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Perchlorate Analysis in Drinking Water

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Experience
California is one of only a few states to currently regulate perchlorate in drinking water and in 2011 proposed a new public health goal (PHG) of 1 ug/L.  Eurofins Eaton Analytical has been testing perchlorate at levels below the proposed CA PHG of 1 ug/L in drinking water and drinking water sources for more than 10 years by both EPA Method 314 and EPA method 331.0.

Eurofins Eaton Analytical reports certified perchlorate data to an MRL of 0.5 ug/L or less using both method 314 (which is limited by total dissolved solids levels and subject to potential matrix interferences, leading to false positives or false negatives) and method 331.0 (LC-MS-MS) and has been certified continuously in Massachusetts for low level perchlorate since certification was first offered. Eurofins Eaton Analytical is the only California-based laboratory to be approved in Massachusetts for low level perchlorate monitoring, having demonstrated the ability to meet the required reporting level.

In 2010, Eurofins Eaton Analytical analyzed more than 500 samples for perchlorate by method 331 and more than 4,000 samples at a 0.5 ug/L reporting level by method 314.  Since then we have analyzed numerous additional samples by 331.0, as clients rely on the reliability of that method.

When Massachusetts first proposed an MCL for perchlorate, Eurofins Eaton Analytical Labs conducted an AWWA funded study of lab capability to meet the target reporting limit of 0.5 ug/L and demonstrated that not all Massachusetts certified labs could consistently provide reliable data at the proposed reporting limit. Results of this study were presented at several national conferences as long ago as 2005.

Until January 7, 2011 California had a public health goal (PHG) of 6 ug/L, and an MCL of 6 ug/L. However on January 7 of that year, the California Office of Environmental Health Hazard Assessment (OEHHA) revised the proposed PHG to 1 ug/L. While we have demonstrated that it is possible to analyze perchlorate at concentrations below the proposed PHG, particularly using method 331.0, care is required to ensure accurate results.  Because perchlorate is considered an acute pollutant, California requires that any detects over the MCL be reported to the utility within 24 hours of analysis completion and there are multiple cases in California where wells were shut down either temporarily or permanently as a result of perchlorate occurrence.

Treatment
The most common treatment techniques for perchlorate are either ion exchange or biological reduction. RO is also an effective treatment. There is little, if any, data available to demonstrate the effectiveness of these treatment technologies to meet the proposed PHG.

Health Effects
In the press release accompanying the revised proposed PHG, OEHHA indicated that exposure to perchlorate can affect infant brain development, growth, and other key body functions. Perchlorate is known to damage the thyroids ability to take in and process iodide, which is a nutrient essential to brain development, growth, heart function, and other systems.

Studies conducted by OEHHA scientists and others revealed that perchlorate harms the health of babies at lower levels than healthy adults. At the same time, a recent study of Boston-area new mothers indicates that nearly half of all infants may not receive enough iodide from their mothers' milk.

OEHHA's draft PHG also incorporates new data on how much water infants consume per pound of body weight. It also considers infants' intake of perchlorate from infant formula.

EPA is still evaluating data on perchlorate to determine a recommended safe level, but some of EPA's data and reports suggest levels as low as 2 ug/L are a possiblity.