PET-bottled Water Research Articles

Concentration of Phthalate Esters in Bottled Water: A Case Study in Effurun, Delta State, Nigeria

Phthalate esters (PAEs), a group of chemical compounds, are extensively used as additives in plastics. The objective of this study was to determine how much of a few target PAEs have leached into various samples of drinking water packaged in PET bottles in Effurun, Delta State, Nigeria as well as how ambient temperature, sunshine exposure, and cold storage conditions have affected the concentration of PAE. The concentrations of Di-ethyl-phthalate (DEP), di-butyl-phthalates (DBP), benzyl-butyl-phthalate (BBP), di-n-octyl phthalate (DnOP), and Bis-(2-ethyl-hexyl) phthalate (DEHP) were determined in bottled water samples. The concentrations of PAEs were determined using a gas chromatography coupled with a mass sepctroscopy analyzer (GC-MS). Phthalate compound was observed to be in all bottled water placed under different storage conditions; cold storage (CW), ambient storage (AW), and sunlight storage (SLW) for a period of 2, 4, 8, 12 and 16 weeks. However, the greatest leaching effect was observed in PET bottled water placed sunlight conditions for sixteen weeks with concentrations of; DEHP (2.1-11.2) µg/L, DEP (0.98-3.87) µg/L, DBP (2.98-13.8) µg/L. The results from this study indicated that, under various storage conditions, DEP, DBP and DEHP from PET bottles may leach more into the drinking water over a period of time under different storage conditions. The result additionally gave indication that DEHP; a known endocrine disruptor, with anti-androgenic and possible human carcinogen effects, exceeded the 6 µg/L USEPA Maximum Contamination Level (MCL) in drinking water, and also greater than 8 µg/L which is the indicated MCL by the World Health Organization (WHO).

Migration of Acetaldehyde and Formaldehyde from PET-bottled Water Under Hot Climate Conditions

Migration of Acetaldehyde and Formaldehyde from PET-bottled Water Under Hot Climate Conditions

Qualitative Determination of Bisphenol A and Phthalate Residues in Drinking Water Alternatives in Kayseri Province of Türkiye

In this study, it was aimed to qualitatively determine Bisphenol A and dibutyl phthalate residues in carboy, pet bottled and tap waters used as drinking water in Kayseri-Türkiye. Being used as an additive in the production of many products and plastics frequently used in daily life, BPA and phthalates are associated with a variety of health issues and environmental problems. Within the scope of this study, a total of 20 drinking water samples (9 pet, 7 carboy and 4 tap water) were analyzed in terms of dibutyl phthalat (DBP), BPA and BPA derivatives (Bisphenol S and Bisphenol F). Among the pet bottled water samples; 8 (88.88%) were found to be contaminated with BPA, 5 (55.55%) with DBP and 7 (77.77%) with BPA derivatives, while 1(14.28%) of the carboy water samples were found contaminated with BPA and 7(100%) with DBP. Among the tap water samples, 2 (50%) were contaminated with BPA and 4 (100%) with DBP. No BPA derivatives were found in carboy and tap water samples while pet bottled waters were found posi- tive for all three contaminants. On the other hand, all carboy and tap waters were found contaminated with phthalates. The findings of this study reveal that the most variety of contamination for these chemicals is determined in pet bottled waters. This study highlighted the situation of BPA and phthalate residues in drinking water sources. Measures should be taken to prevent the contamination of all types of drinking water and to systematically examine the BPA and phthalate-related safety of drinking waters. Further investigation is needed to determine and quantify the occurrence of the target compounds.

Determination of phthalates in bottled waters using solid-phase microextraction and gas chromatography tandem mass spectrometry.

