Pyridine-2-thiol 1-oxide, sodium salt

Short-term toxicity to fish

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

0.007 mg/L

Additional information

See Tables 6.1.1.1, 6.1.1.2, 6.1.1.3, and 6.1.1.4 for summaries on the acute toxicity to fish of sodium pyrithione and its metabolites.

The acute studies on fish indicate that NaPT is toxic to fish. The LC₅₀values range from 0.0066 to 1.3 mg NaPT/L with Onchorynchus mykiss (rainbow trout) being the most sensitive species. The NOEC for this study was 0.0026 mg NaPT/L.

Further, acute toxicity studies in fish for the major metabolites indicate that the most toxic substance is Pyrithione disulphide with a NOEC of 0.011 mg/L, to the freshwater species Pimephales promelas (Fathead Minnow), but that this is many times less toxic than the parent compound Sodium Pyrithione. However, Pyrithione disulphide is very short lived in the environment (photolytic half-life is 2.5 minutes) and the most relevant degradant of NaPT is Pyridine sulphonic acid (PSA). The NOEC for PSA is 46.9 mg/L for the rainbow trout.

Table 6.1.1.1:    Acute toxicity of NaPT to fish

Guideline / Test method	Species	End-point / Type of test	Exposure		Results [mg/L]			Remarks	Reference
			design	duration	NOEC	LC50	LC100
US EPA-540/9-85-006	Freshwater Rainbow trout   Oncorhyncus mykiss	Mortality	Flow-through	96 hours	1.000	1.300	>1.300		6.1.1.001 ESPTF 7041-101 Croudace et al (1996)
U.S. EPA-FIFRA, Guideline 72-1 (comparableto OECD 203)	Freshwater Rainbow trout   Oncorhyncus mykiss	Mortality	Flow-through	96 hours	0.0026	0.0066	0.011		Key Study   6.1.1.002 ESPTF 7041-102 O’Boyle et al (1988)
U.S. EPA-FIFRA, Guideline 72-1 (comparableto OECD 203)	Bluegill sunfish (Lepomis Machrochirus).	Mortality	Flow-through	96 hours	0.88	9.6	n.a.		6.1.1.003 ESPTF 7041-103 Ewell et al (1987)

 

Table 6.1.1.2:    Acute toxicity of Pyridine-N-oxide-2-sulfonic acid to fish

Guideline / Test method	Species	End-point / Type of test	Exposure		Results [mg/L]			Remarks	Reference
			design	duration	NOEC	LC50	LC100
US EPA- 72-1	Freshwater Fathead Minnow   Pimephales promelas	Mortality	Flow-through	96 hours	48.7	58.8		Key study	6.1.1.009 EZPTF 7041-117 Ward TJ, Kowalski PL, Boeri RL (1994)
US EPA- 72-1	Freshwater Rainbow trout   Oncorhyncus mykiss	Mortality	Flow-through	96 hours	73.6	92.3			6.1.1.005 EZPTF 7041-111 Ward TJ, Kowalski PL, Boeri RL (1994)
US EPA- 72-3 (b)	Marine Sheepshead Minnow   Cyprinodon variegatus	Mortality	Flow-through	96 hours	137	>137			6.1.1.007 EZPTF 7041-114 Boeri RL, Kowalski PL, Ward TJ (1994)

 

Table 6.1.1.3:    Acute toxicity of Pyridine sulphonic acid to fish

Guideline / Test method	Species	End-point / Type of test	Exposure		Results [mg/L]			Remarks	Reference
			design	duration	NOEC	LC50	LC100
US EPA- 72-1	Freshwater Fathead Minnow   Pimephales promelas	Mortality	Flow-through	96 hours	55.2	68.5			6.1.1.010 EZPTF 7041-118 Boeri RL, Kowalski PL, Ward TJ (1994)
US EPA- 72-1	Freshwater Rainbow trout   Oncorhyncus mykiss	Mortality	Flow-through	96 hours	46.9	57.1			6.1.1.006 EZPTF 7041-112 Ward TJ, Kowalski PL, Boeri RL (1993)
US EPA- 72-3 (b)	Marine Sheepshead Minnow   Cyprinodon variegatus	Mortality	Flow-through	96 hours	127	>127			6.1.1.008 EZPTF 7041-115 Boeri RL, Kowalski PL, Ward TJ (1994)

 

Table 6.1.1.4:    Acute toxicity of 2,2’-(pyridyl-N-oxide) disulphide to fish

Guideline / Test method	Species	End-point / Type of test	Exposure		Results [mg/L]			Remarks	Reference
			design	duration	NOEC	LC50	LC100
US EPA- 72-1	Freshwater Fathead Minnow   Pimephales promelas	Mortality	Flow-through	96 hours	0.011	0.030			6.1.1.004 EZPTF 7041-116 Ward TJ, Magazu JP, Boeri RL (1995)
US EPA- 72-1	Freshwater Rainbow trout   Oncorhyncus mykiss	Mortality	Flow-through	96 hours	0.018	0.054			6.1.1.011 EZPTF 7041-110 Ward TJ, Magazu JP, Boeri RL (1995)
US EPA- 72-3 (b)	Marine Sheepshead Minnow   Cyprinodon variegatus	Mortality	Flow-through	96 hours	<0.52	1.1			6.1.1.012 EZPTF 7041-113 Ward TJ, Magazu JP, Boeri RL (1995)

  The information contained within this robust summary document comes from studies which are in the ownership of Arch Chemicals Inc. and which are protected in several regions globally. This information may not be used for any purpose other than in support of the Chemical safety Report submitted by Arch Chemicals Inc. under RegulationEC 1907/2006.