Drinking Water Samples Research Articles

ANTIFUNGAL ACTIVITY OF THYMOL ON PLANKTONIC AND BIOFILM CELLS

The purpose of this study was to evaluate the antifungal effects of thymol on fungi planktonic and biofilm cells. Firstly, the antifungal activity of a thymol-based product on reducing fungi load in poultry drinking water samples was assessed in vitro using the plate count method. Samples were treated by increasing concentrations of thymol (1, 2 and 4 g.l-1 of product). Reduction is about one log unit for 1 g.l-1, about two log units for 2 g.l1, and a total desperation for 4 g.l-1. Secondly, the antifungal activity was tested on biofilms formed on coiled pipes using an experimental arrangement simulating animals watering conditions in poultry farming. Two concentrations (1 and 2 g.l-1) were used in two ways, preventive and curative treatment. The first one consisted in preventing fungal development on pipes and the biofilm formation. The second consisted in treating biofilms that have already settled on pipes. The plat count method was used to check the antifungal activity of thymol. Data of this experiment data have shown that thymol may prevent Candida albicans and Aspergillus niger proliferation in the experimental arrangement. After just a week, a significant reduction (P<0,05) was shown with the concentration 1 g.l-1. The reduction was much important when the product was used at a concentration of 2 g.l-1 (about tree log units). For curative treatment, results showed a significant reduction (P<0,05) of C. albicans load after only 24 hours with 1 g.l-1 (about one log unit). With this same concentration, reduction is more important over time for both spices (about four log units after a week). A significant reduction (more than two log units) was showed in just 24 hours of treatment with the concentration of 2 g.l-1. This work offers an alternative solution to chemical biocides, which can treat water and disinfect distribution system in poultry farming.

Microbiological monitoring of coagulase-negative Staphylococcus in public drinking water fountains: Pathogenicity factors, antimicrobial resistance and potential health risks.

The presence of opportunistic bacteria such as coagulase-negative Staphylococcus (CoNS) in drinking water poses public health concerns because of its potential to cause human infection and due to its antimicrobial resistance (AMR) diversity. This study evaluated the occurrence, virulence markers and AMR of CoNS in 468 drinking water samples from 15 public fountains located in four urban parks of São Paulo city (Brazil). Out of 104 samples positive for the presence of Staphylococcus genus, we detected CoNS in 75 of them (16%), which did not meet the Brazilian sanitary standards for residual chlorine. All isolates were of concern to public health for being responsible for infection in humans from low to high severity, nine of them are considered the most of concern due to 63.6% being multiresistant to antimicrobials. The results demonstrated that CoNS in drinking water must not be neglected. It is concluded that the presence of resistant staphylococci in drinking water is a potential health risk, which urges feasible and quick control measures to protect human health, especially in crowded public places.

Household drinking water treatment in rural Indonesia: actual practice, determinants, and drinking water quality

Abstract Household water treatment (HWT) is a solution for households that do not have access to a safe drinking water supply. A cross-sectional study was conducted in Ende District, Province of Nusa Tenggara Timur (NTT), Indonesia. A total of 425 household respondents were interviewed and observed about the HWT practice and water storage condition and 143 household drinking water samples were collected for microbial water quality analysis. Results show that even though HWT is regularly performed, not all the water they drink has been treated. The ‘level’ of psychological factors risk, attitude, norms, ability, and self-regulation (RANAS) were high, indicating that regular HWT practice goes in hand with the underlying psychological factors. Psychological factor action planning was the most influential psychological sub-factor associated related with the frequency of drinking treated water. Drinking water is mostly stored in safe storage, but placed in a less hygienic surrounding environment. Though HWT results in better water quality, water quality was not significantly associated with HWT, drinking water handling, or storage. Finally, promoting always drinking treated water and then storing it in a safe and hygienic environment are still needed in areas where HWT is commonly practiced, so people can get the maximum health impact of HWT.

Solid phase extraction with rotating cigarette filter for determination of bisphenol A in source and drinking water: computational and analytical studies.

