A.I.Chemical Name: Zinc-2-pyridinethiol-1-oxide

Copper-2-pyridinethiol-1-oxide

DP Barcode: D344371

Registrant: Arch Chemicals, Inc.

PC Code(s): 088002, 088001

Executive Summary (for Zn and Cu pyrithione)

Fate Assessment

Zinc Pyrithione (Zinc Omadine®) appears hydrolytically stable in abiotic, 

buffered and simulated water systems with an extrapolated half life between 99 and 123 

days in buffered medium and 96 days (extrapolated) in simulated sea water (MRID. 

43864602). However, Cu omadine hydrolysis is pH-dependent with calculated half-lives 

of 235, 107, and 9 days in pH 5, 7, and 9 buffers, respectively. Hydrolysis in seawater 

occurred with a half-life of 16 days (MRID 45774322). Both Zn and Cu omadine degrade 

rapidly in both fresh and salt irradiated water with half-lives of 11-36 minutes (MRIDs 

44011501, 45774323). In a literature study, both Zn and Cu omadine hydrolyzed rapidly 

in seawater with half-lives of 8.3 and 7.1 minutes, respectively (Maraldo and Dahllof , 

2004). Nitrate and dissolved organic matter increase this degradation rate (Sakkas et al., 

2007). These data indicate that in shallow, well-mixed, and clear irradiated waters, Zn 

and Cu omadine will degrade rapidly. However, suspended sediment and shading will 

inhibit this route of degradation. 

There are multiple microbial degradation pathways for Zn and Cu omadine in 

aquatic systems. Both compounds degrade rapidly in anaerobic aquatic studies 

(representing bottom sediment) with half-lives of 31-75 minutes (MRIDs 44010403, 

44850002, 44850001). However, the two compounds differed in the degradation rate 

under aerobic aquatic conditions (representing surface water). The half-lives were 35-59 

minutes for Zn omadine (MRIDs 44850004 and 45876501) and 4.7 hours for Cu omadine 

(MRID 44850003). In many studies, Zn omadine was observed to transchelate to Cu 

omadine which was more stable. 

Zinc omadine shows a moderately strong tendency to bind with soils and 

sediments: With salt water soil and sediment, the Kds are 50 and 99 ml/g, respectively. 

Tendency to bind with freshwater soils and sediments are less strong and observed Kds are 

11 and 48 ml/g, respectively (MRID 440010402). Zinc omadine is not likely to 

bioconcentrate in aquatic organisms based on the bioconcentration factor of <1 (MRID 

45201401). Copper omadine has a similar sorption potential to soil with a Kd value of 

38.7 and a Koc value of 5528 ml/g. 
Leaching of Zn and Cu omadine does occur from treated paint. For Zn omadine, 

the maximum, minimum, and average leaching rates were 7.3-14.3, 0.95-5.9, and 1.3-7.4

ug/cm2/day, respectively. For Cu omadine, the maximum, minimum, and average 

leaching rates were 5.0-9.3, 2.9-4.6, and 3.9-6 ug/cm2/day, respectively. 

In the UK, Zn pyrithione was not found (<20 ng/l) in seawater. However, it is 

known to undergo transchelation with copper and possibly manganese replacing the zinc 

ion (Konstantinou and Albanis, 2004). The registrant acknowledges this transchelation 

in several studies. 

Even though Zn and Cu omadine are relatively non-persistent, chronic exposure is 

likely to occur due to trannschelation and continuous exposure in aquatic environments. 

In a harbor, boats will reside continuously and the antifoulants in the paint will leach 

while they sit. Also, larger boats and ships will arrive periodically and bring more 

exposure. The primary exposure to these compounds is the non-chelated omadine and 

pyridine degradates with different levels of reduction and oxidation that are formed at 

>10 % of applied parent compound. They include:

Omadine disulfide

Omadine sulfinic acid

Omadine sulfonic acid

Omadine thiosulfonic acid

Pyridine disulfide

Pyridine sulfinic acid

Pyridine sulfonic acid

2-mercaptopyridine/2-mercaptopyrine-N-oxide (mixed disulfides)

Tables 1 and 2 contain the environmental fate data for Zn omadine, and Table 3 

contains the data for Cu omadine. The percentages of each degradate may be seen for 

each individual study in Tables 1 and 3. 

Bridging from Zinc to Copper Omadine

Bridging from Zinc to Copper Omadine

The registrant for zinc omadine is requesting a registration for copper omadine based on 

the zinc omadine data. They are requesting that the Antimicrobial Division bridge the Zn 

omadine data to satisfy the data requirements for Cu omadine. They have several 

proposed justifications for this proposal, including similarity of results in guideline tests 

and different association constants. The registrant used chemical equilibria of Pt 

complexes with Cu(II), Zn(II), Fe(III), Ni(II), Co(II), and Mn(II) to illustrate 

competitive equilibria with the Pt ligand. They did not address the stability of the 

Cu(I)-Pt or Fe(II)-Pt ligand complexes. It is important to note that the activities of 

Cu(I) and Fe(II) will increase in anaerobic (anoxic) environments (Lindsay, 1979). 

The stability diagrams of metal-Pt complexes show that the Cu(II)-Pt complex is the 

predominant metal complex at Cu(II) concentrations ranging from 0.001 to 10 ug/L. 
Therefore, the Cu(II)-Pt, based on chemical equilibria, is expected to be the 

predominant Pt-metal complex in aerobic (oxic) aquatic environments and bridging 

is appropriate. 

The registrant correctly noted that the guideline environmental fate data that incorporates 

both Zn and Cu omadine provide consistent results (See Table 4). The aquatic 

metabolism data show short half-lives in total water:sediment systems with consistent 

degradates that are formed for both chemicals, and sorption is similar for both. 

