Health risk assessment of heavy metal variability in sachet water sold in Ado-Odo Ota, South-Western Nigeria

Refined Cumulative Risk Assessment of Pb, Cd, and as in TCM Decoction Based on Bioavailability through In Vitro Digestion/MDCK Cells

In this study, the oral bioavailability of Pb, Cd, and As in three types of traditional Chinese medicines (TCMs) and TCM decoctions were investigated through in vitro PBET digestion/MDKC cell model. Furthermore, a novel cumulative risk assessment model associated with co-exposure of heavy metal(loid)s in TCM and TCM decoction based on bioavailability was developed using hazard index (HI) for rapid screening and target organ toxicity dose modification of the HI (TTD) method for precise assessment. The results revealed that the bioavailability of Pb, Cd, and As in three types of TCM and TCM decoction was 5.32-72.49% and 4.98-51.97%, respectively. After rapid screening of the co-exposure health risks of heavy metal(loid)s by the HI method, cumulative risk assessment results acquired by TTD method based on total metal contents in TCMs indicated that potential health risks associated with the co-exposure of Pb, Cd, and As in Pheretima aspergillum (E. Perrier) and Oldenlandia diffusa (Willd.) Roxb were of concern. However, considering both the factors of decoction and bioavailability, TTD-adjusted HI outcomes for TCMs in this study were <1, indicating acceptable health risks. Collectively, our innovation on cumulative risk assessment of TCM and TCM decoction provides a novel strategy with the main purpose of improving population health.

Novel Integrated Tiered Cumulative Risk Assessment of Heavy Metals in Food Homologous Traditional Chinese Medicine Based on a Real-Life-Exposure Scenario

In order to serve population health better, the first integrated tiered decision tree for cumulative risk assessment of co-exposure of Pb-, Cd-, and As-associated health risks in food homologous traditional Chinese medicine (TCM) was designed, after measuring their concentrations by inductively coupled plasma-mass spectroscopy (ICP-MS). Basically, our three-step decision tree involving hazard quotient (HQ), hazard index (HI), and target-organ toxicity dose (TTD) modification of the HI method was developed to evaluate the potential risks of 949 batches of 15 types of food homologous TCM. To acquire a real-life exposure scenario, the cumulative risk assessment model was established by optimizing key parameters, such as ingestion rates, frequency, and duration of exposure to food homologous TCM based on questionnaire data. As a result, the mean concentrations of Pb, Cd, and As in 949 batches of food homologous TCM were 0.896, 0.133, and 0.192 mg/kg, respectively. The HQ values of As for Angelica sinensis (Oliv.) Diels and Houttuynia cordata Thunb. were 1.04 and 1.01, respectively, for females. Other HQs of Pb, Cd, or As in food homologous TCM were lower than 1 for both males and females. However, after rapid screening of the co-exposure health risks of heavy metals by the HI method, cumulative risk assessment results acquired by TTD modification of the HI method implied that the potential health risks associated with the co-exposure of Pb, Cd, and As in Lonicera japonica Thunb. and Houttuynia cordata Thunb. ingested as both TCM and food were of concern in the clinic. Additionally, the cumulative risks of Pb, Cd, and As in Mentha canadensis L., Chrysanthemum indicum L., and Zaocys dhumnades (Cantor) only used as food exceeded the human tolerance dose. Collectively, our innovation on the tiered strategy of decision tree based on a real-life exposure scenario provides a novel approach engaging in the cumulative risk assessment of heavy metals in food homologous TCM. All in all, such effort attempts to scientifically guide the rational use of TCM in the treatment of the complex diseases and the improvement of population health.

Evaluating the potability and human health risk of sachet water in Wukari, Nigeria

This study assessed physiochemical and biological properties of sachet waters. In general, sachet waters were within standards for all parameters except lead in batch A & B, iron in batch E, and E. coli in all water brands. Human health risk showed the order of THI as NO₃^- > Pb > F^- > Fe for batch A & B samples and NO₃^- > F^- > Pb > Fe for batch C, D & E. This showed nitrate constituting over 50% of the THI while batch B water samples showed THI above the acceptable limit for all age groups. The THI for infants suggests moderate risk. This indicates infants are more likely to be impacted even though water parameters were within standards. Hence, there is a need to monitor sachet water companies to protect public health.

