, temperature, and total dissolved solids (TDS) - were measured in situ using the Hanna edge® Multiparameter EC/TDS/Salinity Meter-HI2030. Atomic absorption spectrophotometry (AAS) was used to detect and measure the concentration of potentially toxic metals (PTMs): Al, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. The measured concentrations were compared to the WHO, US EPA, and NSDWQ regulatory standards, and a spatiotemporal health risk analysis was performed using HERisk software. Twenty-five percent of the tested samples contained PTM concentrations within the allowable regulatory limits. Spatiotemporal health risk analysis showed that 98.8% of the cumulative carcinogenic risks (CRcum) were entirely from Pb contamination via oral ingestion. PTM concentrations in the samples suggest the degradation of river water quality due to agricultural activities, crude oil exploration activities, and soil composition in the region. Best management practices (BMPs) and treatment processes for the removal of detected contaminants are recommended to improve water quality

Assessing the state of rainwater for consumption in a community in dire need of clean water: Human and health risk using HERisk

This study examines the case of Ekpoma community, Edo State, Nigeria, where roof-harvested rainwater is the primary source of water for drinking and domestic purposes. Eight potentially toxic elements (PTEs), namely aluminum, chromium, copper, iron, manganese, nickel, lead, and zinc, were detected in rainwater samples, collected and analyzed from 54 sampling locations across the community. The elemental concentrations were quantified using atomic absorption spectrophotometry and compared using the regulatory standards of the World Health Organization, United States Environmental Protection Agency, and Nigerian Drinking Water Quality Standards. The PTEs detected in the rainwater samples can be attributed to the nature of the materials used in the roof catchment systems, storage tank conditions, anthropogenic effects from industrial and agricultural processes, and fossil fuel emissions. However, only 20% of the evaluated samples contained PTE concentrations below the allowable regulatory limits. Spatio-temporal health risk analysis conducted using HERisk software showed that children in the development phase (1–18 years) are most vulnerable to health risks in the community. After age 18, the risk increased by approximately 10% and remained constant until old age. In addition, the evaluation of the studied sites showed that 33% of the evaluated sites had negligible carcinogenic risks, while the other 61% were sites with low carcinogenic risks to residents

Data on quantification of PAHs and elemental content in dry Camellia sinensis and herbal tea

Here we present data on potentially toxic metals and polycyclic aromatic hydrocarbons (PAHs) in commercially sold tea brands in Nigeria. The article provides data on the sequential extraction and the pseudo-total concentrations of eight metals (Cd, Cr, Cu, Mn, Ni, Pb, V and Zn) and polycyclic aromatic hydrocarbons (PAHs) in dry Camellia sinensis and herbal tea. The three-step Community Bureau of Reference (BCR) method and acid digestion with aqua regia were adopted for sequential and total metal extractions, respectively. The extraction of branded tea samples for PAHs analysis has been described in “Concentrations, sources and risk characterisation of polycyclic aromatic hydrocarbons (PAHs) in green, herbal and black tea products in Nigeria” [1] and “Polycyclic Aromatic Hydrocarbons (PAHs) Occurrence and Toxicity in C. sinensis and Herbal Tea” [2]. Elemental and PAHs analyses of extracts were determined by Microwave Plasma Atomic Emission Spectroscopy (Agilent MP-AES 4100) and Agilent gas chromatograph 7890A coupled with flame ionization detector (FID), respectively

Chemical Speciation and Characterization of Trace Metals in Dry Camellia sinensis and Herbal Tea Marketed in Nigeria

