Did you know that pesticides can be transformed into other chemicals?
Implications for aquatic life are of potential concern
Pesticide transformation products (TPs) may be a critical missing piece of the toxicity puzzle for aquatic life in small U.S. streams, according to a new study by the USGS.
The continental-scale study of pesticide TPs, the most geographically extensive to date, reveals the near-ubiquity of these chemicals in small U.S. streams. One or more TPs were detected in nearly 90% of 442 small U.S. streams investigated during 2013–2017. The most frequently detected TPs were degradates of nine herbicides, one insecticide, and two fungicides; the summed concentrations of these transformation products frequently exceeded the concentration of the parent pesticide.
The “disappearance” of a pesticide in the environment often is a result of incomplete degradation (transformation) that creates one or more pesticide TPs—new chemicals related to but different from the parent pesticide. Many TPs are less toxic to aquatic life than the parent, but some are more toxic. However, toxicity information is available for only about one quarter of the 117 TPs analyzed for this study. A toxicity analysis using the assumption that TPs have the same toxicity as their parent pesticide indicates that potential aquatic effects of pesticide-related compounds could be underestimated by an order of magnitude or more.
TPs were commonly detected during baseflow conditions, implicating groundwater as an important source of TPs to streams. The presence of TPs in baseflow indicates chronic and potentially long-term environmental exposures of aquatic life to TPs.
Related Content
National Water-Quality Assessment (NAWQA)
Pesticides and Water Quality
Regional Stream Quality Assessment (RSQA)
Stream Ecology
Related Content
- Science
National Water-Quality Assessment (NAWQA)
Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources.Pesticides and Water Quality
Pesticides are chemicals designed to kill pests, including insects (insecticides), weeds (herbicides), and fungi (fungicides). The USGS assesses the occurrence and behavior of pesticides in streams, lakes, and groundwater and the potential for pesticides to contaminate our drinking-water supplies or harm aquatic ecosystems.Regional Stream Quality Assessment (RSQA)
The goals of the Regional Stream Quality Assessment (RSQA) are to characterize multiple water-quality factors that are stressors to aquatic life (contaminants, nutrients, sediment, and streamflow alteration) and to develop a better understanding of the relation of these stressors to ecological conditions in streams throughout the region.Stream Ecology
Who lives in your stream? Rivers and streams, even small ones, are teeming with a vast number of species, including fish, aquatic invertebrates, and algae. Stream ecology is the study of those aquatic species, the way they interrelate, and their interactions with all aspects of these flowing water systems. - Data
Get Our News
These items are in the RSS feed format (Really Simple Syndication) based on categories such as topics, locations, and more. You can install and RSS reader browser extension, software, or use a third-party service to receive immediate news updates depending on the feed that you have added. If you click the feed links below, they may look strange because they are simply XML code. An RSS reader can easily read this code and push out a notification to you when something new is posted to our site.