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Proposition 65

Notice of Intent to List: Atrazine, Propazine, Simazine and their Chlorometabolites DACT, DEA and DIA
[02/07/14]

Comment period extended 03/14/14

Comments posted 04/02/15

The California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) intends to list the chemicals identified in the table below as known to the State to cause reproductive toxicity under the Safe Drinking Water and Toxic Enforcement Act of 1986.1 This action is being proposed under the authoritative bodies listing mechanism.2

Chemical

CAS No.

References

Chemical Use

Endpoints

Atrazine

1912-24-9

U.S. EPA (2002a; 2006 a,b)

Herbicides used to control broadleaf and grassy weeds on corn (field and sweet), guavas, macadamia nuts, sorghum, sugar cane and range grasses. Simazine is used extensively on grapes and tree fruits, especially citrus

Developmental toxicity

Female reproductive toxicity

Propazine

139-40-2

U.S. EPA (2002a; 2005; 2006 a,b,c)

Simazine

122-34-9

U.S. EPA (2002a; 2006 a,b,d)

DACT (G-28273; 2,3-diamino-6-chloro-s-triazine)

3397-62-4

U.S. EPA (2002a,b; 2005; 2006 a,b,c,d)

Environmental breakdown product of propazine, simazine and atrazine

DEA (G-30033; des-ethyl atrazine)

6190-65-4

U.S. EPA (2002a; 2005; 2006 a,b,c)

Environmental breakdown product of propazine and atrazine

DIA (G-28279; des-isopropyl atrazine)

1007-28-9

U.S. EPA (2002a; 2006 a,b,d)

Environmental breakdown product of simazine and atrazine

Background on listing via the authoritative bodies mechanism: A chemical must be listed under Proposition 653 and its implementing regulations when two conditions are met:

  1. An authoritative body formally identifies the chemical as causing reproductive toxicity (Section 25306(d)4).
  2. The evidence considered by the authoritative body meets the sufficiency criteria contained in the regulations (Section 25306(g)).

However, the chemical is not listed if scientifically valid data which were not considered by the authoritative body clearly establish that the sufficiency of evidence criteria were not met (Section 25306(h)).

The U.S. Environmental Protection Agency (U.S. EPA) is one of several institutions designated as authoritative for the identification of chemicals as causing reproductive toxicity (Section 25306(l)).

OEHHA is the lead agency for Proposition 65 implementation. After an authoritative body has made a determination about a chemical, OEHHA evaluates whether listing under Proposition 65 is required using the criteria contained in the regulations.

OEHHA’s determination: Atrazine, propazine, simazine and their chlorometabolites 2,3-diamino-6-chloro-s-triazine (DACT), des-ethyl atrazine (DEA), and des-isopropyl atrazine (DIA) meet the criteria for listing as known to the State to cause reproductive toxicity under Proposition 65, based on findings of the U.S. EPA (2002a, 2002b, 2005, 2006a, 2006b, 2006c, 2006d), as outlined below.

Formal identification and sufficiency of evidence: OEHHA is relying on the U.S. EPA’s conclusion that the triazine pesticides atrazine, propazine, simazine and their chlorometabolites DACT, DEA, and DIA cause developmental and reproductive effects through a common mechanism of toxic action. This conclusion meets the requirements of Section 26306(d)(1)5 and is made in a number of U.S. EPA documents, including:

In addition, U.S. EPA established several reference doses (RfDs) on the basis of reproductive and developmental toxicity, relying on endpoints that included luteinizing hormone (LH) surge suppression and estrous cycle alterations and delayed ossification of certain cranial bones in fetuses. This also meets the requirements of Section 26306(d)(1)6.

Thus, the findings and regulatory actions in these documents satisfy the formal identification and sufficiency of evidence criteria in the Proposition 65 regulations for listing these chemicals.

