Well-water Samples Research Articles

Drinking Water Sources Feasibility Test Based On Escherichia Coli As an Indicator Of Pollutant In Sultan Village Stunting Locus Of

Introduction: Water quality parameters are indicated by the presence of E. coli bacteria. These bacteria come from human feces, warm-blooded animals, and non-fecal coliforms. Decree of the Health Minister of the Republic of Indonesia Number 907/MENKES/VII/2002 concerning requirements and supervision of drinking water quality states that good drinking water has a zero total coliform and fecal coliform. Methods: This research uses a descriptive approach with a cross-sectional design. It aims to determine the quality of water sources in Sulkatan village. Ten (10) water sources were used as the samples using total sampling method. The collected samples were then taken to the laboratory to be tested with a series of MPN tests Results and Discussion: The results show that the amount of Escherichia coli bacteria in water samples in Sulkatan Village is 0MPN/100 ml. It is owing to the location of the water source that is far from industrial activities, household waste and residential areas. Conclusion: The quality of the tested well-water samples is good and within normal limits in accordance with the Decree of the Health Minister of the Republic of Indonesia Number 907/MENKES/VII/2002

Quantitative microbial risk assessment for ingestion of antibiotic resistance genes from private wells contaminated by human and livestock fecal sources.

We used quantitative microbial risk assessment to estimate ingestion risk for intI1, erm(B), sul1, tet(A), tet(W), and tet(X) in private wells contaminated by human and/or livestock feces. Genes were quantified with five human-specific and six bovine-specific microbial source-tracking (MST) markers in 138 well-water samples from a rural Wisconsin county. Daily ingestion risk (probability of swallowing ≥1 gene) was based on daily water consumption and a Poisson exposure model. Calculations were stratified by MST source and soil depth over the aquifer where wells were drilled. Relative ingestion risk was estimated using wells with no MST detections and >6.1 m soil depth as a referent category. Daily ingestion risk varied from 0 to 8.8 × 10-1 by gene and fecal source (i.e., human or bovine). The estimated number of residents ingesting target genes from private wells varied from 910 (tet(A)) to 1,500 (intI1 and tet(X)) per day out of 12,000 total. Relative risk of tet(A) ingestion was significantly higher in wells with MST markers detected, including wells with ≤6.1 m soil depth contaminated by bovine markers (2.2 [90% CI: 1.1-4.7]), wells with >6.1 m soil depth contaminated by bovine markers (1.8 [1.002-3.9]), and wells with ≤6.1 m soil depth contaminated by bovine and human markers simultaneously (3.1 [1.7-6.5]). Antibiotic resistance genes (ARGs) were not necessarily present in viable microorganisms, and ingestion is not directly associated with infection. However, results illustrate relative contributions of human and livestock fecal sources to ARG exposure and highlight rural groundwater as a significant point of exposure.IMPORTANCEAntibiotic resistance is a global public health challenge with well-known environmental dimensions, but quantitative analyses of the roles played by various natural environments in transmission of antibiotic resistance are lacking, particularly for drinking water. This study assesses risk of ingestion for several antibiotic resistance genes (ARGs) and the class 1 integron gene (intI1) in drinking water from private wells in a rural area of northeast Wisconsin, United States. Results allow comparison of drinking water as an exposure route for antibiotic resistance relative to other routes like food and recreational water. They also enable a comparison of the importance of human versus livestock fecal sources in the study area. Our study demonstrates the previously unrecognized importance of untreated rural drinking water as an exposure route for antibiotic resistance and identifies bovine fecal material as an important exposure factor in the study setting.

