ABSTRACT
Zearalenone (ZEN) and deoxynivalenol (DON) and their derivatives are well-known mycotoxins, which can occur not only in crops but also in water bodies, including drinking water sources. In vitro bioassays can be used to detect biological effects of hazardous compounds in water. To this, when studying biological effects and toxicity in vitro, metabolism is important to consider. In this study, ZEN, α-zearalenol (α-ZEL), DON, 3-acetyl DON, and 15-acetyl DON were evaluated in vitro for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and genotoxicity (micronucleus assay) in the presence of an exogenous metabolic activation system (MAS). The ER bioassay proved to be a highly sensitive method to detect low concentrations of the ZEN compounds (EC10 values of 31.4 pM for ZEN, 3.59 pM for α-ZEL) in aqueous solutions. In the presence of the MAS, reduced estrogenic effects were observed for both ZEN compounds (EC10 values of 6.47 × 103 pM for ZEN, 1.55 × 102 pM for α-ZEL). Of the DON compounds, only 3-acetyl DON was estrogenic (EC10 of 0.31 µM), and the effect was removed in the presence of the MAS. Anti-androgenic effects of the ZEN compounds and androgenic effects of the DON compounds were detected in the micromolar range. No induction of genotoxicity was detected for ZEN or DON in the presence of the MAS. Our study highlighted that inclusion of exogenous MAS is a useful tool to detect biological effects of metabolites in in vitro bioassays.
Subject(s)
Biological Assay , Trichothecenes , Zearalenone , Zearalenone/toxicity , Trichothecenes/toxicity , Trichothecenes/metabolism , Biological Assay/methods , Receptors, Androgen/metabolism , Androgens/metabolism , Androgens/toxicity , Humans , Mutagens/toxicity , Mutagens/metabolism , Receptors, Estrogen/metabolism , Receptors, Estrogen/drug effects , Estrogens/metabolism , Estrogens/toxicity , Micronucleus TestsABSTRACT
Manganese is an essential trace element that is required for multiple enzymes in the human body. The general population is mainly exposed to manganese via food intake, in particular plant foods. In areas with elevated concentrations of manganese in groundwater, drinking water can also be an important source of exposure. The gastrointestinal absorption of manganese is below 10%, and it appears to be influenced by the amount of manganese in the diet and by the nutritional status of the individual, especially the iron status. In blood, most of the manganese is found in the cellular fractions. Manganese is primarily eliminated via the bile followed by excretion via faeces. To date, no specific biomarkers of manganese intake have been identified. The dietary intake of manganese in the Nordic countries has been reported to be within the range that has been reported for other European countries (2-6 mg/day). Since manganese is found in nutritionally adequate amounts in food, deficiency is not of public health concern. On the other hand, there is emerging epidemiological evidence that various suggested manganese biomarkers may be negatively associated with children's neurodevelopment. However, the limited number of prospective studies, the lack of appropriate exposure biomarkers, and validated neurodevelopmental outcomes render data uncertain and inconclusive. In 2013, the European Food Safety Authority considered the evidence to be insufficient to derive an average requirement or a population reference intake, and instead an adequate intake for adults was set at 3.0 mg/day.
ABSTRACT
An underemphasized aspect of sampling strategies in effect-based in vitro testing is to determine suitable collection and preparation techniques. In the current study, the impact of sample acidification on bioactivities was assessed using in vitro bioassays for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and the oxidative stress response (Nrf2 activity). Sampling was conducted at a recently upgraded Swedish wastewater treatment plant. Future plans for the treated wastewater include reuse for irrigation or as a potential drinking water source. In the AR and Nrf2 assays, acidification decreased bioactivities in the wastewater influent sample extracts, whereas acidification increased bioactivities following further treatment (disc filtration). In the ER assay, acidification had no impact on the observed bioactivities in the sample extracts. A secondary objective of the study was to assess the stability of the sample extracts over time. Lower activities were detected in the ER and AR assays in all extracts after storage for approximately 1 year. Nrf2 activities did not decrease over time, but rather increased in some of the acidified sample extracts. Overall, the findings suggest that sampling strategies involving acidification may need to be tailored depending on the selected bioassay(s) and the type of wastewater treatments being assessed.
