UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, DC 20460

OFFICE OF  PREVENTION, PESTICIDES,  AND TOXIC SUBSTANCES

 

March 30, 2007

MEMORANDUM:

Subject: 	Environmental Fate Assessment of Octhilinone.      

                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                               

From:	A. Najm Shamim, Ph.D., Chemist

			Regulatory Management Branch II

			Antimicrobials Division (7510P)

To:	Diane Isbell, Acting Team Leader and CRM,

			Regulatory Management Branch II

			Antimicrobials Division (7510P)

	

			Talia Lindheimer, Risk Assessor

			Risk Assessment and Science Support Branch

			Antimicrobials Division (7510P)

		

Thru:	Talia Lindheimer, Risk Assessor/Chemist,

			Antimicrobials Division (7510P)

				And

			Mark Hartman, Chief

			Regulatory Management Branch II

			Antimicrobials Division (7510P)

DP Barcode: 		

Chemical Name:        2-n-Octyl-4-isothiazolin-3-one (Octhilinone or
OIT)	

		

PC Code:		099901 

CAS Registry No.      26530-20-1

ENVIRONMENTAL FATE SCIENCE CHAPTER ON: OCTHILINONE

EXECUTIVE SUMMARY:

Octhilinone is stable and persistent in water under abiotic conditions
with a half life of > 30 days. Soil migration study showed that it is
not likely to migrate from  soil surface. It also does not show a
tendency to run-off with water. The estimated KOC of 2120 indicates it
is likely to bind with soils strongly. With little tendency to migrate
and strong soil bindings, it remains on the surface soils  and  may
contaminate surface water. Its degradation pathway appears to be through
biodegradation in microbial soils as it biodegrade at the top soils
under aerobic and anaerobic condition in less than 120 days.

It is not likely to persist in air with an estimated half life of 3.26
hours, and is not likely to bioaccumulate  in aquatic organisms.

  The Agency has used  DOWN-THE-DRAIN Model to estimate the EECs for
this chemical for its uses as a wood preservative, in paints and in
metalworking fluids are:  CSM = 6 x 10-3 µg/L for the acute concerns
and  CSH = 7.8 x 10-2 µg/L for the chronic concerns.

APPENDIX TO OCTHILINONE ENVIRONMENTAL FATE SCIENCE CHAPTER

		A Summary of Environmental Fate Studies on OCTHILINONE

Hydrolysis Study of Octhilinone

MRID#: 447232-01

CAS#:	   26530-20-1

PC Code: 

Title of the Study: Final Report: [14 C]-Acticide -Octylisothiazolin
(OIT)

Study Author:  Dr. T. Lucas

Submitted by:  Acti-Chem Specialties Inc., 56 Quarry Rd., Trumbull, CT:
06611-4816

Performing Laboratory: Covance Laboratories GmbH, Kesselfeld 29, D-48163
Munster, Germany

Laboratory Report #: 1509-1154-069

Study completed: Nov.1998

A hydrolytic Stability study on radiocarbon labeled octhilinone was
conducted to satisfy the fate data requirements (Guidelines 161-1). The
study was conducted in accordance with the US EPA Good Laboratory
practice Regulations and it conformed with the EC Regulations 91/414/EC.

The study was conducted at pHs 5, 7, and 9 in sterilized and buffered
media. Sterilization was attained by  gamma radiation of the test media.
The radiolabeled carbon purity of the test sample was determined by 
techniques like HPLC  (97%).

The 30-day study was carried at 25 ± 1 o C in the dark.  Samples in
duplicates were analyzed at the intervals of day 1, 3, 7, 15 and 30.

Mean recoveries of the applied radioactivy of radiolabeled samples
ranged from 102.9%-106.6 (pH 5); 103.6-108.1 (pH 7); and 103.7-107.7 (pH
9).

The active was stable at the experimental pHs for duration of  30 days.

Octhilinone is, therefore, likely to be stable and persistent in water.