Production and purification of water using natural based adsorbent from plantain peels

Activated charcoal or carbon commonly employed as filter examinant of water, and air with surface area of 300–2,000m2/g, adsorbs a wide range of impurities and contaminants. This study was undertaken to produce adsorbent from plantain peels (Natural based), for the treatment of water samples, subsequently tested. Pyrolysis activation method was adopted using H3P04 and KOH. Water samples of wells from Gonigora, boreholes from Ungwan Romi, fishponds from Kawo and Kaduna Polytechnic, river water from river Kaduna, rain, tap from Tudun Wada and Eva water from Coca-Cola were used for the analysis. Which include water treatment, pH determination, total suspended, total dissolved, and total volatile solids, colour and odour determination. The results showed activated carbon effectiveness on pH of water samples well within 7.00, for borehole, Tap, and 7.02, for pond, rain and Eva waters, while 7.10 for river water. This indicated that the adsorbent is active and compared favorably with the standard adsorbent which pH of the water samples treated were 7.00 for pond, rain, tap and Eva, while 7.02 and 7.04 for borehole and river water respectively. This validated the production of granular natural based adsorbent via pyrolysis of plantain peels at 4500C by chemical activation method. Therefore an economical adsorbent obtained naturally based as cheap, readily available waste material for future commercial purification application.

Occurrence and Health Risks of Heavy Metals in Drinking Water of Self-Supplied Wells in Northern China.

Self-supplied wells, an important water resource in remote and scattered regions, are commonly deteriorated by environmental pollution and human activity. In this study, 156 self-supplied well-water samples were collected from remote and scattered areas of Inner Mongolia (NMG), Heilongjiang (HLJ), and the suburbs of Beijing (BJ) in Northern China. Twenty-four heavy metals were identified by using the inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES), and the associated human health risks were assessed by using standards of the US Environmental Protection Agency (US EPA). The concentrations of four heavy metals (As, Fe, Mn, and Tl) in HLJ, one heavy metal (Tl) in BJ, and ten heavy metals (Al, As, B, Cr, Fe, Mn, Mo, Se, Tl, and Zn) in NMG exceeded the limits set by China or the World Health Organization (WHO). The total carcinogenic risk (TCR) and total non-carcinogenic risk (THQ) exceeding set limits mainly occurred in NMG, compared to HLJ and BJ. Moreover, As accounted for 97.87% and 60.06% of the TCR in HLJ and BJ, respectively, while Cr accounted for 70.83% of the TCR in NMG. The TCR caused by Cd in all three areas had a negligible hazard (<10−4). As accounted for 51.11%, 32.96%, and 40.88% of the THQ in HLJ, BJ, and NMG, respectively. According to the results of the principal component analysis, heavy metals in well water from HLJ and NMG mainly originated from mixed natural processes and anthropogenic sources, whereas, in BJ, most heavy metals probably originated from natural sources. In the future, long-term monitoring of heavy metals in water from self-supplied wells should be conducted for an extensive range of well-water sites, and well water with high As contamination should be monitored more and fully assessed before being used as a drinking-water source.

Non-carcinogenic and carcinogenic health risks associated with heavy metals and polycyclic aromatic hydrocarbons in well-water samples from an automobile junk market in Ibadan, SW-Nigeria