Subject(s)
Wastewater , Water Pollutants, Chemical , NF-E2-Related Factor 2 , Receptors, Estrogen/metabolism , Oxidative Stress , Hydrogen-Ion Concentration , Hormones , Water Pollutants, Chemical/analysis , Biological Assay/methodsABSTRACT
Molybdenum is an essential element in the form of the molybdenum cofactor (Moco). In humans, Moco is required for four enzymes: xanthine oxidase (XO), aldehyde oxidase, sulfite oxidase (SO), and mitochondrial amidoxime-reducing component (mARC). The enzymes are involved in the oxidation of purines to uric acid, metabolism of aromatic aldehydes and heterocyclic compounds, and in the catabolism of sulfur amino acids. Molybdenum cofactor deficiency is a rare autosomal recessive syndrome due to a defective synthesis of Moco, resulting in a deficiency of all the molybdoenzymes. There are no reports on clinical signs of dietary molybdenum deficiency in otherwise healthy humans. Water-soluble molybdate is efficiently absorbed from the digestive tract. The body retention is regulated by urinary excretion. Plasma molybdenum reflects long-term intake and 24-h urinary excretion is related to recent intake. There are no biochemical markers of molybdenum status. Cereal products are the main contributors to molybdenum dietary intake, estimated to 100-170 µg/day in Nordic studies. Little data are available on molybdenum toxicity in humans. A tolerable upper intake level of molybdenum has been based on reproductive toxicity in rats, but the effects have not been reproduced in more recent studies. The U.S. Institute of Medicine (IOM, present National Academy of Sciences, Engineering, and Medicine; NASEM) established a Recommended Dietary Allowance of 45 µg/day in adult men and women in 2001, based on a small study reporting urinary excretion in balance with intake at 22 µg/day. The European Food Safety Authority (EFSA) considered in 2013 the evidence to be insufficient to derive an Average Requirement and a Population Reference Intake, but proposed an Adequate Intake of 65 µg/day for adults.
ABSTRACT
Artificial infiltration is an established managed aquifer recharge method that is commonly incorporated into drinking water processes. However, groundwater sourced from this type of purification method is prone to contamination with chemical hazards. Such an instance was previously shown at a Swedish DWTP where the river water was contaminated by hazardous chemicals during artificial infiltration. Further, there remains a paucity of research studying the quality of drinking water following this type of treatment from an effect-based bioanalytical perspective. In the current study, an effect-based assessment for chemical hazards was conducted for a Swedish drinking water system comprised of two DWTPs fed artificially-infiltrated river water. In this system, artificial infiltration of the river water takes approximately six to eight months. A sampling event was conducted in the autumn season and the samples were enriched by solid phase extraction. A panel of cell-based reporter gene assays representing several toxicity pathways was selected: oxidative stress response (Nrf2 activity), aryl hydrocarbon receptor (AhR) activation, and hormone receptor-mediated effects (estrogen receptor [ER], androgen receptor [AR]). AhR and ER bioactivities were detected in samples collected from the river intake and in the open-air infiltration basins prior to artificial infiltration. However, the AhR activity decreased and ER activity was effectively removed following artificial infiltration. In the Nrf2 and AR assays, no bioactivities above cut-off levels were detected in any samples collected along the entire treatment process of the drinking water production from source to tap. Using a suite of bioassays, the current study highlighted the effectiveness of artificial infiltration in reducing bioactive compounds in this raw river water. Although artificial infiltration is a common purification method in drinking water production, the limited number of effect-based studies evaluating the effectiveness of this method emphasizes the need for further research to better understand the risks and benefits of this water treatment process.
Subject(s)
Drinking Water , Water Pollutants, Chemical , Water Purification , Environmental Monitoring , NF-E2-Related Factor 2 , Rivers/chemistry , Water Pollutants, Chemical/analysis , Water Purification/methodsABSTRACT
Liquid smoke products are widely used as a food additive to create a desired smoke flavour. These products may contain hazardous chemicals generated during the wood-burning process. However, the toxic effects of these types of hazardous chemicals constituting in the commercially available products are largely unknown. Therefore, a test battery of cell-based in vitro methods, covering different modes of actions of high relevance to human health, was applied to study liquid smoke products. Ten liquid smoke flavourings were tested as non-extracted and extracted. To assess the potential drivers of toxicity, we used two different solvents. The battery of in vitro methods covered estrogenicity, androgenicity, oxidative stress, aryl hydrocarbon receptor activity and genotoxicity. The non-extracted samples were tested at concentrations 0.002 to 1 µL liquid smoke flavouring/mL culture medium, while extracted samples were tested from 0.003 to 200 µL/mL. Genotoxicity was observed for nearly all non-extracted and all hexane-extracted samples, in which the former had higher potency. No genotoxicity was observed for ethyl acetate-extracted samples. Oxidative stress was activated by almost all extracted and non-extracted samples, while approximately half of the samples had aryl hydrocarbon receptor and estrogen receptor activities. This study used effect-based methods to evaluate the complex mixtures of liquid smoke flavourings. The increased bioactivities seen upon extractions indicate that non-polar chemicals are driving the genotoxicity, while polar substances are increasing oxidative stress and cytotoxic responses. The differences in responses indicate that non-extracted products contain chemicals that are able to antagonize toxic effects, and upon extraction, the protective substances are lost.
Subject(s)
Flavoring Agents/toxicity , Oxidative Stress/drug effects , Solvents/chemistry , Acetates/chemistry , Animals , Cell Line , Flavoring Agents/analysis , Hexanes/chemistry , Humans , Mutagenicity Tests , Receptors, Aryl Hydrocarbon/drug effects , Receptors, Estrogen/drug effects , SmokeABSTRACT
Food contact materials (FCMs) can contain hazardous chemicals that may have the potential to migrate into food and pose a health hazard for humans. Previous studies have mainly focused on plastic materials, while data on packaging materials made from paper and cardboard are limited. We used a panel of cell-based bioassays to investigate the presence and impact of bioactive chemicals on human relevant endpoints like oxidative stress, genotoxicity, inflammation, xenobiotic metabolism and endocrine system effects in extracts made from paper and cardboard. In total, 23 methanol extracts of commonly used paper and cardboard available on the Swedish market were extracted as a whole product using methanol to retrieve polar substances, and tested at concentrations 0.3-10 mg/mL and 0.2-6 mg/mL. At the highest concentration bioactivities were observed in a high proportion of the samples: oxidative stress (52%), genotoxicity (100%), xenobiotic metabolism (74%), antiandrogenic- (52%) and antioestrogenic receptor (39%). Packages of potential concern included cake/pastry boxes/mats, boxes for infant formula/skimmed milk, pizza boxes, pizza slice trays and bag of cookies. It should be noted that the extraction for packages like cake/pastry boxes can be considered exaggerated, as the exposure usually is shorter. It can be hypothesised that the observed responses may be explained by inks, coatings, contaminants and/or naturally occurring compounds within the material. To summarise, an effect-based approach enables hazard identification of chemicals within FCMs, which is a valuable tool for ensuring safe use of FCMs.
Subject(s)
Food Analysis , Food Contamination/analysis , Food Packaging , Hazardous Substances/analysis , Paper , HumansABSTRACT
[Table: see text] This guidance describes the scientific data required to allow an evaluation of the safety of new substances that are proposed for use as sources of nutrients in food supplements, foods for the general population or foods for specific groups and an assessment of the bioavailability of the nutrient from the proposed source. This guidance describes the scientific data required to allow an evaluation of the safety of the source within the established framework for risk assessment of food additives and novel food ingredients and the bioavailability of the nutrient from this source. This document is arranged in five main sections: one on technical data aimed at characterising the proposed source and at identifying potential hazards resulting from its manufacture and stability in food; one on existing authorisations and evaluation, providing an overview of previous assessments on the proposed source and their conclusions; one on proposed uses and exposure assessment section, allowing an estimate of the dietary exposure to the source and the nutrient based on the proposed uses and use levels; one on toxicological data, describing approaches which can be used to identify (in conjunction with data on manufacture and composition) and to characterise hazards of the source and any relevant breakdown products; the final section on bioavailability focuses on determining the extent to which the nutrient from the proposed source is available for use by the body in comparison with one or more forms of the same nutrient that are already permitted for use on the positive lists. This guidance was adopted by the Panel on Food Additives and Nutrient Sources added to Food (ANS Panel) on 16 May 2018. Upon request from EFSA, the present guidance has been revised to inform applicants of new provisions set out in Regulation (EC) No 178/2002, as amended by Regulation (EU) 2019/1381 on the transparency and sustainability of the EU risk assessment in the food chain.