Phthalates are synthetic chemicals widely used, mainly as plasticizers, which are ubiquitous and recognized as endocrine-disrupting chemicals. For investigation of phthalate residues leached from PET bottles into drinking water, a simple and sensitive method was developed, validated and applied to a series of real samples. Solid-phase microextraction (SPME) was used in direct immersion mode for concentration of phthalate traces from 10mL of each water sample. Four commercially available SPME fibers were tested and compared, while six dialkyl phthalates were investigated: dimethyl phthalate (DMP), diethyl phthalate (DEP), diisopropyl phthalate (DiPP), diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di-ethylhexyl phthalate (DEHP). The extracted phthalic acid esters were separated and quantified by gas chromatography hyphenated with tandem mass spectrometry (GC-MS/MS) and a detection method based on multiple reaction monitoring (MRM) mode was fully developed, optimized and validated. The fiber which showed the highest ability for extraction of phthalates was DVB/CAR/PDMS which combines a liquid polymeric coating (polydimethyl siloxane and divinylbenzene) with a carboxen porous sorbent layer. The obtained limit of detection was in the range between 0.3 and 2.6ngmL-1. Thus, this fiber was used for extraction of phthalates from twelve commercial PET bottled water samples. All investigated water brands showed the presence of two to six phthalates at concentrations between 6.3 and 112.2ngmL-1. The highest level was observed for DnBP, followed by DEHP, DiBP, DMP, DEP and DiPP.

STUDY OF DRINKING WATER ENRICHED WITH OXYGEN UNDER VARIOUS STORAGE CONDITIONS

The article presents studies to establish the preferred storage conditions for drinking water enriched with oxygen and to determine the dynamics of changes in the content of dissolved oxygen in drinking water. The dynamics of changes in the content of dissolved oxygen in drinking water in PET bottles, depending on the storage conditions, and the dynamics of changes in the content of dissolved oxygen in drinking water with free access of air have been determined. It was found that the content of dissolved oxygen in drinking water in a 0.5 L PET bottle, when it is reopened after 24 hours, decreases by 11 ± 2 mg.

Life cycle assessment of two decentralized water treatment systems combining a constructed wetland and a membrane based drinking water production system

Decentralized (waste) water treatment technologies (DWTS) are suitable for rural areas that are not connected to conventional (municipal) treatment systems due to the longer transport distances. However, the sustainability of DWTS is still debatable. Therefore, the main goal of this study was to use the Life Cycle Assessment tool to perform the life cycle impact assessment of two different decentralized water treatment systems operated in Belgium. The first one was a mobile constructed wetland treating grey water (Scenario 1) at music festivals, coupled to a membrane based drinking water production system (100 m3 of potable water production out of 400 m3 of wastewater generation per festival). The second one was a vertical flow constructed wetland treating black water (Scenario 2) at a restaurant (135 visitors/day), also coupled to a membrane system. Comparison was performed with conventional alternatives (PET bottled water supply and a public drinking water supply, respectively). In most impact categories, Scenarios 1 and 2 had roughly an order of magnitude lower impact than their conventional alternatives. Sensitivity analysis was also performed. In scenario 1, the distance travelled for both the mobile constructed wetland and the PET bottles was varied. In Scenario 2 the distance of the restaurant from a drinking water supply and a sewerage system was varied. These results were also encouraging, showing that the DWTS are still environmentally feasible compared to their conventional alternatives at the shortest distance studied (Scenario 1: 175 km and Scenario 2:75 m). Therefore, DWTS can be considered environmentally beneficial under certain conditions.

Estimation of Physico-Chemical, Trace Metals, Microbiological and Phthalate in PET Bottled Water

Estimation of Physico-Chemical, Trace Metals, Microbiological and Phthalate in PET Bottled Water

PET-Bottled Water Consumption in View of a Circular Economy: The Case Study of Salento (South Italy)

Polyethylenterephtalate (PET) is the preferred packaging material in the bottled water industry and represents the main cause of waste production. This work investigated the drinking water consumption habits, with particular reference to PET-bottled water, of people living in the province of Lecce (Apulia Region, Southern Italy) by age and geographical groups. Their perception about the quality of tap water was also explored. The survey was performed by the administration of a questionnaire to 4137 citizens. Bottled mineral water was consumed by about the 90.4% of respondents with an average consumption of 387.7 L/year per capita (375.2 L/year in PET-bottles, 12.5 L/year in glass bottles). Public supply system was used by the 61.5% of respondents with an average consumption of 169.4 L/year per capita. The consumption of tap water was negatively related to the perception of its bad quality and the residence in a big city (Lecce); while it was positively associated with the age group ≤16 years old. Effective communications strategies must be developed in order to promote the consumption of tap water and implement good practice of circular economy.

Evaluation of the genotoxicity of mineral water in polyethylene terephthalate bottles exposed to solar radiation and temperature at variable timescale

AbstractMost bottling companies in Ethiopia use polyethylene terephthalate bottles to package. However, less attention is given to toxic chemicals that could migrate from packaging material into the water. This study aims to assess leaching and toxicological conditions in PET bottled water due to prolonged storage and exposure to direct sunlight. Allium cepa test was used to determine mitotic index (MI) and chromosomal aberrations (CAs). One‐way analysis of variance (ANOVA) and Dunnet’s multiple comparison test were used. P < 0.05 considered statistically significant. The higher chromosomal aberrations and the lowest mitotic index were significantly observed at high temperature (35°C) for one month at P < 0.000. The lower mitotic index was correlated with growth cycle disturbance leading to cell growth reduction. Further investigation is recommended to describe the mechanism and rate of migration of chemicals from water samples supplied in PET bottle.

Resveratrol diminishes bisphenol A-induced oxidative stress through TRPM2 channel in the mouse kidney cortical collecting duct cells

Bisphenol A (BisPH-A) is a latent danger that threatens our health, which we frequently exposure in our modern life (e.g. the widespread use of drinking water in plastic pet bottles). But the BisPH-A induced transient receptor potential melastatin 2 (TRPM2)-mediated oxidative stress and apoptosis in these cells has not been studied yet. Calcium (Ca2+) plays an important role in a versatile intracellular signal transduction that works over a wide range to regulate oxidative stress processes. TRPM2 is activated by oxidative stress and it has emerged as an important Ca2+ signaling mechanism in a variety of cells, contributing many cellular functions including cell death. Resveratrol (RESV), which belongs to the polyphenol group, acts as an antioxidant, eliminating cellular oxidative stress and increasing the body’s resistance to diseases. The current study aimed to elucidate the effect of antioxidant resveratrol on TRPM2-mediated oxidative stress induced by BisPH-A exposure in the mouse kidney cortical collecting duct cells (mpkCCDcl4). The cells were divided into four groups as control, resveratrol (50 µM for 24 h), BisPH-A (100 µM for 24 h) and BisPH-A + RESV. Intracellular free Ca2+ concentrations and TRPM2 channel currents were high in BisPH-A treated cells, but decreased with resveratrol treatment. In addition, BisPH-A induced mitochondrial membrane depolarization, reactive oxygen species (ROS), caspase 3, caspase 9 and apoptosis values were decreased by the resveratrol treatment. In conclusion, resveratrol protected cells from BisPH-A induced oxidative damage. In this study, we showed that TRPM2 channel mediates this protective effect of resveratrol.

Smaller-sized micro-plastics (MPs) contamination in single-use PET-bottled water in Thailand