According to the registrant, the association constants are much higher for copper 

omadine than for any other chelation product (MRID 45774327). A higher association 

constant indicates higher stability of the chelate. The association constant for Cu is >8.5 

compared to 5.3 for Zn. However, they acknowledged that other ions (e.g. Fe, Mn) will 

be in equilibrium with Zn and Cu and will form omadine chelates as well. To justify 

their argument, the registrant provided association constants and a mole fraction diagram 

for Cu (II/I), Zn, Fe (II/III), Mn, Ca, Mg, and H as a function of pH. The submitted Excel 

spreadsheet and PowerPoint presentation clearly demonstrate this phenomenon. In 

descending order, the maximum predicted chelation was for Cu(II), followed by Fe(III), 

Zn(II), Ni(II), Co(II), Mn(II), Mg(II) and Ca(II).
Table 1. Summary of Results from Environmental Degradation and 

Bioconcentration Data for Zinc Omadine

Guideline Half-life(s) Major degradates Percentages References

Hydrolysis (161-1)

pH 5 

(freshwater)

99 days Omadine disulfide Max of 21 % by end of 

study (30 days)

43864602

pH 7 

(freshwater)

120 days Omadine disulfide Max of 16 % by end of 

study (30 days)

pH 9 

(freshwater)

123 days Omadine sulfinic acid Max of 12 % by end of 

study (30 days)

Seawater (pH 

8.2)

96 days Omadine sulfinic acid Max of 17 % by end of 

study (30 days)

Photodegradation in Water (161-2)

pH 9 

(freshwater)

11 minutes Pyridine disulfide Max of 11.2-11.7 % by 1 

hour, and non-detectable 

by 1-14 days

44011501

Pyridine sulfonic acid Max of 70-71 % by end 

of study (30 days)

Mixed disulfides (2-

mercaptopyridine and 2-

mercaptopyridine-N-oxide

Max of 11 % by 15 

minutes, <10 % 

otherwise

Seawater (pH 

8.2)

14 minutes Pyridine disulfide Max of 12.5 % by 1 

hour, and non-detectable 

by 1 day

Pyridine sulfonic acid Max of 70-74 % by end 

of study (30 days)

Anaerobic Aquatic Metabolism (representing bottom sediment)—162-3

Freshwater 

system

75 minutes Omadine sulfinic acid Max of 13 % by 6 hours, 

and average of 5 % until 

end of study (91 days)

44010403

Omadine disulfide Max of 26 % by 3 days, 

and near non-detectable 

by 30 days

Pyridine sulfinic acid Max of 32 % by end of 

study (91 days)

Pyridine sulfonic acid Max of 23 % by 18 

hours, and 0.46 % by 91 

days 

Mixed disulfides Max of 7-15 % by 2-91 

days

Pyridine disulfide Max of 11 % by 14-91 

days (end of study)

Saltwater 

system

57 minutes Omadine disulfide Max of 31 % at day zero, 

non-detectable by 30 

days

Pyridine sulfinic acid Max of 57 % by 90 days 

(end of study)

Pyridine sulfonic acid Max of 11 % by 7 days, 

2.5 % by 90 days

Pyridine disulfide Max of 11-12 % by 2-3 

days, 0.03 % by 90 days

Saltwater 31 minutes Omadine sulfinic acid Max of 11-14 % at zero 44850002
system days, minor 

concentrations after

2-mercaptopyridine Max of 71-78 % by 7 

days, 33-34 % by 30 

days (end of study)

Aerobic Aquatic Metabolism (representing surface water)—162-4

Saltwater 

system

59 minutes Omadine sulfinic acid Max of 36-46 % by 3-7 

days, 7-18 % by 30 days 

(end of study) 

44850004

Omadine sulfonic acid Max of 22-35 % by 30 

days

Omadine thiosulfonic acid Max of 21-26 % by 0 

days, 7-8 % by 30 days 

Pyridine sulfonic acid Max of 12-15 % by 30 

days

Outdoor microcosm test (Aerobic Aquatic Metabolism with light)—164-2

Saltwater 

system

35 minutes Omadine sulfonic acid Max of 18 % by 1 hour, 

not detected by 8 hours

45876501

Omadine sulfinic acid Max of 19 % by 4 hours, 

non-detectable by 30 

days 

Pyridine sulfinic acid Max of 29 % by 1 day, 

non-detectable by 14 

days

Pyridine sulfonic acid Max of 82 % by 14 days, 

76 % by 30 days 

Bioaccumulation in non-target aquatic organisms (165-5)

Bioconcentration was negligible with bioconcentration 

factors of <1. 

MRID 45201401

Leaching from Green Paint

Maximum average leach rate 

(ug/cm2/day)

9.0 (day 1) MRID 47171304

40.43 % CuO and 3 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.6 (day 45)

Cumulative leach rate 

(ug/cm2)

111 (days 0-45)

Mean leach rate (ug/cm2/day) 2.5 (days 0-45)

Leaching from Red Paint

Maximum average leach rate 

(ug/cm2/day)

7.8 (day 21) MRID 47171305

40.43 % CuO and 3 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.4 (day 45)

Cumulative leach rate 

(ug/cm2)

103 (days 0-45)

Mean leach rate 

(ug/cm2/day)

2.3 (days 0-45)

Leaching from BluePaint

Maximum average leach rate 

(ug/cm2/day)

7.3 (day 1) MRID 47171303

40.43 % CuO and 3 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.5 (day 42)

Cumulative leach rate 

(ug/cm2)

114 (days 0-45)

Mean leach rate (ug/cm2/day) 2.5 (days 0-45)

Leaching from Black Paint
Maximum average leach rate 

(ug/cm2/day)