Unserviceable vehicles imported from developed countries are often dismantled in automobile junk markets and the useable parts sold. This generates hazardous waste oils which contain contaminants detrimental to the environment and human health. In this study, we quantified the potential human health risks associated with oral and dermal exposure to heavy metals and PAHs in well-water samples from a major automobile junk market in Ibadan, SW-Nigeria. Twenty-four to thirty-one water samples from seven wells within the market were analyzed for seven metals and eight PAHs using standard methods. Hazard-Quotient (HQ), Hazard-Index (HI), and Carcinogenic-Risk (CR) were computed for children and adults based on the USEPA Human-Health Risk Assessment model.Iron, Lead, Arsenic, Cadmium, Benzo(a)Anthracene, and Benzo(a)Pyrene exceeded regulatory limits. In children and adults, lead (1.14–3.71), cadmium (1.26–2.60) and arsenic (1.03–4.33) had HQingestion values exceeding 1. In addition, cadmium also posed risks via the dermal route in children in two of the seven sampled wells with an HQ of 1.76. Hazard Index was >1 via both routes in children (HIingestion:- 5.04–10.07; HIdermal:- 1.12–2.12) but only via ingestion in adults (HI ingestion:- 2.36–4.85). Well-3 samples posed the greatest non-carcinogenic risks via ingestion with HI values of 10.07 (children) and 4.85 (adults) respectively. Cadmium, arsenic, lead, and chromium could also elicit carcinogenic risk, with CR values of 1.00E − 02, 1.95E − 03, 1.11E − 04, and 3.30E − 04 which exceeded the 10−4 limit indicating high risk, particularly in children.However, HQ and HI values for PAHs were <1 via both pathways suggesting no non-carcinogenic risk from PAH exposure. Carcinogenic risk estimates for Benzo(a)Anthracene (9.66E − 04) and Benzo(a)Pyrene (2.31E − 04) suggest moderate risks in exposed children via the dermal route. Adverse health effects including cancer may occur in the exposed population on prolonged usage of these polluted water sources. Urgent remediation measures are therefore necessary to protect the exposed population.

Radium radioactivity in soil profiles following long term irrigation with high radioactivity fossil groundwater

High radioactivity in a relatively saline confined aquifer water in different locations of the Disi area (South East of Jordan) was reported by some authors who recommended further investigation on the impact of that water on irrigated soils. Five well water samples (jointly used for irrigation and drinking) and 28 surface and subsurface soil samples from five profiles were collected from that area for the purpose of this study. Selected mineralogical, chemical, and physical properties of the soil samples were determined. Mineralogical compositions of the 28 soil samples were identified using x-ray diffraction, x-ray fluorescence, and ICP-MS techniques. Determination of activity concentrations of 238U, 226Ra and 228Ra in the five well waters and 22 soil samples from 4 sites (including a native soil) were determined using γ-ray spectroscopy. The results showed low salinity levels of both soil and water samples and low clay and organic matter contents in all soil samples. Kaolinite and mica were the dominant clay minerals with Fe substituting Al in the octahedral layer of these minerals. The average activity concentration of 226Ra and 228Ra in the well-water samples were 0.31 ± 0.09 and 1.74 ± 0.12 BqL−1, respectively. Such a high specific activity could be ascribed to the water enrichment with 228Ra diffusing from 232Th-rich sandstone geologic strata. Average concentrations of 238U and 232Th in the soil samples (0–120 cm depth) were 1.48 ± 0.38 mg kg−1 and 4.78 ± 1.55 mg kg−1, respectively. High correlation between these two radionuclides (R2 = 0.90) indicated no specific enhancement of these two metals from external sources, especially through chemical precipitation from irrigation water. Average activity concentration of 238U, 226Ra, and 228Ra in the soil samples were substantially low (20.8 ± 5.6, 16.94 ± 4.48, and 20.7 ± 6.2 Bq kg−1, respectively). No particular changes were observed when comparing concentration or radioactivity of these radionuclides with depth of a given soil or between irrigated and native soil samples at comparable depths. This could lead to the conclusion that there was no appreciable precipitation or adsorption of these radioactive metals from the percolating irrigation water onto the sandy soil complex.

Iron-Doped Bimodal Mesoporous Silica Nanomaterials as Sorbents for Solid-Phase Extraction of Perfluoroalkyl Substances in Environmental Water Samples.

