United States Office of Pestlcidei end Toxic Subrtanen
Environmental Protection Office of Potlddc Programs (TS-766C)
Agency Washington, DC 20460
v°/EPA Pesticide
Fact Sheet
Name of Chemical: NITOAPYRIN
Reason for Issuance:
Date Issued: June 28,1985
Fact Sheet Number: 54
1. Description of chemical
Generic Name: 2-Ghloro-6-(trlchloranethyl)pyrldlne
Cannon name: Nltrapyrin
Trade name: N-Serve
EPA Shaughnessy code: 069203
Chemical Abstracts Service (CAS) number: 1929-82-4
Year of Initial registration: 1974
Pesticide type: Bacterlostat
Chemical family: Pyrldlnes
U.S. and foreign producers: Dow Chemical Company
2. Use patterns and formulations
Application sites: Nltrapyrln Is registered for use as a nitrogen
stabilizer In com, cotton, rice, sorghum, strawberries, and wheat
Types of formulations: Etaulslflable concentrate and soluble concentrate
Types and methods of application: Broadcast or band with soil Injection
or Incorporation during or Immediately after application
Application rates: 0.25 Ib al/A to 1.0 Ib al/A
Usual carrier: Water and/or fertilizer
3. Science findings
Summary science statement: The existing data base Is Insufficient to
fully assess the toxicology, residue chemistry, environmental fate or
ecological effects of nltrapyrln. Previous toxlclty testing had been
conducted using the major metabolite 6-chloroplcollnlc acid and In most
areas, previous testing was found, upon revaluation, to be supplementary
or invalid according to current testing guidelines.
Chemical characteristics:
Nitrapyrln is a white crystalline solid with a mildly sweet odor.
The melting point Is 62-63°C. The vapor pressure of nltrapyrln Is
2.8 x 10-3 ran Hg at 23 C and its solubility Is 0.004 grams (g)/100 g
in water.
Toxicologies! characteristics:
Acute Toxicology:
Nltrapyrin has moderate oral toxiclty (Toxicity Category HI) and is
a moderate dermal Irritant (Toxicity Category III).
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Chronic !Ibxicology:
Chronic feedirg/aicogenicity, teratogenicity and reproduction testing
uair€ riltrapyrin AI have been identified as data gaps. Previous
chronic testing .s conducted using 6—chloropicolinic acid (6-CPA),
a major metabolite which was initially identified as the residue of
concern. A chronic feeding/oncogenicity study in the rat using 6—CPA,
aitbough considered supplementary data, indicated (upon reevaluation)
si ificant canpound related microscopic char€es (biliary hyperplasia)
occurred in f nA 1e rat livers at all doses tested.
Nitrapyrin did not demonstrate an increase in unscheduled rat
hepatocyte DNA synthesis and i s not genotoxic in ixnitageniclty tests.
Gene mutation (Ames) and chra2loscfnal aberration tests are data gaps.
Physiological a ix! biochemical behavioral characteristics:
Mechaniem of Action:
Nitrapyrin is an aninoniacal nitrogen stabilizer which inhibits the
nitriflcation of amoniacal and urea nitrogen fertilizer in the soil
by selectively a id temporarily, inhibiting Nitrosanonas . These
bacteria convert amoniuzn nitrogen to nitrite nitrogen, which in turn
is converted to nitrate nitrogen by other bacteria, e.g., Nitrobacter.
Environnenta]. characterlsitics:
Degradation:
Preliminary data indicate that hydrolysis of nitrapyrin is rapid, the
rate increasing with increasing temperature. It is not affected by pH
aid degrades more rapidly in the light than in the dark.
Persistence:
In soil, nitrapyrin has a half life of < 3 to 35 days, depending
on soil type.
Bloac cumulation:
Nitrapyrin accunni1 tes in the edible aid visceral tissues of bluegill
sunfish with maxlmtun bioconcent ration factors of 33 x and 60 x, respec-
tively. The residues depurate rapidly.
Ecological Characteristics:
Avian 8tudies:
Acute oral (Mallard duck)>2708 xr /kg (slightly toxic).
Avian dietary (Japanese quail) >820 ppm (slightly toxic)
Aquatic species studies:
t phnia magia 8—hour acute Is 5.8 n /l (moderately toxic).
Bluegill sunfish 96—hour acute is 7.876 mg/i (moderately toxic).
Rainbow trout 96—bour acute is 9.191 i Jl (moderately toxic).