8.8 (day 1) MRID 47188401

40.43 % CuO and 3 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.4 (days 21-45)

Cumulative leach rate 

(ug/cm2)

105 (days 1-45)

Mean leach rate (ug/cm2/day) 2.3 (days 1-45)

Leaching from Alumaspray+ 1863 Black Paint

Maximum average leach rate 

(ug/cm2/day)

8.02 (day 24) MRID 46547404

1.43 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.3 (day 45)

Cumulative leach rate 

(ug/cm2)

183 (days 1-45)

Mean leach rate (ug/cm2/day) 4.1 (days 1-45)

Leaching from Alumaspray+ 1763 Gray Paint

Maximum average leach rate 

(ug/cm2/day)

9.1 (day 1) MRID 46547403

1.43 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

1.5 (day 45)

Cumulative leach rate 

(ug/cm2)

136 (days 1-45)

Mean leach rate (ug/cm2/day) 3.0 (days 1-45)

Leaching from Alumaspray+ 1262 Blue Paint

Maximum average leach rate 

(ug/cm2/day)

7.6 (day 10) MRID 46632004

4.95 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

2.8 (day 45)

Cumulative leach rate 

(ug/cm2)

228 (days 1-45)

Mean leach rate (ug/cm2/day) 5.1 (days 1-45)

Leaching from International Copper-Free, White Paint

Maximum average leach rate 

(ug/cm2/day)

14.3 (day 1) MRID 47039201

4.34 % Zn Omadine

Minimum average leach 

rate (ug/cm2/day)

4.3 (day 45)

Cumulative leach rate 

(ug/cm2)

322 (days 1-45)

Mean leach rate (ug/cm2/day) 7.2 (days 1-45)

Leaching from Ecoflex BEA368/G584 Paint

Maximum average leach rate 

(ug/cm2/day)

13 (day 7) MRID 44877103

Zn omadine percentage not available

Minimum average leach 

rate (ug/cm2/day)

5.9 (day 49)

Cumulative leach rate 

(ug/cm2)

423 (days 1-49)

Mean leach rate (ug/cm2/day) 8.6 (days 1-49)

Leaching from Ecoflex BEA369/G044 Paint

Maximum average leach rate 

(ug/cm2/day)

13 (day 1) MRID 44877104

Zn omadine percentage not available

Minimum average leach 

rate (ug/cm2/day)

5.1 (day 49)

Cumulative leach rate 

(ug/cm2)

361 (days 1-49)
Mean leach rate (ug/cm2

/day) 7.4 (days 1-49)

Leaching from Ecoflex BEA468/G580 Paint

Maximum average leach rate 

(ug/cm2/day)

11 (day 3) MRID 44877104

Zn omadine percentage not available

Minimum average leach 

rate (ug/cm2/day)

3.9 (day 49)

Cumulative leach rate 

(ug/cm2)

298 (days 1-49)

Mean leach rate (ug/cm2/day) 6.1 (days 1-49)

Leaching from Ecoflex BEA469/G044 Paint

Maximum average leach rate 

(ug/cm2/day)

7.1 (day 7) MRID 44877106

Zn omadine percentage not available

Minimum average leach 

rate (ug/cm2/day)

3.2 (day 49)

Cumulative leach rate 

(ug/cm2)

242 (days 1-49)

Mean leach rate (ug/cm2/day) 4.9 (days 1-49)

Leaching from Ecoflex BEA469/G044 Paint

Maximum average leach rate 

(ug/cm2/day)

4.5 (day 1) MRID 44833310

4.7 % Zn omadine

Minimum average leach 

rate (ug/cm2/day)

0.95 (day 38)

Cumulative leach rate 

(ug/cm2)

64.6 (days 1-49)

Mean leach rate (ug/cm2/day) 1.3 (days 1-49)

Table 2. Leaching-Adsorption-Desorption Data for Zn Omadine (MRID 44010402)

Soil/Sediment Kads 

(ml/g)

Koc 

(ml/g)

Kdes 

(ml/g)

Koc 

(ml/g)

Comment(s)

Marblehead salt 

soil

50 2,347 71 3,293 Sorption 

unrelated to 

clay, organic 

matter, or pH

Sorption 

coefficients are 

for mixture of 

compounds

Portland fresh soil 11 784 13 873

Marblehead salt 

sediment

99 10,633 202 21,814

Portland fresh 

sediment

48 3,597 87 6,524
Table 3. Summary of Results from Environmental Degradation Data for Copper Omadine

Guideline Half-life(s) Major 

degradates

Percentages References

Hydrolysis (161-1)

pH 5 (freshwater) 235 days None Not applicable 45774322

pH 7 (freshwater) 107 days Omadine sulfinic 

acid

Max of 13 % by 

30 days (end of 

study)

pH 9 (freshwater) 9.1 days Omadine disulfide Max of 10 % by 7 

days, 0.6 % by 30 

days

Omadine sulfinic 

acid

Max of 69 % by 

30 days 

Seawater (pH 8.2) 16 days Omadine sulfinic 

acid

Max of 57-61 % 

by 21-30 days

Photodegradation in Water (161-2)

pH 5 (freshwater) 36 minutes Lactam Max of 29 % by 

17 days (end of 

study)

45774323

Pyridine sulfinic 

acid

Max of 43 % by 6 

hours, 2 % by 17 

days

Pyridine sulfonic 

acid

Max of 42 % by 

17 days

Seawater (pH 8.2) 31 minutes Lactam (reaction 

intermediate)

Max of 64 % by 

17 days (end of 

study)

Pyridine sulfinic 

acid

Max of 38 % by 6 

hours, nondetectable by 17 

days

Pyridine sulfonic 

acid

Max of 36 % by 

7-17 days

Anaerobic Aquatic Metabolism (162-3)

