Humic acids, potassium salts

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil: simulation testing

Data waiving:

other justification

Justification for data waiving:

other:

Justification for type of information:

Simulation testing on soil is part of degradation studies according to Annex IX REACH.
Column 2 of Annex IX states that “Further biotic degradation testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the degradation of the substance and its degradation products. The choice of the appropriate test(s) depends on the results of the chemical safety assessment and may include simulation testing in appropriate media (e.g. water, sediment or soil).”

Relevant physico-chemical properties of substance were tested with following results.
• Adsorption/Desorption study shows low adsorption rate to soil and sludge: log Koc (soil) < 1.3 (pH = 6.1, 25°C), log Koc (sludge) < 1.5 (pH = 6.1, 25°C)
• From results of hydrolysis study, the substance is found hydrolytically stable after preliminary test and the half-time of degradation is estimated to be more than 1 year. Therefore, no degradation products of parental substance are expected in water.

Also, use in terrestrial applications is performed with 13 % solution of substance in water. The solution of desired concentration is prepared by mixing 180 g with 1 litre of water. For 1 hectare of soil, 0,6 litres of 13 % solution is used. Calculated PEC (soil) = 0,0072 mg/kg with density of soil 2500 kg/m3 according to ECHA Guidance on information requirements and chemical safety assessment. Calculated PNEC (soil) = 0,009052 mg/kg.

Therefore, the risk characterisation ratio (RCR) of PEC (soil) to PNEC (soil) is below 1. The risks associated with terrestrial applications are well controlled. Simulation testing of degradation in soil is inappropriate as there is highly limited degradation expected of parental substance in hydrolysis study.

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 307 (Aerobic and Anaerobic Transformation in Soil)

Test material

Test material information

Constituent 1

Reference substance name:

Humic acids, potassium salts

EC Number:

271-030-1

EC Name:

Humic acids, potassium salts

Cas Number:

68514-28-3

Molecular formula:

NA

IUPAC Name:

tetrapotassium 17-[(2-{3-[(carbamoylmethyl)amino]-4-{[10-(carboxylatomethyl)-7-hydroxy-1,4-dioxo-8-({2,3',4'-trihydroxy-[1,1'-biphenyl]-5-yl}oxy)-4,10-dihydro-1H-phenoxazin-2-yl]oxy}phenyl}-7-oxo-3-[(2,3,4,5-tetrahydroxy-6-oxohexanoyl)oxy]-3,7-dihydro-2H-indol-5-yl)oxy]-2,5,16-trihydroxy-20,21-dioxo-10-oxapentacyclo[11.8.0.0³,¹¹.0⁴,⁹.0¹⁴,¹⁹]henicosa-1,3(11),4(9),5,7,12,14(19),15,17-nonaene-6,7-dicarboxylate

Results and discussion

Transformation products:

not specified