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1.
Chemosphere ; 239: 124782, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31520978

RESUMO

Exceptionally high concentrations of radon have been found in drinking water originating from hand pumps in Khetri Copper Belt of Rajasthan. Radon concentration was determined using Durridge RAD7 professional electronic radon detector. The measured radon concentration ranged from 12.5 ±â€¯1.5 to 862 ±â€¯38 Bq l-1. About 35% of the drinking water samples showed radon concentrations above the European Union's parametric value of 100 Bq l-1. The high radon concentration obtained in groundwater is due to local natural geology. The total annual effective doses due to ingestion and inhalation of radon in drinking water varied from 0.10 to 6.7 mSv y-1 for infants, 0.06-3.8 mSv y-1 for children and 0.06-4.4 mSv y-1 for adults.


Assuntos
Água Potável/análise , Água Subterrânea/análise , Radônio/análise , Poluentes Radioativos da Água/análise , Adulto , Criança , Cobre , Exposição Dietética/análise , Humanos , Índia , Lactente , Monitoramento de Radiação , Medição de Risco
2.
Chemosphere ; 240: 124883, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726606

RESUMO

A coupled algal-osmosis membrane treatment system was studied for recovering potable-quality water from municipal primary effluent. The core components of the system included a mixotrophic algal process for removal of biochemical oxygen demand (BOD) and nutrients, followed by a hybrid forward osmosis (FO)-reverse osmosis (RO) system for separation of biomass from the algal effluent and production of potable-quality water. Field experiments demonstrated consistent performance of the algal system to meet surface discharge standards for BOD and nutrients within a fed-batch processing time of 2-3 days. The hybrid FO-RO system reached water productivity of 1.57 L/m2-h in FO using seawater as draw solution; and permeate flux of 3.50 L/m2-h in brackish water RO (BWRO) and 2.07 L/m2-h in seawater RO (SWRO) at 2068 KPa. The coupled algal-membrane system achieved complete removal of ammonia, fluoride, and phosphate; over 90% removal of calcium, sulfate, and organic carbon; and 86-89% removal of potassium and magnesium. Broadband characterization using high resolution mass spectrometry revealed extensive removal of organic compounds, particularly wastewater surfactants upon algal treatment. This study demonstrated long-term performance of the FO system at water recovery of 90% and with membrane cleaning by NaOH solution.


Assuntos
Reatores Biológicos/microbiologia , Água Potável/análise , Membranas Artificiais , Rodófitas/crescimento & desenvolvimento , Purificação da Água/métodos , Filtração/métodos , Compostos Orgânicos/análise , Osmose , Águas Salinas/química , Água do Mar/química , Águas Residuárias/química , Poluentes Químicos da Água/análise
3.
Talanta ; 206: 120207, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514857

RESUMO

Herein, a multicommuted flow-batch setup and a photometric procedure for the determination of mercury at the ppb level in aqueous samples are described. The setup was designed to implement a versatile solvent extraction and pre-concentration strategy by combining flow-batch and multicommuted flow analysis approaches. The photometric method was based on Hg(II) reaction with dithizone in a chloroform medium, which was also used as the extracting organic solvent. The flow analysis system was composed of a homemade syringe pump module, a set of solenoid valves, two Aquarius mini-pumps, and a flow-batch chamber. The homemade photometer was comprised of a light emitting diode (LED), photodiode, and homemade flow cell (50 mm length). The flow system and photometer were controlled using an Arduino Due board, running custom-written software. After optimizing the operational conditions, the effectiveness of the developed system was evaluated for the determination of the mercury concentration in drinking water. For accuracy assessment, samples were analyzed using a spiking methodology and an independent method, yielding a recovery ranging from 92% to 108%. Other important characteristics of the proposed method were found as follows: linear response range, 0.5-10.0 µg L-1 (r = 0.9984); limit of detection 0.38 µg L-1 Hg(II); consumption of dithizone and chloroform, 1.85 µg L-1 and 0.8 mL per analysis, respectively; coefficient of variation, 2% (n = 10); sampling throughput, 20 determinations per h.


