Halogenated polycyclic aromatic hydrocarbons associated with drinking water disinfection

Introduction: Disinfection by-products (DBPs) have been identified in chlorinated water. This fact justifies the growing concern about the potential health effects of emerging unregulated DBPs, some of which appear to be more genotoxic than the regulated DBPs[1]. Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent contaminants detected in environmental samples such as river sediments and tap water. A few studies have already proven that water disinfection can lead to the formation of halogenated derivatives of PAHs, such as chlorinated and brominated PAHs[2] . The available toxicological studies have shown that these compounds possess, in general, greater mutagenicity than the corresponding parent PAHs. Our research group has also shown that exposure of HepG2 cells to a dose-range of 6-Cl-benzo[a]pyrene (6-ClBaP) and BaP resulted in cytotoxicity above 50 µM and that, at the equimolar doses of 100 and 125 µM, 6-ClBaP was able to induce a significantly higher level of DNA damage than BaP[3] . The present study had two main objectives: 1) identification of the major chlorinated and brominated derivatives of benzo[a]anthracene (BaA) and pyrene (Pyr) formed as disinfection by-products and 2) evaluation of their potential hazard to humans, through the characterization of their potential cytotoxic and genotoxic effects in a human cell line.The authors wish to thank Instituto Nacional de Saúde Dr. Ricardo Jorge, Lisboa for financial support by the grant BRJ-DSA/2012- Doenças Oncológica

Drinking water contaminants: toxicity of halogenated polycyclic aromatic hydrocarbons

Food may be contaminated with polycyclic aromatic hydrocarbons (PAHs) in the process of smoking or heating. These contaminants or their derivatives can also be present in drinking water when raw water contacts with discharges of untreated industrial/waste water effluents, forest fires or by solubilisation of organic material from contaminated soils. A few studies have shown that water disinfection can lead to halogenated derivatives of PAHs (HPAHs) as chlorinated and brominated derivatives, and there are evidences that these compounds may have greater mutagenicity than the parent PAHs. In this study the cytotoxic and genotoxic effects of chlorinated/brominated derivatives of pyrene (Pyr) and benzo[a]anthracene (BaA), 1-ClPyr, 1-BrPyr and 7-ClBaA, which can be formed as water disinfection by-products, were studied in HepG2 cells to assess their potential hazard to human health. The formation of 1-ClPyr, 1-BrPyr and 7-ClBaA under aqueous disinfection conditions in waters contaminated with Pyr and BaA, was confirmed with an optimized gas chromatography method. Cells exposed (24h) to several concentrations of BaA and 7-ClBaA (1 to 200μM) displayed a dose-related and significant increase of cytotoxicity (neutral red assay) with IC50 values of 3.37 and 12.63µM respectively. For Pyr, 1-ClPyr and 1-BrPyr (10 to 200μM), a lower but significant dose-related cytotoxicity was observed. At non-cytotoxic concentrations (10 and 15µM), 7-ClBaA was able to induce a significantly higher level of oxidative DNA damage in HepG2 cells than its parent compound, as assessed by the FPG-modified comet assay. Under these conditions neither Pyr nor its derivatives were genotoxic. In conclusion, the disinfection process may give rise to genotoxic HPAHs with potential impact on human health and it should be performed in raw waters with minimal content of total organic carbon. In real conditions, humans may be exposed to a mixture of these organic compounds and thus their combined toxic effects should be further evaluated

Formation of emerging disinfection byproducts in water and evaluation of potential genotoxic effects: the case of chlorinated polycyclic aromatic hydrocarbons

Work performed by Departamento de Genética, Instituto Nacional de Saúde Dr. Ricardo Jorge (INSA); Centro de Química Estrutural, Instituto Superior Técnico, Technical University of Lisbon; Departamento de Saúde Ambiental, INSADisinfection byproducts (DBPs) are formed when disinfectants used in water treatment plants (WTPs) react with natural (or anthropogenic) organic matter present in the source water. Many studies have addressed health risks posed by a life-time exposure to DBPs through chlorinated drinking water or through dermal or inhalation exposure routes. Experimental studies have revealed genotoxic and carcinogenic effects of some DBPs and epidemiological studies evidenced potential associations between chlorinated drinking water and bladder or colorectal cancer. In addition, a possible link between chlorinated drinking water and reproductive/developmental effects has been hypothesized. Many DBPs have been identified in treated water, which justifies the growing concern about the potential health effects of emerging unregulated DBPs, some of which appear to be more genotoxic, in some assays, than the regulated DBPs. Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent contaminants detected in environmental samples such as river sediments and tap water. Water chlorination can lead to the formation of chlorinated derivatives of PAHs (Cl-PAHs) and the few available toxicological studies have shown that Cl-PAHs possess greater mutagenicity than the corresponding parent PAHs. The present study had two main objectives: 1) identification of the major chlorinated derivatives of benzo[a]pyrene (BaP) and fluoranthene (Fluo) formed as chlorination by-products and 2) evaluation of their potential hazard to humans, through the characterization of their potential genotoxic effects in a human cell line. To synthesize chlorinated standards of PAHs, a newly two phase (water/n-hexane) method was developed for BaP and Fluo. 6-Cl-BaP was obtained as the major chlorination product of BaP, and 3-Cl-Fluo and 1,3-Cl2-Fluo of Fluo. The formation of these BaP and Fluo chlorinated derivatives was also observed under WTPs chlorination conditions after at 0.5 until 24 h of exposure. The effects of equimolar concentrations of 6-Cl-BaP vs. BaP and of 3-Cl-Fluo/1,3-Cl2-Fluo vs. Fluo on cell viability and DNA integrity were assessed by the neutral red uptake (NR) and the comet assay, respectively. Exposure of HepG2 cells to a dose-range of 6-Cl-BaP and BaP showed that both compounds are cytotoxic above 50 µM and that, at the equimolar doses of 100 and 125 µM, 6-Cl-BaP is able to induce a significantly higher level of DNA damage than BaP. On the other hand, no changes of cell viability were observed after exposure to several concentrations of Fluo and its derivatives. Likewise, none of the compounds was able to significantly induce DNA damage. In conclusion, the present data confirmed that chlorinated derivatives of BaP and Fluo are formed during WTPs chlorination procedures and allowed the identification of their major chlorinated derivatives that should be further analysed in drinking water. On the other hand, the results from the comet assay evidenced a higher DNA damaging effect of Cl-BaP comparatively to its parent compound, suggestive of a more potent genotoxic effect. In spite of the negative results found for Fluo and its chorinated products, further genotoxicity studies are still needed to allow a definite conclusion. Although health risks of DBPs are small compared to health risks of waterborne diseases, the identification of hazardous Cl-PAHs in water emphasizes the need of development of new and safer water disinfection methods

Polymorphism in CYP17, GSTM1 and the progesterone receptor genes and its relationship with mammographic density

Radiologic breast density is one of the predictive factors for breast cancer and the extent of the density is directly related to postmenopause. However, some patients have dense breasts even during postmenopause. This condition may be explained by the genes that codify for the proteins involved in the biosynthesis, as well as the activity and metabolism of steroid hormones. They are polymorphic, which could explain the variations of individual hormones and, consequently, breast density. The constant need to find markers that may assist in the primary prevention of breast cancer as well as in selecting high risk patients motived this study. We determined the influence of genetic polymorphism of CYP17 (cytochrome P450c17, the gene involved in steroid hormone biosynthesis), GSTM1 (glutathione S-transferase M1, an enzyme involved in estrogen metabolism) and PROGINS (progesterone receptor), for association with high breast density. One hundred and twenty-three postmenopausal patients who were not on hormone therapy and had no clinical or mammographic breast alterations were included in the present study. The results of this study reveal that there was no association between dense breasts and CYP17 or GSTM1. There was a trend, which was not statistically significant (P = 0.084), towards the association between PROGINS polymorphism and dense breasts. However, multivariate logistic regression showed that wild-type PROGINS and mutated CYP17, taken together, resulted in a 4.87 times higher chance of having dense breasts (P = 0.030). In conclusion, in the present study, we were able to identify an association among polymorphisms, involved in estradiol biosyntheses as well as progesterone response, and radiological mammary density.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Disciplina de MastologiaUNIFESP, EPM, Disciplina de MastologiaSciEL

Formation of emerging disinfection byproducts in water and evaluation of potential genotoxic effects: the case of halogenated polycyclic aromatic hydrocarbons

