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1.
Environ Health Perspect ; 118(1): 42-8, 2010 Jan.
Article in English | MEDLINE | ID: mdl-20056583

ABSTRACT

OBJECTIVE: Perchlorate inhibits the uptake of iodide in the thyroid. Iodide is required to synthesize hormones critical to fetal and neonatal development. Many water supplies and foods are contaminated with perchlorate. Exposure standards are needed but controversial. Here we summarize the basis of the Massachusetts (MA) perchlorate reference dose (RfD) and drinking water standard (DWS), which are considerably lower and more health protective than related values derived by several other agencies. We also review information regarding perchlorate risk assessment and policy. DATA SOURCES: MA Department of Environmental Protection (DEP) scientists, with input from a science advisory committee, assessed a wide range of perchlorate risk and exposure information. Health outcomes associated with iodine insufficiency were considered, as were data on perchlorate in drinking water disinfectants. DATA SYNTHESIS: We used a weight-of-the-evidence approach to evaluate perchlorate risks, paying particular attention to sensitive life stages. A health protective RfD (0.07 microg/kg/day) was derived using an uncertainty factor approach with perchlorate-induced iodide uptake inhibition as the point of departure. The MA DWS (2 microg/L) was based on risk management decisions weighing information on perchlorate health risks and its presence in certain disinfectant solutions used to treat drinking water for pathogens. CONCLUSIONS: Current data indicate that perchlorate exposures attributable to drinking water in individuals at sensitive life stages should be minimized and support the MA DEP perchlorate RfD and DWS. Widespread exposure to perchlorate and other thyroid toxicants in drinking water and foods suggests that more comprehensive policies to reduce overall exposures and enhance iodine nutrition are needed.


Subject(s)
Perchlorates/standards , Perchlorates/toxicity , Water Pollutants, Chemical/standards , Water Pollutants, Chemical/toxicity , Water Supply/standards , Conservation of Natural Resources , Government Agencies , Humans , Iodides/metabolism , Ion Transport/drug effects , Massachusetts , Perchlorates/analysis , Risk Assessment , Thyroid Gland/drug effects , Thyroid Gland/metabolism , Water Pollutants, Chemical/analysis
2.
J Environ Manage ; 91(2): 303-10, 2009.
Article in English | MEDLINE | ID: mdl-19850401

ABSTRACT

Perchlorate, an anion that originates as a contaminant in ground and surface waters, is both naturally occurring and manmade. Because of its toxicity, there has been increased interest in setting drinking water safety standards and in health effects when perchlorate is present at low (parts per billion (ppb)) levels. In January 2009, the EPA issued a heath advisory to assist state and local officials in addressing local contamination of perchlorate in drinking water. The interim health advisory level of 15 micrograms per liter (microg/L), or ppb, is based on the reference dose recommended by the National Research Council (NRC) of the National Academy of Sciences (NAS). This paper describes scope and extent of contaminant issues and a legal process of setting standards for perchlorate concentration in drinking water in the United States of America.


Subject(s)
Perchlorates/standards , Water Pollutants, Chemical/standards , Water Supply/standards , Risk Assessment , United States
3.
Int J Environ Res Public Health ; 6(4): 1418-42, 2009 04.
Article in English | MEDLINE | ID: mdl-19440526

ABSTRACT

Perchlorate has been found in drinking water and surface waters in the United States and Canada. It is primarily associated with release from defense and military operations. Natural sources include certain fertilizers and potash ores. Although it is a strong oxidant, perchlorate is very persistent in the environment. At high concentrations perchlorate can affect the thyroid gland by inhibiting the uptake of iodine. A maximum contaminant level has not been set, while a guidance value of 6 ppb has been suggested by Health Canada. Perchlorate is measured in environmental samples primarily by ion chromatography. It can be removed from water by anion exchange or membrane filtration. Biological and chemical processes are also effective in removing this species from water.


