While spaying is traditionally recommended for kitties between 4 and 6 months of age, spaying as young as 8 weeks old is considered safe, according to Cat Channel.
The national drinking water standards state that the maximum residual amount of chlorine is 4 mg/L. Untill recently the USA used chlorine gas extensively for wastewater treatment. Today, the use of chlorine has been forced back.
Since most exposure to chlorine dioxide is likely to come from ingestion of drinking water, a relative source contribution factor of 0.8 is applied to this value. RfD oral = 0.03 mg/kg/day (U.S. EPA, 2000). UF: 100 (10 = interspecies; 10 = intraspecies). MF: 1.