Background. Trace metals from anthropogenic activities have been found to occur in tea brands and pose potential human health risks to consumers. Objectives. The present study assessed the concentrations of trace metals in green, black and herbal tea brands using a modified Community Bureau of Reference sequential extraction method. Methods. Fifteen (15) Camellia sinensis and eight (8) herbal tea samples commonly consumed in Nigeria were collected and analyzed for trace metals. The concentrations of cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in extract fractions were analyzed using microwave plasma atomic emission spectroscopy (MP-AES). Results. Trace metals were detected in all of the samples investigated. The concentrations of trace metals in 4 stages (soluble/exchangeable/carbonates bound fraction, reducible fraction, oxidizable fraction, residual fraction) of sequential and pseudo-total metal extraction procedures are presented. The concentrations of Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn in the exchangeable/carbonate bound fraction for green tea ranged between 0.27–1.47, ND-0.33, ND-0.44, 7.05–33.04, 0.23–0.69, ND-0.51, ND-0.16 and 0.18–1.99 mg/kg, ND-0.73, 0.15–0.36, 0.36–0.59, 1.38–30.07, 0.15–0.54, 0.05–0.76, 0.15–0.34 and 0.27–0.77 mg/kg and 0.54–0.64, 0.25–0.41, 0.35–0.47, 18.72–23.98, 0.30–0.55, 0.15–0.21, 0.15–0.23 and 0.30–0.48 mg/kg for hebal tea, respectively. Conclusion. The metal content in the investigated tea indicated low to enhanced concentrations. Locally produced black teas recorded relatively low trace metal contents compared to the green and herbal tea samples. The most bioavailable trace metal was Mn, while Zn was most preferably bound to the residual fraction. Cadmium, Cr, Cu, Ni, Pb, and V were distributed at varied concentrations among other extractable phases. Daily consumption of the investigated tea products may expose consumers to potentially toxic metals as well as essential elements. Competing interests. The authors declare no competing financial interests

Chemical Speciation and Characterization of Trace Metals in Dry Camellia sinensis and Herbal Tea Marketed in Nigeria

Background. Trace metals from anthropogenic activities have been found to occur in tea brands and pose potential human health risks to consumers. Objectives. The present study assessed the concentrations of trace metals in green, black and herbal tea brands using a modified Community Bureau of Reference sequential extraction method. Methods. Fifteen (15) Camellia sinensis and eight (8) herbal tea samples commonly consumed in Nigeria were collected and analyzed for trace metals. The concentrations of cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) in extract fractions were analyzed using microwave plasma atomic emission spectroscopy (MP-AES). Results. Trace metals were detected in all of the samples investigated. The concentrations of trace metals in 4 stages (soluble/exchangeable/carbonates bound fraction, reducible fraction, oxidizable fraction, residual fraction) of sequential and pseudo-total metal extraction procedures are presented. The concentrations of Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn in the exchangeable/carbonate bound fraction for green tea ranged between 0.27–1.47, ND-0.33, ND-0.44, 7.05–33.04, 0.23–0.69, ND-0.51, ND-0.16 and 0.18–1.99 mg/kg, ND-0.73, 0.15–0.36, 0.36–0.59, 1.38–30.07, 0.15–0.54, 0.05–0.76, 0.15–0.34 and 0.27–0.77 mg/kg and 0.54–0.64, 0.25–0.41, 0.35–0.47, 18.72–23.98, 0.30–0.55, 0.15–0.21, 0.15–0.23 and 0.30–0.48 mg/kg for hebal tea, respectively. Conclusion. The metal content in the investigated tea indicated low to enhanced concentrations. Locally produced black teas recorded relatively low trace metal contents compared to the green and herbal tea samples. The most bioavailable trace metal was Mn, while Zn was most preferably bound to the residual fraction. Cadmium, Cr, Cu, Ni, Pb, and V were distributed at varied concentrations among other extractable phases. Daily consumption of the investigated tea products may expose consumers to potentially toxic metals as well as essential elements. Competing interests. The authors declare no competing financial interests

A new method for assessment of sediment-associated contamination risks using multivariate statistical approach

This paper presents the assimilation of heavy metal concentration data from sequential extraction method (SEM) with metal toxicity factors to develop and propose two new sediment quality indices modified hazard quotient (mHQ) and ecological contamination index (ECI), to predict the potential ecological risks associated with sediment contamination. Chemical speciation data of five heavy metals: cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb) from five coastal aquatic ecosystems of the Equatorial Atlantic Ocean were used in the assessment of the degree of heavy metal contamination. Evaluation based on ECI indicated that sediments of most aquatic ecosystems were considerably to highly contaminated. The results showed that the proposed indices are reliable, precise, and in good agreement with similar existing indices used for evaluating the severity of sediment-associated contamination by heavy metals. The principal component analysis (PCA) and factor analysis indicated that heavy metals in the benthic sediments were mostly from anthropogenic sources. • New indices – modified hazard quotient (mHQ) and ecological contamination index (ECI) - were developed for predicting sediment-associated risk adverse effects. • Newly proposed indices agree closely with the existing pollution indices. • Pollution indices reveal significant anthropogenic contamination by Cd and Pb. Method name: New ecological risk indices, Keywords: Fractionation, Heavy metals, Sediment pollution, Contamination indices, Principal component analysi