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1.
Am J Ophthalmol Case Rep ; 34: 102020, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38404485

ABSTRACT

Purpose: To report a case of unsuccessful transscleral cyclophotocoagulation in a patient with OCA1A tyrosinase-negative oculocutaneous albinism. Observations: A 35-year-old Asian female with molecularly diagnosed OCA1A (tyrosinase-negative) oculocutaneous albinism and unilateral severe mixed mechanism glaucoma underwent transscleral cyclophotocoagulation on two separate occasions to treat elevated intraocular pressure. The intraocular pressure remained markedly elevated approximately 1 month following two separate treatments of transscleral cyclophotocoagulation while using high energy settings. The poor efficacy of both cyclophotocoagulation treatments was most likely due to a lack of melanin in the setting of oculocutaneous albinism. Conclusions and importance: Cyclophotocoagulation in patients with oculocutaneous albinism is less likely to yield a desired lowering of intraocular pressure due to the absence of melanin.

2.
Environ Eng Sci ; 38(5): 355-366, 2021 May 01.
Article in English | MEDLINE | ID: mdl-34079208

ABSTRACT

Household water, sanitation and hygiene (WASH) practices in remote, rural, and unpiped communities are likely to impact exposure to pathogens beyond the fecal-oral transmission routes that are typically prioritized in WASH interventions. We studied 43 homes in two remote, rural, unpiped communities in Alaska to evaluate seasonal water haul, water sources, water quality, and water reuse, as well as greywater and human waste disposal over 1 year. Hauled quantities of water reportedly ranged from 3.0 to 5.4 gallons per capita per day (gpcd) depending on the community and season. Natural, untreated water sources contributed 0.5-1.1 gpcd to household water availability. Reported quantities of water hauled were significantly correlated with total water storage capacity in the home. Total coliforms were detected in 30-60% of stored household water samples from treated and untreated sources, and total coliform counts were significantly higher in specific sources and during specific seasons. Exposure to pathogens during periods of low water access, from untreated water reuse, from greywater disposal and from human waste disposal are important pathways of disease transmission in these remote, rural, unpiped communities. We discuss intermediate steps that can be taken at the household and community levels to interrupt exposure pathways before piped infrastructure is installed. This model of examining specific household practices to determine transmission routes can be applied to other remote communities or unique conditions to aid in the recommendation of targeted WASH interventions.

3.
J Water Health ; 17(5): 788-800, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31638029

ABSTRACT

Rainwater collection is a common source of household water in developed and developing communities where treated on-site water is not available. Although rainwater catchment has been practiced for generations in rural Alaska communities, there are little data available on the quality and quantity of rainwater resources. Forty-eight rainwater samples were collected from nine communities in Alaska over 2 years. Samples were tested for physical water quality parameters, metals, and bacteria. Characteristics of household catchments were recorded. Rainwater quantity in two communities was evaluated. Overall, high-quality water was observed in rain catchments, with average total organic carbon (TOC) and turbidity being lower than or equal to those values in other published rainwater studies. pH was consistently low. Over 80% of samples were below the United States limits for metals and met international microbiological water quality standards. However, variation was observed between households, communities, indoor/outdoor bacteria samples, covered/uncovered storage containers, and over time. The quantity of rainwater available for catchment could supply 17-40% of annual household water and is projected to increase in future decades according to Alaska climate models. Best practices are recommended for rural Alaska communities to maintain the naturally high quality of rainwater and take advantage of large quantities of rainwater available on-site.


Subject(s)
Rain , Water Resources , Water Supply , Alaska , Family Characteristics , Humans , Water , Water Quality
4.
Environ Eng Sci ; 36(7): 843-849, 2019 Jul 01.
Article in English | MEDLINE | ID: mdl-31346306

ABSTRACT

In recent years, there has been increased recognition of the importance of a nexus approach to optimize food, energy, and water (FEW) security at regional and global scales. Remote communities in the Arctic and Subarctic regions in Alaska provide unique examples of closed and isolated systems, wherein the FEW nexus not only needs to be examined to lend resilience to these vulnerable communities but that could also serve as small-scale test beds for a wider and systematic understanding of the FEW nexus. In this short communication, looking at the FEW nexus in Cordova, Alaska, through an energy lens, we introduce an approach (referred to as the "MicroFEWs approach") that may assist remote communities in Alaska in making informed decisions regarding the use of renewable energy to increase FEW security. Our example uses the MicroFEWs approach to assess the impacts of increased renewable energy generation on FEW security in the community, more specifically to food security through potential changes to the community's fish processing industry. This approach can serve as a basis for investigating the FEW nexus in varying contexts and locales.

