BIOD Biodegradation

("not" biodegradable or nonbiodegradable) in biod

bod* in biod

This is one of the fields contained within the Environmental Fate superfield (ZENE). For more general information regarding Environmental Fate, see the Environmental Fate message field (ENEX).

Note the use of quotation marks around the word not; this tells the SPIRS retrieval engine to treat the word literally and not as an operator.

This data in this field focuses on microbial degradation in both soil and water. The half-life of the chemical substance in the environment is reported with its degradation products where possible, giving an indication of the degree of its persistence.

Water pollution factors: BOD, biochemical oxygen demand; COD, chemical oxygen demand; and ThOD, theoretical oxygen demand are stated, where available. BOD estimates the extent of natural purification which would occur if a substance was discharged into rivers, lakes or the sea. COD is a quicker chemical method for this determination which uses potassium dichromate or permanganate to establish the extent of oxidation likely to occur. ThOD indicates the amount of oxygen needed to oxidise hydrocarbons to carbon dioxide and water. When organic molecules contain other elements, nitrogen, sulfur or phosphorus, the ThOD depends on the final oxidation stage of these elements.

BOD data is sometimes accompanied by a numerical value indicating the period of time over which biodegradation has been measured which is actually a subscript. Occasionally, there is a second value as in:

BOD25/35

which is denoting a superscript (25) over a subscript (35). Similar notation is used in the Density/Specific Gravity field (DEN). In this case the superscript refers to a temperature in degrees Centigrade.