Ring testing of the AnBUSDiC test; a new screening method for the anaerobic degradability of surfactants

Environmental Sciences Europe

Table 1 Percentage biodegradation results, with mean, standard deviation and 95% confidence interval

Laboratory	Biodegradation (%) (+/- SD, where available) <lag period in days>
Laboratory	Glucose	Betaine	FA + 7EO	FAS	isoFA + 7EO	LAS
1	81.9 (4.7) <0>	76.8 (4.75) <0>	95.3 (2.88) <0>	97.4 (7.29) <0>	66.3 (30.7) <39>	22.7 (1.66) <0>
2	69.0 <0>	72.0 <0>	103.0 <0>	65.0 <35>	98.0 <0>	0.0 <105>
3	76.0 (4) <0>	53.0 (5.51) <0>	38.0^a (11.02) <0>	37.0^a (48.64) <39>	1.3^a (1.53) <40>	0.0 (1.15) <40>
4	92.7 (3.51) <0>	77.0 (2.83) <0>	106.0 (15.56) <0>	123.0 (8.49) <0>	51.5 (0.71) <0>	31.0 (2.83) <0>
5	79.0 (NA) <0>	83.7 (8.7) <0>	95.9 (1.3) <0>	117.6 (3.4) <0>	51.2 (1.4) <0>	133.4^a (62) <0>
6	74.9 <0>	67.3 <0>	123.4 <0>	84.0 <4>	23.9 <33>	6.2 <0>
7	95.0 <0>	83.0 <0>	118.0 <0>	129.0 <0>	55.0 <0>	26.0 <0>
Mean (+/- SD)	81.2 (8.8)	73.3 (9.8)	97.1 (26.0)	93.3 (31.2)	49.6 (28.5)	31.3 (43.3)
^bMean (+/- SD)			106.9 (10.5)	102.7 (22.8)	57.7 (22.1)	14.3 (12.7)

^aQuestionable result based on the reported anaerobic biodegradability of this type of surfactant, e.g. according to the DID list; ^bMean and standard deviation calculated excluding anomalous result (^a).