| Summary: | Polyethylene-water equilibrium partitioning coefficients (KPEW) have been determined for many hydrophobic organic contaminants (HOCs) for their use in passive sampling methods. Many KPEW data sets are available for polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pesticides (e.g., DDTs), but no researchers have studied KPEW values for estrogen compounds. Estrogens are important endocrine disrupting compounds (EDCs) which can have serious effects
on aquatic organisms, causing them to fail to grow and develop normally, ultimately affecting the function of the entire ecosystem, polluting the environment, and endangering human health. As one of the important tracers for the sewage (a potential source of estrogens to the aquatic environment), carbamazepine is also of great research significance. KPEW for the five most frequently detected steroidal estrogens - estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethynyl estradiol
(EE2), 2-Bromo 17β-estradiol (monoBrE2) - and carbamazepine were determined by liquid-chromatography/tandem mass spectrometry (LC-MS/MS). The experimental samples were divided into two groups. The first group had a salinity of 0 M and an equilibration time of 19 weeks. The second group had salinities of 0 M, 0.25 M, and 0.5 M, respectively, and an equilibration time of 9 weeks. Calculated KPEW for all compounds except E3 were about two times lower in the experiment with longer
equilibration time. For most estrogens, no trends in KPEW were apparent with increasing salinity. The dissolution of carbamazepine in water, however, appeared to decrease with salinity. Laboratory measured KPEW were compared with modeled octanol-water partition coefficients, KOW, and hexadecane-water partition coefficients, KHEX-W. Poor correlation between log KPEW and log KOW for the five estrogens studied were found, however strong correlation was found between and log KPEW and log
KHEX-W: log KPEW = 0.54 ( ± 0.014) log KHEX-W + 1.32 ( ± 0.073) (R2 = 0.95). The measured KPEW values and this linear relationship for estrogens will make it easier for other researchers to use PE as a passive sampler for these compounds in other applications and the result of this research will also increase the accuracy of PE-determined CW.
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