OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION **UNITED ST AT**  **ES ENVIRONMENT AL**  **PROTECTION A GENCY** 

WA SHINGTON, D.C. 20460

September 2 6 , 2013 **MEMORANDUM Subject:**  Human Health and Ecological Risk Assessment of the Proposed Registration of

the New Active Ingredient Ammonium Carbamate as Spectrum XD 1878 to Produce Monochloroamine for Pulp and Paper Mills and Recirculating Cooling Sy stems PC Code(s): 000374 DP Barcode(s)/No(s ): 4 12666 Decision No.: 474381 Registration Number (s): 74655

- GU Petition No(s).: NA Regulatory Action: Product Registration

– Section 3 Risk Assess Ty

pe: Single Chemical Case No(s): NA TXR No.: NA CAS No(s): 1111

- 78

- 0 MRID No(s).: NA 40 CFR: NA
**From:** Timothy

C. Dole , Industrial Hygienist William Erickson, Biologist Jenny Tao , Toxicologist Najm Shamim, Chemist Risk Assessment Science Support Branch (RASSB) Antimicrobials Division (AD) (7510P)
**Thru:** Timothy

L eighton, Senior Scientist Donna Randall, Senior Scientist Steven Weiss, Branch Chief Laura Parsons, Acting Associate Branch Chief Risk Assessment Science Support Branch (RASSB) Antimicrobials Division (AD) (7510P)
**To:** Velma Noble , Product Manager , Team 3 1

Melba Morrow , VM Officer/Special Assistant John Hebert, Acting Branch Chief Regulatory

Management Branch I Antimicrobials Division (7510P)

The Agency ha s assessed the human health and ecological risk s for the proposed registration of ammonium carbamate as a new active ingredient to produce monochloramine to treat pulp and paper mills and re

- circulating cooling water sy stems

. T here are no risks of concern for either ammonium carbamate or monochloroamine provided that the label instructions are followed.2

**BACKGROUND** Ashland Inc. has requested to register Spectrum XD1878 (EPA Reg. No 74655

- GU) containing 19.5 % ammonium carbamate . This product is proposed for use as a slimicide in paper and paperboard water s ys tems and in re

- circulating cooling water s ys tems . This product is to be mixed in situ (on site) with sodium hy pochlorite to produce chloramine. The application rate is expressed as a residual in terms of tota l chlorine and is 0.5 to 10 ppm for paper mills and 0.3 to 5.0 ppm for re

- circulating cooling water s ys tems. **HUMAN HEALTH HAZARD CHARACTERIZATION**  Acute Toxicity Ammonium carbamate is of low acute oral toxicity (i.e. Tox icity Category III) based on an LD 50 of 1080 mg/kg in the rat and is of low dermal toxicity ( Toxicity Category IV) based on a LD 50 of >5000 mg/kg in the rat. It is a severe eye irritant ( Toxicity Category I) based on the primary eye irritation study

in rabbits and it is not a dermal irritant ( Toxicity Category IV) based on the primary dermal irritation study

in rabbits. It is not a dermal sensitizer based on the local ly mph node assay

in mice. The requirement for the acute inhalation study was waived. Repeat Dose Toxicity Ammonium carbamate is of low toxicity

. Ammonium carbamate is in equilibrium with ammonium bicarbonate and ammonium carbonate in aqueous solution at neutral pH. Ammonium carbonate and bicarbonate are used in baking powder formulations, cooling baths and smelling salt s
. **HUMAN EXPOSUR** **E AND RISK ASSESSMENT** Occupational Exposures The registrant’s proposed label and supporting information in MRID 49042918 indicate that the risks for worker exposure are not of concern. As indicated on the proposed label, ammonium carbamate will be mixed with sodium hy pochlorite in a speciall y designed reactor to produce monochloramine onsite. The supporting information indicates that ammonium carbamate is transferred from the shipping container to the reactor via a closed s ys tem and therefore worker exposure to ammonium carbamate is not anticipated. Itis also understood that the reaction will be optimized to produce monochloramine, which is non

- volatile, while preventing the production of unwanted b yproducts , such as trichloro amine , which is volatile and toxic. Residential Exposure No residential exposure scenarios are associated with the proposed use s of ammonium carbamate

.3

Dietary and Drinking Water Exposures
N o dietary (food) risks are expected to be associated with the proposed uses

