Chlorination of drinking water and cancer mortality in Taiwan

Economic, ecological, and health aspects of β-diketonate application in the process of water purification

Water pollution is a constant challenge for humanity. Sustainable economic development and environmental protection through a green economy structure provide the opportunity to project a model of scientific, social, and economic flows. Considering new chemical use in water treatment, we tested two β-diketonates that we previously synthesized in the reaction between methyl ketone and diethyl oxalate under basic conditions. For water treatment, we used the appropriate salts of the mentioned compounds due to better solubility in water. In cooperation with the partner organizations PUC (public utility companies) Kragujevac, LTD (Private Limited Company), "Rudnik," and FIAT (Fabbrica Italiana Automobili Torino), we conducted research on their wastewater treatment. The results appeared to be more convincing in practice than the conventional methods. As a result of the study, no negative effects exerted on living organisms were found. Therefore, we are on the right track for potential application in the treatment of drinking water. Appropriate β-diketonates were tested on twelve microorganisms (isolates from the wastewater and standard strains of bacteria and yeast). One of the two tested compounds showed promising antimicrobial activity. Further investigations showed that the tested compounds significantly reduce the concentration of heavy metals, which was confirmed by statistical calculations. Also, the main advantage of this method is a small volume of waste requiring disposal, no need for driving off excess moisture, used recyclability of the coagulants, reducing hazardous waste, and therefore reducing the costs for water treatment.

Occurrence and Health Risks of Organic Micro-Pollutants and Metals in Groundwater of Chinese Rural Areas

BACKGROUND

Groundwater is a main drinking-water source for Chinese rural residents. The overall pollution status of organic micropollutants (OMPs) and metals in the groundwater and corresponding health risks are unknown.

OBJECTIVES

Our objective was to comprehensively screen for and assess the health risks of OMPs and metals in groundwater of rural areas in China where groundwater is used for drinking so as to provide a benchmark for monitoring and improving groundwater quality in future developments.

METHODS

One hundred sixty-six groundwater samples were collected in the rural areas of China, and 1,300 OMPs and 25 metals were screened by GC-MS, LC-QTOF/MS, and ICP-MS analysis. To assess the noncarcinogenic and carcinogenic risks of the detected pollutants, missing toxicity threshold values were extrapolated from existing databases or predicted by quantitative structure-activity relationship (QSAR) models. Monte Carlo simulation was performed to account for uncertainties in the exposure parameters and toxicity thresholds.

RESULTS

Two hundred thirty-three OMPs and 25 metals were detected from the 166 samples. The concentration summation for the detected OMPs ranged from 2.9 to 1.7×105ng/L among the different sampling sites. Cumulative noncarcinogenic risks for the OMPs were estimated to be negligible. However, high metal risks were calculated in 23% of the sites. Forty-two carcinogens (including 38 OMPs) were identified and the cumulative carcinogenic risks in 34% of the sites were calculated to be >10-4 (i.e., one excess cancer case in a population of 10 thousand people). The carcinogenic risks were estimated to be mainly associated with exposures to the metals, which were calculated to contribute 79% (0-100%) of the cumulative carcinogenic risks.

DISCUSSION

The overall status of OMPs and metals pollution in the groundwater and the corresponding health risks were determined preliminarily, which may provide a benchmark for future efforts in China to ensure the safety of drinking water for the local residents in rural areas. The joint application of QSARs and Monte Carlo simulation provided a feasible way to comprehensively assess the health risks of the large and ever-increasing number of pollutants detected in the aquatic environment. https://doi.org/10.1289/EHP6483.

Formation of trihalomethanes as disinfection byproducts in herbal spa pools

Herbal spa treatments are favorite recreational activities throughout the world. The water in spas is often disinfected to control pathogenic microorganisms and guarantee hygiene. However, chlorinated water may cause the formation of disinfection byproducts (DBPs). Although there have been many studies on DBP formation in swimming pools, the role of organic matter derived from herbal medicines applied in herbal spa water has been largely neglected. Accordingly, the present study investigated the effect of herbal medicines on the formation of trihalomethanes (THMs) in simulated herbal spa water. Water samples were collected from a spa pool, and then, disinfection and herbal addition experiments were performed in a laboratory. The results showed that the organic molecules introduced by the herbal medicines are significant precursors to the formation of THMs in spa pool water. Since at least 50% of THMs were produced within the first six hours of the reaction time, the presence of herbal medicines in spa water could present a parallel route for THM exposure. Therefore, despite the undeniable benefits of herbal spas, the effect of applied herbs on DBP formation in chlorinated water should be considered to improve the water quality and health benefits of spa facilities.

Impacts of Typhoon Soudelor (2015) on the water quality of Taipei, Taiwan

Typhoon Soudelor was one of the strongest storms in the world in 2015. The category 5 hurricane made landfall in Taiwan on August 8, causing extensive damage and severe impacts on the environment. This paper describes the changes of trihalomethane (THM) concentrations in tap and drinking fountain water in selected typhoon-affected areas in Taipei before and after the typhoon. Samples were taken from water transmission mains at various distances from the local water treatment plant. The results showed that organic matter increased between pre- and post-typhoon periods with a greater proportion of aromatic compounds. Although drinking fountains showed moderately less total trihalomethane (TTHM) levels than that of tap water, the intake of high turbidity water considerably diminished the efficiency of their purification systems after the typhoon. The percentage distribution of THM species increased throughout the distribution network, probably due to a longer contact time between chlorine and the organic matter in the pipelines. After 2 to 5 min of boiling, THM reduction was considerable in all cases with the greater extent in post-typhoon samples. It is evident that extreme weather conditions may have a severe impact on water quality, and thus more cautious strategies should be adopted in such cases.

Multipathways human health risk assessment of trihalomethane exposure through drinking water

Life-time human health risk of cancer attributed to trihalomethanes in drinking water in an urban-industrialized area of Karachi (Pakistan) was conducted through multiple pathways of exposure. The extent of cancer risk was compared with USEPA guidelines. Human health cancer risk for total trihalomethanes (TTHMs) through ingestion and dermal routes were estimated in "acceptable-low risk" (≥1.0E-06; ≤5.10E-05), whereas through inhalation route it was estimated under "acceptable-high risk" (≥5.10E-05; ≤1.0E-04) category. However, at some industrial-urban areas cancer risk for CHCl3 were estimated under "unacceptable risk" (≥1.0E-04) through inhalation route.

[Epidemiology of disease conditions in Italy. Has anything changed? Environment, professional exposure, and lifestyle. Is time for screening?]

