Where do we start when considering risk assessment for the use of genetically modified
organisms? It is not clear what the risk might be, as has become obvious. If we are considering an
organism which has become a pathogen to man, animals or plants then the risk is clear, but it is
not simple to define harm to the environment. Where do we start?
First, we need a clear definition of risk. Generally we attempt to separate two parameters, the
hazard associated with the modified organism and the likelihood of this hazard being expressed.
Hazard is an intrinsic property of the organism; the polio virus is considered to be extremely
hazardous, whereas brewer's yeast is considered benign and lacking in hazard under almost any
circumstances. The likelihood of the hazard being expressed will depend on the way it is handled
-- many highly dangerous viruses can be handled without risk in special facilities. Risk is then
likelihood of the hazard being realised. Assessing risk is then simple in principle. The hazard has
to be identified, or putting it another way, examining what in a particular situation could cause
harm or damage and then assessing the likelihood that harm will actually be experienced, and
what the consequences would be.
The risk assessment encompasses everything that has to be considered to decide about the
hazards posed by the organisms and by the activity, or use of the organisms, the likelihood that
they will actually give rise to harm, the control measures employed. The level of detail needed to
perform a risk assessment will vary greatly depending on the circumstances. Most regulatory
regimes require a "suitable and sufficient" risk assessment. For a simple operation involving a low
hazard, well known and well understood organisms, and containment which is clearly suitable, the
result of the assessment could be identified very quickly, and little needs to be noted except that
the risk assessment was actually performed. For dangerous organisms about which there is
uncertainty the risk assessment would obviously be extensive and may require new data before
the work can proceed.
The Presidential and Congressional Commission on Risk Assessment and Risk Management in
the United States has been examining a framework for Environmental Health Risk Management.
In their reports, published in January 1997 and April 1997, they have produced a framework in
which risk management will be conducted by the US Government. They identify Risk to be the
probability that a substance or situation will produce harm under specified conditions. "Risk is
said to be a combination of two factors:
- The probability that an adverse event will occur (such as a specific disease or type of injury).
- The consequences of the adverse event.
Risk encompasses impacts on public heath and on the environment, and arises from exposure and
hazard. Risk does not exist if exposure to a harmful substance or situation does not or will not
occur. Hazard is determined by whether a particular substance or situation has the potential to
cause harmful effects"
We therefore have a starting point, we first have to define the hazard associated with the
modified organism, then look at the way we handle it in order to determine its risk. But our
problem remains, where do we start in determining the intrinsic hazard of a newly manufactured
All of the foregoing implies that it is possible to identify the hazard. The starting point for this is
always the intrinsic ability of the organism to cause harm. In many instances we will have
information -- we will know, for instance that the host organism is pathogenic, or there are forms
of the organism which have been demonstrated as having adverse effects (producing allergens or
toxins, for example). If we know the likely hazards which the organism may cause, we can
consider each of them and identify the risk associated with the hazard, and the likely exposure of
the target individuals or the environment to the hazard. Unfortunately, there is uncertainty
regarding the estimation of hazard, let alone risk. There is often little data available on the
hazardous properties of the biological agents.
In these instances we have tended towards a precautionary approach, where it is assumed that it
is better to be safe than sorry regarding the exposure of people or the environment to the risk.
Where there are significant risks of damage to the environment, the Government will be prepared
to take precautionary action to limit the use of potentially dangerous materials or the spread of
potentially dangerous pollutants, even where scientific knowledge is not conclusive, if the likely
balance of costs and benefits justifies it (UN, precautionary principle)
The approach to risk assessment has also been precautionary. There is not enough information to
allow much generalisation of the risk assessment, and the approach used is to gather as much
information as possible and then, on a case-by-case basis, attempt to formulate a risk assessment.
The information requirements are very similar in all OECD countries. Basically, the data required
- Parent organism (taxonomy, molecular biology, physiology, reproduction)
- Transgenic organism (molecular biology, reproduction)
- Method of transgenesis
- Method, amount and frequency of introduction
- Fate of transgene (transport, reproduction, transfer, establishment)
- Toxicity of transgene products and intermediary metabolism
- Effective dose for toxicity
- Susceptible non-target organisms
- Effect on non-target organisms
- Site characteristics
- Ecological effects