Each treatment was prepared in triplicates. Throughout the experimental period, the moisture content of each sample was kept at 75% water holding capacity (WHC) by adding water and weighing the tubes on a weekly basis as necessary (Houben et al., 2013). At each interval of incubation period (0, 7, 15, 30, 45 and 60 days) the samples were extracted
This is not my specific expertise, so categorize this more as an educated guess. If the plants or bacteria accumulating heavy metals are stressed for water, accumulation may be limited. If there is too much water, oxygen in soil or media may be limited, also reducing bioavailability. The 75% level was probably set as a reasonable experimental standard to use so various studies can be comparable.
If if you wanted to test bioavailability in wetlands, you would use saturated, anoxic media. I suppose if you were interested in arid condition bioavailability with infrequent storms, you might want to reduce moisture, or add it less frequently to better mimic conditions of interest. The methods suggested in your question may be what one might expect to achieve maximum bioavailability where water and oxygen are not limited.
Research study is best when methods are standardized and reasonably representing conditions of interest. I would expect in your methods some description of media, soil type if soils, plants or bacteria inoculated, water used (rainwater, distilled, tap), levels of heavy metals, pH, alkalinity, etc. Water chemistry can affect solubility of metals, such as acidic often more soluble, alkaline, less soluble.
Dear William F. Hansen thanks for your consideration. Actually, i used gold mine tailings which was alkaline with pH 7.9 and its texture Silty loam which high concentration of HM
- Badges
- Science topic
- Similar topics
- Phytochemistry
- Extracts