The uptake of PFOS by animal fodder crops grown in soils contaminated from historic application of biosoloids and the use of these data in agronomic exposure models

Description:
In 2016, the discovery of elevated PFOS levels in water from a municipal monitoring well located in close proximity to a dairy farm well resulted in testing of milk at the farm. The measurement of elevated levels of PFOS in dairy milk that could not be explained by water levels led to the testing of soils and hay. The PFOS levels in hay could explain the observed milk levels, yet the soil PFOS levels were lower than existing health-based soil screening levels. Thus began a multi-year effort to develop a model of the soil-to-fodder-to-cow-to-milk exposure pathway and to improve model inputs through field studies of hay and corn uptake of PFOS from soil. These models were pressed into service as two more dairy farms with elevated PFOS in milk were identified. This talk will review what we have learned over the past several years from studies of the uptake of hay and corn in field settings, the significant variation between fields on a farm in the uptake of PFOS from soil into plant tissues, differences in the accumulation of PFOS in different plant issues, and how these data inform current models for prediction PFOS in milk based on soil PFOS levels. Analytical challenges along the way from the perspective of the non-laboratorian will be discussed.

Speaker: Andrew Smith - Maine Center for Disease Control
Andrew Smith is the State Toxicologist and Manager of the Environmental and Occupational Health Program at the Maine Center for Disease Control and Prevention, Maine Department of Health and Human Services. Dr. Smith as been the State Toxicologist since 1996 and obtained his master's and doctoral degrees in environmental health from the Harvard School of Public Health. His current responsibilities include environmental toxicology, environmental health surveillance, private well water safety, and childhood lead poisoning and prevention. Dr. Smith and his team have been actively working on issues related to PFAS contamination in agricultural settings in Maine since 2016 following the discovery of the first dairy farm with contaminated milk. His team is active in the area of modeling of agronomic exposure pathways and field studies to study the uptake of PFAS by plants and livestock.