5.
Int J Clin Oncol ; 24(6): 706-711, 2019 Jun.
Article in English | MEDLINE | ID: mdl-30707342

ABSTRACT

BACKGROUND: Squamous cell carcinoma (SCC) of the bladder is a rare, aggressive malignancy. Unlike urothelial cell carcinoma, SCC is resistant to chemotherapy and guidelines recommend radical cystectomy (RC) without neoadjuvant chemotherapy (NAC). We aimed to evaluate the current management and survival of patients with invasive SCC treated with or without NAC. METHODS: 671 patients with invasive SCC bladder cancer from 2004 to 2015 in the National Cancer Data Base were identified. Patients were stratified by treatment with RC alone or NAC prior to RC (NAC + RC). Survival analysis was performed with Kaplan-Meier and Cox regression. Secondary outcomes included length of stay and readmission. RESULTS: Of 671 patients, 92.8% were treated with RC alone and 7.2% with NAC + RC. Cox regression for mortality was performed including age, Charlson score, clinical stage, and NAC. Increased risk of mortality was noted with increasing age (OR 1.01, p = 0.023) and Charlson score of 1-3 (HR 1.58-1.68, p < 0.05). NAC did not confer survival advantage (HR 1.17, p = 0.46). On Kaplan-Meier analysis, the overall survival was equivalent (log-rank p = 0.804). Hospital stay and readmission were similar between RC and NAC + RC groups. CONCLUSIONS: Analysis of a national tumor registry suggests a lack of overall survival benefit for NAC with localized, muscle invasive SCC of the bladder. Further research directed at chemotherapy regimens for SCC is needed to optimize treatment and improve survival outcomes.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Squamous Cell/mortality , Carcinoma, Transitional Cell/mortality , Neoadjuvant Therapy/mortality , Urinary Bladder Neoplasms/mortality , Aged , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/pathology , Carcinoma, Transitional Cell/drug therapy , Carcinoma, Transitional Cell/pathology , Female , Humans , Male , Prognosis , Survival Rate , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/pathology
6.
Aesthet Surg J ; 39(5): 463-469, 2019 04 08.
Article in English | MEDLINE | ID: mdl-30107493

ABSTRACT

BACKGROUND: Anesthesia for elective ambulatory procedures must provide appropriate pain control while minimizing perioperative risk. Local anesthesia in combination with oral sedation provides a safe office-based method of anesthesia for rhytidectomy. OBJECTIVES: The purpose of this analysis was to identify the incidence of traditional outcome parameters in ambulatory rhytidectomy performed with local anesthesia and oral sedation. METHODS: A retrospective chart review was performed on all patients who underwent office-based rhytidectomy under local anesthesia with oral sedation from February 2011 to May 2017. A total of 174 patients were included. The data collected included patient medical and surgical history, medications, body mass index, tobacco use history, operative time, technique, and concurrent procedures. All intraoperative and postoperative complications were recorded. RESULTS: One hundred and sixty-five patients were female (94.8%) and 9 were male (5.2%) a mean age of 57.6 years (SD ± 7.90). There were 46 complications, including 23 hematomas (13.2%), 6 seromas, 6 episodes of emesis, 5 infections, 4 scar deformities, and 2 ear deformities. Of the 23 hematomas, only 2 required operative evacuation with local anesthesia in the office procedure room. Twenty-one hematomas were small and managed with percutaneous needle aspiration, followed by surveillance. The 5 infections resolved after oral antibiotics only. There were no thromboembolic events or hospitalizations. CONCLUSIONS: The use of only local anesthesia in combination with oral sedation safely permits the performance of rhytidectomy with similar incidence of rhytidectomy-related complications without the risk related to general anesthesia.