Risk factors analysis in bladder cancer should consider not only the clinical and pathological features of the tumor but also environmental and lifestyle factors. They may play, in fact, a relevant role not only in the pathogenesis but also in the biological behavior of the tumor. The association between cigarette smoking and bladder cancer has been consistently confirmed in several case-control and cohort studies. The risk of bladder cancer seems to increase with duration and intensity of smoking. Another environmental risk factor, although not definitively proved, is water supply. Chlorination or water pollution by pesticides and other chemical factors is considered a relevant risk factor. Familiarity and genetic predisposition, diet and individual risk factors should be taken into account.

Trihalomethanes in drinking water and the risk of death from esophageal cancer: does hardness in drinking water matter?

The objectives of this study were to (1) examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of esophageal cancer occurrence and (2) determine whether calcium (Ca) and magnesium (Mg) levels in drinking water modify the effects of TTHM on risk to develop esophageal cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to esophageal cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All esophageal cancer deaths in the 53 municipalities from 2006 through 2010 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level <4.9 ppb, the adjusted odds ratio (OR) with 95% confidence interval (CI) for esophageal cancer was 1.02 (0.84-1.23) for individuals who resided in municipalities served by drinking water with a TTHM exposure ≥4.9 ppb. There was evidence of an interaction between drinking-water TTHM levels and low Ca and Mg intake. Our findings showed that the correlation between TTHM exposure and risk of esophageal cancer development was influenced by Ca and Mg levels in drinking water. This is the first study to report effect modification by Ca and Mg intake from drinking water on the correlation between TTHM exposure and risk of esophageal cancer occurrence. Increased knowledge of the interaction between Ca, Mg, and TTHM in reducing risk of esophageal cancer development will aid in public policymaking and standard setting for drinking water.

Trihalomethanes in drinking water and the risk of death from kidney cancer: does hardness in drinking water matter?

The objectives of this study were to (1) examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of development of kidney cancer and (2) determine whether hardness levels in drinking water modify the effects of TTHM on risk of kidney cancer induction. A matched case-control study was used to investigate the relationship between the risk of death attributed to kidney cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All kidney cancer deaths in the 53 municipalities from 1998 through 2007 were obtained. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels and levels of hardness in drinking water were also collected. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM and hardness exposure via drinking water. Relative to individuals whose TTHM exposure level was <4.9 ppb, the adjusted OR (95% CI) for kidney cancer was 0.98 (0.77-1.25) for individuals who resided in municipalities served by drinking water with a TTHM exposure ≥4.9 ppb. However, evidence of an interaction was noted between the use of soft water and drinking water TTHM concentrations. Increased knowledge of the interaction between hardness and TTHM levels in reducing risk of kidney cancer development will aid in public policy decision and establishing standards to prevent disease occurrence.

Multi-route risk assessment from trihalomethanes in drinking water supplies

The main objectives of this study were to investigate the concentration and lifetime cancer risk and hazard index of trihalomethanes (THMs) through multiple routes like oral ingestion, dermal absorption, and inhalation exposure in the water samples collected at water treatment plant endpoints. Bromoform has been found in highest concentration followed by chloroform. A lesser concentration of dibromochloromethane has been found than dichlorobromomethane in most of the studied water, which is an unusual scenario, in spite of the high concentration of bromide in the water which can be attributed to the formation, speciation, and distribution of THMs in the breakpoint chlorination curve. Among the three pathways studied, inhalation contributed 80-90% of the total risk followed by oral exposure and dermal contact. Chloroform was found to be the major THM which is having cancer risk in its gaseous form whereas bromoform contributed highest cancer risk through oral ingestion. The average hazard index of total THMs through oral route was higher than unity, indicating high noncarcinogenic risk. The discrepancy between the three exposure pathways may be attributed to different concentration and speciation of THMs present in the waters. The sensitivity analysis by tornado diagram confirmed the highest positive impact of chloroform to the total cancer risk and, indirectly, confirmed inhalation as the major pathway of exposure. This study suggests the modification of the regulatory issues related to THMs based on the health risk associated with each THM and exposure pathway.

Magnesium in drinking water modifies the association between trihalomethanes and the risk of death from colon cancer

The objectives of this study were to (1) examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and death attributed to colon cancer and (2) determine whether magnesium (Mg) levels in drinking water modify the effects of TTHM on risk of colon cancer development. A matched case-control study was used to investigate the relationship between the risk of death attributed to colon cancer and exposure to total trihalomethanes (TTHM) in drinking water in 53 municipalities in Taiwan. All colon cancer deaths of the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM and Mg exposure via drinking water. Relative to individuals whose TTHM exposure levels were <4.9 ppb, the adjusted odds ration (OR) (with 95% confidence interval [CI]) for colon cancer was 1.14 (1.01-1.28) for individuals who had resided in municipalities served by drinking water with a TTHM exposure≥4.9 ppb. Evidence of an interaction between drinking-water TTHM and Mg intake via drinking water was noted. This is the first study to report an effect modification by Mg intake from drinking water in association between TTHM exposure and risk of colon cancer occurrence. Better knowledge of this modifying factor will help in public policymaking and setting health standards.

Sensitivity of morphological change of Vero cells exposed to lipophilic compounds and its mechanism

To find a sensitive cytotoxic response to reflect the toxicity of trace organic pollutants, the sensitivity and reliability of morphological change and proliferation inhibition of Vero cells exposed to lipophilic compounds and the leachate from products related to drinking water (PRDW) were compared, and the mechanism of the morphological change in Vero cells was studied. Results showed the proportion of morphologically changed cells increased with increasing 2,4,6-trichlorophenol (TCP)/perfluorooctane sulfonate (PFOS) concentration. However, at low TCP concentrations, inhibition of cell proliferation did not correlate to TCP concentration. After exposure to the leachate from PRDW extracted at different temperatures, the percentage of morphologically changed cells increased with extracting temperature, but the inhibition of cell proliferation failed to reflect the correlation to extracting temperature. These imply cell morphological change is a more sensitive and reliable method to reflect toxicity of trace organic pollutants than proliferation inhibition. Flow cytometry analysis indicated cell membrane damage was an early and sensitive cytotoxic response comparing with necrosis, resulting in cell morphological change, which may be due to the interference of lipophilic compounds. Lipophilic compound accumulated in cell membrane to interfere the assembly process of membrane protein and phospholipid.

