SRC's BIODEG (BioWin)
Program
The Biodegradation
Probability Program for Windows (BIOWIN) calculates the probability that
a chemical under aerobic conditions with mixed cultures of
microorganisms will biodegrade rapidly or slowly. It uses fragment
constants developed using multiple linear and non-linear regressions and
data from SRC's data base of evaluation biodegradation data
(EFDB BIODEG
file). The results have been published in the following:
Howard, P.H., Boethling,
R.S., Stiteler, W.M., Meylan, W.M., Hueber, A.E., Beauman, J.A., and M.E.
Larosche. 1992. Predictive model for aerobic biodegradability developed
from a file of evaluated biodegradation data. Environ. Toxicol. Chem.
11: 593-603.
Previous version 3 of
the program added new expert survey data. The model uses a slight
revision of the previous fragments and molecular weight to (a) calculate
the probability of rapid biodegradation from the experimental data, and
(b) estimate the primary and ultimate biodegradation times for complete
degradation (days, weeks, months, longer) using the evaluations of 200
chemicals by 17 biodegradation experts. A description is available in
the following journal article:
Boethling, R.S.,
Howard, P.H., Meylan, W., Stiteler, W., Beaumann, J. and N. Tirado.
1994. Group contribution method for predicting probability and rate of
aerobic biodegradation. Environ. Sci. Technol. 28: 459-65.
BIOWIN v4.00 - March
2000
BIOWIN version 4 adds
two new predictive models for assessing a chemical’s biodegradability in
the Japanese MITI (Ministry of International Trade and Industry)
biodegradation test. The new models use an approach similar to the
linear/non-linear regression models already included in BIOWIN. The
following journal article giving a complete description of the MITI
Biodegradation models is being published:
Tunkel,J., Howard,P.H.,
Boethling,R.S., Stiteler,W. and Loonen,H. 2000. Predicting Ready
Biodegradability in the MITI Test. Environ. Toxicol. Chem. accepted for
publication.
Under its Chemical
Substances Control Law (CSCL), the Japanese have tested approximately
900 discrete substances in the Ministry of International Trade and
Industry (MITI)-1 test. This protocol for determining ready
biodegradability is among six officially approved as ready
biodegradability test guidelines of the OECD (Organization for Economic
Cooperation and Development). A total dataset of 884 chemicals was
compiled to derive the fragment probability values that are applied in
this MITI Biodegradability method. The dataset consists of 385 chemical
that were critically evaluated as "readily degradable" and 499 chemicals
that were critically evaluated as "not readily biodegradable".
BIOWIN produces two
separate MITI probability estimates for each chemical. The first
estimate is based upon the fragments derived through linear regression.
The second estimate is based upon the fragments derived through
non-linear regression. Prediction accuracy of the training and
validation sets are as shown below. The numbers correspond to correct
predictions (either "readily degradable" or "not readily degradable"):
Training Set:
Critically Evaluated as "Readily Degradable"
Linear Model: 201/254
(79.1%)
Non-Linear Model:
204/254 (80.3%)
Training Set:
Critically Evaluated as "Not Readily Degradable"
Linear Model: 284/335
(84.8%)
Non-Linear Model:
284/335 (84.8%)
Training Set: TOTAL
Linear Model: 485/589
(82.3%)
Non-Linear Model:
488/589 (82.9%)
Validation Set:
Critically Evaluated as "Readily Degradable"
Linear Model: 105/131
(80.2%)
Non-Linear Model:
103/131 (78.6%)
Validation Set:
Critically Evaluated as "Not Readily Degradable"
Linear Model: 135/164
(82.3%)
Non-Linear Model:
135/164 (82.3%)
Validation Set: TOTAL
Linear Model: 240/295
(81.3%)
Non-Linear Model:
238/295 (80.7%)
The validation set is
completely independent of the training set. Chemicals in the validation
set were not used to derived any fragment values.
The newest version of
BIOWIN runs under Windows (3.1, 95, 98, NT, 2000) making the estimation
of biodegradation probability more convenient and accurate. Methods for
chemical structure input now support SMILES notations as well as
chemical structures produced in popular chemical drawing programs.
Enhanced features of the Windows version include batch-mode data entry
and user functions.
Example
Entry / Results |