Micro-plastic (MP) contamination of drinking water is an emerging global concern. Findings on the cytotoxic effects of MPs in human cells are an incentive to investigate the MP concentration in drinking water. The present study quantitatively and qualitatively analyzes the MPs in 10 brands of single-use PET-bottled water, sourced from Thailand. A set of glass-bottled water was similarly analyzed to compare the MP concentrations between the two packaging. Two sorting techniques were used: 1) fluorescent tagging with Nile Red (≥6.5 μm) and 2) optical microscopy (≥50 μm). ATR-FT-IR (≥50 μm) and confocal Raman spectroscopy (1–50 μm) were also used. The MP concentration was found to be 140 ± 19 p/L in single-use plastic-bottled water and 52 ± 4 p/L in glass-bottled water. Plastic bottles had a significantly higher MP quantity than the latter. Both 6.5–20 μm and 20–50 μm MPs showed significant dominance over the ≥50 μm fraction. Fibers accounted for 62.8% of the total particle content, followed by fragments. Under optical microscopy, ≥50 μm particles were 10 ± 1 p/L (on average), which did not differ largely from that of fluorescent-tagged particles in the same size range (12 ± 1 p/L), implying the suitability of both techniques to sort ≥50 μm MPs. However, fluorescent-tagging was more reliable for MP identification in drinking water, particularly in the 6.5–50 μm range. Among the particles that were confirmed to be polymeric, PET, PE, PP, and PA were dominant. Accordingly, the contamination mainly emanates from the packaging, but could also occur during the manufacturing process. Given the direct human exposure to MPs through bottled water and their cellular toxicity, further studies are encouraged on smaller-sized MPs in drinking water.

Effect of common storage condition on the release of phthalate contaminants of bottled water in polyethylene terephthalate: A chemical analysis and human health risk assessment

Aims: This survey aimed to investigate the impact of common storage conditions on the migration of phthalate esters (PEs) including di-2-(ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP), terephthalic acid (TPA), and phthalic anhydride from polyethylene terephthalate (PET) bottle into the water and to assess the potential human health risk using Monte Carlo simulation (MCS). Materials and Methods: Three different PET-bottled water brands were stored for 7 and 90 days at three temperatures: 5, 25, and >45°C. PEs were extracted from samples using the solid-phase extraction method with gas chromatography–mass spectrometry. Results: The highest concentrations were found for TPA in samples immediately after purchasing. DEHP and DBP were identified at 90 days in all of the samples. Based on the health risk assessment, the hazard quotient of four compounds in the MCS method was

재활용 용이성을 위한 음료 라벨의 비교 분석 - 국내 페트병 생수 주스 음료 중심으로 -

국내 음료 제품 대부분은 페트병을 사용하고 있다. 최근 환경부에 따르면 페트병을 재활용하는 과정에서 페트병에 부착되는 라벨이 문제가 되고 있다. 그래서 본 연구는 재활용에 문제가 되고 있는 생수 주스음료라벨의 구조를 비교 분석하여 재활용을 어렵게 하는 문제점을 확인할 수 있었다. 최근 몇몇 기업에서는 환경문제와 재활용 분리배출 과정에서 페트병 라벨의 분리 제거가 쉽도록 구조를 개선하여 절취선을 적용한 제품을 판매하고 있다. 그러나 본 연구 결과 관련 기업에서 적용하고 있는 주스음료의 절취선은 제 기능을 못하고 있음을 확인할 수 있었다. 현재 페트병의 라벨은 접(점)착식과 비 접착식 2가지 방식을 적용하고 있다. 첫째, 접(점)착식은 생수병에 적용되며 라벨은 폴리프로필렌(PP)소재를 사용하여 부착한다. 그러나 제품마다 부착방식이 다르며 분리 제거가 쉽지 않은 구조로 되어 있었다. 둘째, 비 접착식은 주스음료에 적용되며 폴리에틸렌 테레프타레이트(PET)소재를 사용하여 부착한다. 그러나 절취선이 적용된 제품은 절취선의 기능을 하지 못하고 있음을 확인할 수 있었으며 절취선이 적용되지 않은 제품은 라벨 분리 제거가 불가능하다는 것을 확인할 수 있었다. 그러므로 본 연구결과 생수와 주스음료의 페트병에 부착되는 라벨은 구조개선이 필요하며 재활용의 용이성을 위해서는 국가표준안 마련을 위한 기초연구이다.

Does mechanical stress cause microplastic release from plastic water bottles?