. The only potentially

toxic compound resulting in the water sy stem from the uses of ammonium carbamate is mono chloramine , however, any mono chloramine not consumed in the water s ys tem is e xpected to degrade under the high temperature conditions of the paper drying process (110° C) and it is not expected to remain in the paper to migrate to food.
N o drinking water risks are expected from the proposed uses of ammonium carbamate

. Very low l evels of mono chloramine may survive to the point of discharge. EPA has established a maximum residual disinfectant level (MRDL) of 4.0 ppm for chlorine (which includes chlorine from mono chloramine ) and water utilities are required to maintain chlorine at or below this MRDL

. Because the m aximum application rate s ( 10 ppm for paper mills and 5 ppm for recirculating cooling s ys tem s ) are onl y marginall y above the MRDL and the fact that most of the monochloroamine will be consumed during the treatment process, it is highly unlikel y that drinking water exposures to mono chloramine will result in risks of concern. Aggregate Exposures As there are no dietary

(food or drinking water) or residential exposures associated with the proposed uses of ammonium carbamate , there is no need to estimate aggregate exposures based on the proposed uses.
**CUMULATIVE RISK** EPA does not have, at this time, available data to determine whether ammonium carbamate has a common mechanism of toxicity with other substances or how to include this pesticide in a cumulative risk assessment. This chemical is of low sy stemic toxicity and no adverse effects on human health are expected , other than eye irritation from acute exposure. For the purposes of this Section 3 registration action ; ther efore, EPA has assumed that ammonium carbamate does not have a common mechanism of toxicity with other substances largel y because it elicits no adverse effects in mammals.

**ENVIRONMENTAL FATE AND EXPOSURE**  Ammonium Carbamate Ammonium carbamate is highl y water soluble, and as soon as it is dissolved into water it converts into ammonium carbonate, which is like other ammonium salts: water soluble, and the chemistry and fate of such chemicals is due to ammonia/ammonium ions. Routine ammonium carbamate (or ammonium carbonate) releases or discharges to the environment are not anticipated for the proposed uses because the product is mixed with sodium hy pochlorite a closed sy stem to produce monochloramine. Releases or discharges wou ld only occur as a result of a s ys tem failure or spill and such situations are covered b y the precautionary statements on the product label.4

Monochloroamine Monochloramine exposures to the environment are not of concern for the proposed pulp and paper mill use because of the phy sical/chemical characteristics of monochloroamine (short hydrol yt ic half life and readily biodegradable) and the characteristic of the paper mill process (high organic content of paper mill waste water and the holding time of wastes prior to an y discharge to surface water)

. Monochloramine exposures are not of concern for the proposed recirculating cooling water uses because the proposed label contains the statement that residual monochloroamine must be neutralized so that discharge s not exceed the EPA Office of Water Ambient Water Quality Criteria of 2 ppb for fresh water and 3 ppb for salt water. Summary of Environmental Fate and Exposure As discussed above, no exposure is likely due to ammonium ions, or carbamate, or monochloramine in the environmental media. **ECOLOGICAL EFFECTS AND RISK ASSESSMENT** As discussed above, ammonium carbamate is handled in a closed s ys tem and exposures are onl y anticipated in the event of a s ys tem failure or spill. Inaddition , discharges of monoch lor amine are expected be minimal based on the fate of monochloroamine in paper mill systems and on the label discharge requirements for recirculating cooling water s ys tems. Therefore, the risks to non - target organisms are not of concern

. **ENDOCRINE DISRUPTION**  As required under FFDCA section 408(p), EPA has developed the Endocrine Disrupter Screening Program (EDSP) to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife simil ar to an effect produced b y a "naturall y occurring estrogen, or other such endocrine effects as the Administrator may designate." The EDSP employ s a two

- tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assay s to identify the potential of a chemical substance to interact with the estrogen, androgen, or th yroid (E, A, or T) hormonal s ys tems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal s ys tems will proceed to the next stage of the EDSP where EPA will determine which, if an y, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify an y adverse endocrine related effects caused b y the substance, and establish a dose

- response relationship between the dose and the E, A, or T effect. Between October 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingredi ents and 9 inert ingredients. This list of chemicals was selected based on the potential for human exposure through pathway s such as food and water, residential activity , and certain postapplication agricultural scenarios. This list should not be constru ed as a list of known or likely endocrine disrupters.5

Ammonium carbamate is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide chemicals. Accordingl y, EPA anticipates issuing future EDSP test orders/data call

- ins for all pesticide active ingredients. For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery , please visit our website: http://www.epa.gov/endo/.