Assuntos
Água Potável/análise , Mercúrio/análise , Fotometria/métodos , Poluentes Químicos da Água/análise , Clorofórmio/química , Ditizona/química , Química Verde/instrumentação , Química Verde/métodos , Limite de Detecção , Águas Minerais/análise , Fotometria/instrumentação , Rios/química
4.
Talanta ; 206: 120209, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514865

RESUMO

A novel approach for dispersive liquid-liquid microextraction based on the use of deep eutectic solvent as a disperser was presented for the first time. The procedure was automated based on an in-syringe flow system coupled with UV-Vis detection and demonstrated by the determination of chromium (VI) in beverages. This analytical task was used as a proof-of-concept example. The automated extraction procedure involved the aspiration of aqueous sample into a syringe pump with homogeneous mixture of extraction solvent (1-oсtanol) and deep eutectic solvent (tetrabutylammonium bromide - formic acid) containing color-forming reagent (1,5-diphenylcarbazide). This led to decomposition of deep eutectic solvent in aqueous phase resulting in dispersion of extraction solvent, oxidation of 1,5-diphenylcarbazide to 1,5- diphenylcarbazone in the presence of chromium (VI), and formation of colored chromium (III) complex with 1,5-diphenylcarbazone and its fast extraction. In this case composition of deep eutectic solvent played a key role for analyte extraction. Tetrabutylammonium bromide promoted mass transfer between aqueous phase and the extraction solvent droplets as a salting out agent, bromide ion acted as an ion-pare agent for analyte complex extraction, formic acid provided required pH value for analyte complex formation. Under the optimal conditions the limit of detection, calculated from a blank test based on 3s, was 0.2 µg L-1. The automated dispersive liquid-liquid microextraction using deep eutectic solvent as disperser can be considered as an available, efficient, rapid and environmentally friendly sample pretreatment approach.


Assuntos
Cromo/análise , Contaminação de Alimentos/análise , 1-Octanol/química , Bebidas Gaseificadas/análise , Água Potável/análise , Formiatos/química , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Malus/química , Prunus avium/química , Compostos de Amônio Quaternário/química , Solventes/química , Espectrofotometria Ultravioleta , Seringas
5.
Environ Health Prev Med ; 24(1): 72, 2019 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-31805868

RESUMO

BACKGROUND: Lead is a toxic metal abundant in the environment. Consumption of food contaminated at low levels of lead, especially by small children and pregnant women, raises a health concern. METHODS: Duplicated food portions and drinking water were collected over 3 days from 88 children and 87 pregnant women in Shimotsuke, Tochigi, Japan. Participants were recruited in this study between January 2014 and October 2015. Dust was also collected from their homes. Lead concentrations were measured and consequent oral lead exposure levels were estimated for this population at high risk to environmental toxicants. Lead concentrations of peripheral and cord blood, taken from children and pregnant women, and were also analyzed. RESULTS: Lead concentrations in food, drinking water, and house dust were low in general. Oral lead exposure to lead was higher for children (Mean ± SEM; 5.21 ± 0.30 µg/kg BW/week) than in pregnant women (1.47 ± 0.13 µg/kg BW/week). Food and house dust were main sources of lead contamination, but the contribution of house dust widely varied. Means ± SEM of peripheral and cord blood lead concentrations were 0.69 ± 0.04 µg/dL and 0.54 ± 0.05 µg/dL, respectively for pregnant women and 1.30 ± 0.07 µg/dL (peripheral only) in children. We detect no correlation between smoking situations and blood lead concentration in pregnant women. CONCLUSION: We conclude that oral lead exposure levels for Japanese children and pregnant women were generally low, with higher concentrations and exposure for children than for pregnant women. More efforts are necessary to clarify the sources of lead contamination and reduce lead exposure of the population at high risk even in Japan.


