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The list of chemicals to be monitored is unending.
- Biological
effects often occur at concentrations below analytical capabilities. Many of the
pollutants are present in such low concentrations that instrument sensitivity
is too poor to determine the micro quantity of pollutants.
- The
toxicants and other traces may act quite differently in mixture than individually.
Such toxicants affect the ecosystem in a synergistic manner, which con not be
detected by chemical analysis alone.
- Chemical
nature of toxicant is highly dynamic in environment with time and space, whereas
biological system can integrate all environmental variable over a long period
of time in terms of effects which can be easily measured and quantified.
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