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Characterizing Contamination and Determining Risk in Homeland Security Research

EPA supports its responders' ability to characterize site contamination by developing sampling protocols, sample preparation methods, and analytical methods for chemicals, biotoxins, microbial pathogens, and radiological agents.

EPA develops risk assessment methodologies to determine the human health consequences of exposure to contamination, and develops crisis communication techniques to help responders communicate information about site contamination and health risks to the public.

Sample Collection and Analytical Methods

EPA On-scene coordinators responding to a disaster

EPA must rapidly determine the type and extent of contamination to minimize its spread and exposure.  EPA typically collects large numbers of samples for analysis to characterize the type and extent of contamination.  Contamination involving chemicals, microbial pathogens, or radiological materials requires specialized sampling, handling, and analytical procedures.

To improve the national capability and capacity for responding to contamination incidents, EPA organized the Environmental Response Laboratory Network (ERLN).  This national network of federal, state, and accredited private sector laboratories can be ramped up as needed to support large-scale responses, using the necessary specialized special sampling, handling, and analytical procedures.

Selected Analytical Methods (SAM)

To support the ERLN, EPA continues to update Selected Analytical Methods for Environmental Remediation and Recovery (SAM), which contains analytical methods for samples containing chemicals, radiochemicals, pathogens, and biotoxins.  EPA initiated the SAM based on in the realization that homeland security incidents could involve agents not previously encountered by EPA as environmental contaminants.  EPA needed to develop or adapt methods for these novel contaminants in environmental matrices such as water, soil and surfaces. 

SAM contains method summaries for biological, chemical, and radiochemical analytes. The summaries briefly describe the method, sample preparation, analytical technique, and any special considerations. The summaries also describe the purpose for which the method was developed and the specific use for which it was included.

EPA developed a searchable website for SAM. In addition to a SAM Methods Query that permits searches of the chemical, radiochemical, pathogen, and biotoxin analytical methods, the site also has full documentation of laboratory methods, when available, and links to technical contacts and key collaborators.

EPA continues to refine the SAM methods.  Detecting and identifying, or ruling out, the presence of live biological agents such as Bacillus anthracis is a challenge. EPA must rapidly confirm the presence of live organisms to characterize contamination and plan a response.  EPA continues to work on rapid-viability polymerase chain reaction (RV-PCR) methods that quickly detect the presence of live agents in air, water, and surface samples.

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Assessing and Communicating Risks

Risk Assessment

Researchers provide the scientific basis for EPA's regulatory arm to establish cleanup levels for re-entry or re-use of areas or resumed use of water and wastewater infrastructure following a contamination incident.

EPA's homeland security research includes studies to assess and compile information on exposure, toxicity and dose-response for the many potential chemical, biological, radiological, or nuclear (CBR) agents that might contaminate structures or outdoor areas following an incident. 

Risk assessment techniques for exposure to chemical warfare agents and toxic industrial chemical are used to establish health-based provisional advisory levels (PALs) for responders and the public, including vulnerable groups like infants or the elderly.

PALs are now included in the Support for Environmental Rapid Risk Assessment (SERRA) database, which enhances risk assessment by providing an extensive collection of scientific literature about CBR agents.  Information is evaluated and extracted by subject matter experts and can be used for managing, cleaning up, and reducing the hazards encountered after an incident.

Communicating Risk

During all phases of the response and recovery, information on minimizing risk and exposure is made available to various audiences, including responders, healthcare professionals, volunteers, and members of the public. The form and content of the information is based on risk communication techniques derived from scientific research. 

Risk communicators use science-based tools developed by EPA and subject matter experts for developing crisis communication.

One important risk communication tool is message mapping:  Questions and concerns likely to be raised by different audiences are developed, and detailed, hierarchically organized responses are produced to address the questions, each supported by key information aimed at a particular audience.

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