Subject(s)
Anesthesia, Local/methods , Conscious Sedation/methods , Rhytidoplasty/methods , Adult , Aged , Ambulatory Surgical Procedures , Female , Humans , Male , Middle Aged , Pain Management/methods , Postoperative Complications/therapy , Retrospective Studies
7.
Environ Sci Pollut Res Int ; 25(33): 33025-33037, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29168139

ABSTRACT

Challenges of water and wastewater management in Alaska include the potential need for above-grade and freeze-protected piping, high unit energy costs and, in many rural areas, low population density and median annual income. However, recently developed net-zero water (NZW), i.e., nearly closed-loop, direct potable water reuse systems, can retain the thermal energy in municipal wastewater, producing warm treated potable water without the need for substantial water re-heating, heat pumping or transfer, or additional energy conversion. Consequently, these systems are projected to be capable of saving more energy than they use in water treatment and conveyance, in the temperate USA. In this paper, NZW technology is reviewed in terms of potential applicability in Alaska by performing a hypothetical case study for the city of Fairbanks, Alaska. Results of this paper study indicate that in municipalities of Alaska with local engineering and road access, the use of NZW systems may provide an energy-efficient water service option. In particular, case study modeling suggests hot water energy savings are equivalent to five times the energy used for treatment, much greater savings than in mid-latitudes, due largely to the substantially higher energy needed for heating water from a conventional treatment system and lack of need for freeze-protected piping. Further study of the applicability of NZW technology in cold regions, with expanded evaluation in terms of system-wide lifecycle cost, is recommended.


Subject(s)
Waste Disposal, Fluid/methods , Water Purification/methods , Alaska , Cities , Drinking Water , Humans , Population Density , Temperature , Waste Disposal, Fluid/economics , Water Purification/economics , Water Supply/economics
8.
Environ Sci Pollut Res Int ; 25(33): 32873-32880, 2018 Nov.
Article in English | MEDLINE | ID: mdl-28353111

ABSTRACT

Forty-two communities in rural Alaska are considered unserved or underserved with water and sewer infrastructure. Many challenges exist to provide centralized piped water and sewer infrastructure to the homes, and they are exacerbated by decreasing capital funding. Unserved communities in rural Alaska experience higher rates of disease, supporting the recommendation that sanitation infrastructure should be provided. Organizations are pursuing alternative solutions to conventional piped water and sewer in order to maximize water use and reuse for public health. This paper reviews initiatives led by the State of Alaska, the Alaska Native Tribal Health Consortium, and the Yukon Kuskokwim Health Corporation to identify and develop potential long-term solutions appropriate and acceptable to rural communities. Future developments will likely evolve based on the lessons learned from the initiatives. Recommendations include Alaska-specific research needs, increased end-user participation in the design process, and integrated monitoring, evaluation, and information dissemination in future efforts.


Subject(s)
Waste Disposal, Fluid/methods , Water Supply , Alaska , Drinking Water , Family Characteristics , Humans , Public Health , Recycling/trends , Rural Population , Sanitation , Sewage , Waste Disposal, Fluid/instrumentation , Water Quality , Water Supply/economics , Water Supply/methods
9.
Water Environ Res ; 88(6): 510-20, 2016 Jun.
Article in English | MEDLINE | ID: mdl-27225781

ABSTRACT

Snowpacks in urban environments can retain a high load of anthropogenic contaminants that, upon melting, can deliver concentrated contaminant pulses into the aquatic environment. In climates with an extended period of snowfall accumulation, such as in Anchorage, Alaska, contaminant amplification within meltwater may affect aquatic ecosystem health. A spatiotemporal study of benzotriazoles on snow, meltwater and soils was performed in association with three urban snow disposal facilities. Benzotriazole elution from engineered snow disposal sites behaved similarly to inorganic salt and dissolved organic carbon (DOC) during the initial melt period, with maximum concentrations between 2.23-7.39 µg/L; similar enrichment was observed in creeks. Assays of disposal site soils revealed the presence of tolytriazole. Furthermore, using fluorescence spectroscopy and PARAFAC analysis, a modeled component representative of benzotriazoles was identified, a possible indicator of anthropogenic input rather than a unique indicator for benzotriazole compounds.


