Pirimiphos-methyl

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Series on Testing and Assessment No. 29 (23-Jul-2001): Guidance document on transformation/dissolution of metals and metal compounds in aqueous media

Version / remarks:

CIPAC MT157.1

GLP compliance:

yes

Type of method:

column elution method

Key result

Water solubility:

10 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

pH:

7

Details on results:

The water solubility of pure test substance at 20 °C is 10 mg/L in purified water and 11 mg/L, 10 mg/L and 9.7 mg/L in water buffered at pH 5, pH 7 and pH 9 respectively. It was considered that a 'plateau' had been reached by the fourth 'set' of purified water data which was therefore used to calculate the overall mean result. No flow rate dependency was observed which confirmed that the generated solution was saturated. Having shown that equilibration had been reached with no flow rate dependency the determinations in buffered water were then each performed in a single 'set' at the same flow rate of 3 cm3 min/L.
The pH of the generated solutions were: purified water (pH ~6), pH 5 buffered water (pH 5.1), pH 7 buffered water (pH 7.0) and pH 9 buffered water (pH 9.0). The results are as expected for a test substance that is weakly basic (pKa 4.30). The results are tabulated in 'Any other information on results incl. tables'

Table 1 Water Solubility Results

	Solubility (mg/L)
	ASTM II		pH 5		pH 7		pH 10
Set	Col 1	Col 2	Col 1	Col 2	Col 1	Col 2	Col 1	Col 2
1	9.96a	9.66a	11.1d	11.1d	10.5d	10.1d	9.84d	9.62d
	9.90b	9.43b	11.0d	11.2d	10.6d	10.2d	9.83d	9.61d
	9.88c	9.65c	11.3d	11.2d	10.6d	10.1d	9.81d	9.61d
	9.96d	9.66d	11.3d	11.0d	10.5d	10.1d	9.94d	9.66d
	9.94e	9.70e	11.0d	11.1d	10.5d	10.1d	9.95d	9.56d
2	10.3a	10.1a
	10.2b	10.0b
	10.3c	10.0c
	10.3d	10.0d
	10.3e	10.0e
3	10.5a	10.3a
	10.5b	10.2b
	10.5c	10.2c
	10.5d	10.2d
	10.6e	10.2e
4	10.6a	10.2a
	10.5b	10.2b
	10.6c	10.2c
	10.7d	10.3d
	10.7e	10.7e
Mean (Sr)#	10 (2.1 %)		11 (1.0 %)		10 (2.1 %)		9.7 (1.5 %)

 Determination at: a = 0.5 cm3 /min, b = 1 cm3/ min, c =2 cm3/min, d = 3 cm3/min e = 5 cm3/min

# Data in shaded portion of table used to calculate mean and relative standard deviation (Sr) to 2 Sig. Figs

Conclusions:

The water solubility of pure test substance at 20 °C is 10 mg/L in purified water and 11 mg/L, 10 mg /L and 9.7 mg/L in water buffered at pH 5, pH 7 and pH 9 respectively.

Executive summary:

The water solubility of the pure test substance has been determined using the flask method in accordance with CIPAC MT157.1 and in compliance with GLP criteria. At 20 °C the water solubility was 10 mg/L in purified water and 11 mg/L, 10 mg /L and 9.7 mg/L in water buffered at pH 5, pH 7 and pH 9 respectively.

Description of key information

10 mg/L in water at 20 °C, column elution method, CIPAC MT157.1, Husband 1997.

Key value for chemical safety assessment

Water solubility:

10 mg/L

at the temperature of:

20 °C