Subject(s)
Perchlorates/isolation & purification , Perchlorates/toxicity , Water Pollutants, Chemical/isolation & purification , Water Pollutants, Chemical/toxicity , Animals , Biodegradation, Environmental , Canada , Humans , Perchlorates/standards , Risk Assessment , United States , Water Pollutants, Chemical/standards
4.
Environ Health Perspect ; 115(3): 361-9, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17431484

ABSTRACT

BACKGROUND: Perchlorate is a common contaminant of drinking water and food. It competes with iodide for uptake into the thyroid, thus interfering with thyroid hormone production. The U.S. Environmental Protection Agency's Office of Solid Waste and Emergency Response (OSWER) set a groundwater preliminary remediation goal (PRG) of 24.5 microg/L to prevent exposure of pregnant women that would affect the fetus. This does not account for the greater exposure that is possible in nursing infants or for the relative source contribution (RSC), a factor normally used to lower the PRG due to nonwater exposures. OBJECTIVES: Our goal was to assess whether the OSWER PRG protects infants against exposures from breast-feeding, and to evaluate the perchlorate RSC. METHODS: We used Monte Carlo analysis to simulate nursing infant exposures associated with the OSWER PRG when combined with background perchlorate. RESULTS: The PRG can lead to a 7-fold increase in breast milk concentration, causing 90% of nursing infants to exceed the reference dose (RfD) (average exceedance, 2.8-fold). Drinking-water perchlorate must be < 6.9 microg/L to keep the median, and < 1.3 microg/L to keep the 90th-percentile nursing infant exposure below the RfD. This is 3.6- to 19-fold below the PRG. Analysis of biomonitoring data suggests an RSC of 0.7 for pregnant women and of 0.2 for nursing infants. Recent data from the Centers for Disease Control and Prevention (CDC) suggest that the RfD itself needs to be reevaluated because of hormonal effects in the general population. CONCLUSIONS: The OSWER PRG for perchlorate can be improved by considering infant exposures, by incorporating an RSC, and by being responsive to any changes in the RfD resulting from the new CDC data.


Subject(s)
Environmental Exposure/analysis , Maternal Exposure , Perchlorates/standards , Water Pollutants, Chemical/standards , Water Supply/standards , Adolescent , Adult , Chile , Female , Humans , Infant, Newborn , Milk, Human/chemistry , Perchlorates/analysis , Perchlorates/urine , Pregnancy , United States , United States Environmental Protection Agency/legislation & jurisprudence , Waste Management , Water Pollutants, Chemical/analysis , Water Pollutants, Chemical/urine , Water Supply/analysis
6.
J Chromatogr A ; 1118(1): 94-9, 2006 Jun 16.
Article in English | MEDLINE | ID: mdl-16516898

ABSTRACT

US Environmental Protection Agency (EPA) Method 331 determines perchlorate in drinking water using non-suppressed ion chromatography with tandem mass spectrometry. This study reports the results of calibration and recovery studies in reagent water, as well as of a recovery study in simulated drinking water (i.e., total dissolved solids are 500 mg/mL each of chloride, sulfate, and bicarbonate). The perchlorate concentrations in the study ranged from 0.05 to 64 ng/mL. At 95% confidence, the Hubaux-Vos detection limit (H-V DL) was 0.04 ng/mL for the calibration study and the simulated-drinking-water recovery study, and 0.03 ng/mL for the reagent-water recovery study. The lowest concentration minimum reporting level was 0.03 ng/mL for reagent water and 0.0 7 ng/mL for simulated drinking water, again at 95% confidence.


Subject(s)
Guidelines as Topic , Perchlorates/analysis , Water Supply/analysis , Calibration , Chromatography, Liquid/instrumentation , Chromatography, Liquid/methods , Chromatography, Liquid/standards , Ions/chemistry , Mass Spectrometry/methods , Perchlorates/standards , Reference Standards , Regression Analysis , Reproducibility of Results , United States , United States Environmental Protection Agency
7.
J Chromatogr A ; 1118(1): 100-5, 2006 Jun 16.
Article in English | MEDLINE | ID: mdl-16516902

ABSTRACT

Macrocycle-based ion chromatography provides a convenient, reliable method for the determination of perchlorate ion, which is currently of great interest to the environmental community. This study shows that effective perchlorate determinations can be made using standard conductimetric detection by combining an 18-crown-6-based mobile phase with an underivatized reversed-phase mobile phase ion chromatography (MPIC) column. One unique feature of this method is the flexibility in column capacity that is achieved through simple variations in eluent concentrations of 18-crown-6 and KOH, facilitating the separation of target analyte anions such as perchlorate. Using a standard anion exchange column as concentrator makes possible the determination of perchlorate as low as 0.2 ug/L in low ionic strength matrices. Determination of perchlorate at the sub-ug/L level in pure water and in spiked local city hard water samples with high background ion concentrations can be achieved this way. However, like other IC techniques, this method is challenged to achieve analyses at the ug/L level in the demanding high ionic strength matrix described by the United States Environmental Protection Agency (EPA) (1,000 mg/L chloride, sulfate and carbonate). We approached this challenge by use of the Cryptand C1 concentrator column, provided by Dionex Corporation, to effectively preconcentrate perchlorate while reducing background ion concentrations in the high ionic strength matrix. The retention characteristics of the concentrator column were studied in order to maximize its effectiveness for perchlorate determinations. The method makes possible the determination of perchlorate at the 5 ug/L level in the highest ionic strength matrix described by the EPA.


