Effect of Tetrakis (Hydromethyl) Phosphonium Chloride (THPC) on Zebrafish (Danio rerio)

Primary Faculty Mentor’s Name

Dr. Vinoth Sittaramane

Proposal Track

Student

Session Format

Poster

Abstract

Tetrakis (hydromethyl) phosphonium chloride (THPC) is a tetrakis (hydromethyl) phosphonium salt commonly used in commercial flame retardants. Mainly used by the textile industry, THPC 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. Currently, there are no studies being conducted investigating how this chemical impacts water quality and the toxic effects THPC can have aquatic organisms following exposure. Therefore, studying the toxicity of THPC can provide a knowledge base for assessing toxicological risks associated with this class of flame-retardant chemicals.

In this study, we will use zebrafish (Danio rerio) embryos as a model to study the developmental and stressor effects THPC has on these fish. Zebrafish serve as excellent models because of their ease of manipulation, sensitivity to environmental stress, transparent embryos, and low cost of maintenance. We plan to manipulate a toxic environment by spiking our water with THPC, monitoring development and evaluating stress responses the fish elicit. Using stereomicroscopy, visible embryonic developmental criteria will be evaluated including mortality, morphological malformation, nervous system developments, heartbeat, and pericardial edema. With THPC containing possible stressors, effects can manifest within acute exposure time. Therefore, at various stages post fertilization (24 hours post fertilization, 48 hpf, and 72+ hpf), a portion of the embryos treated will be removed and fixed in 4% paraformaldehyde for further stress-specific effects. We can measure stress responses according to the expression of specific biomarkers utilizing different bioassays. Specifically, one stress response we will evaluate is the expression of heat shock proteins, which is a leading biomarker for environmental stress, because its expression can be induced by pollutant exposure. Another stress response we plan to assess is oxidative stress responses, which is the disturbance between production of reactive oxygen species (ROS) and antioxidant defenses. Environmental stress increases ROS production; therefore, we can assess the expression of specific ROS induced mRNA. Developmental and biological responses observed in THPC treated embryos will provide considerable knowledge on the possible toxicological effects of this chemical.

Keywords

Zebrafish, Danio rerio, Tetrakis (hydromethyl) phosphonium chloride, Biological response, Toxicological effects, Stressor, Ogeechee River, Flame-retardant, Chemical exposure, Development

Location

Concourse/Atrium

Presentation Year

2014

Start Date

11-15-2014 9:40 AM

End Date

11-15-2014 10:55 AM

Publication Type and Release Option

Presentation (Open Access)

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Nov 15th, 9:40 AM Nov 15th, 10:55 AM

Effect of Tetrakis (Hydromethyl) Phosphonium Chloride (THPC) on Zebrafish (Danio rerio)

Concourse/Atrium

Tetrakis (hydromethyl) phosphonium chloride (THPC) is a tetrakis (hydromethyl) phosphonium salt commonly used in commercial flame retardants. Mainly used by the textile industry, THPC 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. Currently, there are no studies being conducted investigating how this chemical impacts water quality and the toxic effects THPC can have aquatic organisms following exposure. Therefore, studying the toxicity of THPC can provide a knowledge base for assessing toxicological risks associated with this class of flame-retardant chemicals.

In this study, we will use zebrafish (Danio rerio) embryos as a model to study the developmental and stressor effects THPC has on these fish. Zebrafish serve as excellent models because of their ease of manipulation, sensitivity to environmental stress, transparent embryos, and low cost of maintenance. We plan to manipulate a toxic environment by spiking our water with THPC, monitoring development and evaluating stress responses the fish elicit. Using stereomicroscopy, visible embryonic developmental criteria will be evaluated including mortality, morphological malformation, nervous system developments, heartbeat, and pericardial edema. With THPC containing possible stressors, effects can manifest within acute exposure time. Therefore, at various stages post fertilization (24 hours post fertilization, 48 hpf, and 72+ hpf), a portion of the embryos treated will be removed and fixed in 4% paraformaldehyde for further stress-specific effects. We can measure stress responses according to the expression of specific biomarkers utilizing different bioassays. Specifically, one stress response we will evaluate is the expression of heat shock proteins, which is a leading biomarker for environmental stress, because its expression can be induced by pollutant exposure. Another stress response we plan to assess is oxidative stress responses, which is the disturbance between production of reactive oxygen species (ROS) and antioxidant defenses. Environmental stress increases ROS production; therefore, we can assess the expression of specific ROS induced mRNA. Developmental and biological responses observed in THPC treated embryos will provide considerable knowledge on the possible toxicological effects of this chemical.