Effect modification of the association between trihalomethanes and pancreatic cancer by drinking water hardness: evidence from an ecological study

The objective of this study was to examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of pancreatic cancer and to determine whether calcium (Ca) and magnesium (Mg) levels in drinking water modify the effects of TTHM on risk to develop pancreatic cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to pancreatic cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All pancreatic cancer deaths in the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level < 4.9ppb, the adjusted OR (95% CI) for pancreatic cancer was 1.01 (0.85-1.21) for individuals who resided in municipalities served by drinking water with a TTHM exposure > 4.9ppb. There was no evidence of an interaction of drinking water TTHM levels with low Ca intake via drinking water. However, we observed evidence of an interaction between drinking water TTHM concentrations and Mg intake via drinking water. Our findings showed that the correlation between TTHM exposure and risk of pancreatic cancer is influenced by Mg in drinking water. Increased knowledge of the interaction between Mg and TTHM in reducing pancreatic cancer risk will aid in public policy making and standard setting.

Sensitivity of different cytotoxic responses of Vero cells exposed to organic chemical pollutants and their reliability in the bio-toxicity test of trace chemical pollutants

OBJECTIVE

To find a sensitive cytotoxic response to reflect the bio-toxicity of trace organic pollutants, the sensitivity and reliability of morphological change and proliferation inhibition of Vero cells exposed to 2, 4, 6-trichlorophenol (TCP) and the leachate from products related to drinking water (PRDW) were compared, and the mechanism of the morphological change in Vero cells exposed to chemical pollutants was studied.

METHODS

Vero cells were treated by different concentration of TCP and the leachate from PRDW. Methylthiazol-2-yl-2, 5-diphenyl tetrazolium bromide (MTT) assay was carried out for proliferation inhibition. Bioluminescence method was carried out as another method to test the toxicity of TCP. Flow Cytometry assay was used to test cell Apoptosis and damage of cell-membrane.

RESULTS

0.25 mg/L TCP had an effect on cell morphology, and the proportion of morphologically changed cells increased with increasing TCP concentration. At low TCP concentrations, inhibition of cell proliferation did not seem to correlate to TCP concentration, and was negative when TCP concentration was <1.0 mg/L. After exposure to leachate from PRDW extracted at different temperatures, the percentage of morphologically changed cells increased with extracting temperature, but the inhibition of cell proliferation failed to reflect the correlation between extracting temperature and proliferation inhibition of Vero cells. Although the Sensitivity of bioluminescence method seems to be similar to morphological change in Vero cells, the bacterial in this method is not homologous enough with human body cells to reflect the toxicity to human body. These imply cell morphological change is a more sensitive and reliable method to reflect bio-toxicity of organic pollutants than proliferation inhibition. Flow cytometry analysis and cell rejuvenation experiments indicated cell membrane damage, which results in cell morphological change, was an early and sensitive cytotoxic response comparing with necrosis.

CONCLUSION

These results indicated that the cell membrane toxicity represented by morphological changes is a more sensitive and reliable method to indicate the composite bio-toxicity of trace chemicals than proliferation inhibition, inhibition on bioluminescence and necrosis. Nevertheless, the quantification of morphological change should be studied further.

Trihalomethanes in drinking water and the risk of death from rectal cancer: does hardness in drinking water matter?

The objectives of this study were (1) to examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and risk of rectal cancer development and (2) to determine whether calcium (Ca) and magnesium (Mg) levels in drinking water might modify the effects of TTHM on risk of developing rectal cancer. A matched cancer case-control study was used to investigate the relationship between the risk of death attributed to rectal cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All rectal cancer deaths in the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from the Taiwan Environmental Protection Administration. Information on the levels of Ca and Mg in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM, Ca, and Mg exposure via drinking water. Relative to individuals whose TTHM exposure level was <4.9 ppb, the adjusted OR (95% CI) for rectal cancer occurrence was 1.04 (0.88-1.22) for individuals who resided in municipalities served by drinking water with a TTHM exposure >or=4.9 ppb. There was no evidence of an interaction of drinking-water TTHM levels with low Ca intake via drinking water. However, evidence of an interaction was noted between drinking-water TTHM concentrations and Mg intake via drinking water. Our findings showed that the correlation between TTHM exposure and risk of rectal cancer is influenced by Mg in drinking water. Increased knowledge of the interaction between Mg and TTHM in reducing rectal cancer risk will aid in public policymaking and standard setting.

Does calcium in drinking water modify the association between trihalomethanes and the risk of death from colon cancer?

The objectives of this study were (1) to examine the relationship between total trihalomethanes (TTHM) levels in public water supplies and mortality attributed to colon cancer and (2) to determine whether calcium levels (Ca) in drinking water modify the effects of TTHM on risk to develop colon cancer. A matched cancer case-control study was used to investigate the relationship between the risk of death attributed to colon cancer and exposure to TTHM in drinking water in 53 municipalities in Taiwan. All colon cancer deaths in the 53 municipalities from 1998 through 2007 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water were collected from the Taiwan Environmental Protection Administration. Information on the levels of Ca in drinking water was obtained from the Taiwan Water Supply Corporation. The municipality of residence for cancer cases and controls was presumed to be the source of the subject's TTHM and Ca exposure via drinking water. Relative to individuals whose TTHM exposure level was <4.9 ppb, the adjusted OR (95% CI) for colon cancer was 1.14 (1.01-1.28) for individuals who resided in municipalities served by drinking water with a TTHM exposure > or =4.9 ppb. Data demonstrated evidence of an interaction between drinking-water TTHM concentrations and Ca intake via drinking water. Our findings showed that the correlation between TTHM exposure and risk of colon cancer development is influenced by Ca in drinking water. Increased knowledge of the interaction between Ca and TTHM in reducing colon cancer risk will aid in public policymaking and standard setting.

Lifestyle Factors, Exposures, Genetic Susceptibility, and Renal Cell Cancer Risk: A Review

Malignant kidney tumors account for approximately 2% of all new primary cancer cases diagnosed in the United States, with an estimated 30,000 cases occurring annually. Although a variety of agents, chemical and biological, have been implicated as causal agents in the development of renal cell carcinoma (RCC), the etiology remains enigmatic. The strongest association has been developed between cigarette smoking and renal cancer however consistent, positive associations between RCC and obesity, diabetes, and hypertension have also been reported. In addition, more recent investigations of familial kidney cancer syndromes indicate that a strong genetic component contributes to RCC development. Several genes have been identified through investigation of familial kidney cancer syndromes. This review article describes recent trends in RCC incidence and the currently identifiable etiological causes that account for approximately half of the RCC cases diagnoses. The remainder of this review then focuses on additional risk factors that have thus far not been well examined but may be helpful in explaining the increasing incidence trends and the geographic or racial variation observed nationally and worldwide.

