Advisor(s)

Charles Wilson

Committee Member(s)

Emily Caffrey
Sarah Donaher

Document Type

Thesis

Date of Award

6-1-2026

Degree Name

Master of Science (MS)

School

School of Health Professions

Department

Health Professions

Abstract

The development of the phosphate fertilizer industry, while integral to the success of modern-day agriculture, continues to produce staggering amounts of phosphogypsum (PG), an acidic and hazardous waste byproduct concentrated with heavy metals, technologically enhanced naturally occurring materials (TENORM), and other toxic elements. Due to the potentially harmful emission of radon from PG, the United States (US) Environmental Protection Agency (EPA) has regulated the disposal of PG in engineered stacks under the National Emission Standards for Hazardous Air Pollutants (NESHAP) for nearly four decades. However, with roughly five tons of PG produced per single ton of phosphoric acid, and a history of PG stacks marred by failures and pollution in the US, the accumulation of PG in stacks is arguably no longer a tenable approach. With land a commodity too valuable to waste on the storage of PG in perpetuity, significant efforts to discover alternative uses for PG despite its hazardous impurities have made recycling PG a rapidly progressing area of research across the world. One promising approach has explored the reuse of PG as a road construction material. With approximately 9 million lane miles of public roads in the US, incorporating PG into future road construction could serve as a long-term solution to not only dwindle the current storage, but also recycle the future production of PG. However, this requires that it does not pose a threat to human health or the environment. The EPA has approved a small-scale pilot PG-based road study in Florida. This paper examines the possibility of the future implementation of PG-based roads nationwide across the US, focusing on states most likely to be impacted first, and assesses whether the reuse of PG in road materials creates a new or equivalent TENORM problem. This research has studied state-specific regulations, site-specific environmental implications, best practices for future use, and long-term performance of PG-based roads in order to compare and complement the current pilot approval and navigate future practical hurtles industry may encounter as they incorporate PG into US road systems.

Keywords

Environment;Phosphogypsum;Recycle;Roads;State-specific;TENORM

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