Saltwater system 34 minutes 2-

mercaptopyridine

Max of 78 % by 7 

days, 2.3 % by 

182 days (end of 

study)

44850001

Omadine sulfinic 

acid

Max of 13.8 % at 

time 0, nondetectable by 14 

days

Aerobic Aquatic Metabolism (162-4)

Freshwater system 4.7 hours Omadine sulfinic 

acid

Max of 42 % by 7 

days, 1.7 % by 84 

days (end of 

study)

44850003

Omadine 

sulfonic acid

Max of 29-35 % 

by 21-84 days

Omadine 

thiosulfonic acid

Max of 41 % by 1 

day, 4.4 % by 84 

days 

Pyridine sulfonic 

acid (M-7)

Max of 25 % by 

84 days.
Leaching from Brown Paint

Maximum average leach rate (ug/cm2/day) 6.5 (day 45) MRID 47107710, 46105309

Minimum average leach 

rate (ug/cm2/day)

4.6 (day 14)

Cumulative leach rate (ug/cm2) 240 (days 1-45)

Mean leach rate (ug/cm2/day) 5.33 (days 1-

45)

Leaching from Dark Red Paint

Maximum average leach rate (ug/cm2/day) 9.3 (day 3) MRID 47107709, 46105308

Minimum average leach 

rate (ug/cm2/day)

4 .1 (day 28)

Cumulative leach rate (ug/cm2) 270 (days 1-45)

Mean leach rate (ug/cm2/day) 6.0 (days 1-45)

Leaching from Dark Red Paint

Maximum average leach rate (ug/cm2/day) 5.0 (day 7) MRID 45793501

Minimum average leach 

rate (ug/cm2/day)

2.9 (day 38)

Cumulative leach rate (ug/cm2) 161 (days 1-45)

Mean leach rate (ug/cm2/day) 3.9 (days 1-45)

Soil Leaching-Adsorption-Desorption

Kd (ml/g) 38.7 MRID 45780508

Koc (ml/g) 5528
Table 4. Comparison of Environmental Fate Results for Copper Omadine and Zinc 

Omadine

Zinc Omadine Copper Omadine

Test Guideline Half-life Degradates Test Guideline Half-life Degradates

Hydrolysis (835.2120, 161-1, MRID 43864602) Hydrolysis (835.2120, 161-1, MRID 45774322)

pH 5 

(freshwater)

99 days Omadine disulfide pH 5 

(freshwater)

235 days None

pH 7 

(freshwater)

120 days Omadine disulfide pH 7 

(freshwater)

107 days Omadine sulfinic 

acid

pH 9 

(freshwater)

123 days Omadine sulfinic 

acid

pH 9 

(freshwater)

9.1 days Omadine 

disulfide

Omadine sulfinic 

acid

Seawater (pH 

8.2)

96 days Omadine sulfinic 

acid

Seawater (pH 

8.2)

16 days Omadine sulfinic 

acid

Photodegradation in Water (835.2240, 161-2, 

MRID 44011501)

Photodegradation in Water (835.2240, 161-2,

MRID 45774323)

pH 9 

(freshwater)

11 minutes Pyridine disulfide

Pyridine sulfonic 

acid

Mixed disulfides 

(2-

mercaptopyridine 

and 2-

mercaptopyridineN-oxide)

pH 5 

(freshwater)

36 minutes Lactam

Pyridine sulfinic 

acid

Pyridine sulfonic 

acid

pH 8.2 

(Seawater)

14 minutes Pyridine disulfide

Pyridine sulfonic 

acid

pH 8.2 

(seawater)

31 minutes Lactam

Pyridine sulfinic 

acid

Pyridine sulfonic 

acid

Anaerobic Aquatic Metabolism (835.4300, 162-3, 

MRID 44010403, 44850002)

Anaerobic Aquatic Metabolism (835.4300, 162-

3, MRID 44850001)

Freshwater 

system

75 minutes Omadine sulfinic 

acid

Omadine disulfide

Pyridine sulfinic 

acid

Pyridine sulfonic 

acid

Mixed disulfides

Pyridine disulfide

No data

Saltwater system 57 minutes Omadine disulfide

Pyridine sulfinc 

acid

Pyridine sulfonic 

acid

Pyridine disulfide

Saltwater system 31 minutes 2-

mercaptopyridine

Omadine sulfinic 

acid

Saltwater system 31 minutes Omadine sulfinic 

acid

2-

mercaptopyridine 

(one of the mixed 

disulfides)
Aerobic Aquatic Metabolism (835.4400, 162-

4/164-4, MRID 44850004, 45876501

Aerobic Aquatic Metabolism (835.4400, 162-4, 

MRID 4850003)

Saltwater system 59 minutes Omadine sulfinic 

acid

Omadine sulfonic 

acid

Omadine 

thiosulfonic acid

Pyridine sulfonic 

acid

Freshwater 

system

5 hours Omadine sulfinic 

acid

Omadine 

sulfonic acid

Omadine 

thiosulfonic acid

Pyridine sulfonic 

acid

Saltwater system 

(Outdoor 

microcosm with 

light)

35 minutes Omadine sulfinic 

acid

Omadine sulfonic 

acid

Pyridine sulfinic 

acid

Pyridine sulfonic 

acid

No data

Leaching and Adsorption Desorption (835.1230, 

163-1, MRID 44010402)

Leaching and Adsorption Desorption (835.1230, 

163-1, MRID 45780508)

Kad (Kads 

values )

ml/g

11-99 (soils 

and 

sediments)

For mixture 

of 

compounds

Not applicable 38 Not 

applicable 

Not applicable

Bioconcentration in non-target organisms 

(850.1710, 165-5, MRID 45201401)

Bioconcentration in non-target organisms (165-

5)

Bioconcentration 

was negligible 

with 

bioconcentration 

factors of <1. 

