Honors College Theses

Publication Date



Biology (B.S.B.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Dr. Vinoth Sittaramane


Tetrakis (hydromethyl) phosphonium chloride (THPC) is a tetrakis (hydromethyl) phosphonium salt commonly used by the textile industry and is polymerized onto cotton fabrics to provide a flame-retardant finish. Traces of THPC were found in the Ogeechee River, a 294 mile-long black river in Georgia, and could have been a toxin contributing to the mass killing of aquatic animals in May 2011. THPC has been known to be carcinogenic and cause other systemic toxicity in various mammalian animals. However given that the chemical is mostly discharged in natural waters, the environmental impact of the discharge on water quality and there by on aquatic organisms following exposure is completely unknown. This study is aimed to provide a knowledge base for assessing toxicological risks associated with this class of flame-retardant chemicals on aquatic organisms. Utilizing zebrafish (Danio rerio) embryos as a model, development and stress responses the fish elicited were evaluated, specifically visible embryonic developmental criteria were evaluated including mortality, morphological malformation, nervous system developments, heart rate, and pericardial edema. In addition, RT-qPCR was used to quantify gene expression changes specifically in stress response genes, including biomarkers of oxidative stress and chemical exposure. Findings provide general knowledge advantageous to understanding toxicological risks associated with THPC exposure and promote implementing future management.