Association of bladder cancer with residential exposure to petrochemical air pollutant emissions in Taiwan

To investigate the relationship between petrochemical air pollution and risk of death due to bladder cancer, studies were conducted using a matched cancer case-control model based upon deaths that occurred in Taiwan from 1995 through 2005. Data on all eligible bladder cancer deaths were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. The control group consisted of individuals who died from causes other than neoplasms or diseases associated with genitourinary problems. The controls were pair matched to the cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each case. The proportion of a municipality's total population employed in the petrochemical industry in a municipality was used as an indicator of a resident's exposure to air emissions from the petrochemical industry. The subjects were divided into three levels (< or =25th percentile; 25th-50th percentile; >50th percentile). Subjects who lived in the group of municipalities characterized by the high levels of petrochemical air pollution had a significantly higher risk of death attributed to bladder cancer than subjects in the group that lived in municipalities with the lowest petrochemical air pollution levels, after controlling for possible confounders. The findings of this study warrant further investigation of the role of petrochemical air pollution in the etiology of bladder cancer.

Trihalomethanes in drinking water and the risk of death from colon cancer in Taiwan

The objective of this study was to evaluate whether exposure to disinfection by-products (DBP) is associated with colon cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to colon cancer and exposure to total trihalomethanes (TTHM) in drinking water in 65 municipalities in Taiwan. All colon cancer deaths of the 65 municipalities from 1997 through 2006 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water in study municipalities were collected from the Taiwan Environmental Protection Administration. The municipality of residence for cancer cases and controls was assumed to be the source of the subject's TTHM exposure via drinking water. The adjusted odds ratios (OR) for colon cancer death for those with high TTHM levels in their drinking water were 1.02 (0.87-1.2) and 1.04 (0.89-1.21) compared to the lowest group. The results of the present study show that there was no statistically significant association between TTHM in drinking water at levels in this study and risk of death from colon cancer.

Preparation and antibacterial characteristic of water-insoluble antibacterial material QPEI/SiO2

Polyethyleneimine (PEI) was grafted onto micron-sized silica gel particles via the coupling action of gamma-chloropropyl trimethoxy silane, and grafting particles PEI/SiO(2) was prepared. Then, polymeric reactions of two steps, tertiary amination reaction and quaterisation, were conducted for the grafted PEI. After quaterisation of the grafted polyethyleneimine, a composite particle, QPEI/SiO(2), was obtained. QPEI/SiO(2) is a water-insoluble antibacterial material. In this work, the antibacterial characteristic of QPEI/SiO(2) was mainly investigated using Escherichia coli (E. coli) as a disease-leading bacterium and adopting a colony count method. The effects of quaterisation degree of PEI and pH of the medium on the antibacterial ability of QPEI/SiO(2) were examined. The antibacterial mechanism of QPEI/SiO(2) was explored profoundly by using two enzyme activity determination methods, beta-D-galactosidase activity determination and TTC-dehydrogenase activity determination. The experimental results indicates that the water-insoluble antibacterial material QPEI/SiO(2) possesses strong antibacterial ability, for the bacterial suspension with a concentration of 10(9) CFU/ml, the antibacterial ratio of QPEI/SiO(2) can reach about 100% only with a dosage of 15 g/l and only for a contact time of 10 min. The main factors influencing the antibacterial ratio of QPEI/SiO(2) are the quaterisation degree of the grafted PEI and pH value of the medium. QPEI/SiO(2) with higher quaterisation degree has stronger antibacterial ability. In a certain range of pH value, the higher the pH value of the medium is, the stronger the antibacterial ability of QPEI/SiO(2 )is. Enzyme activity determination results show that the antibacterial mechanism of the water-insoluble antibacterial material QPEI/SiO(2) is based on a sterilization process and not only is a bacteriostasis action.

Bladder cancer in Taiwan: relationship to trihalomethane concentrations present in drinking-water supplies

The objective of this study was to evaluate whether exposure to disinfection by-products (DBP) is associated with bladder cancer. A matched case-control study was used to investigate the relationship between the risk of death from bladder cancer and exposure to total trihalomethanes (TTHM) in drinking water in 65 municipalities in Taiwan. All bladder cancer deaths of the 65 municipalities from 1996 through 2005 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the cases by gender, year of birth,and year of death. Each matched control was selected randomly from the set of possible controls for each cancer case. Data on TTHM levels in drinking water in study municipalities were collected from the Taiwan Environmental Protection Administration. The municipality of residence for cancer cases and controls was assumed to be the source of the subject's TTHM exposure via drinking water. The adjusted odds ratios for bladder cancer death for those with high TTHM concentrations in their drinking water were 1.8 (1.18-2.74) and 2.11 (1.43-3.11) compared to the lowest group. The results of this study show that there was a significant positive correlation between the concentration of TTHM in drinking water and risk of death from bladder cancer.

Disposition of Bromodichloromethane in Humans Following Oral and Dermal Exposure

Exposure to bromodichloromethane (BDCM), one of the most prevalent disinfection byproducts in drinking water, can occur via ingestion of water and by dermal absorption and inhalation during activities such as bathing and showering. The objectives of this research were to assess BDCM pharmacokinetics in human volunteers exposed percutaneously and orally to (13)C-BDCM and to evaluate factors that could affect disposition of BDCM. Among study subjects, CYP2E1 activity varied fourfold; 20% had the glutathione S-transferase theta 1-1 homozygous null genotype; and body fat ranged from 7 to 22%. Subjects were exposed to (13)C-BDCM in water (target concentration of 36 mug/l) via ingestion and by forearm submersion. Blood was collected for up to 24 h and analyzed for (13)C-BDCM by solid-phase microextraction and high-resolution GC-MS. Urine was collected before and after exposure for mutagenicity determinations in Salmonella. After ingestion (mean dose = 146 ng/kg), blood (13)C-BDCM concentrations peaked and declined rapidly, returning to levels near or below the limit of detection (LOD) within 4 h. The T(max) for the oral exposure ranged from 5 to 30 min, and the C(max) ranged from 0.4 to 4.1 ng/l. After the 1 h dermal exposure (estimated mean dose = 155 ng/kg), blood concentrations of (13)C-BDCM ranged from 39 to 170 ng/l and decreased to levels near or below the LOD by 24 h. Peak postdose urine mutagenicity levels that were at least twice that of the predose mean level occurred in 6 of 10 percutaneously exposed subjects and 3 of 8 orally exposed subjects. These results demonstrate a highly significant contribution of dermal absorption to circulating levels of BDCM and confirm the much lower oral contribution, indicating that water uses involving dermal contact can lead to much greater systemic BDCM doses than water ingestion. These data will facilitate development and validation of physiologically based pharmacokinetic models for BDCM in humans.