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: 23-71-4

Product Name: RH-893 (Octhilinone)

Type of Study: Action of  Radiocarbon Labeled RH-983 on the
Semi-contineous Activated Sludge

The report indicated that at pH 9, 37% of the active radiocarbon labeled
RH-893, under microbial conditions mineralized to 14CO2 in 31 days.  At
least 58% of the active and degradates remained as adsorbed material on
the sludge top.

Conclusion is that the RH-893  does not biodegradate or mineralize fast.

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: 23-72-3

Product Name: RH-893 (Octhilinone)

Type of Study: Leaching Radiocarbon labeled RH-893 (Octhilinone) From
Various Soils

	

Radiocarbon labeled RH-893 was investigated for leaching from various
soil types. Five Maryland soils (Hagerstown, MD) were selected for the
study. These were: sandy, silt loam, clay, clay loam, and silty clay
loam. 

Important physical
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Soil type↓

 parameter→	% OC	pH	% sand,     silt,        clay	Cation exchange
capacity

Sand	0.95	5	98	1.7

Silt loam	3.4	6.4	3.8             34             28	9.4

Clay	6.44	4.7	32             14             28	6.9

Clay loam	15.1	7.4	24            49             32	49.9

Silt clay loam	5.34	6.0	18            64            18	21.4



	Liquid Scintillating Counting (LSC) was used to measure the applied
radioactivity of the radiocarbon labeled samples adsorbed on the
different soils.

Results from the study showed that four out of five soils namely: silt
clay, clay, clay loam, and silt clay loam retained the RH-893 on the top
one inch of the soils while the sandy soil retained the active remaining
segments of the soil.

The study also showed that soils with higher organic carbon content
retained the active on the top one inch segment.

The study conclusions were that the RH-893 as the active is not mobile
in soils.

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: 3923-74-38

Product Name: RH-893 (Octhilinone)

Type of Study:  Soil Run-off Study ( A Laboratory Study)

	

	This lab study was conducted on a Drummer soil  placed on a 3 inch
sloping bed. Silt loam was the soil selected. (As shown in the table
above silt loam soil has the sand, silt and clay in a comparable ratios
with each other). Simulated rain was applied on day 1,3 and 7. run-off
water was collected and analyzed. Soil cores at the top 1, 2 and 3
inches were also analyzed.

Water run-off samples did not show the presence of the active in any
appreciable amounts.

Results from the soil cores showed that the RH-893 remained in the top
one inch and did not migrate into lower segments of the soil due to
water run-off.

It is concluded that RH-893 show no tendency of migrating or running-off
with water from surface to ground water

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: Number not readable

Product Name: RH-893 (Octhilinone)

Type of Study:	dissipation Study in Soil

This laboratory study was conducted on the radiocarbon labeled RH-893 on
silt loam sterilized and non-sterilized soil. The results indicated that
RH-893 did not degrade in sterilized soil (formation of radiocarbon
labeled carbon dioxide was negligible). On the contrary, the
non-sterilized soil (which likely contained microbes)    produced 39%
radiolabeled carbon dioxide after 41 days. This indicates that RH-893
does biodegrade although it is not a fast biodegradation. 

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: 3923-75-3

Product Name: RH-893 (Octhilinone)

Type of Study:	Laboratory leaching Study with Aged RH-893 Soil

	The study was conducted in a greenhouse setting.  A sandy loam soil was
impregnated with 1 ppm of radiolabeled RH-893 and placed in a
greenhouse. 30 days later a sample of this treated soil was layered over
 a column a 12 inch column of sandy loam soil and over a period of 45
days, this soil column was treated with ½ inch of water everyday.
Leaches were collected everyday and analyzed for the presence of
radioactivity. In addition, at the end of study period, soil column was
arbitrarily divided into 2 and three inch sections from the top, and
each section was radioassayed.

Aqueous  leachate samples did not show the presence of any
radioacitivity.

Top 2 inch soil column showed the presence of 69%  of the applied
radioactivity  while the next 3 inch column showed only 18%  of the
applied radioactivity. 

The results indicate that RH-893  has slight tendency to migrate into
soils and  is not likely to migrate into ground water.

