Recently, the EPA announced it intends to propose a rule to reduce mercury waste from dental offices. Mercury is a concern to human health because it is considered a persistent bioaccumulative toxic element.

According to the EPA, dental amalgams, or fillings containing mercury, account for 3.7 tons of mercury discharged into US waterways each year.

Read more about Reducing Mercury from Dental Offices

By Steve Wing

The Environmental Protection Agency’s (EPA) Lead: Renovation, Repair, and Painting Rule, issued in 2008, was to take formal (enforceable) effect on April 22, 2010. However, due to difficulties with compliance, the EPA has extended this deadline to December 30, 2010.

This rule mandates a number of specific practices for contractors to mitigate the health hazards associated with disturbance of lead-based painted surfaces in homes, child care facilities, and schools constructed prior to 1978.¹ Under this rule, all contractors in the U.S. conducting work on lead-based painted surfaces are required to be EPA certified and to follow specified work practices for preparation, clean-up, and record keeping. Painters, plumbers, electrical workers, general contractors, and a miscellany of other service providers will be affected. The rule applies to the disturbance of lead-based painted interior surfaces of six or more square feet and exterior surfaces of 20 square feet or more. Guidelines are also provided for window replacement and demolition in such facilities and homes. Under the statute, contractors not in compliance could be fined as much as $37,500 a day.²

Read more about EPA’s lead paint rule…

By Gregory Salata, Ph.D., Kelso, WA

Many sampling programs include collection and analysis of an equipment blank to ensure there is no contribution of contaminants from the sampling equipment and associated process. To establish that sample collection procedures are contaminant free, an equipment blank is often collected. Equipment blanks are collected by passing water through the sample collection apparatus or utensil and collecting the water into the appropriate containers. To ensure that the water itself is contaminant free, the laboratory will supply the field crew with deionized (DI) water.

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By Pradeep Divvela, Project Chemist, Kelso, WA

Sequential extraction is an analytical process that chemically leaches metals out of soil, sediment and sludge samples. The purpose of sequential “selective” extraction is to mimic the release of the selective metals into solution under various environmental conditions.

One commonly used sequential extraction procedure is designed to partition different trace metals based on their chemical nature.

The sequential extraction process is typically accomplished in four (4) steps using:

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Ultra-trace speciation of arsenic and other metals is performed using a variety of techniques tailored to the specific combination of species, matrix, and detection limits required. Currently, two analytical systems are applied: Ion Chromatography-Inductively Coupled Mass Spectrometry (IC-ICP-MS) and Hydride Generation-Cryogenic Gas Chromatography-Flame Atomic Absorption Spectrometry (HG-CGC-AAS). Each of these techniques has particular strengths that can be exploited depending upon the scientific question being asked. These techniques are combined with specific extraction techniques in order to maximize speciation integrity and data quality.

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Introduction: Historical mining practices in the Coeur d’Alene River Basin (Idaho) have resulted in heavy metal contamination of soil, sediment, surface water, and groundwater. Canyon Creek, located in the upper basin, has elevated levels of dissolved zinc (average concentration ~ 3,000 μg/L), dissolved cadmium (average concentration ~ 22 μg/ L), and total lead (average concentration ~ 174 μg/L). Heavy metal loading near the mouth of Canyon Creek is influenced by surface water/groundwater interactions. Dissolved zinc concentrations in the groundwater have been detected in the 100,000 μg/L range while dissolved cadmium and lead have been detected in the hundreds to thousands μg/L ranges, respectively.

EPA’s consultant, URS Corporation (URS), developed a multi-phase treatability study to obtain quantitative information on a treatment process to effectively remove metals from the water of Canyon Creek. The treatment process incorporated different combinations of pH adjustment, chemical coagulation and coprecipitation, polymer flocculent additions, and additions of ballasted micro-sand to improve sludge settling. The results of the study will be used to help evaluate potential treatment technologies for surface water and/or groundwater at Canyon Creek. These data will also be used to help develop the pilotscale treatability study for Phase II of the study.

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Mercury is responsible for over three-quarters of all contaminant-related advisories for threats to human health. During the 1990’s, the number of mercury related fish consumption advisories more than doubled, despite significant decreases in the total mercury emissions over the last 20 years. The increase in advisories is probably the result of more testing rather than more contamination.

While the contamination is showing up in lakes and fish, most mercury does not come from effluent, rather is derived from atmospheric deposition. Atmospheric transport and subsequent bioaccumulation of mercury can affect aquatic ecosystems far from mercury sources. According to EPA estimates, emissions from coal-fired utilities account for 13 to 26 percent of the total (natural plus anthropogenic) airborne emissions of mercury in the United States. Thus, the EPA has begun to regulate emissions from power plant boilers and process heaters.

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