2

Hydrolysis (161-1, 835.2120)

In the 9/14/11 memorandum from James Breithaupt (D357908, D378130), the conclusion for 

hydrolysis was that the five hydrolysis studies involved in the subject product’s application

together satisfy the 835.2120/161-1 data requirement for Contram ST-1. None of the studies 

were completely acceptable, although there was one study (MRID 47555820) which did not 

address material balance or degradate identification but which was found to be supplemental but 

not acceptable because of the lack of any material balance and degradate identification. The 

absence of either material balance or degradate identification can be a basis for outright rejection 

of the study and a classification of such a study as being unacceptable to satisfy the 

835.2120/161-1 data requirement. Environmental fate studies require a material balance of 90-

110 % of applied radiolabeled substances and 70-120 % of applied non-radiolabeled substances. 

Degradates at or above 10 % of applied substance require identification. However, in this case, 

due to the reasons identified and explained below and in the attached document, information on 

material balance and degradates has been determined to be impractical to obtain for hydrolysis 

testing of this subject substance.

In light of information which has become available to the Agency since 9/14/11 and 

subsequently reviewed, the hydrolysis study (MRID 47555820) is now classified as acceptable

and satisfies the hydrolysis data requirement (835.2120, 161-1), when combined with the 

attached 9/20/11 “Expert Statement” signed by D F White, Supervisor of Physico-Chemical 

Properties of Harlan Laboratories (formerly SafePharm Laboratories). The “Expert Opinion” is 

located in Appendix A. According to the attached “Expert Statement,” material balance was not 

technically feasible in the subject substance’s hydrolysis testing because the extremely short 

half-life of <1 day created the inability to detect any parent compound. The absence of 

degradate identification was based on matrix interference from the buffer compounds that 

prevent pH change in the solutions being tested. The buffer compounds would have absorbed 

the UV/Visible light from detectors and the detected response from buffer compounds could be 

greater than from any degradates of Contram ST-1. Based on the apparent degradation pathway, 

the degradates would be morpholine and formaldehyde in the ratio of 2:1. The factors affecting 

measurement feasibility in this case, which stem from the nature of the subject substance, 

adequately justify not requiring the aforementioned material balance and degradate identification 

information in this instance.

Activated Sewage Sludge Isotherm (835.1110)

Data on activated sewage sludge isotherm are not required at this time for Contram ST-1, contrary to 

the 9/14/11 memorandum. These data are not required under 40 CFR Part 161; the activated sewage 

sludge isotherm study is contained in proposed 40 CFR Part 158W but it is not a current data 

requirement under the existing data requirements regulation. 

Table 1 below contains the current status of environmental fate data requirements.
3

Table 1. Environmental Fate and Transport Properties of Contram

Property Value Comments/Reference

Hydrolysis (835.2120) Half-life of 3.6 months in oilbased metalworking fluids 

(intended use)

Rapid degradation in guideline 

and other non-guideline 

studies with half-lives of <6 

seconds to 1 day.

Guideline study is acceptable 

when combined with 9-20-11 

“Expert Statement” discussed 

above and attached to this 

memo. 

Non-guideline studies provide 

additional information.

Data requirement satisfied by 

MRID 47555820. MRIDs, 

47555821, 48064802, 

48064803, and 48064804

provide additional 

information. 

Leaching-adsorptiondesorption (835.1230)Koc value of 18 ml/g MRID 47555820

Satisfied

Ready Biodegradability 

(OECD 301, 835.3110)

Contram ST-1 was readily 

biodegradable

Biodegradation reached 93 % 

after 28 days

Satisfied

MRID 47571313

Sewage Sludge Respiration 

Inhibition 

(OECD 309, 835.6800) 

NOAEC by 3 hours of 32 

mg/l, EC50 values of 800 and 

340 mg/l by 30 minutes and 3 

hours

EC20 of 133 mg/l for both 

times

EC80 concentrations not 

reached

MRID 47555828

Satisfied

Activated Sewage Sludge 

Isotherm (835.1110)

No Not required as explained 

above. 

If there are any questions, please contact Jim Breithaupt at 703-305-5925 or at

breithaupt.james@epa.gov.
4

Appendix A. September 20th, 2011 Expert Opinion from Harlan Laboratories

Sign-off Date: 09/22/11 DP Barcode No.: D394355