摘要:

The results of a survey of quantitative structure-biodegradability relationships (QSBRs) are presented. The survey was made to evaluate the use of QSBRs for risk assessment and priority setting. It appears that few models can actually be used for legislative purposes. The major reason for this is that many models are either based on biodegradation end-points that are inconvenient for legislative purposes, or are not reproducible, or are based on too few data. It is concluded that single descriptor models cannot accurately predict the biodegradability of a broad range of chemicals. Most of these models therefore apply to narrow subclasses of chemicals only. The development of multiple descriptor models is still rather modest. More generally applicable models are based on molecular fragment contributions to biodegradability. However, for most of these models the chemical domain is uncertain. Despite the fact that none of the models in the survey meet the criteria set for judging a model to be useful for legislative purposes, three models are given the benefit of the doubt and are qualified as “best available”. Finally, some new validation results on the models selected are presented and recommendations for model development are given.

ISSN:1062-936X    

DOI:10.1080/10629369608031702

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Biodegradation occurs mainly through microbial enzyme attack, and enzyme-catalysed reactions are known to depend on hydrophobic, electronic and steric effects. However, most QSBR studies involve correlation with a single parameter, but there is no consistency regarding the class of parameter. This suggests that biodegradation occurs through a range of different mechanisms. A few QSBR studies have reported the need to include more than one class of parameter in correlations.

ISSN:1062-936X    

DOI:10.1080/10629369608031703

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Quantitative Structure-Biodegradability Relationships (QSBRs), relate the molecular structure of an organic chemical to its biological degradability. The high complexity of the microbial degradation process as well as great variety of the interactions between organism, organic pollutant and the environment make it difficult to interpret the results from biodegradability experiments. Literature concerning the various approaches applied in Structure-Biodegradability Relationship modeling is reviewed and the reliability and applicability of the results obtained from different biodegradation tests is discussed. A mechanistic approach, based on comparison of the data measured at different organization levels, will hopefully contribute to a better understanding of mechanisms taking place during the biodegradation. Their description and quantification may lead to improvement of existing QSBR models.

ISSN:1062-936X    

DOI:10.1080/10629369608031704

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The biodegradability of a substance depends on the structure and physical form of the substance, the time that has been available for acclimation, and the environmental conditions. Importantly, these later factors can be just as important as structure in determining the outcome of a biodegradation test. The development of appropriate QSARs for biodegradation and the ultimate value of the final QSAR depends on understanding these factors. This paper will describe what is known about the effect of test conditions on the results of biodegradation tests. The ability of these tests to reflect real environmental conditions will also be examined. Finally, we will discuss what we believe, in the light of this information, should be the goal of biodegradation QSARs and how these QSARs can be most appropriately used in fate assessments.

ISSN:1062-936X    

DOI:10.1080/10629369608031705

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The Free-Wilson QSAR model in the Fujita–Ban modification was used to calculate the quantitative substituent activity contributions to the toxicity againstEuglena gracilisin a series of 91 benzothiazolium salts. An important increase of activity was found for R = styryl or SCH2C6H5group and for R2= propargyl or allyl group. The substituentd on benzene ring also enhance the activity. The possible relations between structure of active groups and their electronic or physicochemical properties are discussed. By using the calculated values it is possible to predict toxicity for 1300 compounds. New compounds with assumed high or low toxicity are predicted.

ISSN:1062-936X    

DOI:10.1080/10629369608031706

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:1062-936X    

DOI:10.1080/10629369608031701

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor