Mercury is a metal that is commonly found in the environment in several forms, all of which are toxic. Depending on its exact chemical form and the dose received, people or wildlife exposed to mercury can suffer serious adverse health effects. Mercury in the environment is derived from both natural sources and human activities. Mercury is mobile and widely dispersed in the biosphere and persists once released. "Organic" (carbon-containing) mercury compounds, such as methyl mercury, are of particular concern because they can become concentrated in living organisms, such as fish.
Mercury is an important environmental concern in Massachusetts and across the country. Extensive fish monitoring programs in Massachusetts and other states have led to some disturbing findings regarding mercury. For many waterbodies in the Northeast, concentrations of methyl mercury in large freshwater fish were found to be above levels currently considered to be safe for regular consumption. These findings have led several states, including Massachusetts, to issue statewide health advisories warning pregnant women to avoid eating native freshwater fish. Pregnant women are of special concern because methyl mercury can cross the placenta and is particularly toxic to developing fetuses. Warnings that citizens should refrain from eating fish from many specific waterbodies have also been issued across the Northeast with 37 such advisories in MA alone.
Such advisories minimize potential health risks from mercury but also indicate a need to further reduce sources of mercury pollution. Ultimately, the only way to achieve this is to identify controllable sources of mercury and to then take steps to reduce them. MADEP is committed to this goal which can be achieved in many ways, including actions that every citizen can take.
Both State and Federal regulatory agencies have taken many recent steps to better delineate and reduce mercury risks. Several reports by the United States Environmental Protection Agency (USEPA) have assessed possible sources of mercury in the environment on a national scale. The potential adverse health effects of mercury have also been extensively considered in recent scientific publications.
These efforts, including analyses presented herein, have helped to clarify our understanding of mercury risks and sources and have pointed to many steps that can be taken to reduce mercury releases. For example, as is discussed in Chapter 3 of this report, disposal of mercury containing products such as batteries, certain types of electric light fixtures, thermostats and thermometers in municipal solid waste can lead to substantial emissions of mercury to the environment.
MADEP has prepared this report as part of its continuing efforts to investigate and control environmental hazards; to inform the public about the potential effects and sources of mercury in the environment; to explain steps that are being taken by regulatory agencies to reduce mercury emissions and risks; and, to identify steps that everyone can take to minimize mercury pollution. It is intended to summarize information about mercury in Massachusetts by providing the most accurate estimates currently available on overall mercury sources in the state, the potential significance of out-of-state mercury sources and the overall environmental impacts of mercury. The significance of in-state vs. out-of-state mercury sources is also considered. Data gaps and areas where additional information and research are needed to support regulatory efforts on mercury are identified.
The report is organized into six primary chapters and several Appendices which provide more detailed information on specific topics. Chapter 2 presents background information about mercury in the environment, including its chemical forms, possible human and environmental health effects, and major sources. Rather than repeat the extensive and excellent reviews which have already been published on these topics, this chapter summarizes their key conclusions. Chapters 3 and 4 assess mercury issues in Massachusetts. Chapter 3 presents emission monitoring data and estimates of annual emissions for several source categories. Chapter 4 summarizes available environmental monitoring data in MA, with a particular focus on the MADEP freshwater fish monitoring program. Chapter 5 summarizes regulatory positions and standards. The concluding chapter discusses specific actions being taken by MA regulatory bodies to reduce mercury emissions and risks as well as steps that every citizen can take to help. Several appendices include supporting information and more detailed assessments of several of the topics considered. Appendix A presents references. Appendix B presents a summary of monitoring data for several Massachusetts landfills. Appendix C presents detailed data on ambient atmospheric monitoring and stack testing. Appendix D is a technical overview of mercury toxicity. Appendix E provides data from monitoring of freshwater fish and information on consumption advisories. Appendix F includes detailed calculations on the sources of mercury found in municipal solid waste. Lastly, Appendix G presents a summary of various "battery bills" designed to reduce environmental impacts of mercury and other heavy metals and MADEP and EOEA positions on battery legislation in MA.