Case control study of the geographic variability of exposure to disinfectant byproducts and risk for rectal cancer

BACKGROUND

Levels of byproducts that result from the disinfection of drinking water vary within a water distribution system. This prompted us to question whether the risk for rectal cancer also varies, depending upon one's long term geographic location within the system. Such a geographic distribution in rectal cancer risk would follow naturally from an association between level of byproduct and rectal cancer risk. We assess the effects of estimated geographic variability in exposure to some of the components of the trihalomethane group of disinfectant byproducts (DBPs) on the odds ratios and probabilities for rectal cancer in white males in a case control study of 128 cases and 253 controls, conducted in Monroe County, Western New York State, U.S.A. The study was designed around health data initially collected at the University at Buffalo (Department of Social and Preventative Medicine) as part of the Upstate New York Diet Study, and trihalomethane (THM) data collected from a separate independent study of THMs conducted by Monroe County Department of Health. Case participants were chosen from hospital pathology records. The controls are disease-free white males between 35-90 years old, living in Monroe County, and chosen from control groups for studies from cancer of five other (unrelated) sites. Using a combination of case control methodology and spatial analysis, the spatial patterns of THMs and individual measures of tap water consumption provide estimates of the effects of ingestion of specific amounts of some DBPs on rectal cancer risk. Trihalomethane (THM) data were used to spatially interpolate levels at the taps of cases and controls, and odds ratios were estimated using logistic regression to assess the effects of estimated THM exposure dose on cancer risk, adjusting for alcohol, dietary beta carotene intake, tap water intake, and total caloric intake.

RESULTS

Trihalomethane levels varied spatially within the county; although risk for rectal cancer did not increase with total level of trihalomethanes, increasing levels of the component bromoform (measured in ug/day) did correspond with an increase in odds ratios (OR = 1.85; 95% CI = 1.25 - 2.74) for rectal cancer. The highest quartiles of estimated consumption of bromoform (1.69-15.43 ug/day) led to increased risk for rectal cancer (OR = 2.32; 95% CI = 1.22-4.39). Two other THMs were marginally associated with an increase in risk - chlorodibromomethane (OR = 1.78, 95% CI = 1.00-3.19) and bromodichloromethane (OR = 1.15; 95% CI = 1.00-1.32).

CONCLUSION

Levels of THMs in the water distribution system exhibited spatial variation that was partially due to variation in water age. We also observed a geographic pattern of increased risk of rectal cancer in areas with the highest levels of bromoform in the county.

Preliminary Report of a Multicentric Study on Environmental Risk Factors in Ta-T1 Transitional Cell Carcinoma of the Bladder

OBJECTIVE

The distribution of potential environmental risk factors among patients affected by superficial transitional cell carcinoma of the bladder (TCCB) has been analyzed.

METHODS

Patients affected by superficial TCCB underwent TUR and early intravesical chemotherapy. Detailed data about age, sex, residence, employment, active and passive cigarette smoking, water resource and hair dye use were centralized. Analysis has been conducted on 474 patients affected by Ta-T1 G1-2 TCCB at medium risk for recurrence. Patients with primary single Ta G1-2, Tis or T1G3 tumors were excluded from the present analysis.

RESULTS

Over 80% of the patients lived in urban areas, 22% were employed in industries presumed at risk for bladder cancer, 8% used hair dye and 75% were smokers. Bottled water was the only water resource in 42% of the patients. Employment in industry at risk (p = 0.01) and cigarette smoking (p = 0.04) resulted in being statistically related to tumor multiplicity. Moreover, the period of cigarette smoking was significantly longer in patients with recurrent tumors (p = 0.026). The municipal water supply represented the main water source in never-smokers (p = 0.01) rather than in smokers and in patients harboring T1 rather than Ta tumors (p = 0.03).

CONCLUSIONS

Employment in industry at risk and cigarette smoking resulted in being related to tumor multiplicity. The length of exposure to cigarette smoking was related to the natural history of the tumor. A drinkable water source emerged as a risk factor in absence of cigarette smoking.

Reduction in kidney cancer mortality following installation of a tap water supply system in an arsenic-endemic area of Taiwan

Arsenic is the major risk factor for blackfoot disease, a peripheral vascular disease that has been endemic to the southwest coast of Taiwan for more than 50 yr because of the consumption of local artesian well water containing high levels of arsenic. Long-term arsenic exposure has been associated with kidney cancer mortality in a dose-response relationship. In the early 1960s, a tap water supply system was implemented in the blackfoot-endemic areas. After the mid-1970s, artesian well water was no longer used for drinking or cooking in the region. The authors examined whether kidney cancer mortality decreased after the elimination of arsenic exposure from artesian well water. Standardized mortality ratios for kidney cancer were calculated for the blackfoot-endemic area for the years 1971-2000. Study results showed that mortality from kidney cancer declined gradually during this time; therefore, the association of arsenic exposure with kidney cancer mortality was likely causal.

Multi-pathway risk assessment of trihalomethanes exposure in Istanbul drinking water supplies

The lifetime cancer risk and the hazard index of trihalomethanes (THMs) through oral ingestion, dermal absorption, and inhalation exposure from tap water of 15 districts in Istanbul are estimated. The most dominant THM compounds are chloroform, bromodichloromethane (BDCM), and dibromochloromethane (DBCM) in Istanbul tap water. The results indicate that within three different pathways, Istanbul residents had a higher cancer risk through oral ingestion than through the other two pathways. The lifetime cancer risks of oral ingestion for total THMs was highest in Esenyurt district, while the lowest lifetime cancer risk for total THMs was in Basaksehir district. The lifetime cancer risks of chloroform, BDCM, and DBCM from tap water of all 15 districts were higher than 10(-6), the negligible risk level defined by the USEPA. Among the 15 districts, people living in Esenyurt have the highest risk of cancer due to the THM exposure through the multi-pathways, mainly because of the exposure to BDCM and DBCM. The total cancer risk analysis concluded that each year approximately 5 of the 8 million Istanbul residents could get cancer from the daily intake of tap water.

