Phytotoxicity testing

TABLE D.1 Degradation Rates for Compostable Samples after 180 Days  

D6400 biodegradation standard requires at least 90% degradation over 180 days. Cellulose samples had comparable degradation conversion and degradation rates as the PHA film and PLA film. The polyethylene plastic bag had negligible biodegradation in the compost environment. 

The compostable materials must not release toxic materials into the compost soil during and after degrading. The compost soil can be tested to assess phytotoxicity, which indicates poisonous environment to plants. The germination of tomato seedlings in the compost soil was evaluated after a 10-day duration. The ph5dotoxicity test was based upon the 

FIGURE D.4 Carbon conversion percentages for samples under industrial composting conditions per ASTM D5338 standards. 

Material Average germination (%) Average length (mm after 10 days) Average germination index Average pH 

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Radetski, C.M. Ferard, J.M. Blaise, C. A semistatic microplate based phytotoxicity test. Environ. Toxicol. Chem. 1995, 14, 299-302. 

Symptoms observed in phytotoxicity tests of soil-applied atrazine and metribuzin were similar to simazine, except they appeared more rapidly after application, progressed more quickly into the interveins, and caused the leaf margins to become necrotic. Symptoms observed in terbutryn and prometryn phytotoxicity tests were chlorosis in the leaf veins, rather than interveins, which is more typical of injury from diuron or terbacil. 

Lewis, M.A. (1995) Use of freshwater plants for phytotoxicity testing a review, Environmental Pollution 87 (3), 319-336. 

Devare, M. and Bahadir, M. (1994b) Ecotoxicological assessment of inorganic waste disposal in salt mines, part 11 phytotoxicity tests, Fresenius Environ. Bull. 3, 119-126. 

Baud-Grasset, F., Baud-Grasset, S. and Safferman, S. I. 1993. Evaluation of the bioremediation of a contaminated soil with phytotoxicity tests. Chemosphere 26, 1365-1374... 

Other effects of cytochalasins on plant growth have been reported 11481. Chaetoglobosin K was Isolated from Dlolodla macrosDora and shown to be structurally related to the cytochalasins 11461. Phytotoxicity tests Indicated Inhibition to wheat coleoptlles at 10 N and may be the most active cytochalasin tested. 

Multispecies tests Experimental streams Ponds Microcosms Bioconcentration tests Effluent toxicity tests Sediment toxicity tests Phytotoxicity tests Algae... 

American Society for Testing and Materials (ASTM) (1996b) Standard Guide for Conducting Renewal Phytotoxicity Tests with Freshwater Emergent Macrophytes, E1841-1896. ASTM, Philadelphia. 

Using standardized phytotoxicity test methods, Rocheleau et al. [40] investigated the effects of TNT, TNB, 2,4-DNT, and 2,6-DNT freshly amended (following a 24-h moisture equilibration period) or weathered and aged (13 weeks) in SSL soil. Tests... 

The potential for phytotoxicity from explosives is discussed at length elsewhere in this volume (see Chapter 3). Few studies of the phytotoxicity of these chemicals have been undertaken, and most of these, which are reviewed in Rocheleau et al. [13], were tests of TNT. Concentrations of TNT that reduce shoot or root biomass in crop test plants in the laboratory range from about 0.1 mg kg-1 to >1600 mg kg 1 dry soil [14-17], Phytotoxicity tests with amended soils produced lowest observed effect concentration (LOEC) values for TNT ranging from 0.1 to 64 mg kg 1 depending on plant species and exposure type used [15] (see Chapter 3). Plant growth was not affected by HMX at concentrations up to approximately 1900 mg kg1 dry forest soil [16], and additional studies suggest that nitroheterocyclic compounds are not as toxic... 

TAL is not toxic to plants and can be used safely in agricultural formulations. Phytotoxicity tests have been carried out on peas and maize plants. After spraying with a 2% solution of TAL, the plants produced flowers and fruits normally, as compared with the controls. ... 

Phytotoxicity testing can be conducted on two classes of flowering plants. These are monocots (plants with one seed leaf) and dicots (plants with two seed leaves). Representatives from both of these classes are typically used in toxicity testing - summer barley to represent monocots and cress to represent dicots. Test involves measuring the yield of both of these plants obtained from the test compost and from the control compost. 

The AAL-toxins are hydroxylated, long-chain alkylamines with one esterified pro-pane-1,2,3-tricarboxylic acid moiety. The difference between TA and TB is that TB lacks a hydroxyl group at R4 (Fig. 1). TA and TB are equally active against susceptible tomatoes (56, 58). However, removal of the hydroxyl group at R3, which produces TC, renders the compound much less active (300 ng vs. 10 ng per plant to cause visible symptoms) (28). TD and TE are acetylated forms of TB and TC, respectively. They represent up to 40% of the AAL-toxins produced by fermentation in liquid medium. TD and TE are essentially inactive in phytotoxicity testing and are probably metabolic products from detoxification of the active metabolites (28). 

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