Subject(s)
Snow/chemistry , Soil Pollutants/analysis , Triazoles/analysis , Water Pollutants, Chemical/analysis , Alaska , Environmental Monitoring , Freezing , Seasons
10.
J Water Health ; 12(4): 663-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25473974

ABSTRACT

Residents of urban developing communities often have a tap in their home providing treated and sometimes filtered water but its microbial quality cannot be guaranteed. Point-of-use (POU) disinfection systems can provide safe drinking water to the millions who lack access to clean water in urban communities. While many POU systems exist, there are several concerns that can lead to low user acceptability, including low flow rate, taste and odor issues, high cost, recontamination, and ineffectiveness at treating common pathogens. An ultraviolet (UV) POU system was constructed utilizing developing community-appropriate materials and simple construction techniques based around an inexpensive low-wattage, low pressure UV bulb. The system was tested at the bench scale to characterize its hydrodynamic properties and microbial disinfection efficacy. Hydraulically the system most closely resembled a plug flow reactor with minor short-circuiting. The system was challenge tested and validated for a UV fluence of 50 mJ/cm(2) and greater, over varying flow rates and UV transmittances, corresponding to a greater than 4 log reduction of most pathogenic bacteria, viruses, and protozoa of public health concern. This study presents the designed system and testing results to demonstrate the potential architecture of a low-cost, open-source UV system for further prototyping and field-testing.


Subject(s)
Bacteria/radiation effects , Developing Countries , Disinfection/methods , Drinking Water/microbiology , Ultraviolet Rays , Viruses/radiation effects , Water Purification/methods , Drinking Water/parasitology , Drinking Water/virology
11.
Water Res ; 49: 327-38, 2014 Feb 01.
Article in English | MEDLINE | ID: mdl-24384525

ABSTRACT

The use of fluorescence spectroscopy for the analysis and characterization of dissolved organic matter (DOM) has gained widespread interest over the past decade, in part because of its ease of use and ability to provide bulk DOM chemical characteristics. However, the lack of standard approaches for analysis and data evaluation has complicated its use. This study utilized comparative statistics to systematically evaluate commonly used fluorescence metrics for DOM characterization to provide insight into the implications for data analysis and interpretation such as peak picking methods, carbon-normalized metrics and the fluorescence index (FI). The uncertainty associated with peak picking methods was evaluated, including the reporting of peak intensity and peak position. The linear relationship between fluorescence intensity and dissolved organic carbon (DOC) concentration was found to deviate from linearity at environmentally relevant concentrations and simultaneously across all peak regions. Comparative analysis suggests that the loss of linearity is composition specific and likely due to non-ideal intermolecular interactions of the DOM rather than the inner filter effects. For some DOM sources, Peak A deviated from linearity at optical densities a factor of 2 higher than that of Peak C. For carbon-normalized fluorescence intensities, the error associated with DOC measurements significantly decreases the ability to distinguish compositional differences. An in-depth analysis of FI determined that the metric is mostly driven by peak emission wavelength and less by emission spectra slope. This study also demonstrates that fluorescence intensity follows property balance principles, but the fluorescence index does not.


Subject(s)
Organic Chemicals/analysis , Algorithms , Fluorescence , Humic Substances/analysis , Reproducibility of Results , Rivers/chemistry , Solubility , Spectrometry, Fluorescence
12.
Chemosphere ; 93(9): 1948-56, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23911263

ABSTRACT

Dimer formation was observed during ultraviolet (UV) photolysis of the anti-inflammatory drug diclofenac, and confirmed with mass spectrometry, NMR and fluorescence analysis. The dimers were combinations of the two parent molecules or of the parent and the product of photolysis, and had visible color. Radical formation during UV exposure and dissolved oxygen photosensitized reactions played a role in dimer formation. Singlet oxygen formed via photosensitization by photolysis products of diclofenac. It reacted with diclofenac to form an epoxide which is an intermediate in some dimer formation pathways. Quantum yield of photolysis for diclofenac was 0.21±0.02 and 0.19±0.02 for UV irradiation from medium pressure and low pressure mercury vapor lamps, respectively. Band pass filter experiments revealed that the quantum yield is constant at wavelengths >200 nm. The same dimers formed in laboratory grade water when either of the two UV sources was used. Dimers did not form in wastewater effluent matrix, and diclofenac epoxide molecules may have formed bonds with organic matter rather than each other Implications for the importance of dimer formation in NOM are discussed.