Disinfection byproducts (DBPs) are formed when disinfectants used in water treatment plants (WTPs) react with natural (or anthropogenic) organic matter present in the source water. Many studies have addressed health risks posed by a life-time exposure to DBPs through chlorinated drinking water or through dermal or inhalation exposure routes. Experimental studies have revealed genotoxic and carcinogenic effects of some DBPs and epidemiological studies evidenced potential associations between chlorinated drinking water and bladder or colorectal cancer. In addition, a possible link between chlorinated drinking water and reproductive/developmental effects has been hypothesized. Many DBPs have been identified in chlorinated water, which justifies the growing concern about the potential health effects of emerging unregulated DBPs, some of which appear to be more genotoxic, in some assays, than the regulated DBPs. Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent contaminants detected in environmental samples such as river sediments and tap water. A few studies have already proven that water disinfection can lead to the formation of halogenated derivatives of PAHs, such as chlorinated (Cl-PAHs) and brominated PAHs (Br-PAHs). The available toxicological studies have shown that these compounds possess, in general, greater mutagenicity than the corresponding parent PAHs. Our investigation group have also showed that exposure of HepG2 cells to a dose-range of 6-Cl-benzo[a]pyrene (6-Cl-BaP) and BaP resulted in cytotoxicity above 50 µM and that, at the equimolar doses of 100 and 125 µM, 6-Cl-BaP was able to induce a significantly higher level of DNA damage than BaP. The present study had two main objectives: 1) identification of the major chlorinated and brominated derivatives of benzo[a]anthracene (BaA) and pyrene (Pyr) formed as disinfection by-products and 2) evaluation of their potential hazard to humans, through the characterization of their potential cytotoxic and genotoxic effects in a human cell line. To synthesize Cl-PAHs and Br-PAHs the method of Mitchell was developed for BaA and Pyr. 1-Cl-Pyr and 1-Br-Pyr were obtained as the major chlorinated and brominated derivatives of Pyr, and 7-Cl-BaA and 7-Br-BaA as the reaction products of BaA. Cell viability and DNA integrity of those derivatives were assessed by the neutral red uptake (NR) and the comet assay, respectively, allowing the comparison of their genotoxic potential. Although health risks of DBPs are small compared to the health risks of waterborne diseases, the formation of hazardous halogenated-PAHs in chlorinated water water emphasizes the need of development of new and safer water disinfection methods.INS

The INTERFRUTA II project and the study of phytossanitary problems that affect Azorean fruit orchards and vineyards

The INTERFRUTA project is financed by the European Commission Interreg III-B Programme and was developed for the islands of “Madeira”, “Tenerife” and “Terceira”, for the improvement of fruit and vineyard production in these three Atlantic regions. The project goal is a better knowledge of the phytossanitary problems that affect apples, bananas, chestnut and vineyards, applying methods that will contribute to solutions based on the survey of key pests, diseases and beneficial organisms. In the three fruit crops and vineyards analyzed, the methodology used was mainly direct observation of predefined parts of each plant (such as leaves and flowers) on which pests might be expected to occur. The key pest C. capitata was monitored as adults using sexual lures in a net of traps around the island of “Terceira” up to 200 meters altitude. The beneficial insect survey was conducted using the beating technique. For diseases, a direct sampling was carried out by the observation of 10 % of the plants in each orchard or vineyard plot looking for visible symptoms. In apples and vineyards, flowers and branches were collected and tested for microorganisms using serologic and molecular techniques (Elisa and PCR). In banana plantations, the most damaging pests were banana weevil, thrips and a fungi complex that causes symptoms similar to Fusarium wilt. In chestnut, the pest that causes the most severe damage, affecting around 40 % of the nuts produced, is the Chestnut tortrix, but there were some difficulties in identifying which of the three known species was present in the Azores islands. In vineyards, diseases that are most frequent and important include grapevine downy mildew, powdery mildew and Botrytis. Invertebrate pests included grape leafhoppers, thrips and eriophyid mites. The European vine moth was also surveyed but none were found and is still not present. In apple orchards the most important problems were thrips, mites, oriental fruit moth and codling moth. Anarsia lineatella Zeller, the peach twig borer, was not detected and new Eriophyid species have been recorded for the first time in the Azores as a result of the surveys. With the information collected it was possible to create a phytossanitary diagnostic database for the Macaronesian islands (PROFITOMAC) on the project internet pages (www.interfruta.uac.pt), to help users to identify problems that affect the studied cultures

Alfvén wave heating and runaway discharges in the TCABR tokamak

Recent results of experiments on Alfvén wave heating and runaway discharges carried out in the TCABR tokamak are presented. A new antenna type has been installed to allow wave excitation with higher RF currents and lower dynamic polarization of the antenna straps than for the one previously used. In spite of edge plasma heating, which causes influx of impurities, we have obtained a clear confirmation of wave deposition inside the plasma from a localized increase of the electron temperature measured with the ECE radiometer. Detailed profiles of the plasma density and Ha emission were obtained in runaway disharges with currents around 100 kA. These profiles confirm our model of a low-temperature plasma maintained in equilibrium by the relativistic electron beam. Analysis of the Ha and density spikes indicate that recombination plays a substantial role in the particle and energy balance