Increases in Trifluoroacetate Concentrations in Surface Waters over Two Decades.

Area of Science:

• Environmental Chemistry
• Pollutant Analysis
• Atmospheric Science

Background:

• Trifluoroacetate (TFA) is a persistent pollutant with significant anthropogenic sources, notably fluorocarbon refrigerants.
• Research on TFA environmental concentrations declined despite increasing precursor emissions, leaving a gap in contemporary data.
• Understanding TFA's environmental fate and transport is crucial due to its persistence.

Purpose of the Study:

• To assess changes in Trifluoroacetate (TFA) concentrations in Northern California streams over 23 years.
• To determine the regional distribution of TFA, comparing urban downwind, upwind, and remote sites.
• To provide updated data on TFA levels in the environment.

Main Methods:

• Resampling of a previously established stream transect originally sampled in 1998.
• Analysis of TFA concentrations in water samples from Northern California and Alaska.
• Comparison of current TFA levels with historical data to quantify changes over time.

Main Results:

• TFA concentrations in streams increased by an average of sixfold over 23 years.
• Median TFA concentration reached 180 ng/L, with a wide range (21.3-2790 ng/L).
• Highest TFA levels were observed in streams located downwind of the San Francisco Bay Area.

Conclusions:

• TFA concentrations in the environment have significantly increased, highlighting the impact of ongoing emissions.
• Regional variations in TFA levels correlate with proximity to major metropolitan areas.
• Further monitoring is needed to track the accumulation of this persistent pollutant.