Subject(s)
Diclofenac/chemistry , Photolysis , Wastewater/chemistry , Water Pollutants, Chemical/chemistry , Water Purification/methods , Diclofenac/analysis , Water Pollutants, Chemical/analysis
13.
Water Res ; 46(15): 4653-64, 2012 Oct 01.
Article in English | MEDLINE | ID: mdl-22763290

ABSTRACT

Ultraviolet (UV) disinfection is being increasingly used in drinking water treatment. It is important to understand how its application to different types of water may influence finished water quality, particularly as anthropogenic activity continues to impact the quality of source waters. The objective of this study was to evaluate the effect of inorganic precursors on the formation of regulated and unregulated disinfection byproducts (DBPs) during UV irradiation of surface waters when combined with chlorination or chloramination. Samples were collected from three drinking water utilities supplied by source waters with varying organic and inorganic precursor content. The filtered samples were treated in the laboratory with a range of UV doses delivered from low pressure (LP, UV output at 253.7 nm) and medium pressure (MP, polychromatic UV output 200-400 nm) mercury lamps followed by chlorination or chloramination, in the presence and absence of additional bromide and nitrate. The regulated trihalomethanes and haloacetic acids were not affected by UV pretreatment at disinfection doses (40-186 mJ/cm²). With higher doses (1000 mJ/cm²), trihalomethane formation was increased 30-40%. While most effects on DBPs were only observed with doses much higher than typically used for UV disinfection, there were some effects on unregulated DBPs at lower doses. In nitrate-spiked samples (1-10 mg N/L), chloropicrin formation doubled and increased three- to six-fold with 40 mJ/cm² MP UV followed by chloramination and chlorination, respectively. Bromopicrin formation was increased in samples containing bromide (0.5-1 mg/L) and nitrate (1-10 mg N/L) when pretreated with LP or MP UV (30-60% with 40 mJ/cm² LP UV and four- to ten-fold increase with 40 mJ/cm² MP UV, after subsequent chlorination). The formation of cyanogen chloride doubled and increased three-fold with MP UV doses of 186 and 1000 mJ/cm², respectively, when followed by chloramination in nitrate-spiked samples but remained below the World Health Organization guideline value of 70 µg/L in all cases. MP UV and high LP UV doses (1000 mJ/cm²) increased chloral hydrate formation after subsequent chlorination (20-40% increase for 40 mJ/cm² MP UV). These results indicate the importance of bench-testing DBP implications of UV applications in combination with post-disinfectants as part of the engineering assessment of a UV-chlorine/chloramine multi-barrier disinfection design for drinking water treatment.


Subject(s)
Chloramines/chemistry , Chlorine/chemistry , Disinfection , Ultraviolet Rays , Water Supply
14.
Environ Sci Technol ; 45(8): 3657-64, 2011 Apr 15.
Article in English | MEDLINE | ID: mdl-21417331

ABSTRACT

The application of UV disinfection in water treatment is increasing due to both its effectiveness against protozoan pathogens, and the perception that its lack of chemical inputs would minimize disinfection byproduct formation. However, previous research has indicated that treatment of nitrate-containing drinking waters with polychromatic medium pressure (MP), but not monochromatic (254 nm) low pressure (LP), UV lamps followed by chlorination could promote chloropicrin formation. To better understand this phenomenon, conditions promoting the formation of the full suite of chlorinated halonitromethanes and haloacetonitriles were studied. MP UV/postchlorination of authentic filter effluent waters increased chloropicrin formation up to an order of magnitude above the 0.19 µg/L median level in the U.S. EPA's Information Collection Rule database, even at disinfection-level fluences (<300 mJ/cm(2)) and nitrate/nitrite concentrations (1.0 mg/L-N) relevant to drinking waters. Formation was up to 2.5 times higher for postchlorination than for postchloramination. Experiments indicated that the nitrating agent, NO(2)(•), generated during nitrate photolysis, was primarily responsible for halonitromethane promotion. LP UV treatment up to 1500 mJ/cm(2) did not enhance halonitromethane formation. Although MP UV/postchloramination enhanced dichloroacetonitrile formation with Sigma-Aldrich humic acid, formation was not significant in field waters. Prechlorination/MP UV nearly doubled chloropicrin formation compared to MP UV/postchlorination, but effects on haloacetonitrile formation were not significant.