An ultrasound assisted solid phase extraction method using rotating cigarette filter is developed herein to preconcentrate and determine trace amount of bisphenol in source and drinking water. Qualitative and quantitative measurements were performed using high-performance liquid chromatography coupled with ultra violet detector. Sorbent-analyte interactions were thoroughly investigated computationally and experimentally using molecular dynamics simulations; and attenuated total reflectance Fourier transform infrared spectroscopy, and Raman spectroscopy, respectively. Various extraction parameters were investigated and optimized. Under the optimal conditions, the results were linear in a low scale range of 0.01-55ng/mL with correlation coefficient of 0.9941 and a low limit of detection (0.04ng/mL, signal/noise = 3:1). A good precision (intra-day relative standard deviation ≤ 6.05%, inter-day relative standard deviation ≤ 7.12%) and recovery (intra-day ≥ 98.41%, inter-day ≥ 98.04%)) are obtained. Finally, the proposed solid phase extraction method offered a low cost, simple, fast, and sensitive analytical method to determine trace amount of bisphenol A in source and drinking water samples with chromatographic detection.

Trace-Level Detection of Pb(II) and Cd(II) Aided by MoS2 Nanoflowers and Graphene Nanosheet Combination

Pb(II) and Cd(II) are featured in the World Health Organization’s (WHO) top 10 list of chemicals of primary public health concern, and their wide use in industries and the acute and chronic effects on humans and the environment make the detection and determination of the ions in environmental and drinking water samples indispensable. This work reports a detailed study on a partially reduced graphene oxide-nano molybdenum disulfide-modified glassy carbon electrode (prGO-MoS2/GCE), which exhibited the simultaneous and selective electrochemical detection of Pb(II) and Cd(II) in drinking water with a 200- and 100-fold increase in the current response, respectively, compared to that on the unmodified GCE. prGO-MoS2 showed almost nil current response for other metal ions such as Hg(II), Ag(I), Fe(II), Co(II), Ni(II), Zn(II), Sn(II), Cu(II), and Cr(VI), evident to the good selectivity toward Pb(II) and Cd(II). The lowest limit of detection (LOD) values were ∼0.0002 and 0.1 ppt, which are very well below the ≤10 and 5 ppb specified as safe for Pb(II) and Cd(II), respectively. The exemplary sensing behavior of prGO-MoS2/GCE toward Pb(II) and Cd(II) shall be assigned to the structure of prGO-MoS2 and the bonding of MoS2 to prGO, thus promoting the electrochemistry mechanism in addition to the affinity.

Arsenic in drinking water, hair, and prevalence of arsenicosis in Perak, Malaysia.

Arsenic is a carcinogen element that occurs naturally in our environment. Humans can be exposed to arsenic through ingestion, inhalation, and dermal absorption. However, the most significant exposure pathway is via oral ingestion. Therefore, a comparative cross-sectional study was conducted to determine the local arsenic concentration in drinking water and hair. Then, the prevalence of arsenicosis was evaluated to assess the presence of the disease in the community. The study was conducted in two villages, namely Village AG and Village P, in Perak, Malaysia. Socio-demographic data, water consumption patterns, medical history, and signs and symptoms of arsenic poisoning were obtained using questionnaires. In addition, physical examinations by medical doctors were performed to confirm the signs reported by the respondents. A total of 395 drinking water samples and 639 hair samples were collected from both villages. The samples were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) to determine arsenic concentration. The results showed that 41% of water samples from Village AG contained arsenic concentrations of more than 0.01 mg/L. In contrast, none of the water samples from Village P exceeded this level. Whilst, for hair samples, 85 (13.5%) of total respondents had arsenic levels above 1 μg/g. A total of 18 respondents in Village AG had at least one sign of arsenicosis and hair arsenic levels of more than 1 μg/g. Factors significantly associated with increased arsenic levels in hair were female, increasing age, living in Village AG and smoking. The prevalence of arsenicosis in the exposed village indicates chronic arsenic exposure, and immediate mitigation action needs to be taken to ensure the wellbeing of the residents in the exposed village.

