Use of Pulsed-UV Processes to Destroy NDMA

About five years ago, N-nitrosodimethylamine (NDMA) began to be detected in drinking water sources. Typically an oxidative degradation product of unsymmetrical dimethylhydrazine, NDMA is a component of rocket fuel and is also formed during numerous industrial manufacturing processes as a byproduct of reactions involving chemicals called alkylamines. The US Environmental Protection Agency has identified NDMA as a probable human carcinogen. However, because NDMA had not historically been considered a common drinking water contaminant, no federal or state drinking water standards were established for it until 1998 in California. In addition to its presence in drinking water, it has recently been suggested that NDMA may be present in sewage and reclaimed water after chlorination, as well as surface water processed by conventional drinking water treatment methods. The mechanisms of NDMA formation appear to be associated with the chlorination process. Therefore, an urgent need has developed for technologies that can remediate drinking water sources contaminated by this compound. This need sparked a growing interest in the potential of pulsed-ultraviolet (UV) and pulsed-UV/hydrogen peroxide treatment processes for removing NDMA from drinking water. The authors of this article evaluated the effectiveness of these treatments for NDMA removal. The results showed that NDMA can be reduced with UV light treatment. This finding will help drinking water utilities to better comply with state and federal standards and to more effectively protect public health

A prospective study of rural drinking water quality and acute gastrointestinal illness

BACKGROUND: This study examined the relationship between the bacteriological contamination of drinking water from private wells and acute gastrointestinal illness (AGII), using current government standards for safe drinking water. METHODS: A prospective cohort study was conducted using 235 households (647 individuals) randomly selected from four rural hamlets. Data were collected by means of a self-administered questionnaire, a self-report diary of symptoms and two drinking water samples. RESULTS: Twenty percent of households sampled, had indicator bacteria (total coliform or Escherichia coli (E. coli)) above the current Canadian and United States standards for safe drinking water. No statistically significant associations between indicator bacteria and AGII were observed. The odds ratio (OR) for individuals exposed to E. coli above the current standards was 1.52 (95% confidence interval (CI), 0.33–6.92), compared to individuals with levels below current standards. The odds ratio estimate for individuals exposed to total coliforms above the current standards was 0.39 (95% CI, 0.10–1.50). CONCLUSIONS: This study observed a high prevalence of bacteriological contamination of private wells in the rural hamlets studied. Individual exposure to contaminated water defined by current standards may be associated with an increased risk of AGII

Many Rivers to Cross: Evaluating the Benefits and Limitations of Strategic Environmental Assessment for the Koshi River Basin

This paper assesses the value of using Strategic Environmental Assessment (SEA) to account for the spatially and temporally diverse and diffuse impacts of hydropower development in South Asia’s Koshi basin. A policy and practice review and key stakeholder interviews identified opportunities for SEA to improve existing planning procedures, but also barriers to effective adoption. Whilst stakeholders are interested in employing SEA to evaluate cumulative impacts, institutional blockages and an economic development imperative for power generation leave little space for consideration of alternative scenarios as part of SEA. The analysis is conducted through the formulation and application of a conceptual framework for SEA best practice which is then used to identify priority next-steps for SEA in the region

Change in Sediment Features and the Macroinvertebrate Community Within an Estuarine Ecosystem Two Years Post‐restoration

Our objective was to assess the response of an estuarine ecosystem to restoration efforts, two years post‐restoration. Sediment attributes of particle size distribution (PSD), %LOI, water content and amounts of fine wood debris (FWD), and the macroinvertebrate community were compared among three sites, two reference and the recently restored site. The restored region had been previously used as a log sorting facility. As indicated by PSD, the restored site showed signs of recovery. However, the macroinvertebrate community had still not responded to restoration efforts. Sediments of reference sites were comprised of fine sand, and the macroinvertebrate community was dominated by Macoma spp. By contrast, at the restored site, sediments were mainly comprised of silt followed by fine sand, Macoma spp. was absent, and the main macroinvertebrate was Glycera americana, a polychaeta characteristic of disturbed regions. The restored site still contained significance amounts of FWD as compared to the two reference sites attributed to its previous use. Although still early in its recovery stage, active restoration did have a positive effect and will have likely kick started the region toward recovery and further follow‐up in five years is recommended