Volatile and semivolatile organic compound concentrations in paired porewater and surface-water samples and groundwater samples at the Garland Creosoting Superfund Site, Longview, Texas, 2023–24

The Garland Creosoting Superfund Site in Longview, Texas is an abandoned wood treatment facility that used creosote to preserve wood products between 1960 and 1997. Previous remediation activities at the contaminated site included excavation of creosote-contaminated soil and the installation of an interceptor collector trench and groundwater treatment system to prevent the movement of contaminated groundwater into an intermittent stream, hereinafter referred to as the "unnamed tributary". The unnamed tributary drains into the Iron Bridge Creek after flowing along the southern boundary of the Garland Creosoting Superfund Site, and Iron Bridge Creek eventually drains into the Sabine River, a source of drinking water for thousands of Texas residents. The U.S. Environmental Protection Agency (EPA) is concerned with potential risks to human health from contaminated groundwater that may be flowing off-site either beneath or within the unnamed tributary. To evaluate the status of volatile organic compound (VOC) and semivolatile organic compound (SVOC) contamination, in November 2023 and January 2024, the U.S. Geological Survey (USGS), in the cooperation with the EPA, collected paired surface water and porewater samples from sampling locations along an unnamed tributary, and groundwater samples from monitoring wells at the Garland Creosoting Site. In total, nine paired porewater and surface water samples (along with one additional surface water sample) were collected from the unnamed tributary. Groundwater-quality samples were collected from five monitoring wells at the Site.