Not 

applicable

Not applicable No data (no 

bioconcentration 

expected)

Not 

applicable

Not applicable

Leaching rates from treated paints (ASTM 5108-

90, MRIDs 47171304, 47071305, 47171303, 

47188401, 46547404, 46547403, 46632004, 

47039201, 44877103, 44877104, 44877105, 

448771016, 44833310)

Leaching rates from treated paints (ASTM 

D5108-90, MRIDs 47107710, 46105309, 

47107709, 45793501)

Maximum 

leaching rates 

(ug/cm2/day)

4.5-14 

(average of 

9.3)

Not applicable Maximum 

leaching rates 

(ug/cm2/day)

5-9.3 

(average 

of 6.9)

Not applicable

Minimum 

average leach 

rate (ug/cm2/day)

0.95-5.9 

(average of 

2.7)

Minimum 

average leach 

rate 

(ug/cm2/day)

2.9-4.6

(average 

of 3.9)

Cumulative each 

rate (ug/cm2)

65-423 

(average of 

207)

Cumulative each 

rate (ug/cm2)

161-270 

(average 

of 224)

Mean leach rate 

(ug/cm2)

1.3-7.4 

(average of 

4.4)

Mean leach rate 

(ug/cm2)

3.9-6 

(average 

of 4.4)
References

Open Literature references

Konstantinou, I.K and T.A. Albanis. 2004. Worldwide occurrence and effects of 

antifouling paint booster biocides in the aquatic environment: a review. Environment

International 30(2004): 235-248.

Lindsay, Willard L. 1979. Chemical Equilibria in Soil. Wiley Interscience, John Wiley 

and Sons, New York.

Maraldo, K. and L. Dahliof. 2004. Seasonal variations in the effect of zine pyrithione 

and copper pyrithione on pelagic phytoplankton communities. Aquatic toxicology 

(2004)): 189-198.

Sakkas, V.A, K. Shibata, Y. Yamaguchi, S. Sugasawa, and T. Albanis. 2007. Aqueous 

phototransformation of zinc pyrithione. Degradation kinetics and by-product 

identification by liquid chromatography-atmospheric pressure chemical ionization mass 

spectrometry. Journal of Chromatography A, 1144 (2007) 175-182.
Submitted Guideline Studies

Zinc Omadine

161-1 Hydrolysis

MRID Citation Reference

43864602 Reynolds, J. (1995) Hydrolysis of (Pyridine-2,6-(carbon 14)) Zinc Omadine: Lab 

Project Number: XBL 94052: RPT00217: 94052. Unpublished study prepared 

by XenoBiotic Labs, Inc. 128 p. 

835.2130 Hydrolysis as a function of pH and temperature

MRID Citation Reference

46101101 Turley, P. (2003) Calculation of Predicted Environmental Concentrations of Zinc 

Pyrithione in Antifouling Applications. Project Number: CASR/04/2003. 

Unpublished study prepared by Biocides Technology. 74 p.

161-2 Photodegradation-water

MRID Citation Reference

43864601 Reynolds, J. (1995) Aqueous Photolysis of (Pyridine-2,6-(carbon 14)) Zinc 

Omadine in pH 9 Buffer and Artificial Sea Water: Lab Project Number: 95025: 

RPT00243: XBL 95025. Unpublished study prepared by XenoBiotic Labs, Inc. 

130 p. 

44011501 Reynolds, J. (1996) Aqueous Photolysis of (pyridine-2,6-(carbon 14))Zinc 

Omadine in pH 9 Buffer and Artificial Seawater: Revised Report: Lab Project 

Number: 95025: RPT00243: XBL 95025. Unpublished study prepared by 

XenoBiotic Labs, Inc. 139 p. 

45876501 McLaughlin, S. (2003) Zinc Pyrithione Outdoor Microcosm Study: Lab Project 

Number: 13778.6100: 082001. Unpublished study prepared by Springborn 

Smithers Laboratories. 141 p. {OPPTS 835.3180, 835.0001} 

835.2210 Direct photolysis rate in water by sunlight

MRID Citation Reference

46101101 Turley, P. (2003) Calculation of Predicted Environmental Concentrations of Zinc 

Pyrithione in Antifouling Applications. Project Number: CASR/04/2003. 

Unpublished study prepared by Biocides Technology. 74 p.
162-3 Anaerobic aquatic metab.

MRID Citation Reference

44010403 Smalley, J.; Reynolds, J. (1996) Anaerobic Aquatic Metabolism of (Pyridine2,6-(carbon 14)) Zinc Omadine in Fresh Water and Sea Water: Lab Project 

Number: 95022: RPT00241. Unpublished study prepared by XenoBiotic Labs., 

Inc. 232 p. 

44509701 Ritter, J. (1998) Summary of the Aerobic and Anaerobic Aquatic Metabolism of 

(pyridine-2,6-(carbon 14)) Copper Omadine and (pyridine-2,6-(carbon 14)) Zinc 

Omadine in Marine Water and Sediment: (Interim Report): Lab Project Number: 

42-96B10CUOM: 45-97B10ZNOM: 49-97B10ZPT. Unpublished study prepared 

by Olin Research Center. 16 p. 

44850001 Ritter, J. (1999) Anaerobic Aquatic Metabolism of (pyridine-2,6-(carbon-14)) 

Copper Omadine in Marine Water and Sediment: Lab Project Number: 50-

97B10CUOM. Unpublished study prepared by Arch Chemicals, Inc. 201 p. 

