Biomedical subjects

U Pagga

Publications and source records attributed to U Pagga.

6 recordsLinked to original sources

PubMed2001

Determination of the aerobic biodegradability of polymeric material in aquatic batch tests.

Results of an international ring-test of two laboratory methods are presented for investigating the biodegradability of organic polymeric test materials in aquatic test systems based on respirometry and the evolution of carbon dioxide. These methods are developed further from the well-known standardized biodegradation tests ISO 9408 (1999) and ISO 9439 (1999), which have been successfully used for many years. The most important improvements are the extension of the test period up to six months, the increase of the buffer capacity and nutrient supply of the inorganic medium, an optimization of the inoculation, and optionally, the possibility of a carbon balance. A ring test, organized by the International Biodeterioration Research Group (IBRG), was run using a poly(,-caprolactone)-starch blend and an aliphatic-aromatic co-polyester as test materials and a microcrystalline cellulose powder as a reference material. The test results and the experience gained by the participants showed that the methods are suitable and practicable. The test methods have been meanwhile established as standards ISO 14851 (1999) and ISO 14852 (1999).

Aerobiosis↗

PubMed1999

Compostable packaging materials--test methods and limit values for biodegradation.

In order to classify packaging materials as capable of organic recovery according to the packaging regulation of the European Union, the intended materials must be tested for their compostability. An important prerequisite is the determination of biodegradability by standardized test methods. Details of the intended tests are not comprehensible without further knowledge of the problems of biodegradation testing. The test methods and the limit values used to evaluate the biodegradation results are presented and discussed against the background of established test methods and limit values for chemicals. Furthermore the problem of ecotoxicity tests in connection with compost quality is discussed and an overview of European test laboratories is given.

Biodegradation, Environmental↗

PubMed1997

Testing biodegradability with standardized methods.

Laboratory test methods are used by industry laboratories to determine biodegradability, an important parameter for the evaluation of the ecological behaviour of substances. Biodegradability has a key role due to the simple fact that a degradable substance will cause no long term risk in the environment. The great variety of biodegradation processes in the natural environment and in technical plants for treating waste water and solid wastes gave rise to a rather large number of test methods based on different test principles. To guarantee the acceptance of the test results by authorities and customers internationally standardized methods (ISO, OECD) and established quality criteria (GLP, EN 45,000, ISO 9000) are used.

Biodegradation, Environmental↗

PubMed1996

A dynamic river model for biodegradability studies: investigations with selected aromatic compounds at low concentrations and comparison with aquatic batch tests.

The objective of this publication is to present a new dynamic aerobic biodegradation test method simulating a river. A laboratory cascade test system and standardized batch shake flask tests were used for biodegradation studies with the non-volatile and non-sorbing model compounds 2,4-dinitrophenol, naphthalene-1-sulphonic acid and sulphanilic acid. To be closer to the often very low concentrations of substances in the environment the concentrations of the compounds used were standard test concentrations and lower. 14C labelled compounds were measured at 50 micrograms/l, capillary electrophoresis at 5000 micrograms/l and the removal of dissolved organic carbon at 50000 micrograms/l. The test results obtained confirmed the known ultimate biodegradability of the test compounds and showed that biodegradation degrees, rates and degradation durations depended on the test systems, the concentrations of test compounds and the inocula. The river model is a suitable simulation test for natural dynamic surface waters which can be used to perform biodegradability studies at low test concentrations if adequate analytical tools, preferably radioactive-labelled substances, are available.

2,4-Dinitrophenol↗

PubMed1996

A growth inhibition test with sewage bacteria--results of an international ring test 1995.

A bacterial toxicity test method using the determination of growth inhibition of sewage bacteria within an incubation period of 6 hours will be standardized at ISO. A ring test was performed with 24 participants using 3.5-dichlorophenol and potassium cyanide as test substances. The analysis of the test results showed that the method is very accurate and appropriate for determining the bacterial toxicity of chemical compounds. Due to the results obtained 3.5-dichlorophenol was proposed as a reference substance.

Bacteria↗

PubMed1995

Determination of the aerobic biodegradability of polymeric material in a laboratory controlled composting test.

A laboratory method is presented for investigating the biodegradation of an organic test material in an aerobic composting system based on the evolution of carbon dioxide. In addition to carbon conversion, biodegradation can also be monitored through weight loss and physical disintegration. The test method is different from other biodegradation tests, especially aquatic tests, because of the elevated temperature representative for real composting conditions and also because of enhanced fungal degradation activities. A ring test was run using paper and poly-beta-hydroxybutyrate/valerate as test materials and cellulose powder as a reference material. The test results and the experience gained by the participants showed that the method is suitable and practicable. Experience with real technical-scale composting facilities confirms that the method provides test results of high predictive value. The test is designed to become a European Standard in connection with determining the compostability of packagings and packaging materials.

Bacteria, Aerobic↗