Abstract:

Partitioning coefficients (Kd) of hydrophobic organic compounds (HOCs) such as 1-methyl naphthalene and phenanthrene at various temperatures and salinities were determined in the laboratory. It was crucial to measure the Kd values at ambient temperature and salinity of deep sea organisms to ensure we were reaching our dosing concentration in dosing chambers. Commercially available Americamysis bahia and deep sea organisms such as Janicella spinacauda, Sergestes sp, Euphausiidae, Systellaspis debilis, and Sergia sp were dosed with single hydrocarbons through passive dosing (PDMS O-rings).

Suggested Citation:

Gopal Bera Anthony Knap. 2017. Partitioning coefficient of 1-methyl naphthalene and phenanthrene at various temperature and salinity. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7PR7TB8

Publications:

Knap, A., Turner, N. R., Bera, G., Abigail Renegar, D., Frank, T., Sericano, J., & Riegl, B. M. (2017). SHORT-TERM TOXICITY OF 1-METHYLNAPHTHALENE TO AMERICAMYSIS BAHIA AND FIVE DEEP-SEA CRUSTACEANS. Environmental Toxicology and Chemistry. doi:10.1002/etc.3926

Purpose:

Precise partitioning coefficient (Kd) values were needed so that we can reach our target dosing concentration in dosing chambers during toxicity experiments. Partitioning coefficient of 1-methyl naphthalene and phenanthrene were measured at various temperatures and salinity. The Kd values were measured at room temperature and below 30 ppt to do the experiment with commercially available species to ensure that our dosing experiment protocols was working correctly. Then the Kd values were measured at ambient temperature of deep sea organisms (our species of interest) and were used in dosing experiments.

Data Parameters and Units:

Partitioning coefficient (Kd) values at different temperature (deg F) and salinity (ppt).

Methods:

A predetermined amount of single hydrocarbon (e.g. 1-methylnapthalene or phenanthrene in this case) was dissolved in 500 ml of MeOH and mixed for 24 hours. A total of 80 pre-cleaned O-rings were then added to the 1-MN or phenanthrene/MeOH solution in a 2 L glass bottle. A magnetic stirrer bar was added and the solution was stirred for 72 hours to reach equilibrium. Thirty loaded O-rings were added to each 2 L aspirator bottle, which was filled with seawater at the appropriate salinity (mysid= 27PSU and deep-sea organisms= 35PSU). O-rings were stirred by a stir bar for another 72 hours. A time-series of water samples was then taken for measurement of 1-MN or phenanthrene in seawater. Water samples were extracted with dichloromethane (DCM) before measurement with an Aqualog Horiba Scanning Spectrofluorometer. For 1-MN or phenanthrene concentrations in loaded O-rings, one O-ring was extracted with 20 ml of DCM and measurements were completed with an appropriate dilution to keep the measurement within the calibration curve. The partition coefficient between PDMS and seawater (SW) was calculated by: K(PDMS:SW)=C_PDMS/C_SW where KPDMS:SW is the partition coefficient between PDMS and seawater, CPDMS is the concentration of 1-MN in the loaded O-ring, and CSW is the concentration of 1-MN in the equilibrated seawater.

Instruments:

Aqualog Horiba fluorometer (Model: Aqualog-UV-800)

Individual Files: