Developing New Methods for Measuring Emerging Environmental Contaminants
New laboratory analytical methods are continuously needed to provide accurate and precise measurements of the presence and levels of new and understudied contaminants in various environmental media (water, sediment, soil, tissue, and air). The environmental media analyzed often varies greatly in analytical complexity; for example, ranging from pristine groundwater or treated drinking waters to waters highly enriched in natural and synthetic contaminants, such as municipal, industrial, and concentrated animal feeding operation (CAFO) wastewaters. Furthermore, scientific demands for environmental data are driving measurement requirements to a wider range of concentrations – to higher levels (parts per million) for studies of sources and the adjacent ecosystems, and to lower levels (parts per trillion) for studies of the environmental occurrence of highly toxic chemicals used in small amounts.
Thousands of synthetic chemicals are used daily in industry, agriculture, and our homes to improve industrial efficiencies and our quality of life. New chemicals, new and expanded uses for traditional chemicals, and new knowledge of the potential human and environmental health significance of exposure to contaminants all place constant and significant demands on analytical method capabilities.
To provide the reliable scientific information essential for the evaluation of the potential significance of emerging water-quality issues as well as the identification of additional science needs required to design effective management strategies.
The following objectives of analytical method development activities support an overall R&D approach to emerging water-quality issues:
- Identify emerging water-quality issues related to new and understudied environmental contaminants.
- Identify the highest priority science questions that need to be answered related to emerging water-quality issues and the associated contaminants.
- Develop analytical methods with the capability to provide high-quality data at environmentally relevant concentrations on the contaminants of concern.
- Conduct field-based research that rigorous tests to see if the methods can be effectively applied to investigate emerging water-quality issues.
- Transfer proven analytical methods to other USGS monitoring and assessment programs and to the scientific community in general.
Major Prioritization Criteria
- Environmental Occurrence. Evidence of environmental occurrence based on (1) actual field data, (2) potential environmental occurrence based on chemical property information, or (3) forensic evidence from chromatographic analysis of unknowns in environmental samples. Actual field data are rarely available for emerging contaminants.
- Chemical Manufacture and Use. Information on the amount of a chemical manufactured, how it is used by the public or industry, and the potential pathways and sources to the environment.
- Toxicity. Information on the environmental and/or human health significance of a contaminant or class of contaminants with similar modes of action. This information often is limited for emerging contaminants or is in a form not directly amenable to assessing adverse effects through environmental exposures.
- Stakeholder Input. Federal and State agency knowledge of the potential human and ecological health effects, and of pending decisions associated with chemical and resource management, regulation, and policy making.
- Methods are developed as part of field-based research projects to ensure that the method is capable of satisfying the data quality objectives (DQO’s) associated with answering high priority questions in practical study designs on an analyte-by-analyte basis.
- A high priority is placed on field and laboratory quality control (QC) data in each study to ensure that the data meet all DQOs, meet acceptable quality standards, and fully document any limitations of the data, while providing useful environmental information.
- Methods are developed with a goal of enabling comprehensive and cost efficient field studies by providing coverage of the groups of chemicals that are anticipated to be important for common field studies. For example: (1) chemicals that are anticipated to enter the environment through common source pathways (e.g., industrial discharges), or (2) chemicals that may have modes of action that are similar and/or could interact (e.g., antidepressants).
- A detailed method description, quality assurance (QA) procedures, results of method validation, and QC data are described and published with environmental datasets associated with a specific study. The evolving nature of research methods requires such an approach.
- The analytical chemists developing the methods are integral members of the study team and are involved in all aspects of study design, execution, and interpretation.
- Field and laboratory QC data are aggregated across studies to provide a broad base of QC data for evaluation of the quality of environmental data for new studies, even those of limited scope and associated limited resources.
- Forensic environmental investigations are conducted for priority source pathways to the environment that evaluate the occurrence of unidentified compounds for which chromatographic evidence of their presence is found (tentatively identified compounds).
- A wide range of prioritization criteria are considered to ensure that contaminants that may have significance to environmental or human health are not overlooked.
Major Classes of Emerging Contaminants Currently Being Evaluated
The following classes of chemicals are currently a high priority for methods development and environmental studies.
- New and Understudied Pesticides
- Disinfection Byproducts
- Personal Care Products
- Selected Industrial Chemicals
- Natural Toxins
- Potential Endocrine Disruptors
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