ABSTRACT
Drinking water quality and treatment efficacy was investigated in seven drinking water treatment plants (DWTPs), using water from the river Göta Älv, which also is a recipient of treated sewage water. A panel of cell-based bioassays was used, including measurements of receptor activity of aryl hydrocarbon (AhR), estrogen (ER), androgen (AR), peroxisome proliferator-activated receptor alpha (PPARα) as well as induction of oxidative stress (Nrf2) and micronuclei formation. Grab water samples were concentrated by solid phase extraction (SPE) and water samples were analyzed at a relative enrichment factor of 50. High activities of AhR, ER and AR antagonism were present in WWTP outlets along the river. Inlet water from the river exhibited AhR and AR antagonistic activities. AhR activity was removed by DWTPs using granulated activated carbon (GAC) and artificial infiltration. AR antagonistic activity was removed by the treatment plants, except the artificial infiltration plant, which actually increased the activity. Furthermore, treated drinking water from the DWTP using artificial infiltration exhibited high Nrf2 activity, which was not found in any of the other water samples. Nrf2 activity was found in water from eight of the 13 abstraction wells, collecting water from the artificial infiltration. No genotoxic activity was detected at non-cytotoxic concentrations. No Nrf2 or AR antagonistic activities were detected in the inlet or outlet water after the DWTP had been replaced by a new plant, using membrane ultrafiltration and GAC. Neither target chemical analysis, nor chemical analysis according to the drinking water regulation, detected any presence of chemicals, which could be responsible of the prominent effects on oxidative stress and AR antagonistic activity in the drinking water samples. Thus, bioanalysis is a useful tool for detection of unknown hazards in drinking water and for assessment of drinking water treatments.
Subject(s)
Drinking Water , Water Pollutants, Chemical , Water Purification , Biological Assay , Drinking Water/analysis , Oxidative Stress , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/toxicity , Water QualityABSTRACT
Linking cellular toxicity to low-tier animal toxicity and beyond is crucial within the adverse outcome pathway concept and the 3R framework. This study aimed to determine and compare the bioavailable effect concentrations in zebrafish cell lines and embryos. Acute, short-term toxicity (48 h) of eight veterinary pharmaceuticals was measured in two zebrafish cell lines (hepatocytes, fibroblasts) and zebrafish embryos. Seven endpoints of cytotoxicity were recorded. The fish embryo acute toxicity test was modified by adding sublethal endpoints. Chemical distribution modeling (mass balance) was applied to compute the bioavailable compound concentrations in cells (Cfree) and embryos (Cint;aq) based on nominal effect concentrations (Cnom). Effect concentration ratios were calculated (cell effects/embryo effects). A low correlation was observed between cytotoxicity and embryo toxicity when nominal concentrations were used. Modeled bioavailable effect concentrations strongly increased correlations and placed regression lines close to the line of unity and axis origin. Cytotoxicity endpoints showed differences in sensitivity and predictability. The hepatocyte cell line depicted closer proximity to the embryo data. Conclusively, the high positive correlation between the cell- and embryo-based test systems emphasizes the appropriate modulation of toxicity when linked to bioavailable concentrations. Furthermore, it highlights the potential of fish cell lines to be utilized in integrated testing strategies.
