New Report Shows Central Chemical’s Pollution May Be Following Groundwater Through Subterranean Voids

Cover Photo: Artist’s rendering of toxic pesticides inside an underground cave system.

HAGERSTOWN, MD News (11/26/2023) – In September, the United States Geological Survey and the Environmental Protection Agency released a new report examining the former Central Chemical site off Mitchell Ave, a site which has been declared a superfund site due to its environmental contamination. The report highlights that an intricate system of subterranean voids under the site may be transporting contaminants into the groundwater of nearby properties.

In collaboration with the U.S. Environmental Protection Agency, scientists have undertaken an extensive investigation into the environmental challenges surrounding the former Central Chemical facility in Hagerstown, Maryland. The facility, with a historical background in pesticide and fertilizer production, has left a lasting impact on the local soil and groundwater.

Background of Central Chemical Superfund Site

Operating from 1937 to 1984, the Central Chemical facility played a pivotal role in pesticide and fertilizer production in the Hagerstown area. The repercussions of this extensive production period have manifested in soil and water contamination, leading to the site’s inclusion on the National Priorities List in 1997. Subsequent investigations aim to address these concerns comprehensively.

The remediation process is bifurcated into two distinct units. The first unit targets surface soils and a former waste disposal lagoon (Operable Unit 1), while the second unit concentrates on groundwater (Operable Unit 2). The overarching objective is to discern the spread of contaminants, including volatile organic compounds (VOCs), pesticides, and metals, and devise effective cleanup strategies.

The report offers insights into the historical timeline of the facility. Over the years, measures such as covering waste disposal areas and employing clay, soil, and vegetation were implemented to mitigate potential hazards.

The groundwater in the vicinity of the Central Chemical facility bears the burden of 41 different compounds, spanning VOCs, pesticides, and metals. These remnants from the production era necessitate thorough management to safeguard the local environment and the health of residents.

Hydrogeological Conundrum

A primary challenge faced by scientists lies in deciphering the movement of contaminants through the groundwater. The subterranean structure of the site resembles a complex puzzle, featuring natural pathways created by fractured rock. This complexity poses challenges in predicting the trajectory of contaminants.

The study reveals a fascinating yet intricate hydrogeological scenario beneath the Central Chemical facility. The underlying geological formations, including the Conococheague Formation, Stonehenge Limestone, and Rockdale Run Formation, primarily composed of carbonate rocks, contribute to the site’s unique groundwater dynamics.

The groundwater plume associated with the deeper bedrock, characterized for Operable Unit 2, unveils lithologic and structural contrasts between the shallow soil, weathered rock, and epikarst, and the deeper, competent, but bedded, dipping, fractured, and karstic limestones. This intricate interplay gives rise to two connected flow systems—a surficial system comprising unconsolidated overburden and epikarst and a structurally dominant bedrock system beneath the epikarst.

While progress has been made in addressing surface soil and waste lagoon concerns, the focus on understanding and remediating groundwater contamination remains an ongoing process. Scientists stress the need for further studies to enhance our understanding of the groundwater system, particularly the uncertainties within the epikarst system.

Karst dissolution features, including sinkholes and dissolution voids, observed in wells at the site during their installation, add another layer of complexity to the remediation efforts. Of particular interest is the connection observed between a on-site well near the former waste lagoon and offsite well to the north at W Irwin Avenue, supported by water-level data and elevated concentrations of total suspended solids (TSS) and chlorobenzene. The potential for offsite transport of contaminants through particle-bound contaminants in the conduit system underscores the need for comprehensive remediation strategies.

According to the report, the groundwater is under the continuous threat of pollution due to the contaminants from Central Chemical. This not only jeopardizes the local environment but also raises concerns about the health implications for nearby residents, although fortunately residents in the immediate area utilize the city water supply and not their own wells. Understanding the dynamics of contaminant movement is pivotal for formulating effective cleanup strategies and ensuring the restoration of safe groundwater.

The full report is available at the USGS website.

Article by multiple RFHC contributors.