Plastic particle ingestion has become of concern as a possible threat to human health. Previous works have already explored the presence of microplastic (MP) in bottled drinking water as a source of MP intake. Here, we consider the release of MP particles from single-use PET mineral water bottles upon exposure to mechanical stress utilizing SEM plus EDS, which allows the implementation of morphological and elemental analysis of the plastic material surface and quantification of particle concentrations in sample water. The aim of this study was to better evaluate the sources of MP intake from plastic bottles, especially considering the effect of daily use on these bottles such as the abrasion of the plastic material. For that, we analysed MP release of PET bottlenecks and HDPE caps on their surfaces after a series of bottle openings/closings (1 x, 10 x, 100 x). Furthermore, we investigated, if the inner surface of the PET bottles released MPs, counted particle increase of the water and identified MPs in the PET bottled water after exposing the bottles to mechanical stress (squeezing treatment; none, 1 min, 10 min). The results showed a considerable increase of MP particle occurrence on the surface of PET and HDPE material (bottlenecks and caps) after opening and closing the bottles. After 100 times the effect was impressive, especially on caps. Moreover, great differences exist in cap abrasion between brands which uncovers a discrepancy in plastic behavior of brands. Interestingly, particle concentrations in the bottled mineral water did not significantly increase after exposure to mechanical stress (squeezing treatment). The morphological analysis of the inner wall surface of the bottles supported this observation, as no stress cracks could be detected after the treatment, implying that the bottles itself are not a consistent source of MP particles after this extent of mechanical stress. However, chances of MP ingestion by humans increase with frequent use of the same single-use plastic bottle, though only from the bottleneck-cap system.

Enhancing solar disinfection of water in PET bottles by optimized in-situ formation of iron oxide films. From heterogeneous to homogeneous action modes with H2O2 vs. O2 – Part 2: Direct use of (natural) iron oxides

Solar disinfection (SODIS) is a well-accepted intervention method, leading to an improvement in contaminated water sources. In this work, we attempted to further enhance the bacterial inactivation process during light exposure. By means of iron oxide addition, we generated a film on the inner surface of PET bottles used in SODIS, in order to induce further pathways of solar-mediated inactivation. More specifically, in this 2nd part, the deposition process has been systematically assessed, using iron oxides (Fe-Ox). The deposition parameters, namely, the precursor concentration (50 mg/L to 1 g/L), deposition time (1–4 h), oxide type (semiconductor, Fe species), size (μm vs. nm), and specific surface area (∼5–150 m2/g), were assessed. The use of H2O2 as the electron acceptor (and heterogeneous photo-Fenton induction) enhanced the efficacy without decreasing the reuse potential. More than 60% and 75% reduction in the treatment time was observed, compared with that for SODIS in a normal bottle, with O2 and H2O2 (in situ photo-Fenton) as the electron acceptors, respectively. The semiconductor mode of action and controlled iron leaching in the system both demonstrated bactericidal capacity; particularly, it was found that the factors affecting the process partially correlated with the oxide characteristics (size, band gap, and isoelectric point), rather than the capacity to photo-dissolve iron. Consequently, the use of a natural Fe source yielded results (deposition parameters and efficacy) resembling those for iron salts, indicating the dominant inactivation pathways governing the process in the presence or absence of H2O2. Finally, the disinfection of natural lake water with natural Fe–deposed bottles showed similar results to those of Fe-salt–deposed bottles, indicating that in a suitable matrix, the process can work equally well.

Enhancing solar disinfection of water in PET bottles by optimized in-situ formation of iron oxide films. From heterogeneous to homogeneous action modes with H2O2 vs. O2 – Part 1: Iron salts as oxide precursors

