Nitrate In Drinking Water Research Articles

UPLC-ESI/MS analysis of disinfection by-products (perchlorate, bromate, nitrate, nitrite and sulfite) in micro-filtered drinking water obtained from spring, well and tap water (desalinated) sources

ObjectivesIn the current study, an analytical technique has been optimized for the analysis of disinfection by-products (perchlorate (ClO4−), bromate (BrO3−), nitrate (NO3−), nitrite and sulfite (SO32–) in drinking water obtained from spring, well and tap water (desalinated) sources. MethodsThe ultra-performance liquid chromatography-electrospray ionization mass spectrometry (UPLC-ESI/MS) conditions have been optimized for oxyhalides ClO4− (isotopes, 37ClO4− and 35ClO4−) and BrO3− (isotopes, 81BrO3− and 79BrO3−), and inorganic anions NO3−, NO2− and SO32–. Separation was achieved by BEH C18 column with methanol (75%) and water (24.99%, HCOOH 0.01%) mobile phase at flow rate 0.2 mL/min. ResultsThe analysis was carried out in <1 min with excellent coefficient of determination, (R2 > 0.995–0.999), limit of detection (0.016–0.043 µg/L), limit of quantification (0.051–0.104 µg/L) and precision (repeatability, 1.54–2.28% and reproducibility, 3.13–4.08%) in terms of RSD%. The method was successfully applied, and the amounts of 35ClO4− (5.33–22.64 µg/L), 81BrO3− (7.52–16.73 µg/L), NO3− (5.42–12.14 mg/L), NO2− (1.08–4.37 mg/L) and SO32– (6.84–32.45 mg/L) were identified in spring water, whereas well and tap water contained 35ClO4− (4.20–21.33 µg/L), 81BrO3− (8.05–15.13 µg/L), NO3− (1.27–16.11 mg/L), NO2− (0.43–10.77 mg/L) and SO32– (7.14–36.10 mg/L), and 35ClO4− (0.89–7.37 µg/L), 81BrO3− (5.15–14.68 µg/L), NO3− (1.12–6.33 mg/L), NO2− (0.67–3.95 mg/L) and SO32– (5.40–23.26 mg/L), respectively. ConclusionsThe levels of 35ClO4−, 81BrO3−, NO3−, NO2− and SO32– were found beyond the maximum contaminant levels and drinking water equivalent levels regulated by the Environmental Protection Agency, respectively. The outcomes also revealed that comparatively tap water produced lower levels of these contaminants especially in the cities with low population densities. In addition, the geographical site would be helpful to categorize the tap water samples.

Drinking-water nitrate and cancer risk: A systematic review and meta-analysis

Background Nitrate is an inorganic compound that occurs naturally in all surface and groundwater, although higher concentrations tend to occur only where fertilizers are used on the land. The regulatory limit for nitrate in public drinking water supplies was set to protect against infant methemoglobinemia, but other health effects were not considered. Risk of specific cancers and congenital disabilities may be increased when the nitrate is ingested, and nitrate is reduced to nitrite, which can react with amines and amides by nitrosation to form N-nitroso compounds which are known animal carcinogens. This study aims to evaluate the association between nitrate ingested through drinking water and the risk of developing cancers in humans. Methods We performed a systematic review following PRISMA and MOOSE guidelines. A literature search was performed using PubMed, EMBASE, the Cochrane Library databases, Web of Science and Google Scholars in the time-frame from their inception to January 2020, for potentially eligible publications. STATA version 12.0 was used to conduct meta-regression and a two-stage meta-analysis. Results A total of 48 articles with 13 different cancer sites were used for analysis. The meta-regression analysis showed stomach cancer had an association with the median dosage of nitrate from drinking water (t = 3.98, p = 0.0001, and adjusted R-squared = 50.61%), other types of cancers didn’t show any association. The first stage of meta-analysis showed there was an association only between the risk of brain cancer & glioma (OR = 1.15, 95% CI: 1.06, 1.24) and colon cancer (OR = 1.11, 95% CI: 1.04, 1.17) and nitrate consumption in the analysis comparing the highest ORs versus the lowest. The 2nd stage showed there was an association only between the risk colon cancer (OR = 1.14, 95% CI: 1.04, 1.23) and nitrate consumption in the analysis comparing all combined higher ORs versus the lowest. Conclusion This study showed that there is an association between the intake of nitrate from drinking water and a type of cancer in humans. The effective way of controlling nitrate concentrations in drinking water is the prevention of contamination (water pollution). Further research work on this topic is needed.