Subject(s)
Chromatography, Ion Exchange/methods , Perchlorates/analysis , Water Supply/analysis , Chromatography, Ion Exchange/instrumentation , Chromatography, Ion Exchange/standards , Crown Ethers/chemistry , Ethers, Cyclic/chemistry , Perchlorates/standards , Reproducibility of Results , Schiff Bases/chemistry , Sodium Compounds/analysis , United States , United States Environmental Protection Agency
8.
J Chromatogr A ; 1118(1): 85-93, 2006 Jun 16.
Article in English | MEDLINE | ID: mdl-16529757

ABSTRACT

Since 1997 there has been increasing interest in the development of analytical methods for the analysis of perchlorate. The US Environmental Protection Agency (EPA) Method 314.0, which was used during the first Unregulated Contaminant Monitoring Regulation (UCMR) cycle, supports a method reporting limit (MRL) of 4.0 microg/L. The non-selective nature of conductivity detection, combined with very high ionic strength matrices, can create conditions that make the determination of perchlorate difficult. The objective of this work was to develop an automated, suppressed conductivity method with improved sensitivity for use in the second UCMR cycle. The new method, EPA Method 314.1, uses a 35 mm x 4 mm cryptand concentrator column in the sample loop position to concentrate perchlorate from a 2 mL sample volume, which is subsequently rinsed with 10 mM NaOH to remove interfering anions. The cryptand concentrator column is combined with a primary AS16 analytical column and a confirmation AS20 analytical column. Unique characteristics of the cryptand column allow perchlorate to be desorbed from the cryptand trap and refocused on the head of the guard column for subsequent separation and analysis. EPA Method 314.1 has a perchlorate lowest concentration minimum reporting level (LCMRL) of 0.13 microg/L in both drinking water and laboratory synthetic sample matrices (LSSM) containing up to 1,000 microg/L each of chloride, bicarbonate and sulfate.


Subject(s)
Guidelines as Topic , Perchlorates/analysis , Water Supply/analysis , Chromatography, Liquid/instrumentation , Chromatography, Liquid/methods , Chromatography, Liquid/standards , Ethers, Cyclic/chemistry , Perchlorates/standards , Reference Standards , Reproducibility of Results , Schiff Bases/chemistry , Sodium Compounds/analysis , Solvents/chemistry , Temperature , United States , United States Environmental Protection Agency
10.
Environ Toxicol Chem ; 23(6): 1441-51, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15376530

ABSTRACT

The anion perchlorate (ClO4-) is an oxidizing component commonly used in solid propellants for rockets and missiles; in explosives, flares, fireworks, chemical processes, and automobile air-bag inflators; and for other assorted uses. With recent advances in analytical detection capability, perchlorate has been found in a variety of ground and surface waters throughout the United States. Because perchlorate has been associated with thyroid problems in humans and may have similar effects on wildlife, it is desirable to develop a water-quality criterion to assist in identifying concentrations of perchlorate in water likely to pose an ecological health risk. In the present study, we compiled all available data regarding the effects of perchlorate to aquatic organisms, and we performed additional toxicity and bioconcentration tests as required by the U.S. Environmental Protection Agency (U.S. EPA) for the development of water-quality criteria for aquatic life. A criterion maximum concentration of 20 mg/L and a criterion continuous concentration of 9.3 mg/L were calculated based on the test results. Although these are not formal Clean Water Act Section 304(a) criteria, which must be published by the U.S. EPA, these criteria may be useful in the determination of remedial action levels for contaminated sites, for National Pollutant Discharge Elimination System permit limits, and other water-quality management practices.