Assuntos
Exposição Dietética/análise , Poeira/análise , Poluentes Ambientais/análise , Contaminação de Alimentos/análise , Chumbo/análise , Adulto , Pré-Escolar , Água Potável/análise , Poluentes Ambientais/sangue , Feminino , Sangue Fetal/química , Humanos , Lactente , Japão , Chumbo/sangue , Masculino , Gravidez , Adulto Jovem
6.
Ann Agric Environ Med ; 26(4): 623-629, 2019 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-31885237

RESUMO

INTRODUCTION: Fluorine is a common element in nature; however, the difference between a beneficial dose and a toxic dose for the organisms is small. The main source of fluoride for humans is water in addition to food. OBJECTIVE: The aim of this study was to estimate the degree of severity of pathological changes, namely, caries or fluorosis, in the mineralized tooth tissue of 15-year-old adolescents with respect to their hygienic and nutritional habits, and the content of fluorine in drinking water, soil and plant products. MATERIAL AND METHODS: 100 adolescents aged 15 from schools in Sosnilka, L'viv region, were examined. The condition of mineralized tooth tissue was evaluated by the caries severity, expressed by the mean number D3MFT, caries frequency and value of the SIC index. Fluorine in plant material and soil were determined according to the PN-G-04543:1982 standard, and water according to the PN-EN ISO 10304 - 1: 2009+ AC: 2012 standard. RESULTS: Severity of caries disease expressed by the D3MFT number in the examined group of 15-year-olds was 3.39; in the group of girls - 3.08, and in the group of boys - 3.76. In the examined group, the average number of teeth with fluorosis was 7.59. Value of the SIC index among the examined population of students (n-31) was 6.26: 5.89 (n-18) for girls and 7.31 (n-13) for boys. Fluorine concentration in the water was 0.78 - 1.25(mg·dm-3). In the soil, it also did not vary across the sampled areas and amounted, on average, to 176 mg·dm-3. The biggest fluorine content noted in the dry mass of beetroots was 3.50 (mg F· kg), and the lowest - 3.34 (mg F· kg). CONCLUSIONS: Close to optimal fluorine content lowers caries severity and frequency of fluorosis. Optimal fluorine content in drinking water and food does not require additional diet supplementation.


Assuntos
Cárie Dentária/epidemiologia , Água Potável/análise , Flúor/análise , Fluorose Dentária/epidemiologia , Adolescente , Calcificação Fisiológica , Cárie Dentária/etiologia , Cárie Dentária/metabolismo , Higienistas Dentários , Água Potável/metabolismo , Feminino , Flúor/efeitos adversos , Flúor/metabolismo , Fluorose Dentária/etiologia , Fluorose Dentária/metabolismo , Humanos , Masculino , Dente/fisiopatologia , Ucrânia/epidemiologia
7.
J Water Health ; 17(6): 957-970, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31850902

RESUMO

The current study was conducted to measure the activity concentration of the gross alpha and beta in 87 groundwater samples collected from the productive aquifers that constitute a major source of groundwater to evaluate the annual effective dose and the corresponding health impact on the population and to investigate the quality of groundwater in Jordan. The mean activity concentration of gross alpha and beta in groundwater ranges from 0.26 ± 0.03 to 3.58 ± 0.55 Bq L-1 and from 0.51 ± 0.07 to 3.43 ± 0.46 Bq L-1, respectively. A very strong relationship was found between gross alpha and beta activity concentrations. The annual effective dose for alpha and beta was found in the range of 0.32-2.40 mSv with a mean value of 0.89 mSv, which is nine times higher than the World Health Organization (WHO) recommended limit and one and half times higher than the national regulation limit. The mean lifetime risk was found to be 45.47 × 10-4 higher than the Jordanian estimated upper-bound lifetime risk of 25 × 10-4. The data obtained in the study would be the baseline for further epidemiological studies on health effects related to the exposure to natural radioactivity in Jordan.