44850002 Ritter, J. (1999) Supplemental Anaerobic Aquatic Metabolism of (pyridine-2,6-

(carbon-14)) Zinc Omadine in Marine Water and Sediment: Lab Project 

Number: 49-97B10ZPT. Unpublished study prepared by Arch Chemicals, Inc. 

126 p. 

46101101 Turley, P. (2003) Calculation of Predicted Environmental Concentrations of Zinc 

Pyrithione in Antifouling Applications. Project Number: CASR/04/2003. 

Unpublished study prepared by Biocides Technology. 74 p.

162-4 Aerobic aquatic metab.

MRID Citation Reference

44010401 Ritter, J. (1996) Aerobic Aquatic Metabolism of (Pyridine-2,6-(carbon 14)) Zinc 

Omadine: (Final Report): Lab Project Number: 29-95B10ZPT. Unpublished 

study prepared by Olin Research Center. 292 p. 

44509701 Ritter, J. (1998) Summary of the Aerobic and Anaerobic Aquatic Metabolism of 

(pyridine-2,6-(carbon 14)) Copper Omadine and (pyridine-2,6-(carbon 14)) Zinc 

Omadine in Marine Water and Sediment: (Interim Report): Lab Project Number: 

42-96B10CUOM: 45-97B10ZNOM: 49-97B10ZPT. Unpublished study prepared 

by Olin Research Center. 16 p. 

44850003 Ritter, J. (1999) Aerobic Aquatic Metabolism of (pyridine-2,6-(carbon-14)) 

Copper Omadine in Marine Water and Sediment: Lab Project Number: 42-

96B10CUOM. Unpublished study prepared by Arch Chemicals, Inc. 168 p. 

44850004 Ritter, J. (1999) Supplemental Aerobic Aquatic Metabolism of (pyridine-2,6-

(carbon-14)) Zinc Omadine in Marine Water and Sediment: Lab Project 

Number: 45-97B10ZNOM. Unpublished study prepared by Arch Chemicals, Inc. 

143 p. 

46101101 Turley, P. (2003) Calculation of Predicted Environmental Concentrations of Zinc 

Pyrithione in Antifouling Applications. Project Number: CASR/04/2003. 

Unpublished study prepared by Biocides Technology. 74 p.
163-1 Leach/adsorp/desorption

MRID Citation Reference

44010402 Wisocky, M.; Reynolds, J. (1996) Adsorption and Desorption of (pyridine-2,6-

(carbon 14)) Zinc Omadine in Two Sediments and Two Terrestrial Soils: 

Revised: Lab Project Number: 95023: RPT00242. Unpublished study prepared 

by XenoBiotic Labs., Inc. 195 p. 

45565201 Ritter, J. (2001) Zinc Pyrithione Soil Column Leaching Study: Lab Project 

Number: 72-00B10ZPT. Unpublished study prepared by Arch Chemicals, Inc. 

179 p. 

47695602 Chang, S. (2009) Measurement of Zinc Pyrithone Leached from Polyester 

Fabrics. Project Number: CASR/01/2009. Unpublished study prepared by Arch 

Chemicals, Inc. 30 p.

164-2 Aquatic field dissipation

MRID Citation Reference

45876501 McLaughlin, S. (2003) Zinc Pyrithione Outdoor Microcosm Study: Lab Project 

Number: 13778.6100: 082001. Unpublished study prepared by Springborn 

Smithers Laboratories. 141 p. {OPPTS 835.3180, 835.0001} 

165-5 Bioaccum-aquatic non-target

MRID Citation Reference

45204101 Ward, T.; Boeri, R. (2000) Bioconcentration Test with Zinc (pyridine-2,6-(14)C) 

Omadine and the Oyster, Crassostrea virginica. Unpublished study prepared by 

T.R. Wilbury Laboratories, Inc. 54 p. 

ASTM D5108-90 Leaching from Treated Paint

44587209 Ritter, J. (1998) Zinc Omadine Leach Rates from Four Ecoloflex Paints in 

Synthetic Seawater: Lab Project Number: 54-97B10ZPT: 57-97B10ZPT: 58-

98B10ZPT. Unpublished study prepared by Olin Biocides. 23 p. 

44833310 Audette, D. (1998) Leach Rate of Zinc and Zinc Omadine from Two E. Paint 

Antifouling Paints: Lab Project Number: 47-97B10ZPT: ASTM D5108-90. 

Unpublished study prepared by Olin Research Center. 92 p. 

44877103 Ritter, J. (1999) Leach Rate of Zinc Omadine from Ecoloflex BEA368/G584 

Paint in Synthetic Seawater: Lab Project Number: 54-97B10ZPT. 

Unpublished study prepared by Arch Chemicals, Inc. 58 p. 
44877104 Ritter, J. (1999) Leach Rate of Zinc Omadine from Ecoloflex BEA369/G044 

Paint in Synthetic Seawater: Lab Project Number: 57-98B10ZPT. 

Unpublished study prepared by Arch Chemicals, Inc. 58 p. 

44877105 Ritter, J. (1999) Leach Rate of Zinc Omadine from Ecoloflex BEA468/G580 

Paint in Synthetic Seawater: Lab Project Number: 58-98B10ZPT. 

Unpublished study prepared by Arch Chemicals, Inc. 58 p. 

44877106 Ritter, J. (1999) Leach Rate of Zinc Omadine from Ecoloflex BEA469/G043 

Paint in Synthetic Seawater: Lab Project Number: 59-98B10ZPT. 

Unpublished study prepared by Arch Chemicals, Inc. 58 p. 

44974202 Boeri, R.; Rondon, C.; Ward, T. (1999) Leach Rate of Zinc Omadine from 

Micron Optima Paint in Synthetic Seawater: Lab Project Number: 1706-OL. 

