Environmental Risk Assessment and Monitoring and Surveillance of Transgenic Crops
Environmental risk assessments (ERAs) play a key role in the evaluation of potential impacts of GMOs on the natural environment and on biodiversity.
Before GMOs are approved for deliberate release or marketing in the EU, an environmental risk assessment (ERA) is conducted to investigate whether any potential adverse effects might arise from their use and whether they pose a risk to human health and the environment. The precautionary principle applies. A lack of knowledge and inadequate data make the assessment difficult. The current ERA procedure takes in a range of potential impacts from GMO uses.
Under Directive 2001/18/EC, the marketing of genetically modified organisms is subject to mandatory monitoring and surveillance.
Environmental Risk Assessment and GMO Approval
In assessing potential GMO-related risks to nature and the environment, focus is placed not on where they will be used but on whether and to what extent GMOs can infiltrate the environment and the potential impacts they can have. In the EU, deliberate release of genetically modified organisms is subject to a notification and approval process whose legal basis is provided by Directive 2001/18/EC. The Directive differentiates between the experimental release of GMOs (temporary release in a restricted area) and approving their commercial use (placement on the market). To protect nature and the environment from GMO-related risks, an environmental risk assessment 1) must be conducted which also serves nature conservation needs.
ERAs are conducted by the notifiers themselves and are examined by the competent authorities. Assessments are based on available data. The meaningfulness of ERAs thus critically depends on data quality.
Inherent Risks from Deliberate Release of GMOs
Transgenic plants have been cultivated commercially since 1995. Their production differs from that of conventional plant breeding, which relies on cellular control and regulation to recombine genes (allele) and produce an organism with altered traits. In contrast, a transgenic organism is produced by introducing DNA from a different species while circumventing the cellular regulation system.
This is not done in a targeted way, but by inducing molecular changes specific to the 
transformation method used. While some of the molecular changes that take place are assessed for their potential impacts, comprehensive assessment and verification does not take place. As living organisms, GMOs can reproduce and disperse their genes throughout the environment. They cannot, therefore, be retrieved and so differ from other substances that are released into the environment such as chemicals, pesticides and pharmaceuticals.
Potential Impacts
Environmental risk assessments involving GMOs look at their traits, any potential adverse effects and the resulting risk to human health and the environment. Some effects only occur after transfer and dispersal of transgenic organisms or their traits. Other effects and issues arise from their use and transformation.
In the cultivation of herbicide-resistant plants focus is placed on the changed cultivation conditions and their effects on the environment and its ecosystems. In the case of insect-resistant maize, assessment centres on whether and to what extent cultivation of the GMO in question can affect non-target organisms and food chains. With regard to second generation GMOs with altered substances, assessment looks at which other metabolic changes are induced and how they effect the compatibility and biodegradability of the GMO and its products.
Annex II of the Deliberate Release Directive lists the types of impacts to be taken into account when conducting environmental risk assessments. These include:
- Direct and indirect effects
- Indirect effects occurring through a causal chain of events
- Immediate effects observed during the period of release
- Delayed effects which occur after release
(Adverse) effects can occur through the spread of GMOs in the open environment, displacement of other species, transfer of the inserted genetic material to other organisms (crossing with related species), phenotypic and genetic instability, interactions with other organisms (e.g. non-target organisms) and changed management practices.
The Directive also provides for an analysis of the cumulative long-term effects that wide-spread use of GMOs have on flora and fauna, soil fertility, decomposition of organic matter in the soil, the food chain, biodiversity, animal health and the frequency of antibiotic resistance.
The Precautionary Principle
The Deliberate Release Directive affords special attention to antibiotic resistance markers and its approach to the problem demonstrates the application of the precautionary principle. Antibiotic resistance markers are marker genes used in the production of GMOs and may remain in them afterwards.
Although these genes occur naturally in bacteria and their transfer from transgenic plants to bacteria is thought to be extremely rare, the Directive's Article 4 requires that in the interests of precaution, the use of antibiotic resistance markers in deliberate release and marketing of GMOs should be phased out by the end of 2004 (in the case of experimental release by the end of 2008) if they cause resistance to antibiotics used in human and veterinary medicine and can thus have potential adverse effects on human health and the environment.