Health and economic impact of nitrate pollution in drinking water: a Wisconsin case study.

Nitrate contamination of drinking water, common in agricultural areas, increases the risk of certain cancers and impacts fetal development during pregnancy. Building on previously published methodology, this study evaluates nitrate-attributable disease cases and adverse birth outcomes as well as their economic costs for Wisconsin, USA. Nitrate is the most common contaminant in groundwater in Wisconsin. Two-thirds of the state's residents use groundwater as the primary source of drinking water. Here, we analyze nitrate exposure from drinking water in Wisconsin based on nitrate test results for community water systems for the period of 2010-2017 and a novel methodology for estimating nitrate exposure for the 28% of state's residents who use private wells. We estimate that annually, 111-298 combined cases of colorectal, ovarian, thyroid, bladder, and kidney cancer in Wisconsin may be due to nitrate contamination of drinking water. Each year, up to 137-149 cases of very low birth weight, 72-79 cases of very preterm birth, and two cases of neural tube defects could be due to nitrate exposure from drinking water. The direct medical cost estimates for all nitrate-attributable adverse health outcomes range between $23 and $80 million annually. Simulating targeted reductions in the counties with the highest current drinking water nitrate concentrations resulted in similar reductions in adverse health outcomes as statewide reduction efforts, up to nitrate reductions of 20%. Time trend analysis suggests that groundwater nitrate concentrations are overall increasing. Thus, nitrate contamination of water supplies in Wisconsin is a public health problem that needs to be addressed.

Association between Drinking Water Nitrate and Adverse Reproductive Outcomes: A Systematic PRISMA Review

One in six couples experience fertility problems. Environmental factors may affect reproductive health; however, evidence is lacking regarding drinking water nitrates and outcomes of male and female fertility. The aim of this study was to investigate if exposure to nitrates in drinking water is associated with adverse reproductive outcomes in humans, and animals of fertile age. We conducted a systematic literature search and included case-control studies, cohort studies, and randomized control trials reporting on the association between drinking water nitrate exposure of men, women, or animals and adverse reproductive outcomes, specified as: Semen quality parameters, time to pregnancy (TTP), pregnancy rates, assisted reproductive technologies (ART), and spontaneous abortion. Findings were reported in a narrative synthesis. A total of 12 studies were included. The only human study included reported a decrease in spontaneous abortion at any detectable nitrate level. Overall, the 11 included animal studies support a potential negative effect on semen quality parameters but report equivocal results on TTP and number of offspring produced, and higher risk of spontaneous abortion. In conclusion, animal studies indicate possible effects on semen quality parameters and spontaneous abortion. However, with a few studies, including some with methodological limitations and small sample sizes, caution must be applied when interpreting these results.

Abstract PR04: Exposure-based assessment and economic valuation of adverse birth outcomes and cancer risk due to nitrate in United States drinking water