The soil chosen for the study was Nixtonton Sandy loam which had: 71%
sand, silt: 22% and clay: 7%. It contained only 2.59% organic carbon,
and native pH of the soil was 5.5.

Technical Report Submitted by: Rohm & Haas Company

Tech Report #: 3923-75-11

Product Name: RH-893 (Octhilinone)

Type of Study:	 RH-893 Greenhouse Soil Metabolism Study

Long-term 270 day aerobic and anaerobic soil metabolism studies were
conducted to ascertain the possibility of biodegradation of RH-893 in
soils under greenhouse conditions. Sandy loam and silt loam soils were
chosen for the study. Sandy loom had the same characteristics as noted
in the previous study. Silt loam  soil had the following
characateristics: organic matter; 3.83%, sand: 13%; silt: 65%; clay:
22%. pH was 5.5

	The two soils were fortified with 1 ppm radiolabeled RH-893 in open
containers. Soils were occasionally moistened and stirred to make the
possible microbial exposure  uniform. The soils were frequently tested
for the applied radioactivity  and also for the rate of biodegradation,
if any. A sample of silt loam soil was  separated out after 30 day
period and  kept under anaerobic conditions to test for biodegradation
under anaerobic conditions for an additional 60 days.

	The radioassays showed that  applied radioactivity declined to 65% in
15 days and to 40% in 120 days for both soils. Extraction and
chromatographic results showed that only 15% of RH-893 remained after 15
days from the 33% extractable samples for both soils. The remaining
samples showed 60% major degradate and two minor (5%  each) degradates.

 It is concluded that RH-893 aerobically and anaerobically undergoes
dissipation quickly in the  two soils and biodegrades to less than 50%
within 120 days. The extractables biodegrade more than 70 % within the
120 day period.

8.	The Agency database like EPI Suite Program showed the following
important fate characteristics. These are estimated values but add to
the overall fate risk assessment.

Persistence in air:  Half life of 3.26 hours

LogKOW = 2.61

KOC = 2120

Total Removal in wastewater treatment facility: 2.97% (~ 3%)

9.	To calculate the time-averaged  surface water concentration of a
pesticide   which may be due to the household release ( disinfectant,
paint) to waste treatment water, tow major equations are used in the
Model Down-the Drain:

		

CSM = HR  x  [1/QH ]  x (1-WWT) x CFI			 Eq.1		

    ----------------------------------------- 								SDFM 

CSH   =  HR  x [1/QH]  x (1-WWT) x CFI   		Eq.2

		       ---------------------------------------

				SDFL	 	

Where  CSM   = median time-averaged surface water concentration  of a
pesticide (used for chronic scenario)

	        CSH  = High-end average surface water concentration  of a
pesticide (used for acute scenario)

HR  = Daily per capita release of a pesticide to a wastewater treatment
facility  ( g/person/day)

And

 HR  = Pd volume of a pesticide / Population x 1000 g / 1 kg x 1year /
365day 

										Eq. 3     

QH = Daily per capita wastewater  volume released = 364 L /person/day
(for US only)

 									 

(Pd volume = yearly volume of a pesticide produced (and used)

 Population:  US population: 2.727 x 108  persons (US Census Bureau,
1999)

WWT = Removal % of a pesticide in a wastewater treatment plant. Obtained
from the monitoring or measured values or from a modeling program like
US EPA’s EPI Suite.

SDFM   = 50th percentile stream dilution (50 %  mixing has taken place)
factor for streams to which wastewater facilities discharge ( 980.69,
estimated)

 SDFL = 10th percentile stream dilution (only 10% mixing has taken
place) factor fro streams to which wastewater facilities discharge
(75.44, estimated)

Note: SDFM  and SDFL  are the ratios of the volume of the receiving
stream or river under mean (average) flow conditions to the volume of
wastewater released from the treatment facility. SDFs have been
calculated for active wastewater treatment facilities and have been
reported in US EPA SORET Industrial Facility Database (IFD).