Assuntos
Água Potável/análise , Água Subterrânea/análise , Monitoramento de Radiação , Radioatividade , Poluentes Radioativos da Água/análise , Radiação de Fundo , Humanos , Jordânia , Doses de Radiação , Medição de Risco , Poluentes Radioativos da Água/normas
8.
Huan Jing Ke Xue ; 40(6): 2675-2685, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854659

RESUMO

To investigate the environmental quality and human health risks of different types of groundwater at Xiangshui, Chongzuo, several regular water quality indexes and concentrations of metals in 60 groundwater samples were measured and analyzed. The environmental quality of groundwater was analyzed by means of the Nemerow index. The health risks were assessed by using a human health risk assessment model. The regular water quality indexes and concentrations of metals of the well water, spring water, and underground river water exceeded the standards to different degrees. The environmental quality of groundwater was at a poor grade. The comprehensive evaluation score of underground river water (F=4.26) was the lowest. The well water had the same score as spring water (F=7.10). The high hardness and salinity were conducive to enrichment of Cr, and the reducing environment was of great advantage for the enrichment of As. The environmental geochemistry of Zn, Pb, Cd, and Cu was similar. The sources of Fe, Al, and Mn were similar. The results of the health risk assessment indicated that the health risks of well water, spring water, and underground river water were relatively high. The health risks decreased in the order of well water > underground river water > spring water. The health risks mainly came from the carcinogenic metallic element Cr. Carcinogenic risks were 4-6 orders of magnitude higher than non-carcinogenic risks. Carcinogenic risks were higher than the maximum allowance levels (5.0×10-5 a-1). Non-carcinogenic risks were lower than the allowance levels (10-6 a-1). Children had greater health risks than adults. The health risks of metals through the drinking pathway were 2-3 orders of magnitude higher than the values caused by the dermal contact pathway. For the sake of drinking water safety, the well water, underground river water, and spring water should be properly treated and the concentration of Cr in groundwater should be controlled before drinking.


Assuntos
Água Subterrânea/análise , Metais Pesados/análise , Medição de Risco , Poluentes Químicos da Água/análise , Qualidade da Água , Adulto , Criança , China , Água Potável/análise , Monitoramento Ambiental , Humanos
9.
Huan Jing Ke Xue ; 40(6): 2722-2729, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854664

RESUMO

In view of the problem of excessive manganese concentrations in the Xi'an Jinpen Reservoir during the flood season in 2017, the vertical distribution of manganese in density currents and its occurrence pattern were monitored at multiple monitoring sections along the upstream reaches to the main basin. The influences of density currents plunging into the reservoir on the migration and transformation of Mn were studied, and sedimentation, output, and deposition of manganese in the reservoir water were also specifically estimated during a single, typical storm runoff process. Devices for avoiding high turbidity and high load inflows in rainfall events were proposed. The results showed that significant increases of total manganese were induced by high-turbidity inflows, which largely degraded water quality during rainfall events. From 12 to 14 October, 9.11 tons of total manganese were transported into the reservoir during a single rainfall event, and the pollution conditions were largely remitted by flood discharges with an output of 6.22 tons; thus, the net deposition (manganese) was 1.47 tons. The manganese content and morphological changes along the upper reaches of the reservoir indicated that soil erosion occurred during the continuous rainfall process, and this caused a large amount of particulate pollutants to flow into the water body with the runoff. More than 70% of the total manganese in the water was in the iron-manganese oxide bound state. Correlation analysis was conducted with particles of different particle size ranges, and granular manganese particle sizes were about 2-20 µm. The findings indicate that when flood discharges with turbidity currents occur, this can effectively reduce the load of pollutants and the safety risks of water.


Assuntos
Água Potável/análise , Manganês/análise , Chuva , Movimentos da Água , Poluentes Químicos da Água/análise , Qualidade da Água , China , Monitoramento Ambiental , Abastecimento de Água
10.
Ig Sanita Pubbl ; 75(4): 303-312, 2019.
Artigo em Italiano | MEDLINE | ID: mdl-31887736

RESUMO

The term asbestos refers to six unique fibrous minerals mostly used in the production of asbestos cement sheets and pipes. According to the World Health Organization and the International Agency for Research on Cancer (IARC), there exists at least "sufficient evidence" that all types of asbestos may cause cancer in humans (mesothelioma, lung cancer, laryngeal tumor and ovarian cancer). The only asbestos limit in drinking water is 7 million fiber/liter. This study is a narrative synthesis about the possible hazards to human health related to the presence of asbestos in drinking water. The various scientific studies and epidemiological reports examined highlight that there is an ongoing debate on the possible carcinogenic risk associated with asbestos exposure through ingestion. Nevertheless, considering the latency with which diseases caused by asbestos may emerge, control measures should be adopted.


Assuntos
Asbestos/efeitos adversos , Água Potável/análise , Exposição Ambiental/efeitos adversos , Poluentes Químicos da Água/toxicidade , Asbestos/toxicidade , Carcinógenos , Humanos , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/prevenção & controle , Mesotelioma/etiologia , Mesotelioma/prevenção & controle
11.
Environ Monit Assess ; 191(12): 777, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31781968

RESUMO

Arsenic (As) is one of the most important dangerous elements as more than 100 million of people are exposed to risk, globally. The permissible threshold of As for drinking water is 10 µg/L according to both the WHO's drinking water guidelines and the Iranian national standard. However, several studies have indicated that As concentrations exceed this threshold value in several regions of Iran. This research evaluates an As-susceptible region, the Tajan River watershed, using the following data-mining models: multivariate adaptive regression splines (MARS), functional data analysis (FDA), support vector machine (SVM), generalized linear model (GLM), multivariate discriminant analysis (MDA), and gradient boosting machine (GBM). This study considers 12 factors for elevated As concentrations: land use, drainage density, profile curvature, plan curvature, slope length, slope degree, topographic wetness index, erosion, village density, distance from villages, precipitation, and lithology. The susceptibility mapping was conducted using training (70%) and validation (30%). The results of As contamination in sediment showed that classifications into 4 levels of concentration are very similar for two models of GLM and FDA. The GBM calculated the areas of highest arsenic contamination risk by MARS and SVM with percentages of 30.0% and 28.7%, respectively. FDA, GLM, MARS, and MDA models calculated the areas of lowest risk to be 3.3%, 23.0%, 72.0%, 25.2%, and 26.1%, respectively. The results of ROC curve reveal that the MARS, SVM, and MDA had the highest accuracies with area under the curve ROC values of 84.6%, 78.9%, and 79.5%, respectively. Land use, lithology, erosion, and elevation were the most important predictors of contamination potential with a value of 0.6, 0.59, 0.57, and 0.56, respectively. These are the most important factors. Finally, these data-mining methods can be used as appropriate, inexpensive, and feasible options to identify As-susceptible areas and can guide managers to reduce contamination in sediment of the environment and the food chain.


Assuntos
Arsênico , Mineração de Dados , Monitoramento Ambiental , Poluentes Ambientais , Sedimentos Geológicos , Modelos Teóricos , Arsênico/análise , Água Potável/análise , Água Potável/normas , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Sedimentos Geológicos/química , Irã (Geográfico) , Curva ROC
12.
Environ Monit Assess ; 191(12): 734, 2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31707592

RESUMO

The quality of drinking water source remains as a major concern in areas of developing and underdeveloped countries worldwide. The treatment and supply of drinking water in Rwanda are carried out by Water and Sanitation Corporation, a state-owned public company. However, it is not able to supply water to all households. Consequently, the non-serviced households depend on natural water sources, like springs, to meet their water requirements. Nevertheless, the water quality in these springs is scarcely known. Therefore, this study assessed and compared metal elements in drinking water sources in the dry and rainy seasons in 2017 using the contamination degree, metal index, and geographic information systems to reveal the spatial distribution of water quality within the considered water sources of springs in Rwanda. The samples were collected monthly from nine water sources of springs and the measured elements are aluminium, calcium, copper, iron, manganese, and zinc. The metal index indicated that during the dry season and rainy season, the sites of Kibungo (1.10 and 1.26) and Kinigi (1.01 and 1.54) have assessed a metal index which is higher than 1. Thus, the water quality of those sites was getting the threshold of warning. The analysis indicated that pollutants are easily transported into water bodies during the rainy season in urban and rural areas to a greater extent than during the dry season .


