Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-)

Endpoint summary

Description of key information

Biodegradation in water

Biodegradability of Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-) (CAS no. 16143-80-9) is predicted using OECD QSAR toolbox version 3.3 (2017) with logKow as the primary descriptor. Test substance undergoes 19.6% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-) was estimated to be not readily biodegradable in water.

Additional information

Biodegradation in water

Predicted data for the target compound Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-) (CAS No. 16143-80-9) and various supporting weight of evidence studies for its read across substance were reviewed for the biodegradation end point which are summarized as below:

 

In a prediction done by SSS (2017) using OECD QSAR toolbox version 3.3 with logKow as the primary descriptor, percentage biodegradability of test chemical, Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-) (CAS No. 16143-80-9) was estimated.Test substance undergoes 19.6% degradation by BOD in 28 days. Thus, based on percentage degradation, the test chemical Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1-) was estimated to be not readily biodegradable in water.

 

In a supporting weight of evidence study from authoritative database (J-CHECK, 2018 and Envichem, 2014) for the read across chemicalTerphenyl (CAS no. 26140-60-3), biodegradation experiment was conducted for 14 days for evaluating the percentage biodegradability of read across substance Terphenyl (CAS no. 26140-60-3). The study was performed according to OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I) under aerobic conditions. Activated sludge was used as a test inoculums for the study. Concentration of inoculum i.e, sludge used was 30 mg/l and initial test substance conc. used in the study was 100 mg/l, respectively. The percentage degradation of substance Terphenyl was determined to be 0.5 and 3.9% degradation by BOD and GC parameter in 14 days. Thus, based on percentage degradation, Terphenyl is considered to be not readily biodegradable in nature.

 

For the same read across chemicalTriphenyl phosphite (CAS no. 101-02-0),biodegradation study was conducted for 28 days for evaluating the percentage biodegradability of read across substance Triphenyl phosphite (CAS no. 101-02-0) (HPVIS, 2017). The study was performed according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) under aerobic conditions. Microorganisms was used as a test inoculum obtained from Secondary effluent from Lulu Island Domestic Wastewater Treatment Plant, Richmond, BC. Initial test substance conc. used in the study was 10 mg/l, respectively. BOD bottles was used as a test vessel for the study. The bottles were gently agitated to improve contact of the inoculum with undissolved test substance by inverting them several times once a day during the test. Temperature ranges from 10 to 24°C during the study. A series of five test solutions were used in the test: inoculum blank, control, filter paper control, test substance treatment, reference substance treatment, and toxicity control. The inoculum blank determined the biological oxygen demand in the absence of either the reference or test substances. The filter paper control was used to monitor the effect of the filter paper on the inoculum, and to provide the blank oxygen uptake values for bottles containing test substance and filter paper. The reference substance sodium benzoate, is classified as readily biodegradable and was used as a positive control to assess the test validity. The toxicity control bottles contained test and reference substances and was used to determine if the test substance inhibited inoculum metabolism. The biodegradability was assessed by measuring the biological oxygen demand (BOD) of a microbial population (secondary effluent) exposed to a low concentration of test substance under controlled conditions and by comparing that BOD to the theoretical oxygen demand (ThOD) of the test substance. Cumulative degradation was plotted versus time Excel 97 SR-2 (Microsoft 1997) to visually assess the rates at which the test substance and the reference substance were degrading. Significant differences in mean DO concentrations between the two controls (inoculum blank and filter paper blank) and percent degradation between the reference substance treatment and toxicity control were also assessed during the study. Sodium benzoate was used as a reference substance for the study.Percent degradation did not reach >60% in a 10 day window within the 28 day test period, and only reached 0.1% by the end of the test. The test substance was non-inhibitory, based on a 79.5% biodegradation of the toxicity control (containing test substance and reference substance) as compared to the 82% biodegradation of the reference substance alone. There was no significant difference in percent biodegradation between the reference substance treatment and the toxicity control (Wilcoxon paired-sample test, p> 0.05).The percentage degradation of test substance Triphenyl phosphite was determined to be 0.54, -0.43, -0.14, -0.18 and 0.14% by BOD parameter in 3, 10, 16, 21 and 28 days, respectively. Thus, based on percentage degradation, Triphenyl phosphite is considered to be not readily biodegradable in nature.

 

On the basis of above results for target chemical Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1 -) (from OECD QSAR toolbox version 3.3, 2017) and for its read across substance (from authoritative database and secondary source), it can be concluded that the test substance Sodium tris(1,2-naphthoquinone 1-oximato-O,O')ferrate(1 -) can be expected to be not readily biodegradable in nature.