Abstract: Sargassum Composting (Arsenic Beaches)-Year 4

Evaluation of Sargassum Recycling Options through Risk-Based Approaches

 Full Proposal Submitted to the HCSHWM on

April 10, 2024

PRINCIPAL INVESTIGATOR: Helena Solo-Gabriele, PhD

AFFILIATION: University of Miami, Dept. of Chemical, Environmental, and Materials Engineering

CONTACT INFORMATION: hmsolo@miami.edu, 305-989-9103

PhD. STUDENT: Brittany Mc Intyre, MS

AFFILIATION: University of Miami, Dept. of Environmental Science and Policy

 CONTACT INFORMATION: bzm4@miami.edu, 479-502-7413

UNDERGRADUATE STUDENT: Melanie Cerna, AA

AFFILIATION: University of Florida, Dept. of Environmental Engineering Sciences

CONTACT INFORMATION: mcern009@fiu.edu, 786-574-1025

ABSTRACT

Sargassum’s high arsenic concentrations have raised concerns about health impacts when repurposed for potential beneficial uses. Potential health impacts depend upon the speciation or specific chemical form of the arsenic, with inorganic forms more toxic than organic forms.  The goal of this study is to assess the risk of arsenic from Sargassum in different recycling scenarios. Specifically, the objectives of this study are to 1) evaluatearsenic levels (total and speciation) in products made from recycled Sargassum (compost, biochar, biogas), and to use this information 2) to determine risks to humans from environmental exposures. Baseline risks will be assessed when Sargassum is not managed by leaving it on the beach.  These baseline risks will be compared to health risks associated with its reuse as either compost, biochar or biogas. Through this study we will produce dried Sargassum to simulate beach conditions and compost. We will collaborate with commercial vendors to provide biochar (BiocharNow Inc.) and biogas digestate (Rum & Sargassum Inc.). Samples will be analyzed for total arsenic and arsenic species (arsenite, arsenate, monomethylarsonic acid, dimethylarsinic acid, arsenobetaine, and others). Results from the arsenic analysis will be combined with exposure assessments to compute risk. The results of this study can be used to identify beneficial re-use options that are acceptable from a human health perspective.