Correlation of Historic Lead Arsenate Use at Orchards and Modern Drinking Water Contamination

Date and Time: April 29, 2025, 10 AM - 12 PM
Location: Live Zoom Webinar

Speakers: Meredith Metcalf, Ph.D. and Gary Robbins, Ph.D.

Continuing Education Credits: 

This is the first time this course is being offered for CT LEP credits. The CT State Board of Examiners of Environmental Professionals (LEP Board) has approved this course/webinar for 2.0 hours of continuing education credits (CTLEP-616 W).

Fees: 

• EPOC Members: $90
• Non-members: $200 (consider joining EPOC at this time to receive the member rate for this program)
• Gov't Employee/Students: $45

Course Description:

Arsenic is a known carcinogen. In recent years, the occurrence of arsenic in Connecticut bedrock drinking water wells has become a widely reported issue. DHS has taken initiatives to inform private well owners about arsenic occurrence in groundwater in certain parts of the state. Although the source of arsenic in the bedrock groundwater in New England has been thought to be geogenic, no such definitive correlation has been established. In addition to the rocks possibly generating the arsenic contamination, it is also possible the arsenic comes from the wide use of lead arsenate pesticide on fruit tree between the 1890s and 1970s. For example, in 1935 there were over 47,000 registered fruit tree orchards in Connecticut alone which corresponds to a period when lead arsenate was commonly used. During spraying, much of the lead arsenate accumulated in the soil. Although lead accumulation tends to be immobile, arsenic can be mobilized under certain environmental conditions.

To evaluate the potential association between arsenic contamination and orchards, the presenters, in cooperation with the Connecticut Departments of Energy and Environmental Protection and Public Health, and local health officials conducted studies in Connecticut that entailed groundwater sampling of domestic wells and soil sampling on nearby orchards or former orchards. That study revealed that elevated levels of lead and arsenic are still present in soil at current or former orchard sites dating back to the period when lead arsenate was sprayed. They also found a statistically significant correlation between the groundwater contamination and location to nearby current or former orchard properties.

Course Agenda:

• Introduction and review of historic lead arsenic usage and environmental chemistry
• Review our research findings on the distribution and sources of groundwater arsenic contamination
• Discussion and Q and A

Speaker Biographies:

Dr. Meredith Metcalf has a diverse background in natural sciences with a bachelor’s degree in Geology from Colgate University and both a master’s degree in Geology and Geophysics and a Ph.D. in Natural Resources and the Environment (with a concentration in hydrogeology) from the University of Connecticut. Dr. Metcalf, a Professor within the Environmental Earth Science Department, is currently completing her fourteenth year at Eastern Connecticut State University where her primary responsibilities are teaching introductory and advanced/applied courses in geographic information systems and remote sensing. Additional areas of teaching include computer-aided drafting and hydrogeology. Her research interests are in the use of geographic information systems to analyze groundwater sustainability, ground water quality, and groundwater flow patterns in fractured rock.

Dr. Gary Robbins is an Emeritus Professor at the University of Connecticut. He has been a hydrogeologist for over 40 years. His professional experience includes working as a Federal regulator, consultant to the USEPA and other Federal agencies, consultant to state environmental regulatory agencies throughout the U.S,, Project Hydrogeologist for Woodward-Clyde Consultants working on a variety of groundwater contamination-related projects, and Professor of Geosciences and Natural Resources. His most recent research focused on improving methods for investigating groundwater flow and contamination in fractured crystalline bedrock.