In several reports, U.S. EPA concluded that these three triazines and their chlorinated metabolites (DACT, DEA, DIA) cause developmental and reproductive toxicity and that these toxic effects are mediated through a common mechanism of action involving disruption of the hypothalamic-pituitary-gonadal (HPG) axis and suppression of luteinizing hormone (LH) surge. The conclusions in the U.S. EPA reports include the following:

Triazine Cumulative Risk Assessment (U.S. EPA, 2006b):

“Neuroendocrine effects are considered the critical endpoints for assessing the health effects of the CMG Triazines. The CMG triazines have been shown to lead to various endocrine-related changes as a result of an effect on the hypothalamic-pituitary-gonadal axis. The consequences of this action include a diminishment of hypothalamic gonadotrophin releasing hormone (GnRH) and norepinephrine levels. These triazines also increase dopamine level which can result in a diminished pituitary secretion of PRL [prolactin]. Therefore, the CMG triazines operate at the level of the hypothalamus. In both humans and rats, hypothalamic GnRH controls pituitary hormone secretion (e.g., luteinizing hormone and PRL).

The hypothalamic-pituitary axis is involved in the development of the reproductive system, and its maintenance and functioning in adulthood. Additionally, reproductive hormones modulate the function of numerous other metabolic processes (i.e., bone formation, and immune, central nervous system, and cardiovascular functions). Therefore, altered hypothalamic-pituitary function can potentially broadly affect an individual’s functional status and lead to a variety of health consequences.” (p. 22)

Interim Reregistration Eligibility Decision for Atrazine (U.S. EPA, 2006a):

Reregistration Eligibility Decision Document for Simazine (U.S. EPA, 2006d):

Report of the FQPA TRED for Propazine (U.S. EPA 2006c):

Propazine: Revised HED Risk Assessment for the TRED (U.S. EPA, 2005):

Therefore, for endpoint selection, the team considered atrazine endocrine-related data for selection of endpoints for propazine. Atrazine’s neuroendocrine-related endpoints were selected for all risk assessment scenarios for propazine, except for the acute reference dose which was based on a study conducted with propazine which found developmental effect (incomplete ossification), the nature of which is not clearly linked to an endocrine mechanism.” (pp. 17-18)

OEHHA has reviewed the studies or study descriptions cited by the U.S. EPA (2002a,b, 2005, 2006a,b,c,d) as providing the basis for the Agency’s conclusions regarding the reproductive and developmental toxicity relative to the criteria in Section 25306(g). The criteria for listing atrazine, propazine, simazine and their chlorometabolites DACT, DEA, and DIA through the authoritative bodies mechanism as causing reproductive toxicity (female reproductive and developmental endpoints) have been met.

Request for comments: OEHHA is requesting comments as to whether these chemicals meet the criteria set forth in the Proposition 65 regulations for authoritative bodies listings.

In order to be considered, comments must be received by OEHHA by 5:00 p.m. on Monday, March 24, 2014 Monday, March 10, 2014. We encourage you to submit comments in electronic form, rather than in paper form. Comments transmitted by e-mail should be addressed to P65Public.Comments@oehha.ca.gov with “NOIL - triazines” in the subject line. Comments submitted in paper form may be mailed, faxed, or delivered in person to the addresses below:

Mailing Address: Sam Delson
Office of Environmental Health Hazard Assessment
P.O. Box 4010, MS-19B
Sacramento, California 95812-4010
Fax: (916) 323-2265
Street Address: 1001 I Street
Sacramento, California 95814

Comments received during the public comment period will be posted on the OEHHA web site after the close of the comment period.

If you have any questions, please contact Sam Delson at sam.delson@oehha.ca.gov or at (916) 445-6900.

References

U.S. Environmental Protection Agency (U.S. EPA, 2002a). Atrazine (PC Code: 080803). Toxicology Disciplinary Chapter for the Reregistration Eligibility Decision Document (Second Revision). April 11, 2002.