Abstract Background: Nitrate ingestion from drinking water has been associated with an increased risk of adverse birth outcomes as well as elevated risk of colorectal cancer and several other cancers. Yet, to date no studies have attempted to quantify the health and economic impacts due to nitrate in drinking water in the United States. Methods: This study presents a first-of-its-kind comprehensive assessment of nitrate exposure from drinking water for the entire United States population. This exposure assessment serves as the basis for our analysis of the annual nitrate-attributable disease cases in the United States and the associated economic losses due to medical costs and lost productivity. Additionally, through a meta-analysis of studies on drinking water nitrate and colorectal cancer, we examine the exposure-response relationship for nitrate and cancer risk. Results: On the basis of national nitrate occurrence data and relative risk ratios reported in the epidemiology literature, we calculated that annually, 2,939 cases of very low birth weight, 1,725 cases of very preterm birth, and 41 cases of neural tube defects could be related to nitrate exposure from drinking water. For cancer risk, combining nitrate-specific risk estimates for colorectal, ovarian, thyroid, kidney, and bladder cancers results in a range of 2,300 to 12,594 annual nitrate-attributable cancer cases (mean: 6,537 estimated cases). For medical expenditures alone, this burden of cancer corresponds to an annual economic cost of $250 million to $1.5 billion U.S. dollars, together with a potential $1.3 to $6.5 billion impact due to lost productivity. With the meta-analysis of eight studies of drinking water nitrate and colorectal cancer, we observed a statistically significant positive association for nitrate exposure and colorectal cancer risk and calculated a one-in-one million cancer risk level of 0.14 mg/L nitrate in drinking water. Conclusion: Health and economic analyses presented here suggest that lowering exposure to nitrate in drinking water could bring economic benefits by alleviating the impacts of nitrate-associated diseases. This abstract is also being presented as Poster A44. Citation Format: Alexis Temkin, Sydney Evans, Tatiana Manidis, Chris Campbell, Olga V. Naidenko. Exposure-based assessment and economic valuation of adverse birth outcomes and cancer risk due to nitrate in United States drinking water [abstract]. In: Proceedings of the AACR Special Conference on Environmental Carcinogenesis: Potential Pathway to Cancer Prevention; 2019 Jun 22-24; Charlotte, NC. Philadelphia (PA): AACR; Can Prev Res 2020;13(7 Suppl): Abstract nr PR04.

The analysis of groundwater nitrate pollution and health risk assessment in rural areas of Yantai, China

BackgroundNitrate is one of the most common chemical contaminants of groundwater, and it is an important unqualified factor of rural groundwater in Yantai. In order to assess the risk of exposure to drinking water nitrate for adults and juveniles, in recent years, we monitored the nitrate concentrations in rural drinking water,a model was also used to assess the human health risk of nitrate pollution in groundwater.MethodsFrom the year 2015 to 2018, the drinking water in rural areas of Yantai was tested according to the “Sanitary Standard for Drinking Water” (GB5749–2006). The principal component analysis was used to analyze the relationship between groundwater chemicals and nitrate. The model was used to assess human health risks of groundwater nitrate through the drinking water and skin contact.ResultsA total of 2348 samples were tested during the year 2015–2018.Nitrate and total dissolved solids, total hardness, chloride are all relevant, the above indicators may come from the same source of pollution; The median nitrate content (CEXP50) was 17.8 mg / L; the risk of exposure in each group was ranked as: Juveniles > Adult female > Adult male;the median health risk (HQ50) for minors and adults exceed 1.ConclusionsThe concentrations of nitrate is stable and does not change over time. The high concentration of nitrate in rural areas of Yantai may be the result of the interaction of fertilizers and geological factors. The risk of exposure to nitrate in juveniles and adults is above the limit, so it is necessary to be on the alert for the high levels of nitrate.

Patterns and predictions of drinking water nitrate violations across the conterminous United States

Excess nitrate in drinking water is a human health concern, especially for young children. Public drinking water systems in violation of the 10 mg nitrate-N/L maximum contaminant level (MCL) must be reported in EPA's Safe Drinking Water Information System (SDWIS). We used SDWIS data with random forest modeling to examine the drivers of nitrate violations across the conterminous U.S. and to predict where public water systems are at risk of exceeding the nitrate MCL. As explanatory variables, we used land cover, nitrogen inputs, soil/hydrogeology, and climate variables. While we looked at the role of nitrate treatment in separate analyses, we did not include treatment as a factor in the final models, due to incomplete information in SDWIS. For groundwater (GW) systems, a classification model correctly classified 79% of catchments in violation and a regression model explained 43% of the variation in nitrate concentrations above the MCL. The most important variables in the GW classification model were % cropland, agricultural drainage, irrigation-to-precipitation ratio, nitrogen surplus, and surplus precipitation. Regions predicted to have risk for nitrate violations in GW were the Central California Valley, parts of Washington, Idaho, the Great Plains, Piedmont of Pennsylvania and Coastal Plains of Delaware, and regions of Wisconsin, Iowa, and Minnesota. For surface water (SW) systems, a classification model correctly classified 90% of catchments and a regression model explained 52% of the variation in nitrate concentration. The variables most important for the SW classification model were largely hydroclimatic variables including surplus precipitation, irrigation-to-precipitation ratio, and % shrubland. Areas at greatest risk for SW nitrate violations were generally in the non-mountainous west and southwest. Identifying the areas with possible risk for future violations and potential drivers of nitrate violations across U.S. can inform decisions on how source water protection and other management options could best protect drinking water.

Ingested Nitrate and Nitrite and Bladder Cancer in Northern New England.

N-nitroso compounds are hypothesized human bladder carcinogens. We investigated ingestion of N-nitroso compound precursors nitrate and nitrite from drinking water and diet and bladder cancer in the New England Bladder Cancer Study. Using historical nitrate measurements for public water supplies and measured and modeled values for private wells, as well as self-reported water intake, we estimated average nitrate concentrations (mg/L NO3-N) and average daily nitrate intake (mg/d) from 1970 to diagnosis/reference date (987 cases and 1,180 controls). We estimated overall and source-specific dietary nitrate and nitrite intakes using a food frequency questionnaire (1,037 cases and 1,225 controls). We used unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI). We evaluated interactions with factors that may affect N-nitroso compound formation (i.e., red meat, vitamin C, smoking), and with water intake. Average drinking water nitrate concentration above the 95th percentile (>2.07 mg/L) compared with the lowest quartile (≤0.21 mg/L) was associated with bladder cancer (OR = 1.5, 95% CI = 0.97, 2.3; P trend = 0.01); the association was similar for average daily drinking water nitrate intake. We observed positive associations for dietary nitrate and nitrite intakes from processed meat (highest versus lowest quintile OR for nitrate = 1.4, 95% CI = 1.0, 2.0; P trend = 0.04; OR for nitrite = 1.5, 95% CI = 1.0, 2.1; P trend = 0.04, respectively), but not other dietary sources. We observed positive interactions between drinking water nitrate and red meat (P-interaction 0.05) and processed red meat (0.07). Our results suggest the importance of both drinking water and dietary nitrate sources as risk factors for bladder cancer.

Application of glycerol as carbon source for continuous drinking water denitrification using microorganism from natural biomass

The contamination of water resources by nitrate is a global problem. Indeed, traditional treatment technologies are not able to remove this ion from water. Alternatively, biological denitrification is a useful technique for natural water nitrate removal. This study aimed to evaluate the use of glycerol as a carbon source for drinking water nitrate removal via denitrification in a reactor using microorganisms from natural biomass. The experiment was carried out in a continuous fixed bed reactor using immobilised microorganisms from the vegetal Phyllostachys aurea. The tests were started in batch mode to provide cells growth and further immobilisation on the support. Then, the treatment experiments were accomplished in an up-flow continuous reactor. Ethanol was used as the primary carbon source, and it was gradually replaced by glycerol. The C:N (carbon to nitrogen) ratio and the hydraulic residence time (HRT) were evaluated. It was possible to remove 98.14% of nitrate using a C:N ratio and HRT of 3:1 and 1.51 days, respectively. The results have demonstrated that glycerol is a potential carbon source for denitrification in a continuous reactor using immobilised cells from natural biomass.

Impact of high drinking water nitrate levels on the endogenous formation of apparent N-nitroso compounds in combination with meat intake in healthy volunteers