Sodium ferrate (IV) and sodium hypochlorite in disinfection of biologically treated effluents. Ammonium nitrogen protection against THMs and HAAs

The work described in this paper presents an evaluation of disinfection by-products generation in four different biological treatment plant effluents, making use of sodium hypochlorite and sodium ferrate (IV) at varying concentration and reaction time. Correlations between pH, chemical oxygen demand, total organic carbon, ammonium nitrogen, combined chlorine and trihalomethanes (THMs) and haloacetic acids (HAAs) were carried out. Disinfection by-products generation presented a direct relation with concentration and sodium hypochlorite reaction time. For the highest hypochlorite concentration employed (20 mg L(-1)) and highest reaction time (168 h), the THMs total did not exceed 312.96 microg L(-1), a value that lies below the Brazilian emission standard for treated effluents (1 mg L(-1) of chloroform). The THMs presented an inverse correlation with ammonium nitrogen, when inverse (R(2) = 0.646; P < 0.001) and exponential (R(2) = 0.707; P < 0.001) function were used. As per HAAs this same relation was observed for logarithmic (R(2) = 0.0397 P < 0.001) and exponential (R(2) = 0.508; P < 0.001) functions. The more nitrified the effluent, the bigger the chlorinated disinfection by-product generation. The disinfectant sodium ferrate (IV) does not lead to halogenated by-product formation.

DNA hypomethylation induced by drinking water disinfection by-products in mouse and rat kidney

Bromodichloromethane (BDCM), chloroform, dibromoacetic acid (DBA), dichloroacetic acid (DCA), and trichloroacetic acid (TCA) are chlorine disinfection by-products (DBPs) found in drinking water that have indicated renal carcinogenic and/or tumor promoting activity. We have reported that the DBPs caused DNA hypomethylation in mouse liver, which correlated with their carcinogenic and tumor promoting activity. In this study, we determined their ability to cause renal DNA hypomethylation. B6C3F1 mice were administered DCA or TCA concurrently with/without chloroform in their drinking water for 7 days. In male, but not female mouse kidney, DCA, TCA, and to a lesser extent, chloroform decreased the methylation of DNA and the c-myc gene. Coadministering chloroform increased DCA but not TCA-induced DNA hypomethylation. DBA and BDCM caused renal DNA hypomethylation in both male B6C3F1 mice and Fischer 344 rats. We have reported that, in mouse liver, methionine prevented DCA- and TCA-induced hypomethylation of the c-myc gene. To determine whether it would also prevent hypomethylation in the kidneys, male mice were administered methionine in their diet concurrently with DCA or TCA in their drinking water. Methionine prevented both DCA- and TCA-induced hypomethylation of the c-myc gene. The ability of the DBPs to cause hypomethylation of DNA and of the c-myc gene correlated with their carcinogenic and tumor promoting activity in mouse and rat kidney, which should be taken into consideration as part of their risk assessment. That methionine prevents DCA- and TCA-induced hypomethylation of the c-myc gene would suggest it could prevent their carcinogenic activity in the kidney.

Bladder cancer mortality reduction after installation of a tap-water supply system in an arsenious-endemic area in southwestern Taiwan

Arsenic has been well documented as the major risk factor for blackfoot disease (BFD), a unique peripheral vascular disease that was endemic in the southwestern coast of Taiwan, where residents had consumed high-arsenic artesian well water for more than 50 years. Long-term arsenic exposure has also been reported to be associated with bladder cancer mortality in a dose-response relationship. A tap water supply system was implemented in the early 1960s in the BFD endemic areas. Artesian well water was no longer used for drinking and cooking after the mid-1970s. The objective of this study is to examine whether bladder cancer mortality decreased after the improvement of the drinking water supply system through elimination of arsenic exposure from artesian well water. Standardized mortality ratios (SMRs) for bladder cancer were calculated for the BFD endemic area for the years 1971-2000. The study results show that mortality from bladder cancer declined gradually after the improvement of the drinking water supply system to eliminate arsenic exposure from artesian well water. Based on the reversibility criterion, this finding strengthened the likelihood of the observed association between arsenic exposure and bladder cancer being causal.

Increased Risk of Preterm Delivery in Women Residing near Thermal Power Plants in Taiwan

In this article, the researchers studied the prevalence of preterm births for women living near thermal power plants. The prevalence of delivery of preterm birth infants was significantly higher among women living within 3 km of a thermal power plant than among women living within 3-4 km of a plant. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, infant gender, and birth site), the adjusted odds ratio was 1.14 (95% confidence interval, 1.01-1.30) for delivery of preterm infants for women living close to the thermal power plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy, although a semiecological study cannot confirm a direct causal relationship.

Drinking water chlorination and adverse birth outcomes in Taiwan

Chlorination has been the major strategy for the disinfection of drinking water in Taiwan. The use of chlorinated water has been hypothesized to lead to several adverse birth outcomes, including low birth weight and preterm delivery. We have performed a study to examine the relationship between the use of chlorinated water and adverse birth outcomes in Taiwan. The study areas included 113 "chlorinating municipalities" (CHMs) (which were defined as municipalities in which more than 95% of the municipality population was served by chlorinated water) and 15 "nonchlorinating municipalities" (NCHMs) (defined as municipalities in which less than 5% of the municipality population was served by chlorinated water). The study population comprised 182,796 women residing in the 128 municipalities who had a first parity singleton birth between 1 January 1994 and 31 December 1996, and for which complete information on maternal age, education, gestational age, birth weight, and sex of the baby were available The results of this study suggest that there was an association between the consumption of chlorinated drinking water and the risk of preterm delivery.

Increased risk of preterm delivery among people living near the three oil refineries in Taiwan

The petrochemical and petroleum industries are two of the main sources of industrial air pollution in Taiwan. Data used in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to oil refinery plants. The prevalence of delivery of preterm birth infants was significantly higher in mothers living near the oil refinery plants than in control mothers in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.14 (95% CI=1.01-1.28) for delivery of preterm infants for mothers living near oil refinery plants. These data provide further support for the hypothesis that air pollution can affect the outcome of pregnancies.

Multipathway risk assessment on disinfection by-products of drinking water in Hong Kong

The lifetime cancer risk and the hazard index of trihalomethanes (THMs) through oral ingestion, dermal absorption, and inhalation exposure from tap water in 19 districts in Hong Kong are estimated. The most dominant THMs are chloroform and bromodichloromethane (BDCM) in Hong Kong tap water. Among the three different pathways, residents have a higher risk of cancer through oral ingestion than through the other two pathways. The lifetime cancer risks through oral ingestion and dermal absorption for BDCM make the highest percentage contribution (59%) to total risks, followed by chloroform (24%). The chloroform and BDCM are at or above the negligible risk level of 10(-6) by a factor of 10 or more in most districts. Among the 19 districts, people living in Sai Kung have the highest risk of cancer due to the THM exposure through the multipathways, mainly because of the exposure to BDCM and dibromochloromethane (DBCM). The total cancer risk analysis indicates that each year approximately 10 out of the seven million Hong Kong residents could get cancer from the daily intake of water.

