Abstract:

This dataset covers part of the data for experiments in which a single PAH (pyrene) was added to mesocosms. Data provided here are the measured concentrations of pyrene in sediment samples (surface and subsurface) and water samples of the mesocosms. Bioturbator data (including survival/recovery) and environmental data (D.O., redox, turbidity, etc.) for sediment and water in the mesocosms are provided in a separate dataset. The dataset contains results for an experiment with ghost shrimp and for an experiment with the razor clam as the bioturbator species.

Suggested Citation:

Klerks, Paul, and Febee Louka. 2017. Mesocosm experiments with single PAH - PAH data. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7MK69WH

Publications:

Klerks, P. L., Kascak, A., Cazan, A. M., Deb Adhikary, N., Chistoserdov, A., Shaik, A., … Louka, F. R. (2018). Effects of the Razor Clam Tagelus plebeius on the Fate of Petroleum Hydrocarbons: A Mesocosm Experiment. Archives of Environmental Contamination and Toxicology, 75(2), 306–315. doi:10.1007/s00244-018-0515-0

Klerks, P. L., Kascak, A., Cazan, A. M., Franco, M. E., & Louka, F. R. (2020). A Mesocosm Assessment of the Effect of Bioturbation by the Ghost Shrimp ( Lepidophthalmus louisianensis ) on the Fate of Petroleum Hydrocarbons in the Intertidal Zone. Environmental Toxicology and Chemistry, 39(3), 637–647. doi:10.1002/etc.4652

Purpose:

Experiment aimed at determining the effect of bioturbators on the distribution and degradation of petroleum hydrocarbons in nearshore environments. This specific dataset provides data on day-1 pyrene concentrations in water, sediment from pyrene-spiked mesocosms (with or without bioturbators). It also includes also the pyrene levels in water, surface sediment and subsurface from these same mesocosms sampled at the end of the experiment (day 10 or day 15). Experiment duration differed among experiments conducted at different times of the year, as an adjustment for anticipated differences in microbial activity.

Data Parameters and Units:

Experimental design worksheet includes details on when the experiment was conducted, when sampling was conducted (for environmental variables and petroleum hydrocarbon) and what tanks received which of 4 treatments (bioturbator present/absent * pyrene added or not). PAH worksheet has info on concentrations of pyrene in water (μg/L), surface and subsurface sediments (μg/kg) in specific tanks. It also includes the mean concentrations as well as # of trials.

Methods:

Water samples of approximately 500 mL were collected from the mesocosms (at approximately mid-depth of the water column) using a sampling device with glass tubing and Erlenmeyer flask where air displacement from the flask resulted in water flowing through the tubing from mesocosms into flask. Samples were placed in 500-mL glass containers and transported to the lab in a cooler. Samples were stored at -4 °C for a maximum of 24 hours. Hydrocarbons were extracted using liquid-liquid extraction. Dichloromethane (DCM) was used for extraction, the organic solvent containing the extracted PAH was then evaporated using a rotary evaporator at 22°C, and the residue was dissolved in hexane. The hexane was then concentrated in a vial to a volume of 1.00 mL by purging nitrogen gas into the vial. An aliquot of the sample was then injected into an Agilent technologies 7820A gas chromatography System with a flame ionization detector (GC-FID) for quantification of the pyrene. Replicates of several of the samples for both treatments (with and without bioturbators) were analyzed to assess reproducibility. The collected sediment (surface and subsurface) samples were collected with a glass coring tube, transferred to the lab in a cooler, and frozen upon arrival. All samples were freeze dried using an SP Scientific freeze dryer (Sentry 2.0). Dry samples were homogenized using mortar and pestle, and 20 g of sediment was placed in Teflon microwave tubes with 25 mL of DCM. One Touch Technology MARS microwave extraction was performed using the US EPA 3546 method. The DCM containing the extracted PAH was then filtered by gravity filtration and the remaining sediment was then washed several times with DCM, the DCM was filtered again, and combined in order to recover all the extracted pyrene. The DCM was evaporated using a rotary evaporator. The remaining residue was then dissolved in hexane. The round-bottom flask was rinsed with hexane several times in order to maximize recovery of PAH in the sample. All the hexane rinses were combined and concentrated in a vial to a volume of 1.00 mL by purging nitrogen gas into the vial. An aliquot of each extracted sample was injected immediately into the GC-FID or was frozen for analysis on the following day. The injections were done using the following conditions: The injector and detector temperatures were set at 250 and 300ᵒC, respectively; helium was used as the carrier gas; samples were injected in the splitless mode; the oven temperature was programmed from a 60ᵒC initial temperature to increase to 300ᵒC at a rate of 5ᵒC /min, was then decreased to 290ᵒC, and was maintained at this temperature for 25 minutes.

Instruments:

Instrumentation information is provided in the methods section.

Error Analysis:

The Gas Chromatography instrument was calibrated prior to every use. Calibration curve was obtained using Restek pyrene standard with exact concentrations. An internal standard was added to all samples prior to analyses. Replicates of samples in presence and in absence of bioturbators were performed for accuracy, as were analyses of samples from mesocosms to which no pyrene had been added.

Provenance and Historical References:

Dataset R2.x226.000:0001 contains the experimental design and bioturbator information from these experiments, along with the environmental data for the water and sediment in the mesocosms during the experiment.

Individual Files: