Dive Brief:

• New research from the U.S. Geological Survey shows that even after leachate is treated, it can contain multiple chemicals from residential, industrial, and commercial waste discarded into US landfills.
• Scientists collected and analyzed treated and stored liquid waste samples from 22 landfills looking for 190 "contaminants of emerging concern" (CEC), including pharmaceuticals, household products, and industrial chemicals.
• A comparison of CEC concentrations between landfills (untreated liquid waste vs treated and stored liquid waste) found significantly lower CECs in treated and stored liquid waste compared to untreated samples, though all contained a complex mixture of CECs. Even treated and stored liquid samples contained 101 of the 190 analyzed CECs, which were in every leachate sample collected. The sampled landfills are detailed in the USGS map below: 

Dive Insight:

This research is the first step in understanding environmental exposures to contaminants originating from liquid wastes in landfills, according to Mike Focazio, coordinator for the USGS Toxics Substances Hydrology Program.

It is of significance that landfill research is now examining not only untreated liquid waste, but treated and stored liquid waste as well.

"The treated product provides a much better understanding of chemical concentrations … being put into the environment by landfills," said Jason Masoner, one of the paper’s authors. These chemicals enter streams, groundwater and are diverted to wastewater treatment plants.

The new findings comes on the heels of research looking at aeration treatment to remove certain landfill leachate before the contaminants reach the environment.