Chlorinated drinking water and micronuclei in urinary bladder epithelial cells

BACKGROUND

Evidence for a causal relationship between disinfection byproducts in chlorinated water and cancer is not conclusive. This study investigates the association between disinfection byproducts in chlorinated water, as measured by trihalomethane concentration, and the frequency of micronuclei in urinary bladder epithelial cells, thereby assessing the carcinogenic potential of disinfection byproducts.

METHODS

A cohort study was undertaken in 1997 in 3 Australian communities with varying levels of disinfection byproducts in the water supply. Exposure was assessed using both available dose (total trihalomethane concentration in the water supply) and intake dose (calculated by adjusting for individual variations in ingestion, inhalation, and dermal absorption). Micronuclei in urinary bladder epithelial cells were used as a preclinical biomarker of genotoxicity.

RESULTS

Cells were scored for micronuclei for 228 participants, of whom 63% were exposed to disinfection by products and 37% were unexposed. Available dose of total trihalomethane for the exposed group ranged from 38 to 157 micro ;g/L, whereas intake dose ranged from 3 to 469 micro g/kg per day. Relative risk for DNA damage to bladder cells, per 10 micro g/L of available dose total trihalomethane, was 1.01 (95% confidence interval [CI] = 0.97-1.06) for smokers and 0.996 (CI = 0.961-1.032) for nonsmokers. Relative risk, per 10 micro g/kg per day of intake dose of total trihalomethane, was 0.99 (CI = 0.96-1.03) for smokers and 1.003 (CI = 0.984-1.023) for nonsmokers.

CONCLUSION

This study provides no evidence that trihalomethane concentrations, at the levels we investigated, are associated with DNA damage to bladder cells.

Evidence for Increased Risks of Preterm Delivery in a Population Residing near a Freeway in Taiwan

Traffic emissions are a major source of air pollution in urban areas. The results of recent studies have suggested that air pollution may be related to adverse pregnancy outcomes such as low birth weight and preterm delivery. The authors investigated the association between traffic-related air pollution and preterm deliveries. The study group included all first-parity singleton live births that occurred during 1992-1997 to women who lived in a zone along the Zhong-Shan Freeway in Taiwan (N = 6,251). The zone was defined as areas 1,500-m wide on either side of the freeway; it was located in the San-Ming, Nan-Tzu, Chienchen, and Linya wards-all of which are residential areas in East Kaohsiung. The prevalence of deliveries of preterm birth infants was significantly higher among mothers who lived within 500 m of the freeway than among mothers who resided 500-1,500 m from the freeway. In their analysis, the authors controlled for several confounders (e.g., maternal age, season, marital status, maternal education, infant gender). The adjusted odds ratio was 1.30 (95% confidence interval = 1.03, 1.65) for delivery of preterm infants born to mothers who lived within 500 m of the freeway. Such data provide additional support for the hypothesis that air pollution can affect the outcome of pregnancy.

The mutagenic potentials of tap water samples in Shanghai

The tap water samples were collected from the users' ends in several areas of Shanghai, which is located in Taihu Lake basin, Eastern China. Source water samples were also collected from two municipal source water facilities at the same time. Samples were assayed by three different short-term mutagenicity test systems: Salmonella/microsome assay (Ames test), the Arabinose resistance test (Ara test) and the SOS/umu test. The data showed that two source water samples did not display direct mutagenic potentials. Two tap water samples from city north, which were directly from Yangtze River, were also not mutagenic. Water samples from city south and middle which used source water originating from Taihu Lake were proved to be contaminated with mutagenic potentials by three different assay techniques. The boiled water displayed an even stronger mutagenic potential compared to its original tap water. The molecular mechanism of mutagenicity was associated with a reading frame-shifting potential. GC-MS analysis of tap water extracts from city middle and corresponding source water was compared. Qualitatively similar spectra were observed except for the peaks of three chlorinated aromatic hydrocarbon compounds, which existed only in the tap water. Since the water source has been polluted, raw water was heavily chlorinated in order to sterilize. More toxic compounds, including mutagens, might form during the multi-chlorination. Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind. A cohort study in the residents of Shanghai is required.

Increased incidence of preterm delivery in mothers residing in an industrialized area in Taiwan

The objective of this study was to determine whether women living in the vicinity of industrial districts where emission levels of air contaminants from multiple sources including petrochemical, petroleum, steel, and shipbuilding industries are highly correlated with increased incidence of preterm births. The prevalence of delivery of preterm-birth infants was significantly higher in mothers living in the industrial study area compared to control regions of Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, infant gender, and birthplace), the adjusted odds ratio was 1.11 (95% CI = 1.02-1.21) for delivery of preterm infants in the industrial area. Data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy, although a semiecological study cannot confirm a direct causal relationship.

Arsenic in drinking water and adverse pregnancy outcome in an arseniasis-endemic area in northeastern Taiwan

The well water in Lanyang Basin, which is located in the northeastern portion of Taiwan island, was found to have high levels of arsenic ranging from undetectable levels (<0.15 ppb) to 3.59 ppm. We performed a study to compare the risk of adverse pregnancy outcomes (preterm delivery and birthweight) between an area with historic high well water arsenic levels (arsenic-exposed area (AE)) and a comparison area with no historic evidence of arsenic water contamination (non-arsenic-exposed area (NAE)). The mean birth weight in the AEs and NAEs were 3132.6 and 3162.6 g, respectively. Babies born in AEs were on average 30 g lighter than those born in NAEs. AEs had a higher rate of preterm delivery than NAEs (3.74% vs 3.43%). The results of this study suggest that, after adjustment for potential confounders, arsenic exposure from drinking well water was associated, although not significantly, with the risk of preterm delivery, with an odds ratio of 1.10 (0.91-1.33). The estimated reduction in birth weight was 29.05 g (95% CI=13.55-44.55). The findings from this investigation provide evidence for a potential role for arsenic exposure through drinking water in increasing the risk of low birthweight.