Subject(s)
Veterinary Drugs , Water Pollutants, Chemical , Animals , Cell Line , Embryo, Nonmammalian , Water Pollutants, Chemical/toxicity , ZebrafishABSTRACT
The EFSA Panel on Food Additives and Flavourings was requested to evaluate 31 flavouring substances assigned to the Flavouring Group Evaluation 72 (FGE.72), using the Procedure as outlined in the Commission Regulation (EC) No 1565/2000. Twenty-three substances have already been considered in FGE.72 and FGE.72Rev1 ([FL-no: 02.011, 02.012, 02.027, 02.029, 02.058, 02.076, 02.109, 05.020, 05.021, 05.124, 05.148, 05.169, 08.036, 08.044, 08.047, 08.055, 08.064, 08.070, 08.079, 09.273, 09.408, 09.931 and 16.001]). The remaining eight flavouring substances have been cleared with respect to genotoxicity in FGE.200Rev1 ([FL-no: 05.114]) and FGE.201Rev2 ([FL-no: 02.174, 05.033, 05.090, 05.095, 05.105, 05.107 and 05.126]) and they are considered in this revision 2 of FGE.72. The substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that none of these 31 substances gives rise to safety concerns at their levels of dietary intake, estimated on the basis of the 'Maximised Survey-derived Daily Intake' (MSDI) approach. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been considered and found adequate for all 31 flavouring substances. For 21 substances, evaluated through the Procedure in the previous revision (FGE.72Rev1), no normal and maximum use levels are available. For four substances, the modified Theoretical Added Maximum Daily Intake (mTAMDI) intake estimates are equal to ([FL-no: 05.090]) or above ([FL-no: 05.107, 05.105, 05.033]) the TTC for their structural class. Therefore, for these 25 substances more detailed data on uses and use levels should be provided in order to refine their exposure assessments and to finalise their safety evaluations.
ABSTRACT
The EFSA Panel on Food Additives and Flavourings was requested to evaluate 49 flavouring substances assigned to the Flavouring Group Evaluation 91 (FGE.91), using the Procedure as outlined in the Commission Regulation (EC) No 1565/2000. Forty-four substances have been considered in FGE.91 and its revisions (FGE.91Rev1 and FEG.91Rev2). With regard to the remaining five flavouring substances considered in this revision 3 of FGE.91: two ([FL-no: 12.065 and 12.079]) have been cleared with respect to genotoxicity in FGE.201Rev2; two ([FL-no: 12.169 and 12.241]) were originally allocated to FGE.74Rev4 and one ([FL-no: 12.304]) to FGE.08Rev5. The Panel considered the flavouring substance [FL-no: 12.169] representative for the tertiary monothiols [FL-no: 12.038, 12.085, 12.137, 12.138, 12.145, 12.252, 12.259, 12.241 and 12.304]. The substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that none of these 49 substances gives rise to safety concerns at their levels of dietary intake, estimated on the basis of the 'Maximised Survey-derived Daily Intake' (MSDI) approach. The specifications for the materials of commerce have also been considered and found adequate for all 49 flavouring substances. For five substances [FL-no: 12.077, 12.162, 12.265, 12.267 and 17.036], evaluated through the Procedure in FGE.91Rev2, no normal and maximum use levels are available. For 10 substances [FL-no: 12.065, 12.038, 12.079, 12.108, 12.139, 12.264, 12.274, 12.252, 12.284 and 12.304], the modified Theoretical Added Maximum Daily Intake (mTAMDI) intake estimates are above the TTC for their structural class. Therefore, for these 15 substances, more detailed data on uses and use levels should be provided in order to refine their exposure assessments and to finalise their safety evaluations.
ABSTRACT
The EFSA Panel on Food Additives and Flavourings was requested to evaluate 12 flavouring substances attributed to the Flavouring Group Evaluation 61 (FGE.61), using the Procedure as outlined in the Commission Regulation (EC) No 1565/2000. Nine substances have already been considered in FGE.61 and FGE.61Rev1 [FL-no: 06.001, 06.004, 06.005, 06.008, 06.009, 06.015, 06.028, 06.037, 06.081]. The remaining three substances [FL-no: 06.025, 06.031 and 06.072] have been cleared with respect to genotoxicity in FGE.200Rev1 and are considered in this revision 2 of FGE.61. The substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that none of the 12 substances gives rise to safety concerns at their levels of dietary intake, estimated on the basis of the 'Maximised Survey-derived Daily Intake' (MSDI) approach. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been considered and found adequate. For nine flavouring substances [FL-no: 06.001, 06.004, 06.005, 06.008, 06.009, 06.015, 06.028, 06.037 and 06.081], use levels are still needed to calculate the modified Theoretical Added Maximum Daily Intake (mTAMDI) values in order to identify those flavouring substances that need more refined exposure assessment and to finalise the evaluation accordingly.
