after preliminary experimentation ( soil burial , sewage and garbage exposure tests ) in the laboratory as well as in the open , a large scale field testing programme under realistic and to some extent extreme conditions was implemented : nine different plastic materials comprising eight plain high polymer plastics and for comparison one synthetic cellulose derivate , together with glass control samples , were exposed in twelve different sewage , garbage , and soil media over a period of 3 months to 2 years , and subsequently examined .
C0032521
polymer
C0032167
plastics