BackgroundNitrate is converted to nitrite in the human body and subsequently can react with amines and amides in the gastrointestinal tract to form N-nitroso compounds (NOCs), which are known to be carcinogenic in animals. Humans can be exposed to nitrate via consumption of drinking water and diet, especially green leafy vegetables and cured meat. The contribution of nitrate from drinking water in combination with meat intake has not been investigated thoroughly. Therefore, in the present pilot study, we examined the effect of nitrate from drinking water, and its interaction with the consumption of white and processed red meat, on the endogenous formation of NOCs, taking into account the intake of vitamin C, a nitrosation inhibitor.MethodsTwenty healthy subjects were randomly assigned to two groups consuming either 3.75 g/kg body weight (maximum 300 g per day) processed red meat or unprocessed white meat per day for two weeks. Drinking water nitrate levels were kept low during the first week (< 1.5 mg/L), whereas in week 2, nitrate levels in drinking water were adjusted to the acceptable daily intake level of 3.7 mg/kg bodyweight. At baseline, after 1 and 2 weeks, faeces and 24 h urine samples were collected for analyses of nitrate, apparent total N-nitroso compounds (ATNC), compliance markers, and genotoxic potential in human colonic Caco-2 cells.ResultsUrinary nitrate excretion was significantly increased during the high drinking water nitrate period for both meat types. Furthermore, levels of compliance markers for meat intake were significantly increased in urine from subjects consuming processed red meat (i.e. 1-Methylhistidine levels), or unprocessed white meat (i.e. 3-Methylhistidine). ATNC levels significantly increased during the high drinking water nitrate period, which was more pronounced in the processed red meat group. Genotoxicity in Caco-2 cells exposed to faecal water resulted in increased genotoxicity after the interventions, but results were only significant in the low drinking water nitrate period in subjects consuming processed red meat. Furthermore, a positive correlation was found between the ratio of nitrate/vitamin C intake (including drinking water) and the level of ATNC in faecal water of subjects in the processed red meat group, but this was not statistically significant.ConclusionsDrinking water nitrate significantly contributed to the endogenous formation of NOC, independent of the meat type consumed. This implies that drinking water nitrate levels should be taken into account when evaluating the effect of meat consumption on endogenous formation of NOC.Trial registrationDutch Trialregister: 29707. Registered 19th of October 2018. Retrospectively registered.

Exposure-based assessment of potential health and economic impacts due to nitrate pollution of drinking water in the United States

OPS 33: Health impact of interventions 2, Room 411, Floor 4, August 28, 2019, 10:30 AM - 12:00 PM Background: Nitrate ingestion from drinking water has been associated with an increased risk of several cancers as well as adverse birth outcomes such as neural tube defects and low birth weight. Within this overall body of research, colorectal cancer has the largest number of high-quality studies which report increased risk at the lowest exposure levels. Yet, to date, no studies have attempted to quantify the health and economic impacts due to nitrate in drinking water in the United States. Methods: This study presents a first of its kind comprehensive assessment of nitrate exposure from drinking water for the entire U.S. population, which serves as the basis for our analysis of the annual nitrate-attributable cancer cases and adverse reproductive outcomes in the U.S. and the associated economic losses due to medical costs and lost productivity. Additionally, through a meta-analysis of studies on drinking water nitrate and colorectal cancer, we examine the exposure-response relationship for nitrate and cancer risk. Results: Combining nitrate-specific cancer risk estimates for colorectal, ovarian, thyroid, and bladder cancers results in an average of 5910 estimated annual nitrate-attributable cancer cases (1884 to 11,718 cancer cases) in the U.S. of which 66-85% are colorectal cancer cases. For medical costs alone, this results in an overall loss of 200 million to 1.4 billion dollars, and a potential 1 to 6 billion dollar loss from lost productivity. With the meta-analysis of eight studies of drinking water nitrate and colorectal cancer, we observed a statistically significant positive association for nitrate exposure and colorectal cancer risk and calculated a cancer slope factor for nitrate in drinking water at 0.04 per mg/L. Conclusion: Health and economic analyses presented here suggest lowering exposure to nitrate in drinking water can help address colorectal cancer risk in the U.S. population and may alleviate the impacts of nitrate-associated diseases.

