DAR soil description

From enviPath Wiki
Jump to navigation Jump to search

enviPath conventions to store data from DAR soil

  • Scenario name: The scenario name is generated using the author name and year of the study, “Author name, Year” and in some cases also the study name, “Study name, Author name, Year”.
  • Scenario description: A small description of the scenario with information concerning the date of the submission of the DAR soil (date of the dossier on the first page).
  • Soil origin: Information on the soil source, typically indicating the place where the sample was collected - city, canton or state and country.
  • Soil description: Information on soil texture classification and percentage of sand, clay and silt in the soil. The soil texture is a qualitative classification used for determination of soil classes based on their physical texture. The soil is assigned to a specific class of a classification system based on the relative proportion of sand, salt and clay particles. The class of a soil is named according the main constituent in terms of particle size or a combination of the most abundant particles sizes. The term loam is also used in soils for which similar concentrations of sand, silt and clay are found. In the USDA classification system particles with diameter smaller than 0.002 are classified as clay particles, particles with diameter between 0.002 and 0.005 as silt particles and particles with diameter larger than 0.005 as sand particles.
  • Soil texture classification system: Information on the soil texture classification system used to derived the soil texture given in “soil description”. Information from the USDA classification system is preferred if information from more than one classification system is available.
  • Redox conditions: All data stored in the package DAR soil are from aerobic studies. Data from anaerobic-aerobic and anaerobic studies are not included.
  • Acidity, pH: pH at which the study was conducted. For cases where pH was determined in different soil solutions (i.e., H2O, KCl, CaCl2), only one value is stored using the following order of preference: CaCl2 > KCl > H2O. If available, the pH range of the experiment is stored.
  • Temperature: Temperature at which the experiment was performed in °C.
  • Water storage capacity: Information on how much water the soil can hold under a given “condition”, in g/100g soil or mass-%. The field “condition” indicates under which conditions the water storage capacity was measured (i.e., “(maximum) water holding capacity”, pF 2, 1/3 bar etc.).
  • Experimental humidity: Indicate in % at what percentage of the “water storage capacity” the experiment was actually run.
  • Organic content: Information on soil organic matter (OM) or organic carbon (OC) content in mass-%. If both values were available in the DAR, the value that has actually been measured (and not derived from the respective other value) is stored.
  • Cation exchange capacity, CEC: Information on the number of exchangeable cations that a soil is capable of holding per dry weight at a given pH value and available for exchange with the soil water solution, measured in milliequivalent of hydrogen per 100 g of dry soil.
  • Bulk density: Weight of dry soil in a given soil volume in g/cm3.
  • Biomass: Biomass is the part of soil organic matter that is made up by living organisms, mostly bacteria and fungi. Data is stored in µg of carbon/g soil.
  • Compound names: Compounds are named according to the DAR key (“identifier”) used in the dossier for each compound. This may lead to different compounds having the same name (e.g., Mxy). Names are therefore not unique in the DAR soil package.
  • DT50 values: The DT50 value (50% dissipation time) is the time required for 50% of the initial concentration of the compound under study to dissipate (in days). DT50 values do not per se assume a specific kinetic model. Only DT50 values measured at the original temperature of the experiment are stored. When several DT50 values are given for the same set of data (e.g., original submission, re-calculated by a “reviewing committee”, different kinetic models etc.), only the value that shows the best quality is stored (e.g., based on quality of fit, R2 values, comments in the text etc.). Additional information on the selected DT 50 value stored: (i) whether or not it is derived from a first-order kinetic model, and (ii) a comment about the reason for selecting that specific value (if needed).

DT50 values should always be available for the parent pesticides. In some cases, they have also been measured for major transformation products, and hence are also stored.

  • Spike concentrations/Spike compounds: The molecular formula of the spike compound, including isotopic information, using SMILES strings. For indicating the specific position of the 14C-label, the following rules were followed:

- If a specific position is indicated in the structures drawn in the DAR, the structure is stored with the label at that specific position - If the radioactivity “mark” (in general, star symbol) is in the middle of the aromatic ring or if the compound is given as [U14C]-compound, then the structure is stored with the 14C-label in all C atoms in the aromatic ring.