Letters from the July 3, 2004, issue of Science News

Whale, of an annoyance

In “Din among the Orcas: Are whale watchers making too much noise?” (SN: 5/1/04, p. 275: Din among the Orcas: Are whale watchers making too much noise?), Rus Hoelzel states, “One thing I want to make clear is that I think whale watching is a good thing.” He then states that the activity may just need “tighter regulations.” I feel that this argument isn’t valid. If whale watching is causing danger to the species, then it’s not good. Whales should have the right to live in peace. If people want to whale watch they should find a safer way to do it, perhaps from shore.

Erica Hodge
San Ramon, Calif.

If the engines of whale-watching boats are disturbing the Orcas, why not switch the boats to sail power? Surely, this means of locomotion would also provide a better experience for the whale watchers.

Lorien Davy
Santa Barbara, Calif.

Tooth truth?

“Unsettling Association: Dental X rays linked to low-birth-weight babies” (SN: 5/1/04, p. 277: Unsettling Association: Dental X rays linked to low-birth-weight babies) suggests that somehow X rays caused low-birth-weight babies in women who had their teeth X-rayed during their pregnancies. Here is an alternative possibility: Perhaps unhealthy people are more likely to have low-birth-weight babies and bad teeth.

Stephen Wood
Orlando, FL.

The article hypothesizes that the dental X-rays hitting the thyroid glands of pregnant women affect birth outcomes. This tentative conclusion was reached without evaluating the thyroid glands of the affected mothers or the controls and therefore seems premature.

The mothers who went to the dentist and had X rays were more likely, I would guess, to have had dental work done than the controls and would therefore be more likely to have been exposed to anesthesia and dental amalgams, which are about half mercury. Amalgam has been determined unacceptable in Canada and some European countries, particularly for pregnant women. The researchers in this case have failed to evaluate a significant risk factor for the population.

Eric Wolf
Santa Fe, N.M.