Known factors:

	

Factor	Value

 QH =   Daily per capita wastewater volume released	364 L

SDFM = 50th percentile stream dilution factor for streams to which
wastewater facilities discharge	980.69

SDFL = 10th percentile stream dilution factor for streams to which
wastewater facilities discharge	75.44

CFI = Conversion factor	1 x 106 µg /g



If the production volume is known , we can calculate the  HR and if  WWT
is known or its estimated value is known, then we can use Eq.1 for the
chronic scenario and Eq.2 for the acute scenario.

For Octhilinone or 2-octyl-siothiazolone or OIT,  the production volume 
for 2004  was obtained ( Diane Isbell, email Memo to A. Najm Shamim,
Feb.02, 2007). The  data source for the production volume is: Specialty
Biocides North America 2000, Kline & Co.

Total production volume in 2004 for OIT was 573, 000 lbs. Of this, for 
volume used for paints/ coatings/ metalworking fluids is 488,000 lbs per
year

Notes:1 ) For our present estimation, we assume that total volume
produced for paints/coatings/metalworking fluids were used and 100% of
this chemical ended up in the  receiving stream  or river.

To find HR use Eq.3

HR  = Pd volume of a pesticide / Population x 1000 g / 1 kg x 1year /
365day

	= 488,000 lbs x 0.454 kg/lbs / 2.727 x 108  persons x 1000 g/ 1 kg x 1
year / 365 days 

 	=  2.22 x10-3 g/person/day

To estimate, CSM and CSH , use equations 1, and 2.

WWT = 3% for Octhilinone  (source: US EPI Suite) 

Calculations:

				Table 2

Surface Water Conc.	Equation	 Results

CSM	 HR  x  [1/QH ]  x (1-WWT) x CFI			

  ---------------------------------------

SDFM 

	6 x 10-3 µg/L

CSH	  HR  x [1/QH]  x (1-WWT) x CFI   	

-------------------------------------------		       

		SDFL 			7.8 x 10-2 µg/L



These are the chronic (CSM) and acute ( CSH ) concentrations of
Octhilinone in surface water

Conclusions: 

	Except for the hydrolysis study which is conducted according to the OPP
guidelines, the remaining  studies were conducted in early to
mid-seventies. At that time, the OPP guidelines did not exist and  Rohm
& Haas developed their own protocols and conducted the  laboratory
studies and submitted the results to the Agency as Technical Reports.

These technical reports suffer from a number of drawbacks which make
these studies less robust. First, the studies were conducted under
non-GPL conditions and the results have not been checked for
consistency. Second, the number of samples for large studies  like
aerobic and anaerobic soil metabolism studies were not large enough for
a very good statistical analysis.

The hydrolysis study  fully satisfies the data requirements according to
the guidelines; the remaining studies, although scientifically
reasonably good, are upgradable and acceptable  and the Agency accept
these as supplemental.

OIT appears stable abiotically in water. It is not mobile in soils and
stays at the top soil surfaces and binds strongly with soils as KOC =
2120. The degradation path way appears to be through biodegradation in
soils  under aerobic and anaerobic conditions. It is not likely to be 
bioaccumualtive  in aquatic organisms like fish as the Log KOW is below
Agency’s level of concern. Its vapor pressure is not high; however,
once in vapor state, it is not likely not to be persistent in air as its
air half life is less than four hour.

The results from Down-the-Drain model  calculations have thier own
limitations. First, the model does not address the possibility of
degradation of the parent nor does it estimate the concentration of the
degradates. Second, It does not indicate what can be done to avoid the
contamination of the POWTs if the chemical remains in water and does not
biodegrade.

			BIBLIOGRAPHY

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葞֠摧庤9

C)-Acticie OIT), 1999, by Dr. T. Lucas MRID#: 447232-01. Submitted by: 
Acti-Chem Specialties Inc., 56 Quarry Rd., Trumbull, CT: 06611-4816.
Performing Laboratory: Covance Laboratories GmbH, Kesselfeld 29, D-48163
Munster, Germany. Laboratory Report #: 1509-1154-069

2.	Rohm& Haas Technical Reports on Environmental Fate Studies.
Reports#s: 23-71-4, 23-72-3, 3923-74-38,  3923-75-3, and 3923-75-11

3.	EPI SUITE (Version 3.12)

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