Association between petrochemical air pollution and adverse pregnancy outcomes in Taiwan

The petrochemical industry is the main source of industrial air pollution in Taiwan. To date, little is known about the possible effects of such pollution on the human fetus. In this study, the authors investigated the relationship between term low birthweight and preterm delivery and residence in a petrochemical industrial municipality (PIM). The study areas included 16 PIMs (which were defined as municipalities in which the number of workers in the petroleum and petrochemical industry made up at least 2% of the municipality's total population) and 16 matched reference municipalities (RFMs). Among 39,750 1st-parity singleton live births, the prevalences of preterm delivery in the PIMs and RFMs were 4.72% and 4.58%, respectively, and the prevalences of term low birthweight were 2.51% and 2.35%, respectively. When PIMs were compared with RFMs, and after controlling for possible confounders (including maternal age, marital status, maternal education, and gender of the baby), the adjusted odds ratios were 1.07 (95% confidence interval [CI] = 0.95, 1.22) for term low birthweight and 1.03 (95% CI = 0.94, 1.13) for preterm delivery, respectively.

Increased risk of preterm delivery in areas with cancer mortality problems from petrochemical complexes

The petrochemical and petroleum industries are the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to petrochemical industrial complexes. The prevalence of delivery of preterm birth infants was significantly higher in mothers living near petrochemical industrial complexes than in control mothers living elsewhere in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.18 (95% CI=1.04-1.34) for delivery of preterm infants in the petrochemically polluted region. The data provide further support for the hypothesis that air pollution can affect the outcome of pregnancy.

Studies on the in vivo and in vitro mutagenicity and the lipid peroxidation of chlorinated surface (drinking) water in rats and metabolically competent human cells

In the present study, DNA damaging and mutagenic effects of chlorinated drinking water (CDW) extracts obtained from polluted raw water resources were examined in metabolically competent human Hep G2 hepatoma cells using the in vitro micronucleus assay and the single cell gel electrophoresis (SCGE, comet assay). Additionally, the in vivo induction of micronuclei (MN) was studied in polychromatic erythrocytes (PCEs) derived from bone marrow of CDW-treated Wistar rats. Furthermore, we examined the influence of CDW on the lipid peroxidation (LpO) in blood, liver, kidney and testicle of rats. The results demonstrated significant increases of micronucleated PCEs in the bone marrow of rats fed with relatively low CDW doses (33.3ml/kg body weight per day). Similar effects, i.e. increases of MN frequencies, were found in Hep G2 hepatoma cells after CDW treatment (41 MN/1000 binucleated cells (BNCs) for 167ml CDW) in comparison to the vehicle control (24 MN/1000 BNC). Additionally, DNA damages caused by CDW were observed in the comet assay. As a product of LpO, the levels of malondialdehyde (MDA) were significantly enhanced almost in all animals and organs tested after CDW treatment. In livers and serum of rats dose-dependent increases of MDA were observed. The data indicated that extracts from CDW obtained from polluted raw water were able to cause oxidative damages and to induce various biological effects in mammalian cells in vivo and in vitro, i.e. clastogenicity and/or aneugenicity, DNA strand breaks and/or alkali-labile damages. The consistency of the results among the various biological systems and endpoints led to the conclusion that the consumption of chlorinated drinking water obtained from polluted raw water may enhance the body burden with mutagenic and/or carcinogenic substances and therefore, means a potential genetic hazard for human health.

Increased risk of preterm delivery in areas with air pollution from a petroleum refinery plant in Taiwan

The petrochemical and petroleum industries are among the main sources of industrial air pollution in Taiwan. Data in this study concern outdoor air pollution and the health of individuals living in communities in close proximity to a petroleum refinery plant. The prevalence of delivery of preterm birth infants was significantly higher in mothers living in a petroleum refinery area compared to controls in Taiwan. After controlling for several possible confounders (including maternal age, season, marital status, maternal education, and infant sex), the adjusted odds ratio was 1.41 (95% CI = 1.08-1.82) for delivery of preterm infants in the polluted region. Data support the view that air pollution can affect the outcome of pregnancy.

Estimation of potential lifetime cancer risks for trihalomethanes from consuming chlorinated drinking water in Taiwan

Data on concentrations of trihalomethanes (THMs) in raw and chlorinated water collected from three water treatment plants in Taiwan and estimates of the lifetime cancer risk for THMs from drinking water, using age-adjusted factors and volatilization terms, are presented. Data on THM levels in drinking water were obtained from the annual reports of the Environmental Protection Administration (EPA) of Taiwan. The methodology for estimation of lifetime cancer risks was taken from the USEPA. Chloroform was the major species of THMs, especially in the water plant of south Taiwan. Chloroform contributed the majority of the lifetime cancer risks (range: 87.5-92.5%) of total risks from the three water supply areas. All lifetime cancer risks for CHCl(3), CHBrCl(2), CHBr2Cl, and CHBr3 from consuming tap water in the three water supply areas were higher than 10(-6). The sum of lifetime cancer risks for CHCl(3), CHBrCl(3), CHBr2Cl, and CHBr3 was highest (total risk for total THMs<1.94x10(-4)) for tap water from south Taiwan.

Long-term chemical carcinogenesis bioassays predict human cancer hazards. Issues, controversies, and uncertainties

Long-term carcinogenesis bioassays are the most valued and predictive means for identifying potential carcinogenic hazards of various agents to humans. Agents may be chemicals, chemical mixtures, multiple chemicals, combinations of chemicals, residues and contaminants, commercial products and formulations, and various exposure circumstances. Life-styles, dietary factors, and occupational exposure circumstances are very difficult, but not totally impossible, to evaluate experimentally. Historically, the first chemical bioassay took place in the early part of this century: Yamagiwa and Ichikawa in 1915, showed that coal tar applied experimentally to rabbit ears caused skin carcinomas. Since then, nearly 1500-2000 bioassays of one sort or another have been carried out. Importantly, however, some of these bioassays must be considered inadequate for judging the absence of carcinogenicity, since there were various limitations on the way they were performed: too few animals, too short a duration, too low exposure concentrations, too limited pathology, as examples. Thus, each bioassay must be critically evaluated, especially those reported to be negative, because "false negatives" are certainly more hazardous to human health than are "false positives". Likewise, one must be careful not to discount bioassay results simply because a target organ in rodents may not have a direct counterpart in humans (e.g., Zymbal glands), or because an organ site in rodents may not be a major site of cancers in humans (e.g., mouse liver). The design and conduct of a bioassay is not simple, however, and one must be fully aware of possible pitfalls as well as viable and often necessary alternatives. Similarly, evaluating results and interpreting findings must be approached with the utmost objectivity and consistency. These and other select issues, controversies, and uncertainties possibly encountered in long-term bioassays are covered in this paper. One fact remains abundantly clear: for every known human carcinogen that has been tested adequately in laboratory animals, the findings of carcinogenicity are concordant.