Ingested nitrate and nitrite and bladder cancer in Northern New England

OPS 36: Health effects of dietary exposures, Room 210, Floor 2, August 27, 2019, 4:30 PM - 5:30 PM Background/Aim: N-nitroso compounds (NOCs) are hypothesized human bladder carcinogens. Nitrate and nitrite are NOC precursors; sources include contaminated drinking water and diet. We examined nitrate and nitrite ingestion and bladder cancer risk in the New England Bladder Cancer Study, a population-based case-control study in Maine, New Hampshire, and Vermont. Methods: Using historical nitrate measurements for public water supplies, measured and modeled values for private wells and self-reported water intake, we estimated average nitrate concentrations (NO3-N mg/L) and average daily nitrate intake (mg/day) from 1970 to diagnosis/reference date for 987 cases and 1180 controls. We also estimated source-specific (animal, plant, processed meat) dietary nitrate and nitrite intakes using a food frequency questionnaire (1037 cases and 1225 controls). We used unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusting for age, gender, smoking, disinfection by-products, and other factors. We evaluated interactions with factors affecting NOC formation (i.e., red and processed meat, vitamin C, smoking). Results: Average drinking water nitrate concentration above the 95th percentile (>2.07 mg/L) compared with the lowest quartile (<=0.21 mg/L) was associated with bladder cancer risk (OR=1.50, CI: 0.97-2.32; p-trend=0.01); the association was similar for average drinking water nitrate intake. We observed positive associations for dietary nitrate and nitrite intakes from processed meat (highest vs. lowest quintile OR=1.42, CI: 1.01-1.98; p-trend=0.04; OR=1.48, CI: 1.04-2.09; p-trend=0.04, respectively), but no trends for other sources. Risk was highest among those with >2.07 mg/L NO3-N and >median red or processed meat intake vs <0.21 mg/L NO3-N/< median intakes (OR=2.61, CI: 1.33-5.11 and OR=3.47 CI: 1.75-6.87; p-interaction=0.05 and 0.07, respectively). We observed no interaction with vitamin C or smoking. Conclusions: Our results suggest the importance of both drinking water and dietary nitrate sources as risk factors for bladder cancer especially among those with high red or processed meat intake

Comments on “Use of Rh (III)-Heteropolymolybdate as Potential Catalysts for the Removal of Nitrates in Human Drinking Water: Synthesis, Characterisation and Catalytic Performance” by María A. Jaworski et al. (Water Air Soil Pollut (2018) 229: 309)

Comments on “Use of Rh (III)-Heteropolymolybdate as Potential Catalysts for the Removal of Nitrates in Human Drinking Water: Synthesis, Characterisation and Catalytic Performance” by María A. Jaworski et al. (Water Air Soil Pollut (2018) 229: 309)

Investigation of the relationship between drinking water nitrate and bladder cancer in Larestan city from the point of view medical geography

Investigation of the relationship between drinking water nitrate and bladder cancer in Larestan city from the point of view medical geography

Exposure-based assessment and economic valuation of adverse birth outcomes and cancer risk due to nitrate in United States drinking water.

BackgroundNitrate ingestion from drinking water has been associated with an increased risk of adverse birth outcomes as well as elevated risk of colorectal cancer and several other cancers. Yet, to date, no studies have attempted to quantify the health and economic impacts due to nitrate in drinking water in the United States. MethodsThis study presents a first-of-its-kind comprehensive assessment of nitrate exposure from drinking water for the entire United States population. This exposure assessment serves as the basis for our analysis of the annual nitrate-attributable disease cases in the United States and the associated economic losses due to medical costs and lost productivity. Additionally, through a meta-analysis of studies on drinking water nitrate and colorectal cancer, we examine the exposure-response relationship for nitrate and cancer risk. ResultsOn the basis of national nitrate occurrence data and relative risk ratios reported in the epidemiology literature, we calculated that annually, 2939 cases of very low birth weight, 1725 cases of very preterm birth, and 41 cases of neural tube defects could be related to nitrate exposure from drinking water. For cancer risk, combining nitrate-specific risk estimates for colorectal, ovarian, thyroid, kidney, and bladder cancers results in a range of 2300 to 12,594 annual nitrate-attributable cancer cases (mean: 6537 estimated cases). For medical expenditures alone, this burden of cancer corresponds to an annual economic cost of 250 million to 1.5 billion U.S. dollars, together with a potential 1.3 to 6.5 billion dollar impact due to lost productivity. With the meta-analysis of eight studies of drinking water nitrate and colorectal cancer, we observed a statistically significant positive association for nitrate exposure and colorectal cancer risk and calculated a one-in-one million cancer risk level of 0.14 mg/L nitrate in drinking water. ConclusionHealth and economic analyses presented here suggest that lowering exposure to nitrate in drinking water could bring economic benefits by alleviating the impacts of nitrate-associated diseases.

