Organizational levels biomarkers

Biomarkers are related to different toxicants and organizational levels. Several examples are given in Table 9.12. Biomarkers range from those that are highly specific to those that are non-specific (a) those highly specific, as the enzyme aminolevulinic acid dehydratase (ALAD), which catalyzes a reaction involved in heme synthesis and is very sensitive to inhibition by inorganic lead (b) those non-specific, as effects in the immune system that can be caused by a wide variety of pollutants. 

Besides the classic floristic, faunal and bio-coenotic investigations that primarily record rather unspecific reactions to pollutant exposure at higher organizational levels of the biological system, various newer methods have been introduced as instruments of bioindication. Most of these are biomarkers and biosensors. 

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