In this work, sorbets based on UVM-7 mesoporous silica doped with Fe were synthesized and applied to solid-phase extraction of perfluoroalkyl substances from environmental water samples. These emerging pollutants were then determined by liquid chromatography coupled with a mass spectrometry detector. Thus, Fe-UVM-7 mesoporous silica materials with different contents of iron, as well as different pore sizes (by using alkyltrimethilamonium bromide surfactants with different organic tail lengths) were synthesized, and their structure was confirmed for the first time by transmission electron microscopy, nitrogen adsorption–desorption, X-ray diffraction, and Raman spectroscopy. After comparison, Fe50-UVM-7-C12 was selected as the best material for analyte retention, and several extraction parameters were optimized regarding the loading and elution step. Once the method was developed and applied to real matrices, extraction efficiencies in the range of 61–110% were obtained for analytes with C8–C14 chain length, both perfluoroalkyl carboxylates, and perfluoroalkyl sulfonates. Likewise, limits of detection in the range of 3.0–8.1 ng L−1 were obtained for all target analytes. In the analysis of real well-water samples, no target compounds were detected. Spiked samples were analyzed in comparison to Oasis WAX cartridges, and statistically comparable results were achieved.

Non-Carcinogenic and Carcinogenic Health Risks Associated with Heavy Metals and Polycyclic Aromatic Hydrocarbons in Well-Water Samples from an Automobile Junk Market in Ibadan, Sw-Nigeria

Non-Carcinogenic and Carcinogenic Health Risks Associated with Heavy Metals and Polycyclic Aromatic Hydrocarbons in Well-Water Samples from an Automobile Junk Market in Ibadan, Sw-Nigeria

Groundwater fluoride across the Punjab plains of Pakistan and India: Distribution and underlying mechanisms

Chronic exposure from drinking well-water with naturally high concentrations of fluoride (F−) has serious health consequences in several regions across the world including South Asia, where the rural population is particularly dependent on untreated groundwater pumped from private wells. An extensive campaign to test 28,648 wells was conducted across the Punjab plains of Pakistan and India by relying primarily on field kits to document the scale of the problem and shed light on the underlying mechanisms. Groundwater samples were collected from a subset of 712 wells for laboratory analysis of F− and other constituents. A handful of sites showing contrasting levels of F− in groundwater were also drilled to determine if the composition of aquifer sediment differed between these sites. The laboratory data show that the field kits correctly classified 91% of the samples relative to the World Health Organization guideline for drinking water of 1.5 mg/L F−. The kit data indicate that 9% of wells across a region extending from the Indus to the Sutlej rivers were elevated in F− relative to this guideline. Field data indicate an association between the proportion of well-water samples with F− > 1.5 mg/L and electric conductivity (EC) > 1.5 mS/cm across six floodplains and six intervening doabs. Low Ca2+ concentrations and elevated bicarbonate (HCO3− > 500 mg/L) and sodium (Na+ > 200 mg/L) in high F− groundwater suggest regulation by fluorite. This could be through either the lack of precipitation or the dissolution of fluorite regulated by the loss of Ca2+ from groundwater due to precipitation of calcite and/or ion exchange with clay minerals. Widespread salinization of Punjab aquifers attributed to irrigation may have contributed to higher F− levels in groundwater of the region. Historical conductivity data suggest salinization has yet to be reversed in spite of changes in water resources management.

When Water Availability Is Low, Two Mediterranean Salvia Species Rely on Root Hydraulics.

Increase in severity and frequency of drought events is altering plant community composition, exposing biomes to a higher risk of biodiversity losses. This is exacerbated in the most fragile areas as Mediterranean biome. Thus, identifying plant traits for forecasting species with a high risk of drought-driven mortality is particularly urgent. In the present study, we investigated the drought resistance strategy of two Mediterranean native species: Salvia ceratophylloides Ard. (Sc) and Salvia officinalis L. (So) by considering the impact of drought-driven water content decline on plant hydraulics. Well-watered samples of Sc displayed higher leaf and stemsaturated water content and lower shoot biomass than So samples, but similar root biomass. In response to drought, Sc showed a conservative water use strategy, as the prompt stomatal closure and leaves shedding suggested. A drought-tolerant mechanism was confirmed in So samples. Nevertheless, Sc and So showed similar drought-driven plant hydraulic conductance (Kplant) recover ability. Root hydraulic traits played a key role to reach this goal. Relative water content as well as loss of cell rehydration capability and membrane damages, especially of stem and root, were good proxies of drought-driven Kplant decline.