Subject(s)
Acetonitriles/chemical synthesis , Halogenation , Methane/analogs & derivatives , Nitroparaffins/chemical synthesis , Ultraviolet Rays , Water Pollutants, Chemical/chemical synthesis , Water Purification/methods , Acetonitriles/analysis , Disinfectants/analysis , Disinfectants/chemistry , Disinfectants/radiation effects , Disinfection/methods , Fresh Water/chemistry , Hydrocarbons, Chlorinated/analysis , Hydrocarbons, Chlorinated/chemical synthesis , Methane/analysis , Methane/chemical synthesis , Nitroparaffins/analysis , Photochemical Processes , Water Pollutants, Chemical/analysis , Water Supply/analysis
15.
Water Res ; 44(12): 3703-13, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20471054

ABSTRACT

Ultraviolet (UV) irradiation has become popular as a primary disinfectant because it is very effective against Cryptosporidium and does not directly form regulated disinfection by-products. Higher UV doses and UV advanced oxidation (UV/H2O2) processes are under consideration for the treatment of trace organic pollutants (e.g. pharmaceuticals, personal care products). Despite the disinfection effectiveness of UV light, a secondary disinfectant capable of maintaining a distribution system residual is required to meet current U.S. regulation. This study investigated changes in disinfection by-product (DBP) formation attributed to UV or UV/H2O2 followed by application of free chlorine to quench hydrogen peroxide and provide residual disinfectant. At a UV dose of 1000 mJ/cm(2), trihalomethane (THM) yield increased by up to 4 microg/mg-C and 13 microg/mg-C when treated with low and medium pressure UV, respectively. With the addition of hydrogen peroxide, THM yield increased by up to 25 microg/mg-C (5mg-H2O2/L) and 37 microg/mg-C (10 mg-H2O2/L). Although no changes in DBPs are expected during UV disinfection, application of UV advanced oxidation followed by chlorine addition was assessed with regard to impacts on DBP formation.


Subject(s)
Disinfection , Halogenation , Hydrogen Peroxide/chemistry , Ultraviolet Rays , Water Purification/methods , Water Supply/analysis , Bromine/analysis , Chlorine/analysis , Hydroxyl Radical/chemistry , Organic Chemicals/analysis , Pressure , Solubility
16.
Environ Sci Technol ; 43(2): 466-72, 2009 Jan 15.
Article in English | MEDLINE | ID: mdl-19238981

ABSTRACT

Strong base anion-exchange resins represent an important option for water utilities and homeowners to address growing concerns with nitrate, arsenate, and perchlorate contamination of source waters. Most commercially available anion-exchange resins employ quaternary amine functional groups. Previous research has provided contradictory evidence regarding whether these resins serve as sources of nitrosamines, considered as highly carcinogenic nitrogenous disinfection byproducts (N-DBPs), even without disinfectants. For three common varieties of commercial anion-exchange resins, we evaluated the importance of releases of nitrosamines, and two other N-DBPs (dimethylnitramine and chloropicrin), when the resins were subjected to typical column flow conditions with and without free chlorine or chloramine application upstream or downstream of the columns. In the absence of disinfectants, fresh trimethylamine- and tributylamine-based type 1 and dimethylethanolamine-based type 2 anion-exchange resins usually released 2-10 ng/L nitrosamines, likely due to shedding of manufacturing impurities, with excursions of up to 20 ng/L following regeneration. However, the lack of significant nitrosamine release in a full-scale anion-exchange treatment system after multiple regeneration cycles indicates that releases may eventually subside. Resins also shed organic precursors that might contribute to nitrosamine formation within distribution systems when chloramines are applied downstream. With free chlorine or chloramine application upstream, nitrosamine concentrations were more significant, at 20-100 ng/L for the type 1 resins and approximately 400 ng/L for the type 2 resin. However, chloropicrin formation was lowest for the type 2 resin. Dimethylnitramine formation was significant with free chlorine application upstream but negligible with chloramines. Although no N-DBPs were detected in cation-exchange-based consumer point-of-use devices exposed to chlorinated or chloraminated waters, our results indicate that inclusion of anion-exchange resins in these devices, as in laboratory deionized water systems, would likely be problematic.


Subject(s)
Alkalies/chemistry , Anion Exchange Resins/chemistry , Dimethylamines/chemical synthesis , Hydrocarbons, Chlorinated/chemical synthesis , Nitrosamines/chemical synthesis , Chloramines/chemistry , Chlorine/chemistry , Dimethylnitrosamine/analysis , Nitrogen/chemistry , Nitrosamines/analysis , Oxidants/chemistry , Waste Disposal, Fluid , Water/chemistry
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