Nitrate-nitrogen levels in rural drinking water: Is there an association with age-related macular degeneration?
ABSTRACT We examined the association of nitrate-nitrogen exposure from rural private drinking water and incidence of age-related macular degeneration (AMD). All participants in the Beaver Dam Eye Study (53916 improvement plan code) completed a questionnaire and had an ocular examination including standardized, graded fundus photographs at five examinations. Only information from rural residents in that study are included in this report. Data from an environmental monitoring study with probabilistic-based agro-chemical sampling, including nitrate-nitrogen, of rural private drinking water were available. Incidence of early AMD was associated with elevated nitrate-nitrogen levels in rural private drinking water supply (10.0% for low, 19.2% for medium, and 26.1% for high nitrate-nitrogen level in the right eye). The odds ratios (ORs) were 1.77 (95% confidence interval [CI]: 1.12-2.78) for medium and 2.88 (95% CI: 1.59-5.23) for high nitrate-nitrogen level. Incidence of late AMD was increased for those with medium or high levels of nitrate-nitrogen compared to low levels (2.3% for low and 5.1% for the medium or high nitrate-nitrogen level, for the right eye). The OR for medium or high nitrate-nitrogen groups was 2.80 (95% CI: 1.07-7.31) compared to the low nitrate-nitrogen group.
SourceAvailable from: Qian Li[Show abstract] [Hide abstract]
ABSTRACT: Degradation of water quality is an emerging problem in many developing countries. Bioassay is an effective approach to monitor quality of water in aquatic environments. Studies have used luminescent bacteria and zebrafish embryos as bioassay tools in monitoring river water quality. In this study, luminous bacteria (Vibrio qinghaiensis sp. Q67) assay and zebrafish (Danio rerio) embryo toxicity test were performed to assess the ecotoxicity of surface water from the Huangpu River, China, collected during 2012–2013. River water samples inhibited the luminescence [inhibition rates 0–34.6% (±4.82%)] of Q67 and increased the lethal rates and induced morphological abnormalities in zebrafish embryos. The toxicity to luminous bacteria and zebrafish embryos were higher in winter than in summer months. In addition, samples collected in industrial area, urban sampling sites near drainage outlets, and at the intersection of the tributary that flows into the Huangpu River showed higher toxicity.Ecotoxicology and Environmental Safety 11/2014; DOI:10.1016/j.ecoenv.2014.10.037 · 2.48 Impact Factor
[Show abstract] [Hide abstract]
ABSTRACT: Nitrate is harmful to humans as it can form endogenous nitrosamines which can cause cancer. The major contribution of nitrate contamination in well water is largely from agricultural activities (e.g.; fertilizers and pesticide), wastewater treatment plant discharge, animal yard and manure storage lagoons. Biomarkers such as urine and saliva can be used to determine the occurrence and formation of nitrosamines in the human body. This paper provides an overview of nitrate occurrence in groundwater and the mechanism of nitrosamines formation and its excretion from human body via urine and saliva. The suitability of urine and saliva as biomarkers of endogenous nitrosamines formation were also discussed in this review.