Evaluation of underground water quality for drinking and irrigation purposes in New Valley Governorate, Egypt

Abstract Underground water is the main and probably the only source of drinking and irrigation in New Valley Governorate (Egypt). To assess water suitability for such purposes, 30 well-water samples (80–1300m depth) were collected from three oases i.e., El-Kharga, Baris and El-Dakhla. The pH values of these waters ranged from 6.5 to 7.88. SO 4 2 − was the dominant anion in such waters while Ca2＋ was the dominant cation. Concentrations of both ions (SO 4 2 − and Ca 2 + ) exceeded the maximum allowable limits for drinking and irrigation purposes. Although sodium adsorption ratio (SAR) values did not exceed “10” in all waters samples; however, Mg-hazards and low infiltration rate might threaten the suitability of water for irrigation in many locations. Concentrations of Zn, Mn, Cu, Pb, Cd, As and Se were below the maximum allowable concentrations suggested by FAO for irrigation water. On the other hand, Fe was the only potentially toxic element (PTE) whose concentrations exceeded the permissible levels of WHO regulations for drinking water. According to the principal component analysis (PCA), these metals were originated from natural (Fe, Mn, Zn and Cu) and anthropogenic (As, Pb, Cd and Se) sources. Their existence represents potential chronic threats to children, particularly Fe, Mn, Pb and As. Moreover, the majority of water samples were within the moderate grade of irrigation quality index while exhibited low grades for the drinking quality index. Accordingly, more attention should be paid towards improving the quality of underground water in New Valley governorate for either drinking or irrigation purposes.

Effect of exogenously-applied abscisic acid, putrescine and hydrogen peroxide on drought tolerance of barley

The objective of this study was to identify the effect of abscisic acid (ABA), putrescine (Put) and hydrogen peroxide (H2O2) foliar pre-treatment on drought tolerance of barley. Despite water limitation, ABA-sprayed plants preserved increased water content, photosynthetic efficiency of PSII (ΦPSII) and CO2 assimilation rate (Pn) compared to untreated stressed plants. The ABA-treated plants presented also the lowest rate of lipid peroxidation (MDA), lowered the rate of PSII primary acceptor reduction (1 – qP) and increased the yield of regulated energy dissipation (NPQ) with higher accumulation of PGRL1 (PROTON GRADIENT REGULATION LIKE1) protein. These plants preserved a similar level of photochemical efficiency and the rate of electron transport of PSII (ETRII) to the well-watered samples. The significantly less pronounced response was observed in Put-sprayed samples under drought. Additionally, the combined effects of drought and H2O2 application increased the 1 – qP and quantum yield of non-regulated energy dissipation in PSII (ΦNO) and reduced the accumulation of Rubisco activase (RCA). In conclusion, ABA foliar application allowed to balance water retention and preserve antioxidant capacity resulting in efficient photosynthesis and the restricted risk of oxidative damage under drought. Neither hydrogen peroxide nor putrescine has been able to ameliorate drought stress as effectively as ABA.

An assessment of hydrologic factors that influence contaminant concentrations determined from domestic well-water samples

Open borehole wells in fractured crystalline rock are commonly used for domestic water supply. Concentrations of contaminants present in the well water, typically collected from the tap after some degree of purging, are weighted average concentrations. In this study, factors which influence sample concentrations collected from domestic wells are evaluated through the use of conceptual models and confirmatory field tests. Focus is on the extent of drawdown during sampling, distance between the pump inlet and contaminated fractures, relative fracture transmissivity, fracture discharge rate into the borehole, and the hydraulic head distribution of the fractures. Simplified spreadsheet models were developed to assess the relation between these factors and sample concentrations. The models show that in addition to fracture transmissivities, drawdown in relation to fracture head plays a significant role in how much water recharges a well from each fracture, yet it is rarely measured when sampling domestic wells. To evaluate the extent of drawdown that may occur under typical household usage, water levels were monitored in three domestic wells. Pumping tests were conducted in three wells to measure changes in concentration as a function of pumping duration. Downhole profiling was conducted to examine how pumping induces changes to water quality within the wellbore. The results indicate that these factors can have a strong influence on contaminant concentrations in samples collected from these wells. As such, the weighted averaging factors should be considered in sample collection, in data interpretation, in assessing exposure risk and in mapping contaminant distributions.

