|CHAPTER 17: CHEMICALS AND GENETICALLY MODIFIED ORGANISMS - INTRODUCTION|
This chapter considers the pressures on the environment and potential risks arising from the use and marketing of chemical substances and the development, production, field testing, and release through placing on the market of living, genetically modified organisms. Such substances or organisms may not necessarily be released directly into the environment, but may eventually end up there either during their production and use, or at the end of the product's useful lifetime.
|CHEMICALS AND CHEMICAL PRODUCTS|
Natural processes are continually transforming chemicals and redistributing them in the environment. Background ('natural') concentrations can be described by media or location, but there are large variations. Many natural chemical compounds are, at specific concentrations, necessary for sustaining life, and most have existed for billions of years. Human activities are increasingly changing the way in which chemicals are distributed in the environment and, with the introduction of new compounds (xenobiotics), are causing new pressures on the environment, both actual and potential.
Technology has provided new materials, methods and processes which have given rise to a whole range of novel industries making use of the ever-increasing number of new compounds in the manufacture of new products. In the service of this need the production of chemicals has increased enormously over the past few decades. It is estimated that more than 13 million synthetic chemical compounds have been produced in laboratories. These either reproduce the structure of compounds found in nature or are made of completely new structures. They can be organic or inorganic, chemically active or inert, and are used in different sectors of the economy. According to EINECS (the European Inventory of Existing (commercial) Chemical Substances), about 100 000 chemicals are marketed in the EU (Box 17A) and it is commonly understood that the chemicals industry markets 200 to 300 new chemicals each year.
The speed and complexity of the development and use of chemical products over the past few decades has not allowed knowledge of environmental effects to keep pace with development. This has already led to a number of unexpected environmental impacts. The state of knowledge of the toxicity and ecotoxicity of chemicals in use and circulation, particularly about their potential impacts on humans and the environment, is in fact very unsatisfactory (see Box 17A). This state of affairs is one of the main reasons why, so often, unexpected, undesirable effects on human health and the environment occur. Rather than just reacting to problems as they arise, more strategic, pro-active approaches are being developed with the aim to control chemical risk (see Chapter 38). The backlog of work to be done testing the numerous existing marketed chemicals, about which little is known concerning their health and environmental impacts, is such that a great deal of time and resources will be necessary to complete the work. The EC Existing Chemicals Directive (93/793/EEC) and notification scheme designed to address this problem and improve basic knowledge about chemicals is already being implemented.
|GENETICALLY MODIFIED ORGANISMS|
In recent years, the development and use of new techniques of genetic engineering have profoundly changed the traditional methods and scope of biotechnology. These sophisticated techniques enable the identification of many genes which confer desirable characteristics, and the transfer of these genes to organisms which did not possess them before. The bacteria, fungi, viruses, plants, insects, fish and mammals which are designer-made in this way are referred to as genetically modified organisms (GMOs), and can be defined as organisms in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination.
Traditional selection and breeding techniques have been used for a long time in industry and agriculture to produce organisms with more desirable characteristics. However, the new, more powerful tools of molecular biology allow biological barriers to be bypassed and novel organisms with new or enhanced properties to be created. For example, a gene from a microbe responsible for expressing a certain natural toxin against insects can be introduced into the genetic material (DNA) of crop plants, which can then protect themselves from insect attack without the need for application of pesticides. In principle, genes from any species could be inserted into any other species.
The development of a growing number and range of GMOs has opened up significant potential for many useful applications in agriculture and food-processing, pharmaceuticals and diagnostics, environmental clean-up, chemicals production and the development of new materials and energy sources. At the same time, however, there are some concerns about the potential risks to human health and the environment associated with the use and the release of these novel organisms into the environment, and in particular in relation to longer-term effects which are very difficult to predict. The need to undertake environmental risk assessments and to implement risk management measures as required has been recognised by the EU, and also by the USA and the other industrialised countries who are members of the OECD. Many non-OECD countries are also realising the need to take a preventative approach, especially as a result of the discussions at the UNCED in Rio de Janeiro in 1992 and the implications for biotechnology of the UN Biological Diversity Convention.
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