Persistence of herbicides in seawater. Herbicide concentrations recorded over time in standard flask experiment 2013. (NERP TE 4.2, AIMS and UQ)

This dataset shows the concentrations of multiple herbicides remaining over time in a simulation flask persistence experiment conducted in 2013.
The aim of this study was to quantify the persistence multiple herbicides in a standard flask experiment. Time it takes for degradation of half of this herbicide is termed the &quot;half-life&quot;. The half-life can be used to help develop environmental risk assessments.
Methods:
Herbicide degradation experiments were carried out in flasks according to the OECD methods for &quot;simulation tests&quot;. The tests used natural coastal seawater and were carried out in the incubator shakers under 3 conditions: (1) 25&deg;C in the dark, (2) 31&deg;C in the dark and (3) 25&deg;C in the light. The light levels were ~40 &micro;E on a 12:12 light:dark cycle and the flasks shaken at 100 rpm for up to 365 days.
Herbicides included:
Atrazine, Diuron, Hexazinone, Tebuthiuron, Metolachlor, 2,4-D,
Water samples were taken periodically and analysed by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS).
Uncertainty in the analytical method for repeated injections into the LC-MS results in a concentration uncertainty of approximately &plusmn; 0.2 &micro;g/L
Reductions in the concentration of herbicides were plotted to predict the persistence of each herbicide (its &quot;half-life&quot;).
The emergence of the three herbicide breakdown products were also quantified: Desisopropyl Atrazine and Desethyl Atrazine from Atrazine and 3,4-dichloroaniline from Diuron.
Format:
Excel spreadsheet: Herbicide_persistence_standard_flask_16042015.xlsx
Data Dictionary:

Time (days): Time in days from the start of the experiment
Sample replicate: Up to three replicate flasks were used containing herbicides and these were incubated under identical light and temperature conditions
D25 Atrazine: Concentration of Atrazine remaining in flasks under dark conditions at 25&deg;C
D25 Desisopropyl AtrazineAtrazine: Concentration of Desisopropyl AtrazineAtrazine remaining in flasks under dark conditions at 25&deg;C
D25 Desethyl Atrazine: Concentration of Desethyl Atrazine remaining in flasks under dark conditions at 25&deg;C
D31 Atrazine: Concentration of Atrazine remaining in flasks under dark conditions at 31&deg;C
D31 Desisopropyl AtrazineAtrazine: Concentration of Desisopropyl AtrazineAtrazine remaining in flasks under dark conditions at 31&deg;C
D31 Desethyl Atrazine: Concentration of Desethyl Atrazine remaining in flasks under dark conditions at 31&deg;C
L25 Atrazine: Concentration of Atrazine remaining in flasks under light conditions at 25&deg;C
Sample lost: missing data because the sample was lost
L25 Desisopropyl AtrazineAtrazine: Concentration of Desisopropyl AtrazineAtrazine remaining in flasks under dark conditions at 25&deg;C
L25 Desethyl Atrazine: Concentration of Desethyl Atrazine remaining in flasks under dark conditions at 25&deg;C
D25 Diuron: Concentration of Diuron remaining in flasks under dark conditions at 25&deg;C
D25 Di Cl Analine: Concentration of 3,4-dichloroaniline remaining in flasks under dark conditions at 25&deg;C
D31 Diuron: Concentration of Diuron remaining in flasks under dark conditions at 31&deg;C
D31 Di Cl Analine: Concentration of 3,4-dichloroaniline remaining in flasks under dark conditions at 31&deg;C
L25 Diuron: Concentration of Diuron remaining in flasks under light conditions at 25&deg;C
L25 Di Cl Analine: Concentration of 3,4-dichloroaniline remaining in flasks under light conditions at 25&deg;C
D25 Hexazinone: Concentration of Hexazinone remaining in flasks under dark conditions at 25&deg;C
D31 Hexazinone: Concentration of Hexazinone remaining in flasks under dark conditions at 31&deg;C
L25 Hexazinone: Concentration of Hexazinone remaining in flasks under light conditions at 25&deg;C
D25 Tebuthiuron: Concentration of Tebuthiuron remaining in flasks under dark conditions at 25&deg;C
D31 Tebuthiuron: Concentration of Tebuthiuron remaining in flasks under dark conditions at 31&deg;C
L25 Tebuthiuron: Concentration of Tebuthiuron remaining in flasks under light conditions at 25&deg;C
D25 Metolachlor: Concentration of Metolachlor remaining in flasks under dark conditions at 25&deg;C
D31 Metolachlor: Concentration of Metolachlor remaining in flasks under dark conditions at 31&deg;C
L25 Metolachlor: Concentration of Metolachlor remaining in flasks under light conditions at 25&deg;C
D25 2,4-D: Concentration of 2,4-D remaining in flasks under dark conditions at 25&deg;C
D31 2,4-D: Concentration of 2,4-D remaining in flasks under dark conditions at 31&deg;C
L25 2,4-D: Concentration of 2,4-D remaining in flasks under light conditions at 25&deg;C


Organization: Australian Ocean Data Network