Assuntos
Água Potável/análise , Monitoramento Ambiental , Sistemas de Informação Geográfica , Poluentes Químicos da Água/análise , Abastecimento de Água/estatística & dados numéricos , Cádmio/análise , Cobre/análise , Ferro/análise , Metais/análise , Compostos Orgânicos/análise , Chuva , Ruanda , Estações do Ano , Poluentes Químicos da Água/normas , Qualidade da Água , Zinco/análise
13.
Environ Sci Process Impacts ; 21(11): 1899-1907, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31641706

RESUMO

In the present study analytical methodologies were developed for two newly emerging polar perfluorinated alkyl substances (PFAS), namely F3-MSA, and HFPO-DA, in order to assess the occurrence and levels of these PFAS in Dutch and Belgian waters. Two separate methods were needed for analysing F3-MSA and HFPO-DA. A mixed-mode and a reversed phase C18 method were developed for F3-MSA and HFPO-DA, respectively, using a high resolution Orbitrap Fusion mass spectrometer for detection, yielding satisfactory LOD and LOQ results for both analytes. A sample campaign was performed collecting single grab samples from various locations and different stages of the drinking water production chain. Whereas both PFAS were absent in groundwaters, they were found to be present in surface waters, river bank and dune infiltrates, process water, and drinking water, demonstrating the persistence and mobility of both compounds. Based on provisional health-based guideline values (0.15 µg L-1 for HFPO-DA, 11.9 mg L-1 for F3-MSA), the current levels in drinking water from the suppliers involved in this study do not pose a health risk for the human population. Common removal processes used in drinking water production appeared to remove these polar compounds at most partially. At locations close to potential sources of these chemicals (e.g. fluoropolymer production sites), the quality of surface water or river bank filtrate abstracted for production of drinking water must therefore be monitored.


Assuntos
Água Potável/análise , Monitoramento Ambiental/métodos , Fluorcarbonetos/análise , Mesilatos/análise , Poluentes Químicos da Água/análise , Abastecimento de Água/normas , Água Subterrânea/química , Humanos , Rios/química
14.
Se Pu ; 37(11): 1185-1192, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642271

RESUMO

A method was developed for the rapid determination of bisphenol A (BPA) and eight structural analogs in children's plastic water bottles by online enrichment coupled with high performance liquid chromatography-fluorescence detection (HPLC-FLD). The correlation coefficients of the nine bisphenols were greater than 0.998. The limits of detection (LOQs) ranged from 0.13 ng/L to 66.7 ng/L. The recoveries ranged from 90.7% to 112.4% (RSD<11.3%, n=6). This method was applied to monitor nine bisphenols in children's water bottles. The results showed that except 4,4'-(9H-fluoren-9-ylidene)bisphenol (BPFL), all the remaining eight bisphenols were detected in different water bottles. The amounts of bisphenols leached increased with the increase of soaking time, and decreased after washing several times at 100℃. The proposed strategy is rapid, sensitive, reliable and eco-friendly, and is suitable for the simultaneous analysis of new bisphenols in water samples.


Assuntos
Compostos Benzidrílicos/análise , Água Potável/análise , Embalagem de Alimentos , Fenóis/análise , Cromatografia Líquida de Alta Pressão , Humanos
15.
Environ Pollut ; 255(Pt 3): 113339, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31627052

RESUMO

A total of 152 groundwater samples were collected around a contaminated site to evaluate the carcinogenic and noncarcinogenic risks of exposure to twelve volatile chlorinated hydrocarbons (VCHs) by oral ingestion, dermal contact and inhalation absorption during showering. Although toxicity data of some VCHs are fragmentary, the results showed that the carcinogenic and noncarcinogenic risks of exposure to VCHs in contaminated drinking groundwater for local residents needs immediate attention. The main risk contributors for the carcinogenic and noncarcinogenic risks are carbon tetrachloride and 1,1,2-trichloroethane through inhalation exposure pathway, respectively. The health risk contribution rates associated with three exposure pathways for a specific VCH were intrinsic to the compound, and the dermal contact corresponded to a negligible contribution for almost every VCH species. Although most of the evaluated VCHs had a higher risk contribution by inhalation than by oral ingestion pathway, the integrated multi-VCH health risk contributions of the three exposure pathways were mainly dependent on the VCH compositions. Drinking boiled water not only decreased the exposure risk but also affected the risk contribution rates of three exposure pathways, which indicates that it is feasible to reduce the risk of VCH exposure during daily activities based on the risk contribution of the exposure pathways. In addition to the VCHs included in the drinking water standards, species such as 1,1,2,2-tetrachloroethane and hexachloroethane also showed a remarkable exposure health risk according to the standardized health risk calculation, which implied that improved drinking water standards are urgently required.