ABSTRACT
The EFSA Panel on Food Additives and Flavourings was requested to evaluate 39 flavouring substances assigned to the Flavouring Group Evaluation 71 (FGE.71), using the Procedure in Commission Regulation (EC) No 1565/2000. Nine substances have already been considered in FGE.71 [FL-no: 08.054, 08.073, 08.123, 09.037, 09.156, 09.157, 05.158, 09.235, 09.239]. The remaining 30 substances [FL-no: 02.020, 02.050, 02.090, 02.112, 02.137, 02.156, 02.210, 05.037, 05.060, 05.070, 05.073, 05.076, 05.078, 05.102, 05.109, 05.150, 05.171, 05.179, 09.276, 09.277, 09.303, 09.385, 09.394, 09.395, 09.396, 09.397, 09.398, 09.399, 09.678 and 09.841] have been cleared with respect to genotoxicity in FGE.200Rev1 and they are considered in this revision. The substances were evaluated through a stepwise approach that integrates information on the structure-activity relationships, intake from current uses, toxicological threshold of concern (TTC), and available data on metabolism and toxicity. The Panel concluded that none of the 39 substances gives rise to safety concerns at their levels of dietary intake, estimated on the basis of the 'Maximised Survey-derived Daily Intake' (MSDI) approach. Besides the safety assessment of the flavouring substances, the specifications for the materials of commerce have also been considered and found adequate, except for [FL-no: 08.073 and 09.235]. For these two substances, data on the composition of the stereoisomeric mixture should be requested. Normal and maximum use levels should be provided for nine flavouring substances [FL-no: 08.054, 08.073, 08.123, 09.037, 09.156, 09.157, 05.158, 09.235, 09.239]. For two flavouring substances [FL-no: 02.020 and 05.076], the 'modified Theoretical Added Maximum Daily Intake' (mTAMDI) estimates are above the TTC for their structural class I. Therefore, additional information on uses and use levels should be provided for these eleven substances in order to finalise their evaluation.
ABSTRACT
Ionic liquids are a diverse range of charged chemicals with low volatility and often liquids at ambient temperatures. This characteristic has in part lead to them being considered environmentally-friendly replacements for existing volatile solvents. However, methylimidazolium ionic liquids are slow to break down in the environment and a recent study at Newcastle detected 1 octyl 3 methylimidazolium (M8OI) - an 8 carbon variant methylimidazolium ionic liquid - in soils in close proximity to a landfill site. The current M8OI toxicity database in cultured mammalian cells, in experimental animal studies and in model indicators of environmental impact are reviewed. Selected analytical data from the Newcastle study suggest the soils in close proximity to the landfill site, an urban soil lacking overt contamination, had variable levels of M8OI. The potential for M8OI - or a structurally related ionic liquid - to trigger primary biliary cholangitis (PBC), an autoimmune liver disease thought to be triggered by an unknown agent(s) in the environment, is reviewed.
Subject(s)
Imidazoles/toxicity , Ionic Liquids/toxicity , Liver/drug effects , Animals , Cell Line , HumansABSTRACT
Sodium meta-arsenite (NaAsO2) has been suggested to play a role both in initiation/progression of prostate cancer and as a future antiprostate cancer drug. We have studied the effects of NaAsO2 on cell proliferation of prostate cancer and noncancer cells, breast cancer cells, and adrenocortical carcinoma cells in vitro. Further, we have investigated the effect of NaAsO2 on the androgen receptor. We report that NaAsO2 alters the cell proliferation of prostate cells, in a hormetic manner, by increasing cell proliferation at low concentrations and decreasing the cell proliferation at high concentrations. No activation of the androgen receptor was detected. We conclude that NaAsO2 is able to increase cell proliferation of prostate cells in vitro at low concentrations, while it decreases cell viability at high concentrations. This novel finding has to be further addressed if NaAsO2 should be developed into an antiprostate cancer drug.
