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 Addressing
the Radioactivity Issue: IMPHOS Undertakings and Accomplishments
In late 1970's, IMPHOS was already
tackling some environmental concerns about phosphate
fertilizers production but reserved particular attention
to the radioactivity issue by initiating work on uranium
in phosphates. The aim of this preliminary undertaking
was to develop a process for the recovery of uranium
from phosphoric acid with the objective of eliminating
a potential source of radioactivity and obtaining a
by-product that might have a market value. This undertaking
resulted in an IMPHOS patented process of uranium recovery.
But because of its unprofitability, the process was
not further developed to an industrial-scale level.
In May 1996, the European Union issued
the EURATOM-BSS Directive that sets limits on radioactivity
concentration in Naturally Occurring Radioactive Materials
(NORM), along with the annexed documents (RP 95) that
explain the Directive. To address appropriately this
issue, IMPHOS decided to entrust a study to a French
center with reputable knowledge and experience in radioactivity
protection, called CEPN (Centre d'Etude sur l'Evaluation
de la Protection dans le Domaine Nucléaire).
The study had the following objectives:
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To
provide more background on the objectives, underlying
principles, and field of application of the looming
Directive;
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To
explain, as far as the phosphate industry is concerned,
the general framework for the application of the
Directive, discuss in detail its articles dealing
with exposure at workplace, and any implementation
scenarios that can be deduced by EU member States;
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To provide
a detailed method for initial evaluation of degree
of annual exposure of workers from different phosphate
industry activities, including rock mining, beneficiation,
wet-processing, thermal treatment, and ultimately
from the distribution of the phosphate fertilizers;
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To
update data related to particular activities and
dosimetry data relevant to the phosphate industry;
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To assess
the interest and feasibility of developing eventually
a tool that will help in making more specific
calculations, which would facilitate accounting
for particular parameters relevant to different
exposure scenarios: external irradiation, inhalation
of dust, exposure to radon, etc.
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The study under the title "Modes
of enforcement of Title VII of the Directive 96/29/EURATOM
relative to phosphate industry: analysis of the European
regulation and presentation of a method for exposure
assessment " was conducted in 2000-2001. It
provides a large set of data and information on: 1)
Radiological protection system with data on individual
doses and risk limits as outlined in tables 1a and 1b
and figure1; 2) Classification of workplaces and working
conditions; 3) Workplace monitoring for external radiation;
4) Workplace monitoring for surface contamination; 5)
Individual monitoring for external radiation; 6) Individual
monitoring for internal exposure; and 7) Individual
monitoring for skin contamination.
The study provides equally updated information on progress
made in the nationwide adaptation of the Directive;
the industries concerned with the new regulation with
a special emphasis on the phosphate industry; and the
new references and exemption levels that can differ
from one country to the other.
Table 1a: Individual dose and risk limits-Protection
against determined effects
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