Environmental Health - Toxic Substances Hydrology Program
Landfill leachate contains a variety of chemicals that reflect our daily activities, U.S. Geological Survey (USGS) scientists concluded as a result of a nationwide study. Landfills are a common disposal mechanism for our Nation's solid waste from residential, commercial, and industrial sources. The scientists found that pharmaceuticals, personal-care products, and other contaminants of emerging concern are widespread in water that has passed through landfills, known as leachate. This study is the first national assessment of these chemicals in landfill waste in the United States.
This study of 19 landfills across the United States found 129 of 202 pharmaceutical (prescription and nonprescription), household, and industrial chemicals in untreated leachate samples (that is, prior to treatment and environmental release). The number of chemicals measured in the leachate samples ranged from 6 to 82 (with a median of 31). An analysis of the data revealed that landfills located in areas receiving the greatest amounts of precipitation had the greatest number of chemicals detected and the highest concentrations measured.
The chemicals most frequently found during this study included bisphenol A, cotinine, N,N-diethyltoluamide (DEET), lidocaine, and camphor. The measured concentrations spanned six orders of magnitude—steroid hormone concentrations generally ranged from 1 to 100's ng/L (nanograms per liter or parts per trillion), prescription and nonprescription pharmaceutical concentrations generally ranged from 100 to 1,000's ng/L, and household and industrial chemical concentrations generally ranged from 1,000 to 1,000,000's ng/L.
Maximum concentrations and frequencies of detection observed for this study include:
Max Concentration |
Percent Frequency of Detection |
Chemical |
---|---|---|
7,020,000 ppt |
55 |
para-cresol (plasticizer and flame-retardant, antioxidant in oils, rubber, polymers, and wood preservative) |
4,080,000 ppt |
95 |
bisphenol A (used in plastics, thermal paper, and epoxy resins) |
705,000 ppt |
65 |
ibuprofen (analgesic, antipyretic) |
254,000 ppt |
95 |
DEET (insect repellent) |
147,000 ppt |
90 |
lidocaine (local anesthetic, topical anti-itch treatment) |
97,200 ppt |
84 |
camphor (natural compound with medicinal uses and embalming) |
51,200 ppt |
95 |
cotinine (transformation product of nicotine) |
2,590 ppt |
75 |
carbamazepine (anticonvulsant and mood stabilizer) |
168 ppt |
55 |
estrone (natural estrogenic hormone) |
This is the first step in USGS efforts to quantify the contribution of leachate from active landfills to the environment. The study is intended to inform policies for chemical disposal. For example, it is currently recommended that unused pharmaceuticals be disposed of in solid waste (and ultimately to landfills) rather than being flushed. Follow-up research will examine the concentrations of these chemicals in treated leachate that is released to the environment through various pathways.
This study was supported by the USGS Toxic Substances Hydrology Program.
Contaminants of emerging concern in fresh leachate from landfills in the conterminous United States: Environmental Science--Processes and Impacts, 2014, v. 16, no. 10, p. 2335-2354, doi:10.1039/C4EM00124A.