Recent environmental restrictions are limiting the use of broad-spectrum biocides for wood preservation. There is an urgent need for new, sharply targeted, environmentally benign wood preservatives. N'N-Napthaloylhydroxylamine (NHA), a water-soluble calcium-precipitating agent, has been shown to inhibit decay by brown-rot and white-rot fungi in soil-block tests and prevent damage by Eastem subterranean termites under lab conditions. In order to further evaluate the capacity of NHA to prevent decay and termite damage, SYP stakes were pressure treated with three concentrations of NHA (0.1, 0.5 and 1.0%) and CCA (1.0%) and placed in-ground at the Harrison Experimental Forest, Gulfport, Mississippi, in June, 1997. Similarly, treated sticks were placed in soft-rot fungal cellars at FPL. One percent NHA-treated stakes were also leached for 72 hours in water and the leachates tested by an acute, five dilution bioassay using Ceriodaphnia dubia in EPA Protocol 600/4-90/27F. Results to date: 1) NHA stakes (0.5 and 1.0%) are as durable as CCA; 2) NHA does not inhibit soft-rot fungi and, 3) NHA is a relatively benign molecule with LD50 130-fold less than copper for C. dubia.

Download document (507 kb)
free for the members of IRG. Available if purchased.

Purchase this document