Ecotoxic Effects appearing during Degradation in Soil

4 Ecotoxic Effects Appearing During Degradation in Soil 

From a theoretical point of view, inherently biodegradable polymers should not behave other than dead biomass (leave litter, wood, whole plants) which is a significant part of the natural carbon cycle. General effects of degradable substances on physical and chemical soil properties as well as on the soil ecology are described by Coleman [23]. They are almost always of positive nature distinct as a long time increase of productivity and soil fertility. 

It is very difficult if not impossible to extrapolate the appearance of ecotoxic degradation metabolites or residues exclusively from the chemical structure of a polymer. Nevertheless, some basic guidelines concerning the presence (or absence) of heteroatoms and aromatic compounds in the polymer chain could be followed. The use of combined tests for biodegradability and ecotoxicity is strongly recommended. 

Results from ecotoxicological investigations of biodegradable polymers after composting are rare. Biotest design and evaluation of results should focus on the detection of influences 

Probable ecotoxic effects arising from the biodegradation of polymers are rarely predictable from theoretical approaches. Furthermore the routine chemical analysis for quality control of compost and soil will not be suitable to detect all possible effects harmful for the environment. Bioassays will be necessary to supplement the other analyses and to complete the information about the environmental behaviour of hiodegradahle polymers. That need is already expressed in the inclusion of mandatory hioassays in the relevant standards for compostable products. 

---