Assuntos
Hidrocarbonetos Clorados/análise , Poluentes Químicos da Água/análise , Água Potável/análise , Etano/análogos & derivados , Água Subterrânea/química , Humanos , Hidrocarbonetos Clorados/toxicidade , Medição de Risco
16.
Environ Monit Assess ; 191(9): 557, 2019 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-31402397

RESUMO

This report describes the available drinking water quality monitoring data on the Centers for Disease Control and Prevention (CDC) National Environmental Public Health Tracking Network (Tracking Network). This surveillance summary serves to identify the degree to which ten drinking water contaminants are present in finished water delivered to populations served by community water systems (CWS) in 24 states from 2000 to 2010. For each state, data were collected from every CWS. CWS are sampled on a monitoring schedule established by the Environmental Protection Agency (EPA) for each contaminant monitored. Annual mean and maximum concentrations by CWS for ten water contaminants were summarized from 2000 to 2010 for 24 states. For each contaminant, we calculated the number and percent of CWS with mean and maximum concentrations above the maximum contaminant level (MCL) and the number and percent of population served by CWS with mean and maximum concentrations above the MCL by year and then calculated the median number of those exceedances for the 11-year period. We also summarized these measures by CWS size and by state and identified the source water used by those CWS with exceedances of the MCL. The contaminants that occur more frequently in CWS with annual mean and annual maximum concentrations greater than the MCL include the disinfection byproducts, total trihalomethanes (TTHM), and haloacetic acids (HAA5); arsenic; nitrate; radium and uranium. A very high proportion of exceedances based on MCLs occurred mostly in very small and small CWS, which serve a year-round population of 3,300 or less. Arsenic in New Mexico and disinfection byproducts HAA5 and TTHM, represent the greatest health risk in terms of exposure to regulated drinking water contaminants. Very small and small CWS are the systems' greatest difficulty in achieving compliance.


Assuntos
Água Potável/análise , Monitoramento Ambiental , Poluentes Químicos da Água/análise , Abastecimento de Água/estatística & dados numéricos , Arsênico , Desinfecção , Humanos , Nitratos , Saúde Pública , Trialometanos/análise , Estados Unidos , Poluição da Água/estatística & dados numéricos , Qualidade da Água
17.
J Agric Food Chem ; 67(35): 9942-9949, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31403785

RESUMO

We develop an ultrasensitive T2-mediated immunosensor based on the coordination chemistry and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide andalkyne (CuAAC) and apply it for the detection of pesticide residues. We functionalize polyglutamic acid (PGA) on polystyrene to form a brush-like nanostructure that has a large loading capacity of Cu(II) through the coordination chemistry between PGA and Cu(II). Such a brush-like nanostructure could be used to chelate Cu(II) to modulate the CuAAC between azide-functionalized 1000 nm polystyrene (PS1000) and alkyne-functionalized 30 nm magnetic nanoparticles (MNP30), and the MNP30-PS1000 conjugate as a product of CuAAC can act as a magnetic probe in this T2-based immunosensor. This click chemistry and coordination chemistry-mediated immunosensor allows for an ultrasensitive detection for chlorpyrifos residue (0.022 ng/mL), a 58-fold enhancement compared with that of enzyme-linked immunosorbent assay (1.28 ng/mL), providing a promising platform for detection of trace small molecules.