Solar disinfection (SODIS) is a WHO-accepted intervention method for improving water sources in developing countries. Despite its effectiveness, the limitations of long exposure and bacterial regrowth risk demand further improvement of the practice. In this work, we have generated an iron oxide film on the inner surface of PET bottles used in SODIS, to generate further pathways of solar-mediated inactivation, namely a semiconductor mode of action and controlled iron leaching in the system, which both have demonstrated bactericidal capacity. More specifically, in this Part 1, the deposition process using Fe salts has been scrutinized, assessing the use of various homogeneous Fe precursors (FeCl3, FeSO4 and Fe2(SO4)3), amounts of iron (0.5–20 g/L) and deposition time (1–8 h) to find the delicate balance among deposition layer thickness and light penetration. At the optimal conditions (4 h deposition, 1 g/L FeCl3) SODIS was enhanced, reducing 60% the exposure time; a simple washing step brought a further reduction (70%), while eliminating regrowth in volumes from 330 up to 1500 mL reactors. A robust process and reactor was attained, able to reuse its precursor solution almost 10 times and the reactor in 5 consecutive tests, without the need for re-deposition. The modification also proved to be an invaluable iron source to fuel the photo-Fenton process, when H2O2 as an electron acceptor was added to the system. The improvement induced by the heterogeneous photo-Fenton process was around 80% compared to the SODIS/H2O2 process in plain PET bottles and exceeded 85% when compared to SODIS, while being durable to the high oxidative conditions. Finally, in the view of application in drinking water treatment, the process performed well in the lightly acidic region, due to the physicochemical implications of natural waters’ pH in iron cycling.

Escassez hídrica: estudo de caso em uma comunidade rural do pantanal mato-grossense

A água é um recurso de grande importância para o desenvolvimento e sobrevivência humana, porém a problemática referente à sua quantidade e qualidade representa motivo de preocupação mundial. O objetivo deste estudo foi apresentar a situação das famílias que sofrem com a escassez hídrica, por meio do relato das mulheres que residem no Assentamento Laranjeira I, situado na borda do Pantanal de Cáceres – MT. À coleta de dados adotou-se abordagem qualitativa descritiva, de caráter exploratório e como método de pesquisa optou-se pelo estudo de caso com a utilização de questionário estruturado, entrevista semiestruturada proposta por Kaufmann, rodas de conversa e registros em diário de campo. A amostra reuniu 20 famílias. No que diz respeito ao abastecimento de água 70% das famílias tem como fonte de água principal as minas (nascentes) que são obtidas por meio de gravidade, bombas, baldes e outros recipientes. Todas as famílias entrevistadas alegaram recorrer às fontes alternativas como as nascentes para a coleta de água para o consumo humano e armazenar a água em galões e garrafas pet. Através das falas foi possível constatar que pouco se avançou no processo de obtenção de água, no entanto algumas famílias conseguiram adquirir água em seus lotes através da perfuração de poços. As familiais utilizam moto, carro, bicicleta como meio de locomoção para a coleta de água. No Assentamento Laranjeiras I também foi constatado que muitas famílias por vezes ansiaram pelo desejo de ir embora do assentamento devido a problemática da falta de água. Foram observados também conflitos entre os moradores do assentamento relacionado ao uso da água, onde famílias disputam por minas e lançam mão de estratégias como a instalação de diversos encanamentos que levam a água às residências. Foi possível identificar também que as famílias adotaram medidas de adaptação para superar a falta de água como a coleta e captação da água da chuva. Por fim, esta realidade da comunidade estudada evidencia a necessidade de transformações estruturais e ações que visam ampliar o acesso aos sistemas de abastecimento de água. Atender aos excluídos do acesso demanda reconhecer a situação de alta vulnerabilidade na qual essa parcela da população está inserida e considerar as múltiplas dimensões e a diversidade de desafios para a efetividade de ações setoriais, como são as intervenções em abastecimento de água para consumo humano.

GENETIC EFFECT OF MIGRATORY COMPOUNDS FROM BOTTLED NATURAL DRINKING WATER STORED UNDER DIRECT SUNLIGHT

The drinking water is one of the important routes for human exposure to contaminants through releasing of antimony (Sb) and polymers from polyethylene terephthalate (PET) plastic. The aim of this study was to investigate the effect of sunlight on chemical compounds migration into PET-bottled water and studying the cytotoxicity of di-butyl phthalate (DBP) and di-octyl phthalate (DOP) by SMART in Drosophila melanogaster. Four random water bottle samples produced by various companies as: A (PET, clear, 0.6L), B (PET, clear, 1.5L), C (PET, blue, 1.5L) and D (polycarbonate PC, blue, 19L) for studying the effect of direct sunlight exposure on migration of antimony and phthalates. Experiment was carried out in the presence of sunlight (7 h daily) for 210 day. The migrated compounds profile (µg/L) that detected sample (A) before storage were only two compounds formaldehyde (FA) and acetaldehyde (AA) out of nine compounds. During storage under sunlight, four compounds (Sb), bis-phenol A (BPA), dimethyl phthalate (DMP) and diethyl phthalate (DEP) were increased till 30th day then did not affect till the end of storage. Other detected compounds were continuously progressed till the end of storage with different rates. The highest rate was appeared in case of FA, it was 222 fold followed by DOP compound (173 fold) as well as DBP (75.3 fold) and finally the AA compound with 17.9 fold. Regarding to another sample B, only 3 compounds (BPA, DMP and DBP) were not detected at zero time. The AA compound was detected with the highest concentration (0.9µg/L) and the lowest one was DOP (0.007µg/L). Only four compounds were detected before storage named Sb, DOP, FA and AA, the lowest level (0.006µg/L) was noticed in DOP, while the moderate level was recorded in FA (0.03µg/L) and Sb (0.08µg/L). Other detected compounds; i.e. DBP, DOP, AA and FA were consequently increased with higher levels. This study investigated genotoxic effects of (DBP) and (DOP) at 30µg/ml concentration using the somatic mutation and recombination test (SMART). The cytotoxicity of the tested phthalate compounds was also assessed at five different concentrations 0.5, 1, 5, 10 and 20µg/ml in two types of human cell lines; liver cancer (HepG2), colon cancer (HCT-116) using neutral red cytotoxicity assay. All of tested compounds significantly showed high levels of tumor induction and frequency compared to the negative control in SMART assay. It was also reduced the viability of the HepG2 cell lines cells using different concentrations and the highest cytotoxic effect. While, on HCT-116 showed no cytotoxic effect.

Behavior of Nitrate-Nitrogen and Nitrite-Nitrogen in Drinking Water.

Nitrate-nitrogen (NO3-N) and nitrite-nitrogen (NO2-N) are constituents of the nitrogen cycle. NO3-N is toxic to humans, primarily due to its reduction to NO2-N. In Japan, NO3-N and NO2-N levels in tap water must not exceed 10 mg/L and only NO2-N alone not 0.04 mg/L, respectively. In this study, we verified the effect of microorganisms and ultraviolet (UV) to increase of NO2-N in water. First, all tested drinking-waters including tap water and commercial mineral water in PET bottles had < 2 mg/L NO3-N and undetectable levels (< 0.01 mg/L) of NO2-N. However, we found that NO2-N was generated in tap water left to stand at room temperature for several days, leading to increases in CF and TC counts and reduction of NO3-N. We also demonstrated that direct UV and sunlight irradiation of NO3-N-containing drinking water generated NO2-N in 1-2 h, with NO2-N reaching > 0.04 mg/mL by 4-6 h. On the other hand, NO3-N and NO2-N were undetectable in commercially purified water.

Effects of storage temperature and time of antimony release from PET bottles into drinking water in China.

Antimony (Sb) concentrations were measured in 10 brands of PET bottled drinking water available in supermarkets in China. To simulate general storage habits based on market research, these PET bottles with drinking water were stored for 4weeks in a lab or a car trunk during the summer. Although the PET package material of brand A had the lowest Sb level (142.71±29.81μg/g), it showed a significant increase in Sb concentrations when stored in both the car trunk and the lab. There was significant release of Sb from the PET bottles into the water following 24h of incubation at ≥40°C (40, 50, 60, and 70°C), especially at 70°C. The potential health risk of Sb release from PET bottles was calculated based on daily intake values and determined to be acceptable for consumers under normal storage conditions.