Backgorund Introduction


The World Commission on Environment and Development estimates that the world population will increase from ca. 5 billion at present to ca. 8.2 billion by the year 2025. As much as 35% of this increase will take place in Latin America.  Human populations in the area tend to be clustered around estuaries and along coastal margins, resulting in the exploitation of coastal resources. Indeed, many millions of people living in these coastal areas  are entirely dependent on seafood for their survival.  Thus, the introduction of pollutants into the environment, which is likely to escalate dramatically when  the population grows, potentially poses a major threat to both human and ecosystem health.

To minimize impacts, effective control of sewage, wastewater and industrial discharges, agrochemical runoff and exploitation of coastal fisheries is urgently required.  Environmental managers are faced with having to determine the extent of environmental contamination and identify localities and habitats most at risk.  In Europe and USA, environmental protection agencies protect the environment using a combination of legislation, and enforced chemical and biological monitoring programmes to check compliance.  However, the financial resources and the technical expertise to operate such procedures, are seldom available in developing countries.

There is an urgent need to develop inexpensive, easy to use ecotoxicological and chemical tools, which can provide preliminary information about the extent of environmental contamination and the well-being of natural biota.  Such tools will allow identification of sites particularly at risk which posse pose a threat to human and environmental health, and provide a sound scientific basis upon which environmental management decisions can be based.

Traditionally biological effects of pollutants have been monitored using acute lethal toxicity tests, e.g. LC 50. Such tests provide information on the concentration of a particular chemical which will kill a certain proportion of the population. Regulatory bodies aim to ensure that environmental levels do not exceed concentrations that cause mortality.  the usefulness of this approach in environmental monitoring is dubious, as death represents a gross biological  endpoint that only becomes apparent when biological damage has already occurred (Curtis 1998).  Thus, attention ha focused on detection of sub-lethal biological responses to provide early warning of organism/environmental disturbance.  Such biological responses to environmental chemicals are termed biomarkers.  Responses that indicate than an organism has been exposed to a contaminant are known as "biomarkers of exposure," whilst those that indicate that exposure to a contaminant has caused adverse effects are termed "biomarkers of effect."  these effects may be at the biochemical, cellular, physiological r behavioral level of biological organization.

RAMP involves three complementary biomarker techniques. Invertebrate cardiac monitoring using the CAPMON apparatus and the neutral red assay are general stress indicators. The acetylcholinesterase inhibition assay is a specific indicator of exposure to organophosphorous or carbamate pesticides.