Assuntos
Técnicas Biossensoriais/métodos , Clorpirifos/análise , Nanoestruturas/química , Resíduos de Praguicidas/análise , Alquinos/química , Azidas/química , Técnicas Biossensoriais/instrumentação , Quelantes/química , Química Click , Cobre/química , Água Potável/análise , Lagos/análise , Ácido Poliglutâmico/química , Sensibilidade e Especificidade , Poluentes da Água/análise
18.
Environ Res ; 177: 108648, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31421451

RESUMO

Per- and polyfluoroalkyl substances (PFAS) are a group of water-soluble chemical compounds with an important number of applications, which have been widely used during the last 60 years. Two of them, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are the most known and well investigated. As for many other organic substances that are of environmental concern, the diet is the main route of human exposure to PFAS. However, in certain cases drinking water may also mean a significant contribution to human exposure, and to a lesser extent, dust and air (indoor exposure). In recent years, the environmental persistence of PFAS, their biomagnification in food webs, as well as their potential accumulation and toxicity, have generated a notable interest, which has been evidenced by the considerable number of publications in this regard. Recently, we carried out a wide revision on the levels of PFAS in food and human dietary intake. In the current review, we have summarized the recent information (last 10 years) published in the scientific literature (Scopus and PubMed) on the concentrations of PFAS in drinking water and the human health risks derived from the regular water consumption, when available. A large amount of data belongs to PFOS and PFOA and corresponds to studies mainly conducted in countries of the European Union, USA and China, although no information is available for most countries over the world. According to the toxicological information about PFAS that is so far available, the current health risks for the regular consumers of municipal/tap water do not seem to be of concern according to the levels considered as acceptable for various regulatory institutions.


Assuntos
Exposição Dietética/análise , Água Potável/análise , Fluorcarbonetos/análise , Poluentes Químicos da Água/análise , Humanos
19.
Sci Total Environ ; 686: 1238-1250, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31412520

RESUMO

In densely populated urban areas of many low-income countries, water scarcity, poor water quality, and inadequate wastewater management present complex challenges to ensuring health and wellbeing. This study was conducted in an impoverished peri-urban community in Dar es Salaam, Tanzania that experiences water scarcity and relies on domestic wells for drinking water. The objective of this study was to identify the sources of domestic well water contamination and assess the relationship and association of water contamination with three variables 1) the proximity of the well to a sanitation system, 2) well age, and 3) well depth. Out of the 71 wells tested, samples from >80% of wells contained Escherichia coli (E. coli) and 58% had nitrate levels above WHO guidelines. The average concentration of total dissolved solids (TDS) was 882 mg/L, which exceeded the WHO guideline of 600 mg/L. Bivariate correlation analysis showed a strong correlation between water contamination and proximity of the well to a sanitation system along with well depth. Univariate regression analysis confirmed the association of contaminants with distance of a well from a sanitation system and well depth (p < 0.05) but age of the well did not show any significant influence on water quality. Our findings indicate significant contamination of wells from nearby septic tanks and pit latrines. New regulatory mandates for the distance of domestic wells from sanitation systems are essential to prevent groundwater contamination and to protect human health.


Assuntos
Água Potável/análise , Água Potável/microbiologia , Escherichia coli/isolamento & purificação , Poluentes Químicos da Água/análise , Qualidade da Água , Poços de Água , Cidades , Nitratos/análise , Tanzânia , Abastecimento de Água
20.
Artigo em Inglês | MEDLINE | ID: mdl-31374814

RESUMO

Recent events have drawn increased attention to potential lead exposures from contaminated drinking water. Further, homes with older infrastructure are at greatest risk due to the presence of the disinfectant chemical chloramine, which can leach lead from older pipes. There is a growing need to determine the extent of lead leaching especially within vulnerable communities and homes with children. This pilot study collected survey data and performed lead analysis on drinking water in the small community of Manchester in Houston, TX. Manchester is characterized by industrial sites, flooding, and a low socioeconomic population. Surveys and water analyses were completed on randomly selected homes (N = 13) and documented perceptions of participants on their drinking water regarding presence and concentration of lead. Lead was discovered in 30.8% of homes ranging from 0.6 to 2.4 (µg/L), all below the US Environmental Protection Agency action level of 15 ppb, but above the water standard goals. These findings further suggest that contaminated water is a broad issue requiring concerted efforts to ensure the health of US residents.


Assuntos
Água Potável/análise , Chumbo/toxicidade , Populações Vulneráveis , Poluentes Químicos da Água/toxicidade , Adulto , Idoso , Feminino , Humanos , Chumbo/análise , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Navios , Texas , Estados Unidos , United States Environmental Protection Agency , Poluentes Químicos da Água/análise
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