Letters from the November 26, 2005, issue of Science News

Roads to ruin?

Chloride concentration in streams should be a concern to everyone. However, projecting problems at century’s end based on the present rate of chloride increase is bad science (“Steep Degrade Ahead: Road salt threatens waters in Northeast,” SN: 9/24/05, p. 195). Salt use in some New England areas has roughly doubled in the past decade due to a change in winter highway-maintenance philosophy. But salt is expensive and there is no foreseeable need to increase salt use beyond current levels. Chloride concentration in water bodies should plateau at the current level, not increase at a rate averaged over the past decade. I do have concern about chloride concentrations in the pristine lakes and streams of our beautiful state. However, I am also concerned about knee-jerk public reactions based on wild projections rather than sound science.

Gregory H. Brown
Waterville, Maine

Chloride concentrations are increasing because of both increased use per kilometer of road and increasing development (more highways). Even if highway departments maintain current rates of use, chlorides will increase in some areas because there will be more roads.—S. Perkins

Great waste, less filling

“Growing Expectations: New technology could turn fuel into a bumper crop” (SN: 10/1/05, p. 218) didn’t mention the effect of large-scale conversion of cellulosic biomass to fuel on disposal sites. Here in southern California, we are running out of places to dump urban waste. Taking waste to a fuel-generating facility would reduce the environmental effects and might even cost less than burying it.

Bob Koster
North Tustin, Calif.

Your story highlighted the downside of corn-based ethanol production. Hemp would be a greener alternative to corn, as hemp uses much less fertilizer and is tenacious on slopes. Hemp as fuel biomass has the further advantage of yielding a seed cake with high protein content, seed oil that has the highest amount of omega-3 fatty acids content of any plant, and long fibers for paper production.

Gene Tinelli
Syracuse, N.Y.