ABSTRACT
Disinfection of drinking water using chlorine can lead to the formation of genotoxic by-products when chlorine reacts with natural organic matter (NOM). A vast number of such disinfection by-products (DBPs) have been identified, making it almost impossible to routinely monitor all DBPs with chemical analysis. In this study, a bioanalytical approach was used, measuring oxidative stress (Nrf2 activity), genotoxicity (micronucleus test), and aryl hydrocarbon receptor (AhR) activation to evaluate an innovative water treatment process, including suspended ion exchange, ozonation, in-line coagulation, ceramic microfiltration, and granular activated carbon. Chlorination was performed in laboratory scale after each step in the treatment process in order to investigate the effect of each treatment process to the formation of DBPs. Suspended ion exchange had a high capacity to remove dissolved organic carbon (DOC) and to decrease UV absorbance and Nrf2 activity in non-chlorinated water. High-dose chlorination (10â¯mg Cl2 L-1) of raw water caused a drastic induction of Nrf2 activity, which was decreased by 70% in water chlorinated after suspended ion exchange. Further reduction of Nrf2 activity following chlorination was achieved by ozonation and the concomitant treatment steps. The ozonation treatment resulted in decreased Nrf2 activity in spite of unchanged DOC levels. However, a strong correlation was found between UV absorbing compounds and Nrf2 activity, demonstrating that Nrf2 inducing DBPs were formed from pre-cursors of a specific NOM fraction, constituted of mainly aromatic compounds. Moreover, high-dose chlorination of raw water induced genotoxicity. In similarity to the DOC levels, UV absorbance and Nrf2 activity, the disinfection-induced genotoxicity was also reduced by each treatment step of the innovative water treatment technique. AhR activity was observed in the water produced by the conventional process and in the raw water, but the activity was clearly decreased by the ozonation step in the innovative water treatment process.
Subject(s)
Drinking Water , Water Pollutants, Chemical , Water Purification , DNA Damage , Disinfection , Oxidative StressABSTRACT
The Panel on Food Additives and Flavourings of the European Food Safety Authority was requested to evaluate the genotoxic potential of 12 flavouring substances from subgroup 4.1 of FGE.19 in the Flavouring Group Evaluation 217 (FGE.217). Based on experimental data, in previous versions of this FGE (FGE.217 and FGE217Rev1), for 6-methylcoumarin [FL-no: 13.012] and 5-ethyl-3-hydroxy-4-methylfuran-2(5H)-one [FL-no: 10.023] the concern for genotoxicity was ruled out. 6-Methylcoumarin was evaluated using the Procedure in FGE.80Rev1. For 5-ethyl-3-hydroxy-4-methylfuran-2(5H)-one [FL-no: 10.023] and the structurally related substance 3-hydroxy-4,5-dimethylfuran-2(5H)-one [FL-no: 10.030], no further EFSA considerations were needed because these substances were evaluated by JECFA before 2000. Also based on experimental data, in FGE217Rev1, the concern for genotoxicity could not be ruled out for furan-2(5H)-one [FL-no: 10.066] and 3,4-dimethyl-5-pentylidenefuran-2(5H)-one [FL-no: 10.042], which later substance represents the following flavourings: [FL-no: 10.034, 10.036, 10.043, 10.046, 10.054, 10.057, 10.060 and 10.170]. In the current revision of this FGE (FGE217Rev2), based on the results of additional genotoxicity studies, the FAF Panel concluded that [FL-no: 10.066] is genotoxic in vivo. Therefore, furan-2(5H)-one [FL-no: 10.066] cannot be evaluated according to the Procedure. For [FL-no: 10.042] in order to rule out a concern for clastogenicity at site of first contact, the FAF Panel requests results from an in vivo comet assay in duodenum. In addition, [FL-no: 10.042] has also been identified as an aneugenic substance in vitro. Until the concern for clastogenicity at site of first contact for [FL-no: 10.042] and the concern for aneugenicity can be ruled out, this substance and [FL-no: 10.034, 10.036, 10.043, 10.046, 10.054, 10.057, 10.060 and 10.170] cannot be evaluated through the Procedure.