Monitoring Environmental Pathways of Trace Elements in the Northern East Area of Egypt

Nile Delta aquifer is one of the largest aquifers worldwide that receives the agrochemical leachates from the surrounding environments. To assess the status of some trace-elements (As, Co Cd, Pb, Cu and Ni) in the North-East area of Egypt, well-water samples beside of surface, subsurface and deep-soil-samples were collected from 17 different locations to represent three environmental-pathways: the first one signifies areas relatively nearby Damietta-branch, while the third pathway stands for the arable lands nearby Ismaellia-canal. The second pathway is in-between these two pathways. Furthermore, a reference soil (irrigated with fresh-Nile-water) was sampled for data comparison. These samples were estimated for their total and AB-DTPA-extractable contents of the aforementioned trace elements (TEs). Results revealed that AB-DTPA-extractable-TEs were in dynamic equilibrium with the corresponding soluble contents in irrigation water. Likewise, AB-DTPA-extractable-TEs significantly correlated with their corresponding total contents in soil. Concentrations of TEs in surface-soil-layer were higher than the corresponding ones in the subsurface and deep-soil-layers. The calculated values of contamination factor indicated moderate to very high levels of soil contamination with TEs. According to principal component analysis, total and AB-DTPA-extractable-TEs in soil were affected by only one-principal-component, recording 86.13 % of the data variance. This indicates that these contaminants originated probably from the same source. Moreover, multivariate-analyses revealed that total TEs significantly and positively correlated with soil hydraulic conductivity and bulk density, while negatively correlated with exchangeable sodium percentage, clay and organic matter contents. These results indicate that the groundwater flow is the potential source that enriched soils with TEs.

Assessment of groundwater quality based on principal component analysis and pollution source-based examination: a case study in Ho Chi Minh City, Vietnam.

The current study aimed to assess the quality of apportion pollution sources and examine the impacts of anthropogenic activities on groundwater. The study was implemented in two sequential steps of (1) bulk examination of groundwater quality followed by principal component analysis/factor analysis (PCA/FA) to apportion pollution sources and (2) pollution source-based examination to assess the effects of anthropogenic activities. Well-water samples were taken in Ho Chi Minh City, Vietnam, in 2015 (233 samples) and 2019 (20 samples) and analyzed for 8 and 15 water quality parameters, respectively. The results showed that 99% of studied wells had pH value lower than the permissible limit, and 29, 20, 15, and 14% of studied wells had concentrations of Fe, NH4+, COD (chemical oxygen demand), and coliform, respectively, higher than the maximum permissible limit. PCA/FA revealed that three pollution sources, ranked in the order of importance: agricultural, urban, and industrial activities, could mainly contribute to enriching the pollutant concentrations of groundwater. While agricultural activities may contaminate groundwater with organic substances, the urban area may enrich bacterial-pathogen density such as E. coli and coliform, and the industrial area may contribute to contaminating groundwater with some inorganic parameters. Groundwater quality index and ANOVA showed that groundwater of the studied area was poor to very poor in quality and that in the agricultural area was the worst of the three land-use types. In brief, the groundwater quality in the studied area was degraded and agricultural activities were the most important factor causing the degradation followed by urban and industrial activities.

Assessment of Physicochemical Properties of Well-water Samples in Zing Local Government Area of Taraba state. Nigeria

Assessment of Physicochemical Properties of Well-water Samples in Zing Local Government Area of Taraba state. Nigeria

Water Deficit Transcriptomic Responses Differ in the Invasive Tamarix chinensis and T. ramosissima Established in the Southern and Northern United States.

