Risk of Congenital Anomalies Around a Municipal Solid Waste Incinerator - Recent Advances and Issues in Environmental Science - page 108

In the present study, we studied the extent to which the risk for congenital anomalies
varied with maternal exposure to emissions from a modern municipal waste incin-
erator, by conducting a population-based case-control investigation near a plant with
intermittent operation during the study period, and by using a GIS-based approach for
exposure assessment and for geographical localization of cases and controls.
MATRIALS AND METHODS
Study Area
A MSWI with a capacity of 70,000 tons/year is located in the city of Reggio Emilia,
Emilia-Romagna region (extension 232 km 2 , population approximately 150,000). The
incinerator consists of two combustion lines that started operating in 1968, and has
been equipped since 1992 with a dry scrubbing of flue based on sodium bicarbonate
for acidic pollutants gas and since 1994 by an activated carbon device for dioxins,
furans, and mercury adsorption. This plant stopped its activity in April 20, 2002 due
to abnormalities in the combustion process and excess emissions of carbon monoxide
and other contaminants, and started to operate once again in June 16, 2005.
We estimated through a dispersion model the average concentrations of dioxin
and furans in the lower part of the atmosphere in the city territory, aiming at iden-
tifying municipal areas with different amounts of exposure to incinerator emissions
at man's height by using the estimated fall-out of polychlorinated dibenzo-p-dioxins
and dibenzo-p-furans (henceforth referred to as “dioxins”) as indicators. The disper-
sion model was computed by using the meteorological database “CALMET”, pre-
processor developed by the Emilia-Romagna Region Meteorological Service, for the
years 1999, 2000, 2001 (data for 1998 were partially corrupted) and from July 1, 2005
to June 30, 2006. We estimated concentration levels through the model WinDimula
3.0 for Windows [12], an air dispersion model initially developed in the 1980s by
Enea (Ente per le Nuove Tecnologie, Energia e Ambiente, Rome) and Maind (Maind
s.r.l., Milan) and recently updated [12], based on the Gaussian analytic solution of the
turbulent diffusion equation. Its main peculiarity is a special algorithm designed to
deal with calm wind conditions that are usual in many Italian regions [13]: the model
simulates both short-term and climatological concentrations caused by sources with
different geometry, and output concentrations are given on regular grids or on user se-
lected receptors. In the present study, the area over which the computations were made
was 20 km × 12 km, with a resolution of 100 m, with the emission source located at
(7.022; 6.031) km as respect the South-West corner of the domain. We designed maps
of different (A-low, B-intermediate, and C-high) ground level exposure to incinerator
emissions of dioxins and furans in a geographic information system (GIS) environ-
ment, using ArcGIS software (version 9.2, ESRI, Redlands, CA 2006) to implement
a project georeferenced in the Italian cartographic system (Gauss Boaga) and in the
Modena municipality regional technical map layer (Figure 1) and as cutoff points
5 and 10 × 10 -9 μg/m 3 of dioxins, based on maximum incinerator allowed emission
(Figure 1). We also computed a dispersion model predicting heavy metals concentra-
tions, using as cutoff values 0.50 and 1.00 μg/m 3 : the intermediate exposure area was