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Potential prob1 na for endangered species:
Based on an estimated envirorinental concentration ( C) of 0.1 p n
in water (due to z,inoff), the expected hazard to aquatic organ-
isms is expected to be minimal. However, use in rice, although
estimated to be negligible, me y result in an C in floodwater of
0. 4 ppn. This level may impact on endangered or threatened species,
such as the Fat Pocketbook Pearly Mussel, which 18 bott d ller,
and as such would be exposed to nitrapyrin in the both the water
and sediments • The aquatic invertebrate toxicity test data are not
appropriate in assessing hazard to bivalves. Therefore, marine
n llusc shell deposition testing is required. For nal consultation
with the Office of Endangered Species, USFWS, will be considered
after these data are received arid evaluated.
Tolerance assessment8:
U.S. tolerances for residues of nitrapyrin [ 2—chloro—6—(trichloranethyl)
pyridine] and Its inetabolite, 6-chloroplcolinic acid in or on
raw agricultural ca nodities are as follows [ Z 0 CFR h80.350]:
Caiinodlties Tolerance (pm)
Cattle, fat 0.05
Cattle, mbyp 0.05
Cattle, meat 0.05
Corn, fodder 1.0
Corn, forage 1.0
Corn, grain 0.1
Corn, fresh 0.1
Cottonseed 1.0
Goats, fat 0.05
Goats, inbyp 0.05
Goats, meat 0.05
Hogs, fat 0.05
Hogs, yp 0.05
Hogs, meat 0.05
Horses, fat 0.05
Horses, mbyp 0.05
Horses, meat 0.05
Poultry, fat 0.05
Poultry, mbyp 0.05
Poultry, meat 0.05
Rice, grai.n 0.2
Rice, straw 2.0
Sheep, fat 0.05
Sheep, inbyp 0.05
Sheep, meat 0.05
Sorghtin, fodder 0.5
Sorglium, forage 0.1
Sorghum, grain 0.1
strawberries 0.2
Wheat, forage 0.5
Wheat, grain 0.1
Wheat, straw 0.5
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No mexican tolerances or Codex t’ Ls have been established for residues
of nltrapyrin. A Canadian tolerance of 0.1 ppm exists for, presumably,
residues of nitrapyrin per se in or on corn.
esidue studies are not adequate to support existing tolerances.
The plant arid animal metaboli&n of nitrapyrln are not adequately
understood and analytical methodolog.y may need to be revised
,then required data are evaluated. Storage stability data and
additional, more geographically representative residue data
are required for most calEodities.
Tolerances have been proposed for residues of nitrapyrin arid Its
metabolite, 6—CPA, in or on the crop group cereal grains;
lettuce; potatoes; soybeans and soybean forage and hay. The
Agency has decided, however, that no new tolerances or ex np-
tioris will be established until all major toxicology and residue
ch iiatry data requir nenta have been satisfied.
44• S rTn .ry of Regulatory Position and Rationale
Risk/benefit review: None of the risk criteria set forth in Title
140 Code of Federal Regulations S162.11 for caitnencing a special
review have been met or exceeded by nitrapyrin.
Growxl Water Potential: Nitrapyrin se has not been previ isly
identified as a potential ground water contaminant arid in moni-
toring studies conducted to date nitrapyrin residues have not
been found in ground water. However, one study using the 6-CPA
metabolite indicated a moderate potential for 6-CPA to leach in
loam soil. Therefore, envirorinental chamistry studies are being
required in the minimum times necessary to conduct the tests arid
will be evaluated on an expedited basis when received.
5. Sm iar’y of major data gaps and when these are due to be filled
6 Months:
Product identity and canposition
Physical and Che!nIcal characteristics
Avian subacute dietary and freshwater fish toxicity
Acute freshwater Invertebrate toxicity
9 Months:
H.ydrolys Is, photodegradat ion
Acute dermal and inhalation toxicity
Primary eye Irritation and dennal sensitization
Gene mutation (Ames)
12 ?bnths:
Preliminary analysis of’ product samples
Leaching and adsorpticn/desorPtion
Structural chranosr l aberration
Acute toxicity to estuarine and marine organisms
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15 Months:
Teratolog i (2 species)
18 Months:
Animal metabolism and residues
214 Months:
Plant metabo].isrn
Storage stability
Analytical methods and stability of residues under storage
Crop residue studies for corn, sorgjiurn, strawberries,
wheat and cottonseed
General metabolism
27 Months:
Aerobic aquatic metaboli i
Field dissiçation (soil) and di.ssipation aquatic (sediment)
39 Months:
Rotational, crops (confined)
Irrigated crops
Reproduction (2—generation)
50 Months:
Chronic feeding (2 species)
Oncogenicity (2 species)
Rotational crops (field)
6. Contact person at EPA
Richard P. Mountfort
Product Manager (23)
&ivirorinental Protection Agency (TS—767C)
1401 M Street, S’vI
Washington, DC 201460
(703) 557—1830
DISCLAIM : The information presented in this Ch iica.l Information Fact
Sheet is for informational purposes only and m&y not be used
to fulfill data requirenents for pesticide registration and
reregistratial.
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