FOCUS_TOXSWA_1.1.1 Note 2

08/Jul/03 : Another known bug in released version of FOCUS_TOXSWA_1.1.1:

5. Crashed run for D4 pond and compounds with Koc values above 50 000 L/kg

Some D4 pond runs for substances with a Koc higher than 50 000 L/kg are reported to stop by a mass balance error in the sediment occurring before the first application of the simulated year. (This implies that the mass balance error is caused by the small traces of drained pesticide mass left over from applications made during the warming up period.) The error message in the runid.err output file reads as follows:

"A fatal error occurred in subroutine wbmb at time: 01-May-1985-04:30
Mass missing in mass balance sediment greater than 1%
Mass missing in segment 1 is 1.0% of total mass: 0.451E-17 g
See error file 00021p_pa.err"

The run will not crash anymore if you change manually all pesticide fluxes (last column) that are smaller than 1E-18 mg.m-2.h-1 into 0.0 in the m2t file. If you do so, we suggest that you report this explicitly and also that you demonstrate that this does not change your simulation significantly by comparing:

(You can find the masses entered in the pond in the TOXSWA output file runid.sum (section 'Table: Monthly input of substance into waterbody') or by accumulating the last column of the m2t file and next, multiplying this sum (i.e. total mass drained in mg.m-2 during the 16 months simulated) by 4500 m2, representing the area contributing its drainage fluxes into the pond.