A critical review of on-site inorganic arsenic screening methods

Approximately 94 to 220 million people worldwide are at risk of drinking well water containing arsenic > 10 μg/L, the WHO guideline value. To identify non-compliant domestic wells, assess health risks and reduce exposure, accurate and rapid on-site inorganic arsenic screening methods are desirable because all domestic wells worldwide need to be tested.Here, the principles, advantages and limitations of commonly used colorimetry, electrochemistry, and biosensing methods are critically reviewed, with the performance compared with laboratory-based benchmark methods. Most commercial kits are based on the classic Gutzeit reaction. Despite being semi-quantitative, the more recent and more expensive products display improved and acceptable accuracy and shorter testing time (~10 min). Carried out by trained professionals, electrochemical methods are also feasible for on-site analysis, although miniaturization is desirable yet challenging. Biosensing using whole bacterial cells or bio-engineered materials such as aptamers is promising, if incorporated with function specific nanomaterials and biomaterials. Since arsenic is frequently found as arsenite in reducing groundwater and subject to oxidation during sampling, transportation and storage, on-site separation and sample preservation are feasible but the specific methods should be chosen based on sample matrix and tested before use. To eliminate arsenic exposure among hundreds of millions of mostly rural residents worldwide, we call for concerted efforts in research community and regulatory authority to develop accurate, rapid, and affordable tests for on-site screening and monitoring of arsenic in drinking water. Access to affordable testing will benefit people who are socioeconomically disadvantaged.

Nutritional status of Vietnamese infants assessed by Fenton growth chart and related factors:A cross-sectional study

Importance:Nutritional status of infants,measured by birth weight and length,is an essential factor in neonatal development.Malnutrition in newborns may lead to a higher risk of mortality,neurological and cognitive impairment,and poor language development.Objective:This study aims to assess the nutritional status of infants and related factors regarding maternal anthropometric characteristics and medical history.Methods:A cross-sectional study was conducted at the National Hospital of Obstetrics and Gynecology,Vietnam from May 2021 to May 2022 on 340 infants and mothers.Low birth weight was defined following the Intergrowth-21 standards.Stunting was evaluated using the Fenton growth chart when the length was below the 10%percentile line of the gestational week.Multivariate regression models were applied to identify factors associated with the nutritional status of infants.Results:We found that 12.4%and 14.1%of infants in our study fell into stunted and underweight categories,respectively.Infants of mothers over 35 years old,having a height lower than 150 cm or experiencing anemia during pregnancy were more likely to be stunted or have low birth weight.Serum albumin deficiency during pregnancy was strongly associated with the infant being underweight(odds ratio[OR]=2.8,95%confidence interval[95%CI]1.1–7.3).Newborns were more likely to be stunted if their mothers had a history of preterm birth(OR=3.3,95%CI 1.1–10.2).Interpretation:Maternal nutritional status is closely related to infant malnutrition,particularly in preterm infants.Improving the understanding of mothers regarding prenatal care,reproductive healthcare,adequate nutritional diet,and multi-micronutrient supplements during pregnancy is therefore important.

Efficient photocatalytic destruction of recalcitrant micropollutants using graphitic carbon nitride under simulated sunlight irradiation

The ubiquity of micropollutants(MPs)in aquatic environments has attracted increasing concern for public health and ecological security.Compared to conventional biological treatment,photocatalytic processes show more efficiency in degrading MPs,but they require expensive materials and complicated synthesis processes.This study developed an economic photocatalytic process to degrade micropollutants.We synthesized urea-based graphitic carbon nitride(g-C_(3)N_(4))by a facile one-step pyrolysis method and evaluated the photocatalytic efficiency of carbamazepine(CBZ).Under simulated solar irradiation,g-C_(3)N_(4) could achieve 100% removal efficiency of 0.1 mg/L CBZ in spiked wastewater effluent within 15 min,and 86.5% removal efficiency in wastewater influent after 20 min of irradiation.The porous structure of g-C_(3)N_(4) promoted effective charge separation and mass transport of CBZ near the catalyst surface,enabling a high kinetic rate(0.3662 min^(-1)).Reactive oxygen species trapping experiments revealed that superoxide radicals(O_(2)^(·-))and holes(h^(+))were the major active radicals.Electron paramagnetic resonance(EPR)further confirmed the presence of O_(2)^(·-),·OH,^(1)O_(2) and holes.The pH,light intensity and initial CBZ concentration were found to have significant impacts on the removal efficiency of CBZ.Possible reaction intermediates were identified and the degradation pathway was proposed.Multiple MPs were selected to further demonstrate photocatalytic efficiency of g-C_(3)N_(4).The facile synthesis,superior efficiency,and versatility of g-C_(3)N_(4) make it a promising catalyst for application in tertiary wastewater treatment processes.

Temporal trends of per-and polyfluoroalkyl substances(PFAS)in the influent of two of the largest wastewater treatment plants in Australia

Per-and polyfluoroalkyl substances(PFAS)are found ubiquitously in wastewater treatment plants(WWTPs)due to their multiple sources in industry and consumer products.In Australia,limited spatial data are available on PFAS levels inWWTPs influent,while no temporal data have been reported.The aim of this study was to investigate the occurrence and temporal trend of PFAS in the influent of two large WWTPs in Australia(WWTP A and B)over a four-year period.Daily influent samples were collected over one week at different seasons from 2014 to 2017.Eleven perfluoroalkyl acids(PFAA)(i.e.seven perfluoroalkyl carboxylic acids(PFCAs)and four perfluoroalkyl sulfonic acids(PFSA))were detected with mean S11PFAA concentrations of 57±3.3e94±17 ng/L at WWTP A,and 31±6.1e142±73 ng/L at WWTP B.The highest mean concentrations were observed for perfluorohexanoate(PFHxA)(20±2 ng/L)in WWTP A,and perfluorooctane sulfonate(PFOS)(17±13 ng/L)in WWTP B.The precursor 6:2 fluorotelomer sulfonate was detected over five sampling periods from Aug 2016 to Oct 2017,with mean concentrations of 37±18e138±51 ng/L for WWTP A and 8.8±4.5e29±5.1 ng/L for WWTP B.Higher concentration of 6:2 FTS(1.8e11 folds)than those of PFOA and PFOS in WWTP A indicate a likely substitution of C8 PFAA by fluorotelomer-based PFAS in this catchment.Temporal trends(annual and seasonal)in per-capita mass load were observed for some PFAA,increasing for PFPeA,PFHxA,PFHpA,PFNA,and PFHxS,while decreasing for PFBS and PFOS in either WWTPs.Notably,elevated levels of PFOS in October 2017 were observed at both WWTPs with the highest per capita mass load of up to 67 mg/day/inhabitant.For some PFAS release trends,longer sampling periods would be required to achieve acceptable statistical power.

Monitoring the levels of brominated and organophosphate flame retardants in passenger cars:Utilisation of car air filters as active samplers

Filters in residential and office air conditioning(A/C)systems have been used as sampling devices for monitoring different pollutants.However,cabin air filters(CAFs)in the A/C system of passenger cars have not been utilised for this purpose.In this study,we collected22 used CAFs from passenger cars in Hanoi,Vietnam to analyse for 8 polybrominated diphenyl ethers(PBDEs)and 10 organophosphate esters(OPEs).All the analytes were detected in more than 50%of samples with the exception of BDE153 and BDE154.The average concentrations of∑10OPEs and∑8 BDEs in the captured dust were 2600 and 40 ng/g,respectively with Tris(1-chloro-2-propyl)phosphate(TCIPP)and BDE209 as the dominant congener in OPE and BDE groups,respectively.CAFs are a potential tool to qualitatively assess the levels of semi-volatile chemicals in suspended dust in cars as a screening step for exposure assessment of those chemicals.

Concentrations of phthalates metabolites in blood and semen and the potential effects on semen concentration and motility among residents of the Pearl River Delta region in China

Exposure to phthalate acid esters(PAEs)has been found to have adverse effects on reproduction of human and animal.However,the effects on the semen quality are controversial.In this study,we have collected paired blood and sperm samples from patients(n=103)at a medical clinic in Guangzhou,China,to determine the concentrations of eight phthalate metabolites∑8m-PAEs).The concentration ranges of P8m-PAEs were 2.7-55 and 0.99-17 ng/mL in blood and semen samples,respectively.MEHP(median,3.6 ng/mL in blood and 0.55 ng/mL in semen)and MnOP(median,3.4 ng/mL in blood and 0.69 ng/mL in semen)were the predominant analytes in both blood and semen samples.However,analytes were not correlated in paired blood and semen.Semen motility was significantly associated to the concentrations of∑8m-PAEs in semen,but it did not associate to the concentrations of PAEs in blood.Multi-linear regression analysis,including concentrations of PAEs in both blood and semen,as well as BMI,occupation,living habits,suggested that exposure to PAEs at current environmental levels had very limited effects on semen quality of population in Guangzhou,China.