Subject(s)
Perchlorates/standards , Perchlorates/toxicity , Sodium Compounds/standards , Sodium Compounds/toxicity , Water Pollutants, Chemical/standards , Water Pollutants, Chemical/toxicity , Animals , Humans , Perchlorates/pharmacokinetics , Public Health , Quality Control , Reference Values , Risk Assessment , Sodium Compounds/pharmacokinetics , Tissue Distribution , United States , United States Environmental Protection Agency , Water Pollutants, Chemical/pharmacokinetics
11.
Regul Toxicol Pharmacol ; 39(3): 348-62, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15135213

ABSTRACT

Despite many physiological similarities, humans and rats exhibit notably different susceptibilities to thyroid perturbation. Considerable research has recently been conducted on the thyroid-active chemical perchlorate, a chemical of emerging environmental and regulatory interest. While the data indicate humans and rats exhibit similar dose-response relationships in terms of acute inhibition of thyroidal iodide uptake, the two species appear to exhibit notable differences in terms of thyroid hormone response, the toxicologically significant consequence of iodide uptake inhibition. We analyzed dose-response data for changes in serum T(3), T(4), and TSH levels from studies in humans, rats, mice, and rabbits. We found that thyroid homeostasis in the rat appears to be strikingly more sensitive to perchlorate than any of the other species. Rats exhibited an increase in serum TSH at 0.1mg/kg-day whereas other species remained unresponsive even at doses of 10mg/kg-day. Less pronounced but consistent effects were seen with serum T(3) and T(4). These cross-species comparisons provide strong evidence that data obtained from rat studies should be critically evaluated for their relevance to humans. If rat data are used to develop toxicity criteria for perchlorate, we propose that this is an instance where an inter-species uncertainty factor less than one is supportable. DISCLOSURE STATEMENT: One of the authors (BDB) has been hired by Lockheed Martin Corporation as an expert in litigation involving perchlorate. A portion of the initial research presented in this paper was conducted in conjunction with her role in that matter.


Subject(s)
Perchlorates/pharmacology , Sodium Compounds/pharmacology , Thyroid Gland/drug effects , Animals , Dose-Response Relationship, Drug , Homeostasis/drug effects , Humans , Iodides/metabolism , Models, Animal , Perchlorates/standards , Perchlorates/toxicity , Rats , Risk Assessment , Sodium Compounds/standards , Sodium Compounds/toxicity , Species Specificity , Symporters/metabolism , Thyroid Gland/metabolism , Thyroid Gland/physiology , Thyrotropin/blood , Thyrotropin/metabolism , Thyroxine/blood , Thyroxine/metabolism , Toxicity Tests, Acute , Triiodothyronine/blood , Triiodothyronine/metabolism , Uncertainty
13.
Water Res ; 35(12): 3034-8, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11471705

ABSTRACT

Perchlorate (ClO4-) has been detected in numerous ground and surface waters, and has recently been added to the drinking water Candidate Contaminant List in the United States. Perchlorate can be removed from drinking water using ion exchange, but this results in the production of highly saline (7-12%) perchlorate-contaminated brines. Perchlorate-degrading microbial enrichments capable of growth in highly saline water were obtained by screening six salt water environments including marine and lake surface waters, salt marshes, subtidal sediments, and a biofilm/sludge from a seawater filter. Perchlorate reduction was obtained in three of these samples (seawater, saline lake water, and biofilm/sludge) at a salinity of 3%. The salinity range of two of these cultures was extended through serial transfers into media having higher salt concentrations (3-7%). Growth rates were measured over a salinity range of 1-15%. The maximum growth rate measured for the saline lake-water enrichment was 0.060+/-0.003 d(-1) (doubling time of 11.6+/-0.8 d) at a salinity of 5%. Growth rates decreased to 0.037+/-0.002 d(-1) at a salinity of 11%, and no growth was observed at salinities of 13 or 15%. These results demonstrate for the first time that biological perchlorate reduction is possible in solutions having a salinity typical of ion exchange brines.


Subject(s)
Perchlorates/metabolism , Seawater/microbiology , Sodium Compounds/metabolism , Water Microbiology , Water Pollutants, Chemical/metabolism , Water Purification/methods , Biodegradation, Environmental , Biofilms/growth & development , Fresh Water/chemistry , Fresh Water/microbiology , Geologic Sediments , Ion Exchange , Oxidation-Reduction , Perchlorates/standards , Salts/pharmacology , Seawater/chemistry , Sewage/microbiology , Sodium Compounds/standards , Solubility , United States , Water Pollutants, Chemical/standards , Water Supply/analysis , Water Supply/standards
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