Health risk assessment of a modern municipal waste incinerator.
During the modernization of the municipal waste incinerator (MWI, maximum capacity of 180,000 tons per year) of Metropolitan Grenoble (405,000 inhabitants), in France, a risk assessment was conducted, based on four tracer pollutants: two volatile organic compounds (benzene and 1, 1, 1 trichloroethane) and two heavy metals (nickel and cadmium, measured in particles). A Gaussian plume dispersion model, applied to maximum emissions measured at the MWI stacks, was used to estimate the distribution of these pollutants in the atmosphere throughout the metropolitan area. A random sample telephone survey (570 subjects) gathered data on time-activity patterns, according to demographic characteristics of the population. Life-long exposure was assessed as a time-weighted average of ambient air concentrations. Inhalation alone was considered because, in the Grenoble urban setting, other routes of exposure are not likely. A Monte Carlo simulation was used to describe probability distributions of exposures and risks. The median of the life-long personal exposures distribution to MWI benzene was 3.2 x 10(-5) micrograms/m3 (20th and 80th percentiles = 1.5 x 10(-5) and 6.5 x 10(-5) micrograms/m3), yielding a 2.6 x 10(-10) carcinogenic risk (1.2 x 10(-10)-5.4 x 10(-10)). For nickel, the corresponding life-time exposure and cancer risk were 1.8 x 10(-4) micrograms/m3 (0.9 x 10(-4)-3.6 x 10(-4) micrograms/m3) and 8.6 x 10(-8) (4.3 x 10(-8)-17.3 x 10(-8)); for cadmium they were respectively 8.3 x 10(-6) micrograms/m3 (4.0 x 10(-6)-17.6 x 10(-6)) and 1.5 x 10(-8) (7.2 x 10(-9)-3.1 x 10(-8)). Inhalation exposure to cadmium emitted by the MWI represented less than 1% of the WHO Air Quality Guideline (5 ng/m3), while there was a margin of exposure of more than 10(9) between the NOAEL (150 ppm) and exposure estimates to trichloroethane. Neither dioxins nor mercury, a volatile metal, were measured. This could lessen the attributable life-long risks estimated. The minute (VOCs and cadmium) to moderate (nickel) exposure and risk estimates are in accord with other studies on modern MWIs meeting recent emission regulations, however.
Boudet
C
C
Public Health Laboratory, GEDEXE, Grenoble University Medical School, La Tronche, France.
Zmirou
D
D
Laffond
M
M
Balducci
F
F
Benoit-Guyod
J L
JL
D000393:Air Pollutants / Q000009:adverse effects; D004782:Environmental Health; D005602:France; D006801:Humans; D006841:Hydrocarbons, Aromatic / Q000009:adverse effects; D017745:Incineration; D019216:Metals, Heavy / Q000009:adverse effects; D009010:Monte Carlo Method; D018570:Risk Assessment
D000393:Air Pollutants; D006841:Hydrocarbons, Aromatic; D019216:Metals, Heavy