The EU applies the precautionary principle in its policies on consumer protection, health, food safety and environment protection. It was a guiding principle in preparing Directive 2001/18/EC and is also required to be applied in its implementation. The precautionary principle is mentioned on many occasions throughout the Directive, including as regards how to proceed in the case of knowledge gaps or unreliable data when conducting environmental risk assessments.
Environmental Risk Assessment Requirements
Compliance with the precautionary principle is a prerequisite of environmental risk assessment. Annex II of the Directive lists further general principles that must be followed when performing ERAs:
- To identify potential adverse effects, the traits of the GMO should be compared with those presented by the non-modified organism from which it is derived
- The ERA should be carried out in a scientifically sound and transparent manner
- The ERA should be carried out on a case by case basis
- If new information on the GMO and its effects becomes available, the environmental risk assessment may have to be repeated to determine whether the risk has changed and whether it is necessary to amend the risk management strategy
Annex II also contains a list of points that notifiers must address. Conducting ERAs on a case by case basis means that the information required may vary depending on the GMOs and their uses, the donor and recipient organisms, the traits introduced, the GMO's intended use and the receiving environment.
Taking Bt maize as an example, the following points must be addressed in the ERA:
A bacterial toxin 2) gene from the Bacillus thuringiensis bacterium makes Bt maize resistant to certain insects such as the European corn borer. Depending on its genetic modification, the maize produces one or more Bt toxins. These are not resistant to specific species but to specific groups of organisms like butterflies and moths (Lepidoptera) and beetles (Coleoptera). The specificity is not absolute, meaning that toxins may also be toxic to other organisms (non-target organisms).
Bt maize produces the toxin throughout the vegetation period and in almost all parts of the plant. The toxin enters the environment via a range of different pathways: it is dispersed with maize pollen and the roots discharge it into the soil, where it also occurs through root decomposition and biomass that has been dug in. Thus, the pest and all other (soil) organisms become exposed to the toxin over time.
Apart from its direct effects, the toxin may, via the food chain, indirectly damage other organisms or alter the composition of the soil's microflora and fauna. To estimate organisms' exposure to the toxin, reliable data are required on inputs and on the rate of decline of deposits of the toxin in the various environmental media. Environmental risk assessments should thus take account of the receiving environment and the impact of further releases; in such cases, the assessment should investigate longer-term cultivation of Bt crops and the potential for toxin accumulation in the soil.
ERAs should be conducted in phases, firstly to identify whether a GMO's traits could have adverse effects and later to assess the outcome of those effects, the likelihood of their occurring and their potential risk to human health and the environment. Finally, a risk management strategy must be devised to minimise and control the identified risks. Specific measures such as restrictions on use, isolation distances and equipment-cleaning requirements may also be included in the approval documentation.
It must be said, however, that this type of risk identification does not allow comprehensive study of the specific traits of living organisms, especially their ability to reproduce and adapt to altered environmental conditions. An environmental risk assessment always takes the form of an investigative, empirical study involving evaluation and normative action. While Annex II of Directive 2001/18/EC provides examples of potential adverse effects and of what requires protection from them (and despite publication of the Guidance Notes to Annex II 3) ), no definition is provided as to what environmental damage may constitute or when it is deemed to have occurred.
1) Because the term 'environmental impact assessment' is already used in the Environmental Impact Assessment Directive, the Deliberate Release Directive (2001/18/EC) uses the term 'environmental risk assessment'.
2) A toxin is a poison given off by bacteria, plants or animals or during bacterial decomposition.
3) See Commission Decision of 24 July 2002 establishing guidance notes supplementing Annex II to Directive 2001/18/EC of the European Parliament and of the Council on the deliberate release into the environment of genetically modified organisms and repealing Council Directive 90/220/EEC. OJ L200/22 dated 30.07.2002.