Effect of Drinking Water Nitrates and Vitamin C on Rat Liver Enzymes and Oxidative Markers

Background: Liver cells or hepatocytes facilitate different hepatic functions. The liver reportedly accounts for up to 500 separate functions, alongside other systems and organs. The high consumption of the food containing high levels of nitrate in the community and the presence of this harmful substance in water endanger the health of many people. N-nitroso compounds, as potential free radicals, can damage the tissues through oxidative stress. Objectives: The current study was targeted toward examining the impact of drinking water nitrate and vitamin C on hepatic enzymes and oxidative markers in rats. Methods: The present experimental study was performed on 49 rats in Mashhad, Iran, during 2017 - 2018. The subjects were assigned into seven groups. Group one received water without nitrates (control) while groups two, three, and four received different concentration of nitrates (10, 45, 200 mg/L). Groups five, six, and seven received the same concentration of nitrates and vitamin C (20 mg/100g body weight). After 91 days, blood samples were obtained to determine hepatic enzymes (namely, ALT/SGPT: alanine aminotransferase, AST/SGOT: aspartate aminotransferase, and ALP: alkaline phosphatase). Furthermore, an autopsy was carried out to examine the liver tissue regarding the markers of oxidation (namely, MDA: Malondialdehyde, SOD: Superoxide-dismutase, CAT: Catalase enzyme, and GSH: Glutathione), according to the protocol. Results: The results revealed a significant elevation in ALP (P = 0.034), AST (P = 0.018), and ALT (155.14 ± 25.67, 92 ± 17.72, P = 0.000), compared to those in the control group. In addition, the fourth group demonstrated a significant enhancement in MDA level, collated to the group one (P = 0.44), while there was a significant drop in CAT (P = 0.025), SOD (P = 0.002), and GSH levels (P = 0.000). Furthermore, use of vitamin C led to a significant drop in the levels of ALP, AST, ALT, and MDA, as well as a significant elevation in GSH, SOD, and CAT in the seventh group in comparison to the fourth group (P < 0.05). Conclusions: As the findings indicated, drinking water nitrate and Vitamin C exerted a non-significant effect on the doses of nitrate (10 and 45 mg/L). Nonetheless, a nitrate dose of 200 mg/L had a significant impact on ALT, ALP, AST, and oxidative stress indicators leading to hepatic diseases.

Protective effects of sodium nitrate against testicular apoptosis and spermatogenesis impairments in streptozotocin-induced diabetic male rats

AimsAs nitric oxide (NO) production is essential for insulin signaling, glucose uptake, endothelial function, and regulation of apoptosis, the loss of bioavailable NO may be a mechanism underlying the development of diabetes complication. Dietary nitrate acts as a substrate for NO generation, thus serving as a physiological source of NO. This study evaluated the therapeutic effects of nitrate supplementation on the apoptosis-induced testicular disorders in diabetic rats. Main methodsFifty male Wistar rats were divided into five groups; control, control with 100 mg/L nitrate in distilled drinking water, diabetes, diabetes treated with 2–4 U/day NPH insulin, diabetes treated with 100 mg/L nitrate in distilled drinking water. After 8 weeks, blood samples, testis, and epididymis were collected to assess the apoptosis process and the stereology of testis tissue, sperm motility, morphology and DNA fragmentation, and also mRNA expression of miR-449a, p53, Pdcd4, and Pacs2 mRNA, as well as serum glucose, insulin, and NOx levels were investigated. Key findingsThe results of this study indicated that nitrate treatment ameliorated the sperm parameters, testicular morphometrical and stereological alterations, reduced blood glucose, the number of TUNEL positive cells and tubules, and testicular expressions of p53, Pdcd4, and Pacs2 mRNA as well as increased body weight, serum insulin and NOx levels, and testicular expression of miR-449a in streptozotocin-induced diabetic rats. SignificanceOur in vivo evidence revealed that nitrate treatment may has a favorable effect as an exogenous NO donor on experimental diabetic testicular damages in which NO bioavailability is impaired.