Development of a Sensitive Method for Cadmium Determination in Fish Tissue and Drinking Water Samples by FAAS Using SQT In Situ Atom Trapping.

A sensitive and robust trap method was developed for the determination of cadmium (Cd) by using a slotted quartz tube. Using this method at a sample suction rate of 7.4 mL/min for 4.0 min collection, a 1467-fold increase in sensitivity was obtained compared to the flame atomic absorption spectrometry method. Under the optimized conditions, a limit of detection of 0.075 ng mL-1 was obtained for the trap method. The interference effects of hydride-forming elements, transition metals, and some anions on the Cd signal were investigated. The developed method was evaluated by analyzing "Sewage Sludge-industrial origin (BCR no: 146R)", "NIST SRM 1640a Trace elements in natural water", and "DOLT: 5 Dogfish Liver". There was a good agreement between the certified and found values at the 95% confidence level. This method was applied successfully for the determination of Cd in drinking water and some fish tissue samples (liver, muscle, and gill) obtained from Muğla province.

Synthesis, photophysical and DFT studies of a new p-phenylenevinylene material based on triazole for fluorescent sensing application

This paper covers the elaboration of a new semi-conducting material (PPVTRI) for sensing application.This new material containing highly emissive chromophore type p-phenylenevinylene (PPV) and chelating triazole moieties, is soluble in common organic solvents. The molecular structure of PPVTRI was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectroscopies. Thermal characterization shows that the material has a good thermal stability up to 220 °C. The intrinsic optical properties of this π-conjugated material were investigated by UV–vis absorption and photoluminescence spectroscopies. The UV–vis absorption shows the presence of the phenomen of intramolecular charge transfert in dilute solution between donor (conjugated system) and acceptor (spacer unit) groups. The organic material PPVTRI exhibits a yellowish-green emission in dilute solution. The HOMO and LUMO levels were estimated using cyclic voltammetry analysis. The computational analyses on the synthesized chemical structure were performed using Density Functional Theory (DFT) and time-dependent (TD-DFT) employing the B3LYP functional with the 6–31g(d) basis set to get insight into the conformation, electronic and optical properties. Based on theory study, the configuration of the elaborated semi-conducting material PPVTRI is composed majority of Z-E isomer. The Molecular electrostatic (MEP) results show that there are electronegative groups that can be trapping sites for metal cations. Then, the PPVTRI was investigated as a fluorescent sensor by analyzing the photoluminescence quenching of its dilute solution in the presence of different metals, showing remarkable responses towards Cu2+ and Fe2+ cations. The value of limit of detection (LOD) of the Cu2+ and Fe2+ provide that PPVTRI material could be suitable for the detection of those cations in drinking water samples.

Evaluation of Chemical Compounds and their Relationship to the Breaking Point after adding Chlorine to Water

Evaluation of the chemical compounds formed during the process of sterilizing water with chlorine is a very important point. During sterilization the water goes through three stages each stage resulting different chemical compounds. In the first stage, chlorine reacts with iron, magnesium and nitrates. In the second stage it reacts with ammonia and in the third stage it reacts with the organic compounds in the water. Chlorine in these three stages is called combined chlorine. Then it reaches the breaking point, after this point the water must be free from side chemical compounds, and chlorine after this point is called the residual free Chlorine. Drinking water samples were taken from 3 city in Kirkuk governorate, and the concentrations of magnesium, nitrate, sulfate, acetic acid derivatives, as well as the halomethane group in addition to some physical determinants were evaluated.
 There were deviations in some chemical concentrations when comparing the results with the last Iraqi specification NO. 417. The deviations that appeared in some concentrations were treated by using two chemical methods, the first using activated carbon and the second using aluminum chloride polymer. The importance of the study is to ensure the effectiveness of chlorine by eliminating chemical compounds dangerous in the water.

Feasibility of using quantitative 1H-NMR spectroscopy and ultra-microbalances for investigation of a PET microplastic reference material

Here, we report on the feasibility of using quantitative NMR and ultra-microbalances for additional measurements of the mass of poly-ethylene terephthalate (PET) particles in a reference material (RM). The microplastic (MP) PET particles were immobilised in solid NaCl following freeze-drying of a 1-ml NaCl suspension. The particles ranged from 30 to about 200 µm (Feretmin). In a 3-day process, more than 500 such units of PET particles in the NaCl carrier were prepared and later used in a large-scale inter-laboratory comparison. The homogeneity of PET in the salt carrier over these 500 units had previously been evaluated with respect to the mass of PET using an ultra-microbalance. In addition to the original results obtained by weighing, two independent results of quantitative 1H-NMR have been obtained for further investigation of this reference material together with one additional set of weighing data. The NMR data were used for confirmation of the weighed amount of PET (as weighing is non-specific for PET). Average masses of 0.293 ± 0.04 mg and 0.286 ± 0.03 mg of PET were obtained using two different ultra-microbalances (14% RSD for n = 14 and 9% RSD for n = 4, respectively). The corresponding 1H-NMR data was 0.300 ± 0.02 mg of PET (6.7% RSD for n = 5) and 0.345 ± 0.04 mg of PET (12.5% RSD for n = 14), respectively. The average mass of PET obtained by 1H-NMR measurements was in agreement with the weighed amounts within their standard deviations. A mean value of 0.306 mg PET with an expanded uncertainty of 0.058 mg (± 19% relative) was calculated, and it is traceable to the SI system of measurements. Measurement of PET by quantitative 1H-NMR spectroscopy is also reported for a water sample. The PET contained in one RM sample was transferred to 1 L of water to mimic a drinking water sample for microplastics.Graphical abstract

Characterization of pregnant women exposure to halogenated parabens and bisphenols through water consumption

Exposure of pregnant women to endocrine disruptor compounds, such as parabens and bisphenol A is of concern for fetal transition. Their halogenated degradation products, mainly coming from water treatment plans, could be problematic as well, depending on their occurrence in drinking water in the first place. Thus, 25 halogenated compounds were synthesised in order to investigate 60 substances (Bisphenols, parabens and their degradation products) in 325 drinking water samples coming from a French cohort study of pregnant women. Analysis was performed by tandem mass spectrometry coupled to gas chromatography (GC-MS/MS) after SPE extraction and derivation of the contaminants. Results indicate that parabens (methylparaben, n-propylparaben, ethylparaben and n-butylparaben), bisphenols S, A and F, and their degradation product, 4-hydroxybenzoic acid, were detected up to several hundred ng/L in drinking water, with detection frequencies between 16% and 88%. Regarding halogenated degradation products, the highest detection frequencies were found for monochlorinated products (about 50% for 2-chlorobisphenol A), which were quantified up to several tens of ng/L. Such analytical approaches with broader spectrum of monitoring (i.e. chemical hazards and their degradation products) constitute in the beginning of a solution to exhaustively answer the questions related to the characterization of the human chemical exposome.

Estimation of Inhalation and Ingestion Dose Due to Radon Concentration in Drinking Water Samples of Shankaraghatta Forest Environment, Karnataka, India

Objectives: To estimate inhalation and ingestion doses due to radon concentration in rural areas of Shankaraghatta forest environment, India. Methods: In this study, the risk due to radon concentration in underground drinking water samples of the Shankaraghatta region has been estimated using emanometry technique. The 44 drinking water samples were collected from different water sources in sample bottles (500 ml) and were carefully sealed to ensure there is no air gap and were analysed within 24 hours by radon bubbler technique using a Lucas cell. Findings: The radon (222Rn) concentration in underground and surface water samples of the entire region varies from 1.10  0.25 Bq l􀀀1 to 30.67  5.10 Bq l􀀀1 with an average value of 13.10  2.2 Bq l􀀀1, is higher than the USEPA proposed maximum contamination threshold of 11Bql􀀀1.The Annual Effective Dose Equivalent (AEDE) ranges from 3.86 mSv y􀀀1 to 83.80 mSv y􀀀1 with an average value of 36.35mSv y􀀀1, which is slightly higher than the global average value. Novelty: The present work focuses on the public health of the study area where such estimation was not carried out. The estimated annual effective, inhalation and ingestion doses due to radon in underground drinking water samples are found to be substantially below the 100 mSvy􀀀1recommended by WHO and EC. Hence, public of the study area won’t receive any serious health hazard due to radon in drinking water and the water is fit for drinking without any additional treatment. Keywords: Radon Concentration; Underground and Surface water; Emanometry Technique

Analysis of Antimicrobials in Muscle and Drinking Water in Terms of Reducing the Need of Antimicrobial Use by Increasing the Health and Welfare of Pig and Broiler.

Antimicrobial residues may pose harmful effects on the health of consumers. At the same time, an adequate quality of drinking water for animals is one of the important element to ensure animal welfare and food without antibacterials. The presented study is aimed at estimating the residue levels of antibacterial compounds, such as penicillins, cephalosporin, macrolides, tetracyclines, quinolones, sulphonamides, aminoglycosides, diaminopirymidines, pleuromutilines and lincosamides in meat and on-farm drinking water samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS), as a part of a surveillance system on pig and broiler farms within the project Healthy Livestock. A total of 870 samples of muscle from pig and broiler, as well as 229 water samples were analysed for antibiotic residues. Samples were collected from farms in EU countries in two steps, before and after implementation of a tailor-made health plan. In muscle samples, the detected concentrations of doxycycline in the post-intervention step (15.9-70.8 µg/kg) were lower than concentrations in the pre-intervention step (20.6-100 µg/kg). In water samples, doxycycline in an average concentration of 119 µg/L in the pre- and 23.1 µg/L in the post-intervention step, as well as enrofloxacin at concentrations of 170 µg/L in the pre- and 1.72 µg/L in the post-intervention step were quantified. Amoxicillin was only present before intervention. The obtained results confirm the effectiveness of the intervention actions. The concentrations of antibiotics in muscles and water were lower after implementation of a health plan on the farms.

Enhanced adsorption of PFOA with nano MgAl2O4@CNTs: influence of pH and dosage, and environmental conditions

Perfluorooctanoic acid (PFOA) has received extensive attention due to its widespread distribution in the environment and concerns of its exposure to human health. Nano-MgAl2O4 modified carbon nanotubes (CNTs) were synthesized, characterized, and used as nanoadsorbents to remove ppb (μg/L)-levels of PFOA from drinking water and brackish groundwater. Nano-MgAl2O4@CNTs composite materials were characterized by UV-Vis, FT-IR, DLS, p-XRD, BET, and SEM with EDX. The adsorption isotherms and kinetic studies were fitted to a Freundlich and to a pseudo-second-order models, respectively. Composite nano-MgAl2O4@CNTs remove over 99% of PFOA (100 ppb) from water in 3 hours, and completely (100%) in 3.5 hours. The optimal pH range is under mild alkaline conditions (pH = 7.5-9.0). Electrostatic and hydrophobic interactions drive the PFOA adsorption onto MgAl2O4@CNTs. The adsorption data of ground and drinking water samples indicated that nano-MgAl2O4@CNTs is an efficient nanoadsorbent for PFOA removal.

Enhanced selectivity for acidic contaminants in drinking water: From suspect screening to toxicity prediction

A novel analytical workflow for suspect screening of organic acidic contaminants in drinking water is presented, featuring selective extraction by silica-based strong anion-exchange solid-phase extraction, mixed-mode liquid chromatography-high resolution accurate mass spectrometry (LC-HRMS), peak detection, feature reduction and compound identification. The novel use of an ammonium bicarbonate-based elution solvent extended strong anion-exchange solid-phase extraction applicability to LC-HRMS of strong acids. This approach performed with consistently higher recovery and repeatability (88 ± 7 % at 500 ng L-1), improved selectivity and lower matrix interference (mean = 12 %) over a generic mixed-mode weak anion exchange SPE method. In addition, a novel filter for reducing full-scan features from fulvic and humic acids was successfully introduced, reducing workload and potential for false positives. The workflow was then applied to 10 London municipal drinking water samples, revealing the presence of 22 confirmed and 37 tentatively identified substances. Several poorly investigated and potentially harmful compounds were found which included halogenated hydroxy-cyclopentene-diones and dibromomethanesulfonic acid. Some of these compounds have been reported as mutagenic in test systems and thus their presence here requires further investigation. Overall, this approach demonstrated that employing selective extraction improved detection and helped shortlist suspects and potentially toxic chemical contaminants with higher confidence.