Unpublished study prepared by T.R. Wilbury Labs., Inc. 52 p. 

45347201 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Micron Optima Red in Synthetic Seawater: Lab Project Number: 1980-IP. 

Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 50 p. 

45347202 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Micron Optima Black in Synthetic Seawater: Lab Project Number: 1981-IP. 

Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 50 p. 

45349801 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Intersmooth 360 Ecoloflex BEA 363 Dark Brown in Synthetic Seawater: Lab 

Project Number: 1976-IP. Unpublished study prepared by T.R. Wilbury 

Labs., Inc. 51 p. 

45349802 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Intersmooth 360 Ecoloflex BEA 364 Dark Red in Synthetic Seawater: Lab 

Project Number: 1977-IP. Unpublished study prepared by T.R. Wilbury 

Labs., Inc. 50 p. 

45349803 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Intersmooth 460 Ecoloflex BEA 463 Dark Brown in Synthetic Seawater: Lab 

Project Number: 1978-IP. Unpublished study prepared by T.R. Wilbury 

Labs., Inc. 50 p. 

45349804 Boeri, R.; Rondon, C.; Ward, T. (2000) Leach Rate of Zinc Omadine from 

Intersmooth 460 Ecoloflex BEA 464 Dark Red in Synthetic Seawater: Lab 

Project Number: 1979-IP. Unpublished study prepared by T.R. Wilbury 

Labs., Inc. 50 p.

45690201 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Multi-Micron Antifouling--Blue in Synthetic Seawater: Lab Project Number: 

2348-IP. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 44 

p. 
45690202 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Multi-Micron Antifouling--Red in Synthetic Seawater: Lab Project Number: 

2349-IP. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 44 

p. 

45690203 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Multi-Micron Antifouling--Black in Synthetic Seawater: Lab Project Number: 

2350-IP. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 44 

p. 

45811901 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Superyacht 800 Antifouling--White in Synthetic Seawater: Lab Project 

Number: 2369-IP. Unpublished study prepared by T.R. Wilbury Laboratories, 

Inc. 44 p. 

45811902 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Superyacht 800 Antifouling--Red in Synthetic Seawater: Lab Project 

Number: 2371-IP. Unpublished study prepared by T.R. Wilbury Laboratories, 

Inc. 44 p. 

45811903 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Superyacht 800 Antifouling--Blue in Synthetic Seawater: Lab Project 

Number: 2370-IP. Unpublished study prepared by T.R. Wilbury Laboratories, 

Inc. 44 p. 

45811904 Boeri, R.; Rondon, C.; Ward, T. (2002) Leach Rate of Zinc Omadine from 

Superyacht 800 Antifouling--Black in Synthetic Seawater: Lab Project 

Number: 2372-IP. Unpublished study prepared by T.R. Wilbury Laboratories, 

Inc. 44 p. 

46059703 Sinning, D. (2002) Leach Rate Determination of Pettit Marine Paint 

Alumacoat SR Antifouling Paint 1261 Blue Containing Zinc Omadine. 

Project Number: 390/59. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 22 p.

46059704 Sinning, D. (2002) Leach Rate Determination of Pettit Marine Paint 

Alumacoat SR Antifouling Paint 1861 Black Containing Zinc Omadinet. 

Project Number: 390/60. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 22 p.

46059705 Sinning, D. (2002) Leach Rate Determination of Pettit Marine Paint 

Alumacoat SR Antifouling Paint 1161 White Containing Zinc Omadine. 

Project Number: 390/62. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 22 p.

46059706 Sinning, D. (2002) Leach Rate Determination of Pettit Marine Paint 

Alumacoat SR Antifouling Paint 1661 Red Containing Zinc Omadine. Project 

Number: 390/63. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 22 p.
46088608 Sinning, D. (2003) Leach Rate Determination of Sea Nine TM21 1 

Antifouling Agent and Zinc Omadine from Sea Grand Prix CF-10: Final 

Report. Project Number: 2750/03. Unpublished study prepared by Case 

Consulting Laboratories, Inc. 34 p.

46248002 Sinning, D. (2004) Leach Rate Determination of Pettit Marine Paint 

Alumacoat SR Antifouling Paint 1461 Yellow Containing Zinc Omadine. 

Project Number: 390/71, ASTM/D/5108/90. Unpublished study prepared by 

Case Consulting Laboratories, Inc. 22 p.

46547403 Sinning, D. (2004) Leach Rate Determination of Pettit Marine Paint 

Alumaspray + Aerosol Antifouling Paint 1763 Gray Containing Zinc 

Omadine. Project Number: 390/78. Unpublished study prepared by Case 

Consulting Laboratories, Inc. 22 p.

46547404 Sinning, D. (2004) Leach Rate Determination of Pettit Marine Paint 

Alumaspray + Aerosol Antifouling Paint 1863 Black Containing Zinc 

Omadine. Project Number: 390/77. Unpublished study prepared by Case 

Consulting Laboratories, Inc. 22 p.

46625103 Sinning, D. (2005) Leach Rate Determination of Cuprous Oxide 40% and 

4.4% Zinc Omadine (Solvent) Island 77 Plus Black Antifouling Paint 

Containing Zinc Omadine. Project Number: 2450/09. Unpublished study 

prepared by Case Consulting Laboratories, Inc. 22 p.

46640501 Sinning, D. (2005) Leach Rate Determination of Cuprous Oxide Free with 4% 

Zinc Omadine (Solvent) White Antifouling Paint Containing Zinc Omadine. 

Project Number: 2450/07. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 22 p.

46640601 Sinning, D. (2005) Leach Rate Determination of Cuprous Oxide Free with 

4.2% Zinc Omadine (Water Base) White Antifouling Paint Containing Zinc 

Omadine. Project Number: 2450/08. Unpublished study prepared by Case 

Consulting Laboratories, Inc. 22 p.

