Screening Tests

Screening potential compounds before committing to a particular formulation can reduce testing costs. The aim is to identify compounds with the lowest toxicity and highest biodegradability. The biodegradation of test compounds may be evaluated by monitoring a variety of factors, including CO₂ evolution, oxygen consumption, removal of dissolved organic carbon, and other specific end points. Springborn screens for aerobic and anaerobic biodegradation via a suite of test procedures designed to satisfy regulatory requirements.

Biodegradation can be described as the growth (metabolism) of an initial population of microorganisms on a substrate (test substance). This is accomplished with either the use of oxygen in aerobic environments, or other electron acceptors in anaerobic environments. Metabolism results in transient biodegradation intermediates, final oxidized (aerobic) or reduced (anaerobic) metabolic products and an increased population of the degrading microorganisms. Simple (ready) biodegradation screening tests generally examine the disappearance of oxygen or dissolved organic carbon and/or the formation of carbon dioxide with relatively dilute microbial populations.

Tests can be conducted with or without acclimation of the inoculum to the test substance prior to test initiation. Testing without acclimation is more stringent and results indicate the extent of "ready biodegradation", i.e., the percent theoretical biodegradation without pre-exposure of the inoculum to the test chemical. Following disappearance of the test substance and the possible formation of transient biodegradation intermediates with specific analytical methods provides additional information.

Species maintained, cultured or used at SPRINGBORN

Ready Biodegradability
Biodegrad. Screening Test	Test	Biodegrad. Measurement	Water Soluble	Water Insoluble	Volatile	Adsorbing
OECD 301A	DOC Die-Away	DOC	+	-	-	-
OECD 301B	CO2 Evolution	CO2	+	+	-	-
OECD 301D	Closed Bottle	O2	+	+/-	+	+/-
OECD 301E	Modified OECD Screening	DOC	+	-	-	-
OECD 301F	Manometric Respirometry	O2	+	+	-	+
ISO/DIS 14593 OPPTS 835.3120	Sealed Vessel CO2 Production	CO2	+	+	+	+

Tests with Pre-Acclimation
Biodegrad. Screening Test	Test	Biodegrad. Measurement	Water Soluble	Water Insoluble	Volatile	Adsorbing
OPPTS 835.3100	Aerobic Aquatic "Gledhill Test"	CO2	+	+	+	+
FDA 3.11	Aerobic Aquatic	CO2	+	+	+	+
CONCAWE (draft 4/04/96)	Sealed Vessel CO2 Production	CO2	+	+	+	+

Springborn's highly experienced Environmental Fate team can provide comprehensive services in support of product registration, effluent management and other more specific requirements as client needs dictate.