Selenium in drinking water and cereal grains, and biomarkers of Se status in urine and fingernails of the Main Ethiopian Rift Valley population

BackgroundSelenium (Se) plays an important role in human health, yet Se overexposure or deficiency can lead to deleterious health effects. This study aims to determine the concentration of Se in drinking water and staple cereal grain (maize, wheat, and teff) samples from the Main Ethiopian Rift (MER) Valley, and correspondingly, assesses Se biomarkers and their status as measured in the urine and fingernails of 230 individuals living in 25 MER communities. MethodThe concentration of Se in drinking water and cereal grain (maize, wheat, and teff) samples, and urine and fingernail samples were measured using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Demographic, anthropometric, and elemental concentrations were described by their quartiles and mean ± standard deviations. The 5th and 95th percentiles were used to describe the concentrations Se biomarkers ranges. The Se biomarker distributions in different study communities were further characterized according to Se levels found in drinking water, sex, and age using ANOVA, and multivariate regression. We conducted a correlation analysis (with Pearson correlation coefficient) and fitted a regression to evaluate the associations between these variables. ResultsThe mean concentration of Se in the drinking water samples was 0.66 (range: 0.015–2.64 µg/L; n = 25), and all samples were below the threshold value of 10 μg/L for Se in drinking water set by the World Health Organiation (WHO). In Ethiopia, most rural communities rely on locally produced cereal grains. We found mean Se concentrations (µg/kg) of 357 ± 190 (n = 14), 289 ± 123 (n = 14), and 145 ± 100 (n = 14) in wheat, teff, and maize, respectively. Furthermore, Se concentrations in drinking water showed no significant correlation with biomarker measures, indicating that the primary source of dietary Se is likely from local foods including staple grains. The mean±SD (5th–95th percentiles) of Se concentrations in fingernails and urine among study subjects were 1022 ± 320 (624–1551 µg/kg), and 38 ± 30 (1.9–100 µg/L), respectively. ConclusionA sizeable share of study participants (31%) fell below the lower limits of what is considered the currently accepted Se range of 20–90 µg/L in urine, though relatively few (only 4%) had similarly low fingernail levels. On the other hand, none of the samples reached Se toxicity levels, and the biomarker levels in this study are comparable to results from other studies that find adequate Se. Our results show that Se toxicity or deficiency is unlikely in the study population.

Drinking water evaluation for some wells ground water in Al-madab village, Al-mahweet, Yemen

In this paper we studied of drinking water samples for five water sources wells in the Almadab village, Al-mahweet city, Yemen. The main purpose was determine the fluoride ion of water from these sources, the values were in the range of (1.31±0.08 - 3.61±0.25) mg/L, more than the permissible limits for World Health Organization (WHO). The analysis data were statically treatment with relative standard deviation (RSD) less than 6%. In another side, the measurements of pH, total dissolve salts (TDS), electroconductivity (EC), total hardness (TH), Cl-, Mg2+, Ca2+, NO- 3 and salnity have been determined.

