Table 2.
Phytotoxicity tests.
| Trophic level: terrestrial | |||
|---|---|---|---|
| Bioindicators | Plant Seeds (ryegrass) | Microorganisms (fungi and bacteria) | |
| Samples (at 98 days) | Seedling emergence (%) | Plant biomass (mg) | Net apparent CO2 production rate (g/d) |
| Blank compost [threshold 90%] | 78 ± 15 [70%] | 84 ± 28 [76 mg] | 0.46 ± 0.02 [0.41 g/d] |
| Cellulose | 89 ± 8 | 115 ± 30 | 0.78 ± 0.01 |
| No phytotoxicity | No phytotoxicity | No ecotoxicity | |
| Sepia Melanin | 76 ± 12 | 77 ± 24 | 0.61 ± 0.01 |
| No phytotoxicity | No phytotoxicity | No ecotoxicity | |
| Polyethylene | 66 ± 19 | 48 ± 26 | 0.49 ± 0.05 |
| No phytotoxicity | Potentially phytotoxic | No ecotoxicity | |
| Copper (II) phthalocyanine | 57 ± 13 | 50 ± 33 | 0.40 ± 0.01 |
| No phytotoxicity | No phytotoxicity | Potential ecotoxicity | |
| Polyphenylene sulfide | 42 ± 15 | 14 ± 6 | 0.48 ± 0.05 |
| Potentially phytotoxic | Potentially phytotoxic | No ecotoxicity | |
Seedling emergence and plant biomass in wet sandy soil (used as a “pristine” or “clean” substratum). After 19 days, the number of plants in this wet sandy soil is 20 ± 0. In addition, a second bioindicator, the compost microbiota (fungi and bacteria), representing a lower trophic level than the plants, was used. Thus, the microbial respiration rate (apparent CO2 production) is also reported in this table, in g/d. As recommended by ASTM, a 90% threshold value is used to validate potential phytotoxicity. Statistical analysis is detailed in SI.