Sachet water quality and Vendors’ practices in Damongo, northern Ghana during the emergence of SARS-CoV-2 using multivariate statistics, water quality and pollution indices, and panel assessment

The emergence of the SARS-CoV-2 has affected several production services including the water production and delivery processes. This study considered sachet water quality during the advent of the SARS-CoV-2 pandemic using multivariate statistics and Water Quality Index, Water Pollution Index and, hygienic and sanitation practices of sixty-two (62) sachet water vendors using a panel assessment approach. The findings showed that vendors did not adhere to proper hygienic practices as ninety-four (94%) of them did not have health clearance, ninety (90%) did not frequently wash their receptacles for selling daily, and most of them stored and sold in unhygienic environments. Majority of the producers violated Food and Drugs Authority Regulations. The Empirical Orthogonal Function analysis showed that total iron, Total Heterotrophic Bacteria, Salmonella, Cl⁻, E. coli, and fecal and total coliforms were the controlling elements in the water. All the brands were below threshold limits based on the physical water assessment. However, enteric bacteria were observed in all the brands. Water Quality and Water Pollution Indices (WQI and WPI) described all the sachet water brands (vendors and production sites) as excellent for drinking. The WQI computations for samples from the production and vending sites respectively ranged from 0.12 to 0.36 and 0.27–0.42 whereas WPI presented 0.22–0.31 and 0.23–0.32. Comparatively, samples from vendors had elevated elemental concentrations and loads. This suggests that besides sachet water contamination during production and transportation, vendors significantly impacted the quality of sachet water. Sensitization on proper hygienic practices for sachet water production and vending and routine assessment of the quality of sachet water produced or sold is recommended.

Environmental and human health risk evaluation of heavy metals in ceramsites from municipal solid waste incineration fly ash

Municipal solid waste incineration (MSWI) for power generation can reuse waste effectively, but it generates a large amount of fly ash enriched with heavy metals. If this fly ash cannot be treated properly, it can cause ecological damage and human health risk. According to the production of ceramsites from MSWI fly ash, an evaluation methodology is established, in which the influence of heavy metal stability on the environment is considered for the first time, and the health risks of heavy metals via different exposure pathways are distinguished. The results show that heavy metals in MSWI fly ash have moderate potential environmental risks to environment and have strong non-carcinogenic and carcinogenic risks both to children and adults. By contrast, heavy metals in ceramsites pose little risk to environment and human health. This paper explains some reasons of heavy metal content and leaching ratio change in ceramsite and also illustrates why stability is a concern through comparing the potential risk index method and the improved evaluation method. This evaluation system can be applied to different production processes of building materials using solid hazardous waste and provides a quantitative evaluation method for reducing environment and human health risks of heavy metals.

Estimation of some trace metal pollutants in River Atuwara southwestern Nigeria and spatio-temporal human health risks assessment

Over twenty thousand persons rely on water from Atuwara River for drinking and other domestic purposes, hence the need to ascertain the human health risk inherent in such practice. Seventy-two water samples were collected from River Atuwara during the dry and wet seasons of 2018, and the concentration of heavy metals (Pb, As, Ni, Cr, Zn, Cu, and Cd) were measured using ICP-OES. A newly developed human health risk assessment method, HHRISK code was used to estimate the health risks associated with consumption of water from Atuwara River. Results obtained revealed that the concentration of heavy metals in the river was as follows: Cd < Ni < Pb < Cr < Cu < As < Zn in the wet season and Cd < Pb < Ni < Cu < Cr < As < Zn during the dry season. Principal component analysis suggested that industrial effluents, agricultural activities and base-rock interaction are responsible for pollution of Atuwara River. The cumulative hazard index (HIcum) obtained was 678.0 ± 36.8 (for adult) and 1392.0 ± 132 (for child) for non-carcinogenic risks. A cumulative carcinogenic risk (CRcum) of 1.01E-1±5.26E-3 and 4.96E-2±5.05E-3 was obtained for adult and children respectively, suggesting that up to 1 in 10 adults and 1 in 20 children may suffer from cancer over their lifetime as a result of consumption and exposure to water from River Atuwara. These results highlight the fact that unavailability of safe drinking water in many parts of the world remains a real and persistent risk which must be tackled.

Human health risk assessment of trace elements in drinking tap water in Zahedan city, Iran

Daily intake of elements through the consumption of drinking water, due to its detrimental effects, is accounted for an important concern. Although the health risk assessment of heavy metals in different water sources has extensively carried out in various studies, the effect of age and the concentration of all trace elements in drinking tap water have neglected. Therefore, this study was conducted to evaluate the concentrations of heavy metals, e.g., As, Cd, Cr, Ni, Pb, B, Al, Hg, Mn, Zn, Cu, Fe, Se and Ba in the drinking tap water of Zahedan city and to estimate their non-carcinogenic and carcinogenic effects. Moreover, this is the first research in Iran that has also been dedicated to complete investigation on daily intakes of trace elements in tap water. A total of 155 samples of drinking water were randomly taken from the tap water and were analyzed using ICP-OES device. The estimation of the carcinogenic and non-carcinogenic risks of analyzed elements was carried out based on the guidelines of the U.S EPA. The hazard index (HI) values for children and adult age groups were 9.84E-01 and 4.22E-01, respectively. The cumulative Excess Lifetime Cancer Risk (ELCR) for carcinogenic trace elements was in range of tolerable carcinogenic risk 10^-6 to10^-4 and for all carcinogenic elements were in the order of Pb > Cd > Cr. It also detected that the total carcinogenic risks of the Cd, As and Cr in water samples through the ingestion route are at the levels of "low risk" and "low-medium risk".

Evaluation of groundwater contamination in Chandigarh: Source identification and health risk assessment

The major objective of the current study is to estimate the groundwater quality and identify the likely sources of contamination in Chandigarh, India. Total 80 groundwater samples were collected from different locations and at various depths. Further, physcio-chemical analysis was done to estimate pH, electrical conductivity (EC), total dissolved solids, total hardness (TH), total alkalinity (TA), Na⁺, K⁺, Cl^-, SO₄^2-, PO₄^3- and NO₃^-. The groundwater samples collected from shallow water sources contain higher concentration of total dissolved salts. EC, TA, Cl^-, TH, Na⁺, and K⁺ were found relatively higher in the shallow aquifer (<150 ft). Based on the location of pollution sources at the surface and consecutive geo-statistical distribution of physicochemical characteristics, this study suggests that non-scientific disposal of municipal solid waste, dumping of industrial waste and agricultural activities, in the nearby areas lead to the deterioration of groundwater of shallow aquifer. These observations were also confirmed using various water quality indices and outcomes of multivariate modeling, including principal component analysis. Health risk assessment for nitrates indicated that 29 groundwater samples pose non-carcinogenic health risk for children due to dermal and oral exposure. Hence, there is a need to establish a system for regularly assessing the groundwater quality to minimize public health risks.

Probabilistic risk assessment and spatial distribution of potentially toxic elements in groundwater sources in Southwestern Nigeria

The study investigated the concentration of potentially toxic heavy metals (PTHM) in groundwater sources (hand-dug wells and boreholes), spatial distribution, source apportionment, and health risk impact on local inhabitants in Ogun state. One hundred and eight water samples from 36 locations were analysed for Cr, Ni, Pb, Fe, Mn, Mg, Ca and Al. Mean values of 0.013, 0.003, 0.010, 0.088, 0.004 and 3.906 mg/L were obtained for Pb, Cr, Ni, Fe, Mn, and Al respectively at Iju district. Meanwhile, the average values of Pb, Ni, Fe, Mn, and Al concentrations at Atan district were 0.008, 0.0023, 0.011, 0.003, and 1.319 mg/L respectively. Results also revealed that the 44.4% and 11.13% of the borehole and well-water samples surpassed the World Health Organization limits for Pb at Atan. In Iju, the concentration of Pb and Al were relatively high, exceeding the stipulated standard in 100% of the samples. The Multivariate statistical analysis employed produced principal factors that accounted for 78.674% and 86.753% of the variance at Atan and Iju region respectively. Based on this, PTHM were traced to geogenic sources (weathering, dissolution, leaching) and anthropogenic emissions from industrial activities. In addition, the hazard quotient values obtained from the health risk assessment identified potential non-carcinogenic risk due to Pb via ingestion route. Ni was found to have high carcinogenic risk on adult and children, having exceeded the threshold limit. The outcome of the carcinogenic risk assessment revealed that 88.67% (for adults) and 1.12% (for children) of the cancer risk values surpassed the specified limits at Iju, whereas the cancer risk values were considerably lesser at Atan. In conclusion, the report of this study should serve as a beacon that will spark up strategic planning, comprehensive water resource management, and extensive treatment schemes in order to address the health complications linked with environmental pollution.

Distribution and health risk assessment of arsenic and selected heavy metals in Groundwater of Chandigarh, India

Groundwater quality of Chandigarh was assessed by collecting 80 groundwater samples from different depths varying between 10 ft and 1200 ft. These samples were analyzed for possible contamination with metal pollutants such as Al, Cd, Co, Cr, Cu, Fe, Mo, Mg, Ni, Pb, V, Zn. Geospatial interpolation of the contaminants identified poor sanitary practices of waste management, agrarian activities, and industrial pollution as the prominent sources of groundwater contamination. Quality assessment of groundwater performed using Heavy metal Pollution Index (HPI), and Metal Index (MI) revealed HPI as a better method for health risk assessment. HPI indicate poor groundwater quality near municipal solid waste dumping sites and industrial areas of Chandigarh. The shallow aquifer was reported to be more contaminated than deeper aquifer. Further, health risk assessment of Chandigarh's groundwater indicated non-carcinogenic health impacts due to contamination of As, Cr, Co, Cd, Cu, Ni, Pb, Zn and carcinogenic health impacts from As, Cd, Cr, Cu, Pb. The study suggests that groundwater should also be regularly monitored for metal contamination as over-extraction, industrialization, disposal of municipal solid waste and informal E-waste recycling activities increases the public health risks in countries worldwide, facing similar environmental pollution problems of the groundwater.

Optimal sizing of roof gutters and hopper for rainwater harvesting

Bernoulli's equation was applied to a section of hopper collector to determine the appropriate dimensions of the hopper for rainwater harvesting. Also, the hopper surface area (SFA) for a given volume was minimized by differentiating it in relation to the slant angle (SA). Combining the rational formula-Manning's equation and the best hydraulic section criteria-expressions were obtained for the optimum sizes of rectangular and circular gutters. Minimum hopper SFA for a given volume was found to occur at an optimum hopper SA of 35.282°. With the optimum conditions, design charts were produced for the hopper, circular, and rectangular roof gutters. The ratio of hopper larger radius to the smaller radius designated as (α) gave hopper dimensions with excessively wide upper radius for values of 0.1 ≤ α ≤ 0.2. Alpha (α) values of 0.8 and 0.9 gave values of R and Z which are almost too close to be distinguished. The valid range of α for hopper design was found to be 0.292 ≤ α ≤ 0.8. The study revealed that roof plan area has more effect on hopper dimensions than gutter slope. In addition, the case of excessive long gutters can be addressed by placing the hopper at the lateral epicenter of the eaves. In this regard, regions with abundant rainfall can solve water scarcity issues if proper design parameters of RWH components are considered in order to avoid waste of water through the overflow of water collection systems.

Computation of human health risk in surface water in Ado-Odo Ota, Ogun State, Nigeria

Heavy metals find their way into surface and groundwater due to degrading environmental conditions, and as such consistent monitoring to avoid the adverse health implications associated with the consumption of polluted water is required. This study examined the concentrations for Lead (Pb), Nickel (Ni), Zinc (Zn), Chromium (Cr), Cadmium (Cd), Copper (Cu) and Arsenic (As) in the Surface water of River Balogun in Ota, Ogun State, Nigeria during the wet season and estimated the human health risk resulting from prolonged consumption by children and adult of dissimilar age groups without treatment. Although there were persistent occurrence of Nickel (Ni), Copper (Cu), Zinc (Zn) and Arsenic (As) in all stations sampled, the health risk assessment conducted revealed that both population groups are more likely to be affected by high concentration levels of Arsenic than any other Heavy metal present.

Fluoride contamination in groundwater sources in Southwestern Nigeria: Assessment using multivariate statistical approach and human health risk

The present study investigated the ionic and fluoride concentrations in tap water and its associated health risk to local dwellers of Ogun State (Abeokuta south), Nigeria. 63 samples were collected from twenty-one different locations. Results obtained revealed the mean concentration of fluoride (F^-) as 1.23 mg/L. Other water quality parameters such as total dissolved solids (TDS), electrical conductivity (EC), F^-, Fe^2+, and SO₄^2- surpassed the WHO guidance for drinking water. Strong positive correlation was observed between F^- and TDS; F^- and pH; TDS and EC; TDS and Mg²⁺; TDS and SO₄^2-; TDS and HCO₃^-; EC and HCO₃^-; EC and SO₄^2-; Na⁺ and Cl^-; SO₄^2- and Cl^-. In addition, Empirical Bayesian Kriging (EBK) model was employed to spatially distribute the concentration of the analyzed elements within the study region. The chronic daily dose (CDD) and hazard quotient (HQ) were also used to evaluate the health risk associated with F^-, considering dermal and ingestion as pathways. The results revealed that the associated HQ for infants between the age range of 6-12months within about 91% of the study region surpassed the accepted HQ limit. However, the HQ for age categories 11-16years; >65years; 18-21years; 21years; 16-18years within 95.2%, 90.5%, 80.95% and 100% of the study location were less than 1. Conclusively, the HQ values obtained in this study should serve as a baseline information for water management authorities, policymakers and the society at large towards addressing these pollution issues.

Assessment of geospatial and hydrochemical interactions of groundwater quality, southwestern Nigeria

Groundwater pollution resulting from anthropogenic activities and poor effluent management is on the rise in Nigeria. Hence, groundwater used for domestic purposes is questionable and therefore calls for scientific scrutiny. Investigation of hydrochemical interactions and quality of groundwater resource is essential in order to monitor and identify sources of water pollutants. As a result, groundwater samples were collected from 21 locations in Abeokuta South, Nigeria and analyzed for physicochemical parameters using standard methods. Results obtained were subjected to hydrochemical and geospatial analyses. Water quality parameters investigated exhibited wide variations from location to location. Fe²⁺, Mg²⁺, SO₄^2-, Cl^-, total hardness (TH), Mn, Na⁺, NO₃^-, SiO₂, and alkalinity exhibited the highest levels of variation with coefficients of variation of 131.3, 92.8, 83.9, 76.7, 65.9, 64.3, 57.6, 57.2, 57.0, and 52.5, respectively. The average pH value was 6.76 with 71% of the water samples being slightly acidic. Na²⁺, Mg²⁺, Fe²⁺, and EC contents exhibited the most violation of drinking water standards with percent violations of 100, 52.4, 47.6, and 47.6%, respectively. Parameters, such as Mn, Ca²⁺, NO₃^-, and CO₃^2-, were within the WHO guideline values for drinking water in all the samples. The highest level of significant correlation was found to exist between Na⁺ and Cl^- (r = 0.84, α = 0.01). Six principal components, which explained 83.5% of the variation in water quality, were extracted with the first (34.1%) and second components (15.7%) representing the influence of mineral dissolution and anthropogenic practices, respectively, on the hydrochemistry of the area. Four hydrochemical clusters were identified with distinctly partitioned water quality. Further analysis revealed that 38, 29, 24, and 9% of the samples were the Na-K-HCO₃, Na-K-Cl-SO₄, Ca-Mg-HCO₃, and Ca-Mg-Cl-SO₄ types, respectively. Anthropogenic activities are increasing threat to groundwater quality in the study location and therefore call for urgent attention. There is also a need for routine monitoring of groundwater in Abeokuta.

Human health risk assessment data of trace elements concentration in tap water-Abeokuta South, Nigeria

Constant drinking water monitoring schemes are necessary because hazardous substances tend to enter water bodies through geodetic and anthropogenic sources. The main goal of this study was to evaluate the human health risk assessment posed by high fluoride and iron concentration in tap water used for domestic activities and consumption. In this study, the concentration of fluoride in tap water varied at different locations, ranging from 0.48 mg/L to 1.84 mg/L with an average value of 1.23 mg/L while that of iron ranged from 0.02 to 2.96 mg/L. The cluster analysis displayed three popular groups in which the samples can be classified. The non-carcinogenic risk was determined with defined methods outlined by US EPA considering dermal and ingestion pathways. Total Hazard Index greater than 0.8 for fluoride consumption in the analyzed locations was obtained from location R16, R17, R15, R4, and R6.