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.
The EPA is considering hexabromocyclododecane, a brominated flame retardant made up of various mixtures of its 16 isomers (herein: HBCD), for action under the Toxic Substance Control Act (TSCA). This is in addition to two other groups of compounds already discussed in previous Lab Science News articles.
HBCD is ubiquitous in the environment throughout the world and is also found in human tissues, including blood, adipose, and breast milk. When released into the environment, it can travel great distances, bioaccumulating and biomagnifing in the food chain. In addition to its high toxicity to aquatic organisms, studies have also linked HBCD to reproductive, developmental, and neurological effects in humans, with a potentially higher impact on children because of their smaller size.
In June 2010, the U.S. Environmental Protection Agency (EPA) took action to ban the use of endosulfan in the United States because it poses unacceptable risks to agricultural workers and wildlife, and can be pervasive in the environment.
The decision was based on a revised ecological risk assessment report, first written in 2002, which highlights that farm workers face greater risks than were previously known. The EPA also found that endosulfan, a colorless solid, poses excessive risk to aquatic and terrestrial wildlife, as well as to birds and mammals that consume aquatic prey which have ingested endosulfan.
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.
 NEW! Allowable Levels Established for DEHP in Bottled Water
January 17, 2012 |
 Vapor Intrusion Investigations: Air Sampling Tips for Meeting Data Quality Objectives
September 26, 2011 |
 Incremental Sampling Methodology
June 22, 2011 |