Determination of trace cobalt ions in bottled drinking water samples from Fiji Island by spray-assisted fine droplet formation-liquid phase microextraction based on simultaneous complexation and extraction before flame atomic absorption spectrometer measurement

In this study, a green, simple and effective preconcentration method named as spray-assisted fine droplet formation-liquid phase microextraction (SAFDF-LPME) before the flame atomic absorption spectrophotometry (FAAS) measurement for cobalt determination was developed. The method reduces the external dispersive solvent usage by using a simple spraying apparatus to obtain fine droplets of the extraction solvent. SAFDF-LPME method also consists of simultaneous complexation and extraction which indicates the environmental benevolence of the developed method. This method minimized the relative errors with high repeatability and accuracy by reducing the experimental steps. The influential parameters such as buffer type, buffer solution volume, extraction solvent/ligand solution volume (spraying cycle), and mixing period were systematically optimized by the univariate optimization procedure. With the optimum parameters applied, the detection power of the FAAS system was enhanced to about 110-folds with respect to 2.2ngmL-1 detection limit calculated for the proposed method. Bottled drinking water samples from Fiji Islands were used to demonstrate the applicability of the developed method for the accurate determination of trace cobalt in real sample matrices. Percent recovery results obtained between 95.5 and 88.5% showed the suitability of the developed method in the determination of cobalt at trace levels even in complex sample matrices.

Fluorescence Detecting of Paraquat and Diquat Using Host-Guest Chemistry with a Fluorophore-Pendant Calix[6]arene.

Paraquat (PQ) and diquat (DQ), some of the most widely used herbicides in the world, both present a high mortality index after intentional exposure. In this paper, a fluorescence sensing method for PQ and DQ, based on host-guest molecular recognition, is proposed. Calix[6]arene derivatives containing anthracene or naphthalene as pendant fluorophore at their lower rim recognize DQ and PQ in hydroalcoholic solution with a broad linear response range at the μg L-1 level concentration. The linear response ranges were found from 1.0 to 18 μg L-1 with the detection limit of 31 ng L-1 for paraquat, and from 1.0 to 44 μg L-1 with the detection limit of 0.16 μg L-1 for diquat. The recognition process is detected by following the decrease in the fluorescence emission consequent to complexation. The proposed quenching method has been applied to the determination of paraquat in drinking water samples.

Investigation of radioactivity level in drinking water resources and soil samples collected from the Hawraman villages, Iraq

In the present study, the RAD7 and NaI(Tl) techniques were utilized to determine the radon concentrations in drinking water resources and the natural primordial radionuclides in soil samples collected from Hawraman villages. The measured radon concentrations ranged from 1.7 ± 0.6 to 34.0 ± 2.8 Bq L−1 with an arithmetic mean of 14.8 ± 1.2 Bq L−1. This research demonstrates that roughly 54% of drinking water samples exceed the EPA-recommended level of 11.1 Bq L−1. For adults, children, and infants, the total annual effective doses for the three types (Ding, Dinh, and Ddi) vary from 7.6 to 149.2 μSv y−1 with an average of 65.0 μSv y−1, 8.1–160.0 μSv y−1 with an average of 69.7 μSv y−1, and 10.5–207.0 μSv y−1 with an average of 90.2 μSv y−1.18.2%, 22.7%, and 36.4%, respectively, of the annual effective dose for adults, children, and infants exceeds the 100 μSv y−1 level recommended by WHO and UNCEAR 2000.The activity concentrations of 226Ra, 232Th, and 4 K in soil samples varied from 10.9 ± 0.1 to 32.6 ± 0.2 Bq kg−1, 18.3 ± 0.4 to 52.1 ± 0.6 Bq kg−1, and 252.7 ± 2.5 to 585.6 ± 3.7 Bq kg−1. The arithmetic mean concentrations of 226Ra, 232Th, and 4 K were determined to be 19.4 ± 0.2 Bq kg−1, 36.2 ± 0.5 Bq kg−1and 426.6 ± 3.2 Bq kg−1, respectively.This research reveals that the average soil activity concentrations of 226Ra, 232Th, and 4 K are within the global average limits of 32, 45, and 420 Bq kg−1, respectively. Comparing the concentrations to global averages, some soil samples revealed significant amounts of radionuclides, with around 18% of 232Th and 41% of 4 K. The computed radiological hazard indices of 100% of Raeq., 82% of Dout, 82% of Eout, and 95.5% of ELCRout are all below the internationally recommended levels declared by Unscear 2000.