Activities Involving Radioactive Substances
Hazards:
Radioactive substances emit ionising radiation as atomic or sub-atomic particles
(alpha (beta (particles or neutrons) or electromagnetic radiation (gamma (
and X-rays) which interact with and change the structure and function of the
molecules of a living organism. Irradiation may occur from a radioactive source
outside the body (external radiation) or from substances inhaled, absorbed or
ingested into the body (internal radiation); such changes may be associated with
the following hazards:
a. Deterministic effects (cataract formation, radiation sickness, skin
disorders) the severity of which increases with dose and there is a
threshold radiation dose;
b. Stochastic effects (cancer and genetic damage) the probability of which
increases with dose but there is no threshold radiation dose.
Risk Factors:
 Work with high-risk substances being those of high levels of radioactivity,
above 1Megabequerels, which energetic and penetrating radiation,
principally -sources and -sources with energies (Emax) above 0.75 MeV;
 Work with or in close proximity to high risk radioactive substances for
prolonged periods of time unless the emitted radiation is effectively
absorbed or attenuated by the container or other shielding;
 Work with any radioactive substance likely to produce an external
radiation dose in excess of any statutory limit or if the amount ingested or
inhaled is likely to exceed any prescribed annual limit for intake;
 Work with any sealed or closed radiation source which is not fully
enclosed or kept within a shielded housing when not in use or which may
damage the source;
 Work with any unsealed substance of high or upper medium radiotoxicity
according to the classification scheme of the International atomic Energy
Agency;
 Work with any unsealed substance which is a volatile liquid or a fine
powder or likely to generate any aerosol, gas, spray or vapour unless
contained in an efficient fume hood, glove box or enclosed apparatus;
 Failure to protect against spills and contamination of the working area;
 Failure to monitor and decontaminate the work area after handling
unsealed radioactive substances;
 Failure to observe good occupational safety and hygiene practices;
 Failure to store safely radioactive waste in readily identifiable, labelled,
secure and where necessary shielded containers;
Risk control Measures:
1. Avoid the use of radioactive substances where practicable, otherwise
use the least radiotoxic and smallest quantity of radionuclide consistent
with the work to done;
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2. Restrict radiation work to those staff and students who are informed of
the hazards involved and have received practical training in the safe
working procedures according to any College, Departmental or
Laboratory Local Rules;
3. Store and handle radioactive substances with activities only as
permitted for the designated room or laboratory, allow entry to any
designated SUPERVISED or CONTROLLED radiation area by
authorised persons only;
4. Maintain accurate and legible records of the acquisition, use and
disposal of radioactive substances according to local rules;
5. Use tongs or long handled forceps or handling aids to manipulate vials
or other containers of radioactive substances and sealed sources and
confine radiation work to designated areas away from non-radiation
work;
6. Use appropriate shielding according to the type and energy of the
radiation, 1cm Perspex will absorb  radiation but it may re-emit high
energy Bremsstrahlung with 32P, use lead shielding of suitable
thickness with X-ray and -emitters;
7. Wear appropriate personal whole-body radiation dosimeters or badges
except when working with low energy  emitters such as 3H, 14C and
35S, finger or hand ring badges for work with high energy emitters
such as 32P;
8. Wear protective clothing including fully-buttoned laboratory coat,
disposable gloves and eye protection when working within the radiation
area, cover cuts and breaks in the skin of the hands with an adhesive
water-proof dressing;
9. Cover benches, spill trays and other work surfaces with plastic-backed
absorbent paper, used or contaminated absorbent paper is radioactive
waste and must be disposed of accordingly;
10. use an effective fume hood for all work with gases, vapours and
volatile liquids;
11. Monitor the work area and the hands with a radiation or contamination
monitor, either a Geiger-Muller or scintillation detector, after each
manipulation and on completion of the work, monitor apparatus and
equipment before it is removed from the radiation area, decontaminate
surfaces promptly;
12. Return part-used vials, stock solutions and other unused radioactive
material in suitably and clearly labelled containers to a designated
locked store;
13. Wash contaminated gloves before removing, wash the hands after
removing gloves and then monitor for contamination, re-wash if
necessary;
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14. Do not accumulate radioactive waste in the work area, it should be
disposed of on completion of the work or discarded into a designated
labelled waste container, use only authorised routes of disposal, record
details of all waste disposals and discards into communal containers
according to local rules;
Persons at Special Risk:
Pregnant workers.
Health Surveillance:
Classified workers and those who believe they may have received a radiation
dose in excess of the specific limit.
Exclusions:
This model assessment may not be adequate for work carried out in
SUPERVISED or CONTROLLED radiation areas.
Relevant Statutory Provisions and Other Guidance:
Ionising Radiation Regulations 1999
Radioactive Substances Act 1993
Radioactive Material (Road Transport) (Great Britain) Regulations 1996
Approved Code of Practice for the Protection of Persons Against Ionising
Radiations Arising from any Work Activity, HSC, 1994
A framework for the restriction of occupational exposure to Ionising Radiation,
HSE, HS(G)91, 1992
Guidance Notes for the protection of persons against ionising radiations arising
from medical and dental use, NRPB, 1995
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