Registration Dossier

Administrative data

Endpoint:
biological effects monitoring
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Very complete and well documented study that gives proper information on the potential consequences of an accidental spill in standing waters.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Polymeric MDI, 46.8% monomer. (Desmodur 44V20; Bayer AG).

Results and discussion

Any other information on results incl. tables

The hydrolytic degradation of the MDI layer to insoluble polymerised product (virtually 100%), with some evolution of CO2 in the early stages, was observed. Neither MDI nor MDA (diaminodiphenylmethane, an intermediate in the hydrolysis - cf section 5.1.2) was detectable in the pond water at any stage (<0.005 mg/l), or was accumulated in the fish (detection limits 0.36 mg/kg and 0.69 mg/kg respectively). The pH of the treated ponds fell during the study, by ca 2.0 and 0.7 units for the high and low dosed ponds respectively, this due to liberation of CO2 which also caused an increase in hardness. The biological and chemical oxygen demand were not affected by either application rate of MDI. Neither dose rate caused any direct effect on the pelagic community (phytoplankton, zooplankton, fish, macrophytes) of the test ponds. Some minor indirect effects caused by the production of CO2 were observed in phyto- and zoo- plankton community structures and an increase in macrophyte growth was noted (42% higher than control for the high dose pond). Organisms living in sediment (macrobenthos) were affected by physical obstructions in the habitat (e.g. the crust of hydrolysing MDI) but regained densities equivalent to control after some weeks except for Bivalvia which have too long a generation time for the test period. Satisfactory homogeneous analysis of the sediment was rendered difficult because test substance had spilt over onto the untreated sediment layer.(This layer was actually covered by test substance in the high dose pond). In consequence, relatively high concentrations of MDI were detected in the high-dose pond sediment during the early stages of the test (widely varying, up to 14.5 g/kg) but these declined throughout the study, to ca 0.5 mg/kg. In the low-dose pond a mean concentration in sediment of 5 mg/kg on day 7 declined to <= 0.5 mg/kg at the end of the test. MDA was not detected in the sediment except on day 7, when 12 mg/kg for the high-dose pond and 7 mg/kg (one reading only) for the low-dose pond were detected. (The detection limit was 0.3 mg/kg.)

Applicant's summary and conclusion

Executive summary:

The hydrolytic degradation of the MDI layer to insoluble polymerised product (virtually 100%), with some evolution of CO2 in the early stages, was observed. Neither MDI nor MDA (diaminodiphenylmethane, an intermediate in the hydrolysis - cf section 5.1.2) was detectable in the pond water at any stage (<0.005 mg/l), or was accumulated in the fish (detection limits 0.36 mg/kg and 0.69 mg/kg respectively). The pH of the treated ponds fell during the study, by ca 2.0 and 0.7 units for the high and low dosed ponds respectively, this due to liberation of CO2 which also caused an increase in hardness. The biological and chemical oxygen demand were not affected by either application rate of MDI. Neither dose rate caused any direct effect on the pelagic community (phytoplankton, zooplankton, fish, macrophytes) of the test ponds. Some minor indirect effects caused by the production of CO2 were observed in phyto- and zoo- plankton community structures and an increase in macrophyte growth was noted (42% higher than control for the high dose pond). Organisms living in sediment (macrobenthos) were affected by physical obstructions in the habitat (e.g. the crust of hydrolysing MDI) but regained densities equivalent to control after some weeks except for Bivalvia which have too long a generation time for the test period. Satisfactory homogeneous analysis of the sediment was rendered difficult because test substance had spilt over onto the untreated sediment layer.(This layer was actually covered by test substance in the high dose pond). In consequence, relatively high concentrations of MDI were detected in the high-dose pond sediment during the early stages of the test (widely varying, up to 14.5 g/kg) but these declined throughout the study, to ca 0.5 mg/kg. In the low-dose pond a mean concentration in sediment of 5 mg/kg on day 7 declined to <= 0.5 mg/kg at the end of the test. MDA was not detected in the sediment except on day 7, when 12 mg/kg for the high-dose pond and 7 mg/kg (one reading only) for the low-dose pond were detected. (The detection limit was 0.3 mg/kg.)