Early-life exposure to persistent organic pollutants and health outcomes in common bottlenose dolphin (Tursiops truncatus) calves: a comparison of weighted exposure indices Öffentlichkeit

Si, Jing (Spring 2019)

Permanent URL: https://etd.library.emory.edu/concern/etds/d217qq65d?locale=de
Published

Abstract

Objective:The aim of this study is to evaluate the association of maternal exposure to POPs with five health outcomes (calf length, calf weight, and three thyroid hormones) in bottlenose dolphin calves, comparing results from regression models using each of these methods of weighting POP exposures: simple sums, principal component analysis (PCA), and weighted quantile sum (WQS).

Method: Data for this study were from a research initiated in 1970 in Sarasota Bay, Florida by the Sarasota Dolphin Research Program. Complete exposure data including 69 different POPs in dolphin blubber from four moms and 32 calves, including 53 polychlorinated biphenyls (PCBs) congeners, five polybrominated diphenyl ethers (PBDEs) congeners, four organochlorine pesticides (OCPs) and five Dichlorodiphenyltrichloroethane (DDT) compounds. Health outcomes of interest are calf length, calf weight and three thyroid hormones of calves including triiodothyronine (T3), thyroxine (T4), and free T4 (fT4). We performed generalized linear regression, principal component analysis (PCA) and sparse principal component analysis regression and weighted quantile sum (WQS) regression to assess the associations. Root-mean-square error (RMSE) of each model were calculated to evaluate the model fit.

Results: Higher concentrations of total PCBs were positively and significantly associated with calf length and calf weight regardless of controlling for parity and calf age in WQS with associations constrained to be positive. We did not find an association between maternal exposure to POPs and any of the five health outcomes using simple sums method and PCA method with the statistically significant threshold of 0.0008. WQS method (positive or negative) had the root-mean-square error (RMSE) for all the models. 

Conclusion: This study showedassociation between exposure to POPs, especially PCBs, with health endpoints of dolphin calves. Models using WQS showed stronger association than the simple sums and PCA methods, but the estimation is likely to be unstable due to small sample size. 

Table of Contents

Introduction ........................................................................................ 1

Methods............................................................................................... 5

Results .................................................................................................9

Discussion ...........................................................................................12

References ….......................................................................................16

Tables...................................................................................................19

Figures .................................................................................................23

Appendices ..........................................................................................24

About this Master's Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
School
Department
Degree
Submission
Language
  • English
Research Field
Stichwort
Committee Chair / Thesis Advisor
Zuletzt geändert

Primary PDF

Thumbnail Title Date Uploaded Actions
Early-life exposure to persistent organic pollutants and health outcomes in common bottlenose dolphin (Tursiops truncatus) calves: a comparison of weighted exposure indices () 2019-04-23 23:46:07 -0400

Supplemental Files

Thumbnail Title Date Uploaded Actions