Tamarix spp. (saltcedar) were introduced from Asia to the southern United States as windbreak and ornamental plants and have spread into natural areas. This study determined differential gene expression responses to water deficit (WD) in seedlings of T. chinensis and T. ramosissima from established invasive stands in New Mexico and Montana, respectively. A reference de novo transcriptome was developed using RNA sequences from WD and well-watered samples. Blast2GO analysis of the resulting 271,872 transcripts yielded 89,389 homologs. The reference Tamarix (Tamaricaceae, Carophyllales order) transcriptome showed homology with 14,247 predicted genes of the Beta vulgaris subsp. vulgaris (Amaranthaceae, Carophyllales order) genome assembly. T. ramosissima took longer to show water stress symptoms than T. chinensis. There were 2068 and 669 differentially expressed genes (DEG) in T. chinensis and T. ramosissima, respectively; 332 were DEG in common between the two species. Network analysis showed large biological process networks of similar gene content for each of the species under water deficit. Two distinct molecular function gene ontology networks (binding and transcription factor-related) encompassing multiple up-regulated transcription factors (MYB, NAC, and WRKY) and a cellular components network containing many down-regulated photosynthesis-related genes were identified in T. chinensis, in contrast to one small molecular function network in T. ramosissima.

A New Fluorescent Sensor for Arsenic(III) Determination in Aqueous Media.

A novel polymeric membrane sensor was developed by using 2-hydroxyethyl acrylate, trimethylolpropane triacrylate, (3-mercaptopropyl)trimethoxysilane, and poly(ethylene glycol)diacrylate for As(III) determination. Various parameters, like the pH, response time, the foreign ions, and concentration effects were investigated for deciding the optimum working conditions of the polymeric sensor. As a result of this investigation, the optimum pH was found to be 2, and the response time was found to be 30 s. The linear range of the sensor was 6.65 × 10-9 - 3.99 × 10-8 mol L-1 (0.50 - 2.99 μg L-1) with a detection limit of 2.33 × 10-9 mol L-1 (0.18 μg L-1). Soy flour and well-water samples were successfully analyzed with the developed sensor. The sensor can be used at least 100 times after regeneration. It could be reused by washing with purified water and showed good stability for 6 months.

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.

Cell Membrane Stability and Relative Water Content of Cymbopogon citratus (Lemon Grass)

In this research the cell membrane stability (CMS), relative water content (RWC) and effect of different water interval on Cymbopogon citratus (lemon grass) was assessed. The cell membrane stability and relative water content of the plant shows the physiological activity of the plant. The plant sample was subjected to three different watering regimes viz: one, two- and three-days intervals with a control sample irrigated daily for a period of twelve months. Uniform stalk of lemon grass plants were planted into a depth of 7.5 cm composted soil, each treatment was made in triplicate. The evaluated growth parameters where height of the plant, number of leaves and tillers, which were taken weekly for period of twelve months (year). The height shows a significant difference from first to twelfth month after planting. The height of the plant increases simultaneous with the age of the plant. First month after planting show significant difference in height of sample watered daily and treated samples. The results shows that the RWC (07.14%) and CMS (52.58%) was low in samples under water stress respectively when compared to well-watered samples (55.41%). No significant difference was observed between samples under one, two and three days interval. The number of leaves differs significantly in the first MAP except in the samples watered daily and three days interval. Maximum number of leaves was achieved at twelfth MAP under one day interval (137.33) followed by samples watered daily (126) and two days interval, while three days interval has the least number of leaves (leaf number). The number of tillers shows significant differences between the means at fifth and sixth MAP, (fifth MAP = 73.33 and sixth MAP = 126) and the treatments under one day intervals (fifth MAP = 18.33 and sixth MAP = 35.67). In the research, samples watered daily and under one day intervals shows high productivity when compared to the remaining treatment.