Use of Rh (III)-Heteropolymolybdate as Potential Catalysts for the Removal of Nitrates in Human Drinking Water: Synthesis, Characterisation and Catalytic Performance

The investigation and development of technologies to remediate water contaminated with NO3− are constantly increasing. An economically and potentially effective alternative is based on the catalytic hydrogenation of NO3− to N2. With this objective, bimetallic RhMo6 catalysts based on Anderson-type heteropolyanion (RhMo6O24H6)3− were prepared and characteri3ed in order to obtain well-defined bimetallic catalyst. The catalysts were supported on Al2O3 with different textural properties and on silica. The heteropolyanion-support interaction was analysed by temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). The differences obtained in activity and selectivity to the different products can be assigned to the different interaction between the RhMo6 Anderson phase and the supports. The RhMo6/G, (G: γ-Al2O3) system showed the best catalytic performance. This catalyst exhibited the lowest reduction temperature of Rh and Mo in the TPR assay and a Rh/Mo surface ratio similar to that of the original phase, as observed by XPS analysis. These studies allowed us to verify a synergic effect between Rh and Mo, through which Mo reducibility was promoted by the presence of the noble metal. The catalytic activity was favoured by the active sites generated from the Anderson phase. This fact was confirmed by comparing the activity of RhMo6/G with that corresponding to a conventional catalyst prepared through successive impregnation of both Rh (III) and Mo (VI) salts.

Drinking Water Nitrate and Human Health: An Updated Review.

Nitrate levels in our water resources have increased in many areas of the world largely due to applications of inorganic fertilizer and animal manure in agricultural areas. The regulatory limit for nitrate in public drinking water supplies was set to protect against infant methemoglobinemia, but other health effects were not considered. Risk of specific cancers and birth defects may be increased when nitrate is ingested under conditions that increase formation of N-nitroso compounds. We previously reviewed epidemiologic studies before 2005 of nitrate intake from drinking water and cancer, adverse reproductive outcomes and other health effects. Since that review, more than 30 epidemiologic studies have evaluated drinking water nitrate and these outcomes. The most common endpoints studied were colorectal cancer, bladder, and breast cancer (three studies each), and thyroid disease (four studies). Considering all studies, the strongest evidence for a relationship between drinking water nitrate ingestion and adverse health outcomes (besides methemoglobinemia) is for colorectal cancer, thyroid disease, and neural tube defects. Many studies observed increased risk with ingestion of water nitrate levels that were below regulatory limits. Future studies of these and other health outcomes should include improved exposure assessment and accurate characterization of individual factors that affect endogenous nitrosation.

Health-risk assessment related to the fluoride, nitrate, and nitrite in the drinking water in the Sanandaj, Kurdistan County, Iran

ABSTRACTThe concentration of fluoride and nitrate in groundwater is usually higher than that of surface water. The main objective of this study was to estimate the health-risk assessment associated with fluoride, nitrate, and nitrite in drinking water in Sanandaj and its villages. The number of samples in the Sanandaj and its rural was 106. The average concentration of fluoride in urban and rural drinking water was 0.22 mg/l and 0.27 mg/l, respectively. Fluoride concentration was also close to urban and rural drinking water. The concentration of nitrate in urban and rural drinking water was in the range between 0.28–27.77 mg/l and 1.28–80 mg/l, respectively. The concentration of nitrate reported in rural samples was higher than that of urban samples. The maximum concentration of nitrate reported in this study was 80 mg/l. The mean CDI for nitrate in the men, women, and children was 0.4258, 0.5110, and 1.1454, respectively. The findings of this study indicated that all three groups studied were exposed to nitrate contact hazards (HQ > 1). Therefore, the HQ in each of the three groups was higher than 1, which should be carefully monitored and necessary measures should be performed.