Date of Submission

2019

Document Type

Thesis

Degree Name

Master of Science in Environmental Science

Department

Biology and Environmental Sciences

First Advisor

John Kelly

Second Advisor

Nicholas Stasulli

Third Advisor

Jean-Paul Simjouw

MeSH

Endocrine Disruptors, Fundulidae

LCSH

Mummichog, Crumb rubber, Endocrine disrupting chemicals

Abstract

The increase in crumb rubber used in artificial turf fields, playgrounds, and other landscape development projects has sparked concern for the health of humans and aquatic species across the United States. The crumb rubber produced from the recycling of automotive tires is suspected of interfering with the endocrine pathways used by teleost fish species, leading to the reduction of growth rate and reproductive success. The estuarine baitfish, Fundulus heteroclitues, is native to Long Island Sound and was used as a laboratory bioindicator for the physiological impact of crumb rubber on the growth and reproduction of local aquatic fishes. Male F. heteroclitus were exposed to crumb rubber for approximately three months. Growth rate in length, weight, and gonadosomatic index were calculated. As a molecular assessment of gene expresion, RT-qPCR was used to measure the amplification in the expression of the female estrogenic hormone vitellogenin-1 in male liver tissue, and a histological analysis of male gonad tissue was used to observe any feminization or anatomical changes in tissue structure. A geographic information systems (GIS) assessment was performed to predict the locations along the Connecticut shoreline that are at the highest risk of exposure to crumb rubber runoff. The largest observed impacts of crumb rubber exposure were in total growth rate and testicular interstitial tissue structure. Total growth rate in individuals exposed to the rubber treatment were significantly less than those not exposed, and the interstitial tissue within the testes of individuals exposed to the rubber treatment was significantly reduced than those not exposed. The GIS analysis showed that New Haven Harbor and the Bridgeport shoreline are at the greatest risk to crumb rubber effluent than any other regions of the Connecticut coast.

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