U.S. Environmental Protection Agency (U.S. EPA, 2002b). Office of Pesticide Programs. Special Docket for Pesticide Reregistration Risk Assessments. Memorandum on ATRAZINE/DACT - Fourth Report of the Hazard Identification Assessment Review Committee. TXR NO. 0050592.

U.S. Environmental Protection Agency (U.S. EPA, 2005). Propazine: Revised HED Risk Assessment for the Tolerance Reassessment Eligibility Decision (TRED) which includes a New Use on Grain Sorghum. PC Code: 080808, DP Barcode: D323271 Memorandum from J. Morales et al. Office of Pesticide Programs and Toxic Substances (OPPTS) Health Effects Division to D. Sherman OPPTS, December 13, 2005.

U.S. Environmental Protection Agency (U.S. EPA, 2006a). Decision Documents for Atrazine. U.S. EPA Office of Prevention, Pesticides and Toxic Substances. Available at http://www.epa.gov/pesticides/reregistration/REDs/atrazine_combined_docs.pdf.

U.S. Environmental Protection Agency (U.S. EPA, 2006b). Triazine Cumulative Risk Assessment (March 28, 2006). Available at http://www.epa.gov/pesticides/cumulative/common_mech_groups.htm#triazine.

U.S. Environmental Protection Agency (U.S. EPA, 2006c). Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment Progress and Risk Management Decision (TRED) for Propazine. U.S. EPA Office of Prevention, Pesticides and Toxic Substances, EPA 738-R-06-009. Available at http://www.epa.gov/opp00001/reregistration/status_page_p.htm.

U.S. Environmental Protection Agency (U.S. EPA, 2006d). Reregistration Eligibility Decision Document for Simazine. U.S. EPA Office of Prevention, Pesticides and Toxic Substances. EPA 738-R-06-008. Available at http://www.epa.gov/opp00001/reregistration/status_page_s.htm

1 Commonly known as Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986 is codified in Health and Safety Code section 25249.5 et seq.

2 See Health and Safety Code section 25249.8(b) and Title 27, Cal. Code of Regs., section 25306.

3 Health and Safety Code section 25249.8(b).

4 All referenced sections are from Title 27 of the Cal. Code of Regulations.

5 “the chemical … is the subject of a report which is published by the authoritative body and which concludes that the chemical causes … reproductive toxicity”.

6 “the chemical … has otherwise been identified as causing … reproductive toxicity by the authoritative body in a document that indicates that such identification is a final action”.

Index of the Notice of Intent to List Comments Received on Atrazine, Propazine, Simazine and their Chlorometabolites DACT, DEA, and DIA
[04/02/14]

No.

Commenter

Chemical (pages)

1

Pinky Kushner
 

Atrazine (1 page)

2

Francesca Mariani
 

Atrazine, propazine, simazine and their chlorometabolites DACT DEA, DIA (1 page)

3

Tina E. Levine, Ph.D.
Toxicologist

Triazine compounds (3 pages)

4

James C. Lamb, IV, Ph.D.
Exponent
Principal Scientist and Center Director  

Atrazine (8 pages)

5

Gary Burin, Ph.D., MPH, DABT
Senior Managing Toxicologist
Technology Sciences Group, Inc.

Atrazine (3 pages)

6

Debra Edwards, Ph.D.
Pesticide Regulatory Consultant

Atrazine, simazine, propazine and certain of their chlorometabolites
(5 pages)

7

Edwin F. (Rick) Tinsworth
Exponent
Principal and Director

Atrazine, simazine, propazine and their associated chlorometabolites
(5 pages)

8

John R. Fowle III, Ph.D., DABT
Principal
Science to Inform, LLC

Atrazine, simazine, propazine and certain of their chlorometabolites
(2 pages)

9

Christian Volz
Stanley W. Landfair
McKenna Long & Aldridge LLC
For Syngenta Crop Protection LLC

Atrazine, propazine, simazine and their chlorometabolites DACT DEA, DIA (8 page letter and
101 pages of attachments)

 

 
 
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