Lead exposure in indoor firing ranges: environmental impact and health risk to the range users.

Health risk from airborne lead exposure were evaluated in 54 trainees and 31 firearm instructors at two indoor firing ranges in Amman, Jordan. Airborne lead concentration was measured during shooting sessions of conventional lead ammunition. Venous blood was collected from the trainees, instructors and controls. The levels of blood lead (PbB) and the activity of amino levulinic acid dehydrogenase (ALAD) were measured. High concentrations of air lead that markedly exceeded the internationally adopted safe exposure levels were found on both ranges. Despite the absence of symptoms of lead poisoning, there was a significantly higher PbB in the instructors (19 +/- 7 micrograms/dl) and trainees (22.9 +/- 4.6 micrograms/dl) than in the controls (2.1 +/- 1.4 micrograms/dl). Furthermore, the activity of ALAD was significantly lower in both groups (29.2 +/- 1.3, 18.9 +/- 1.2 U/L, respectively) than in the controls (47.5 +/- 1.1 U/L) indicating a subcritical lead effect. In the trainees, levels of PbB rose from a pre-training mean of 2.2 to 22.9 micrograms/dl and the activity of ALAD decreased from 46.9 to 18.9 U/L. It is concluded that indoor firing range users are at risk of lead absorption and intoxication and, therefore, periodic biological monitoring of the frequent users of firing ranges is highly recommended. Environmental hygienic actions to control excessive emissions of lead on the ranges are also imperative.