46934508 Serak, K.; Hanh, J. (2006) Determination of the Leach Rate of Econea from 

Paint (International Copper Free) in Synthetic Seawater. Project Number: 

49702, 49702/7. Unpublished study prepared by Analytical Bio-Chemistry 

Labs., Inc. 62 p.

47039201 Schofield, D. (2007) International Copper Free, White Antifouling Paint 

(Zinc Pyrithione) 45 Day Leaching Study. Project Number: 

STUDY/1304560. Unpublished study prepared by Intertek ASG. 42 p.

47171303 Sinning, D. (2006) Leach Rate Determination of Pettit Marine Paint ULTIMA 

SPC Antifouling Paint 1299 Blue Containing Zinc Omadine. Project Number: 

390/81. Unpublished study prepared by Case Consulting Laboratories, Inc. 26 

p.
47171304 Sinning, D. (2006) Leach Rate Determination of Pettit Marine Paint ULTIMA 

SPC Antifouling Paint 1399 Green Containing Zinc Omadine. Project 

Number: 390/82. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 26 p.

47171305 Sinning, D. (2006) Leach Rate Determination of Pettit Marine Paint ULTIMA 

SPC Antifouling Paint 1699 Red Containing Zinc Omadine. Project Number: 

390/83. Unpublished study prepared by Case Consulting Laboratories, Inc. 26 

p.

47188401 Sinning, D. (2006) Leach Rate Determination of Pettit Marine Paint Ultima 

SPC Antifouling Paint 1899 Black Containing Zinc Omadine. Project 

Number: 390/84. Unpublished study prepared by Case Consulting 

Laboratories, Inc. 26 p.

47238912 Serak, K. (2007) Determination of the Leach Rate of Organic Biocides from 

Two Paints in Substitute Ocean Water: Seaguard HMF 1 and Seaguard HMF 

2: HMC Antifouling Paint. Project Number: 49912, 49912/1. Unpublished 

study prepared by ABC Laboratories, Inc. 125 p.

47550801 Tunink, A. (2008) Determination of the Leach Rate of Organic Biocides from 

Four Paint Colors, Code No. LAg 2007 025 - Black, Red, Blue, and Green in 

Substitute Ocean Water. Project Number: 63315, AGR/3766, 

ASTM/D/6903/07. Unpublished study prepared by ABC Laboratories, Inc. 98 

p.

Copper Omadine

161-1 Hydrolysis

MRID Citation Reference

45774322 Fenn, R. (1999) Hydrolysis of (Pyridine-2,6-Carbon 14) Copper Omadine: Final 

Report: Lab Project Number: 40-96B10CUOM. Unpublished study prepared by 

Arch Chemicals, Inc. 106 p. {OPPTS 835.2120} 

161-2 Photodegradation-water

MRID Citation Reference

45774323 Fenn, R. (2000) Photolysis of (Pyridine-2,6-Carbon 14) Copper Omadine: Final 

Report: Lab Project Number: 56-98B10CUPT. Unpublished study prepared by 

Arch Chemicals, Inc. 185 p. {OPPTS 835.2240} 
163-1 Leach/adsorp/desorption

MRID Citation Reference

45774327 Sun, P.; Fernando, Q.; Freiser, H. (1964) Formation Constants of Transition 

Metal Complexes of 2-Hydroxypyridine-1-Oxide and 2-Mercaptopyridine-1-

Oxide. Analytical Chemistry 36(13):2485-2488. 

45780508 Ritter, J. (2002) Adsorption/Desorption (Batch Equilibrium) Characteristics of 

Copper Omadine. Unpublished study prepared by Arch Chemicals, Inc. 10 p. 

{OPPTS 835.1240, 835.1230} 

ASTM D5108-90 Leaching from Treated Paint

45793501 Fenn, R. (2000) Leach Rate of Copper Pyrithione from Antifouling SeaQueen 

Paint in Synthetic Seawater: Final Report: Lab Project Number: 71-

00B10CUPT. Unpublished study prepared by Arch Chemicals, Inc. 58 p. 

45827702 Dahling, M. (2002) Leaching Rates of Copper Pyrithione from Antifouling 

Seaqueen by Calculation Method: Lab Project Number: MD/8068-1/016. 

Unpublished study prepared by Jotun AS. 9 p. 

46105308 Boeri, R.; Rondon, C.; Ward, T. (2003) Leach Rate of Copper Omadine from 

Interswift 655 (Code Number BMA004) Dark Red in Synthetic Seawater. 

Project Number: 2617/IP. Unpublished study prepared by T.R. Wilbury 

Laboratories, Inc. 44 p.

46105309 Boeri, R.; Rondon, C.; Ward, T. (2003) Leach Rate of Copper Omadine from 

Interswift 655 (Code Number BMA008) Brown in Synthetic Seawater. 

Project Number: 2618/IP. Unpublished study prepared by T.R. Wilbury 

Laboratories, Inc. 44 p.

47107709 Boeri, R.; Rondon, C.; Ward, T. (2003) Leach Rate of Copper Omadine from 

Interswift 655 (Code Number BMA004) Dark Red in Synthetic Seawater. 

Project Number: 2617/IP. Unpublished study prepared by T.R. Wilbury 

Laboratories, Inc. 44 p.

47107710 Boeri, R.; Rondon, C.; Ward, T. (2003) Leach Rate of Copper Omadine from 

Interswift 655 (Code Number BMA008) Brown in Synthetic Seawater. 

Project Number: 2618/IP. Unpublished study prepared by T.R. Wilbury 

Laboratories, Inc. 44 p.

Sign-off Date : 11/17/10

DP Barcode No. : D344371