Date of Award

12-31-2017

Document Type

Campus Access Thesis

Degree Name

Master of Science (MS)

Department

Environmental Sciences

First Advisor

William E. Robinson

Second Advisor

Helen C. Poynton

Third Advisor

Robyn Hannigan

Abstract

4-Nonylphenol (NP) and 17α-ethinyl estradiol (EE2) are two endocrine disrupting compounds (EDCs) that are released into the environment via wastewater and sludge disposal. Measuring these EDCs in water can be problematic due to their occurrence at low concentrations and sample matrix complexities. To address this, we first developed an improved protocol for measuring NP and EE2 in mussel tissues by microwave assisted extraction and gas chromatography/mass spectrometry. Limits of quantification (LOQ) for NP and EE2 were 47.5 ng g-1 (dw), and 223.0 ng g-1 (dw), respectively. Earlier work in our lab has demonstrated that both compounds bioconcentrate differentially in the tissues of the blue mussel, Mytilus edulis L., with the highest concentrations found in the digestive gland (DG). Therefore, I hypothesized that measuring EDCs in mussel DGs may be a better alternative than measuring them in water or even whole body mussel tissues. DGs and remaining tissues (RTs) of mussels exposed to NP (1 µg L-1) and EE2 (100 ng L-1) for 14 days were extracted and analyzed separately for comparison. DG concentrations were higher than RTs for EE2 (1372 vs. 347 ng g-1; dw) but not for NP (BDL vs. 49 ng g-1; dw). Mean percent recoveries of an internal standard were higher and less variable in DG samples (70 % ± 24%) compared to RTs (61% ± 34%). DGs took approximately 3 fewer minutes to process than RTs and cost $1.14 less per sample on average. Although the hypothesis was confirmed, it is concluded that these gains are not substantial enough and whole body analysis is still preferred.

Comments

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