INTERNATIONAL UNION
   OF PURE AND APPLIED
   CHEMISTRY
contact
maleic hydrazide
** maleic hydrazide acid ** MH ** Translations

Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home

GENERAL INFORMATION Click here for an explantaion of the general chemical status information
for maleic hydrazide

Description: A plant growth regulator used to suppress growth and to induce dormancy in some crops

Example pests controlled: Growth; Suckers; Sprout suppression

Example applications: Lawns; Amenity turf; Non-cropped areas; Fruit including citrus; Potatoes; Carrots; Onions, shallots & garlic; Tobacco; Ornamenial shrubs

Efficacy & activity: -

Availability status: Current

Introduction & key dates: after 1950

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Denmark/Belgium
Date inclusion expires 31/10/2032
EU Candidate for substitution (CfS) No
Listed in EU database Yes

Approved for use () or known to be used () in the following European countries: Click to access a note on the approvals information on this site

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also used in: Australia, USA

Chemical structure: Click here for further information on the general chemical status information used on this site
Isomerism -
Chemical formula C4H4N2O2
Canonical SMILES C1=CC(=O)NNC1=O
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) BGRDGMRNKXEXQD-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C4H4N2O2/c7-3-1-2-4(8)6-5-3/h1-2H,(H,5,7)(H,6,8)
Structure diagram/image available? Yes

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Plant growth regulator, Herbicide
Substance group Pyridazine
Minimum active substance purity 979 g/kg
Known relevant impurities EU dossier - Hydrazine <= 1 mg/kg
Substance origin Synthetic
Mode of action Suppresses sprout and bud growth, absorbed by leaves and roots and translocated.
CAS RN 123-33-1
Alternative/old CAS RN 10071-13-3
EC number 204-619-9
CIPAC number 310
US EPA chemical code 051501
PubChem CID 21954
Molecular mass (g mol-1) 112.1
PIN (Preferred Identification Name) -
IUPAC name 6-hydroxy-2H-pyridazin-3-one
CAS name 1,2-dihydro-3,6-pyridazinedione
Other status information Chemical subject to PIC regulations
Relevant Environmental Water Quality Standards -
Herbicide Resistance Classification (HRAC) Not known
Herbicide Resistance Classification (WSSA) -
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance -
Physical state White crystalline solid
Related substances & organisms -

Formulations:
Property Click here for information on the general product and branding information used on this site Value
Example manufacturers & suppliers of products using this active now or historically
  • Bayer CropScience
  • Dow AgroSciences
  • Nufarm UK
  • Vitax Ltd
Example products using this active
  • Fazor
  • Source II
  • Retard
  • Sprout Stop
  • Sucker Stuff
UK LERAP status None
Formulation and application details Usually supplied in liquid formulations.


ENVIRONMENTAL FATE

for maleic hydrazide

Property Click here for information on the parameters used to describe environmental fate on this site Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with fate data Interpretation Click here for information on the way in which we interpret environmental fate data
Solubility - In water at 20oC (mg l-1) 156000 A5 High
Solubility - In organic solvents at 20oC (mg l-1) 4200 A5 - Methanol -
1 A5 - Toluene -
1 A5 - Hexane -
35.9 A5 - Ethyl acetate -
Melting point (oC) 298 A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 310 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 1.48 X 10-02 Calculated -
Log P -1.83 A5 Low
Bulk density (g ml-1)/Specific gravity 1.61 A5 -
Dissociation constant (pKa) at 25oC 5.64 A5 -
Note: Weak acid
Vapour pressure at 20oC (mPa) 3.1 X 10-03 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 4.05 X 10-08 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index -0.25 Calculated Low leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Click here for a note on the limitations of the SCI-GROW index Value 7.90 X 10-04 Calculated -
Note -
Potential for particle bound transport index Click here for a note on the limitations of the potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 Neutral solution: 326nm = 2444, and 217nm = 16816; [Acidic solution: 306nm = 2376 and 223nm = 8052; [Basic solution: 328nm = 2462 and 217nm = 16241 A5 -
Surface tension (mN m-1) 56.5 A5 at 21 degC, 99.9% -

Degradation:
Property Click here for information on the parameters used to describe substance degradation Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with degradation data Interpretation Click here for information on the way in which we interpret substance degradation data
General biodegradability -
Soil degradation (days) (aerobic) DT50 (typical) 0.8 Click here to see a warning relating to modelling and this active substance A5 Non-persistent
DT50 (lab at 20oC) 0.8 A5 Non-persistent
DT50 (field) 3 A5 Non-persistent
DT90 (lab at 20oC) 5.5 A5 -
DT90 (field) 10.4 A5 -
DT50 modelling endpoint - - -
Note EU 2016 dossier field studies DT50 range 0.3-2.3 days, DT90 range 1.4-12.9, Soils=7 days; Other sources: DT50 30 days anaerobic (DW4)
Dissipation rate RL50 on plant matrix Value - - -
Note -
Dissipation rate RL50 on and in plant matrix Value - - -
Note -
Aqueous photolysis DT50 (days) at pH 7 Value Stable A5 -
Note pH sensitive: stable pH 5 to pH 7, DT50 ~34 days at pH 9
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable pH 3 to pH 9
Water-sediment DT50 (days) 186 A5 Slow
Water phase only DT50 (days) 106 A5 Stable

Soil adsorption and mobility:
Property Click here for information on the parameters used to describe substance adsorption and mobility Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with adsorption and mobility data Interpretation Click here for information on the way in which we interpret substance adsorption and mobility
Linear Kd 0.725 A5 Mobile
Koc 45.8
Notes and range EU 2016 dossier Kd range 0.2-1.7 mL/g, Koc range 14.5-124.3 mL/g; Other sources: 250 mL/g (DW3)
Freundlich Kf 0.48 A5 Mobile
Kfoc 28.16
1/n 0.912
Notes and range EU 2016 dossier Kf range 0.16-1.51 mL/g, Kfoc range 14.4-108.0, 1/n range 0.860-0.987, Soils=4
pH sensitivity No

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
maleic acid - Soil - -


ECOTOXICOLOGY

for maleic hydrazide

Property Click here for information on the parameters used to describe substance ecotoxicology Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with ecotoxicology data Interpretation Click here for information on the way in which we interpret substance ecotoxicology
Bio-concentration factor BCF (l kg-1) Low risk A5 Based on LogP < 3 Low potential
CT50 (days) - -
Mammals - Acute oral LD50 (mg kg-1) > 2000 A5 Rat Low
Mammals - Short term dietary NOEL (mg kg-1) > 25 A3 Dog High
(ppm diet) > 750 -
Birds - Acute LD50 (mg kg-1) 4640 A5 Anas platyrhynchos Low
Birds - Short term dietary (LC50/LD50) > 10000 mg kg feed-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) > 1000 A5 Salmo gairdneri Low
Fish - Chronic 21 day NOEC (mg l-1) - - -
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 107.7 J4 Daphnia magna Low
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 0.95 A5 Daphnia magna Moderate
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) - - -
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1) - - -
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l-1) - - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) - - -
Aquatic plants - Acute 7 day EC50, biomass (mg l-1) > 110 A5 Lemna gibba Low
Non-target plants - - -
- - -
Algae - Acute 72 hour EC50, growth (mg l-1) > 100 A5 Chlorella vulgaris Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) 20 Q2 Unknown species Low
Honeybees Contact acute 48 hour LD50 (μg bee-1) > 100 A5 Low
Oral acute 48 hour LD50 (μg bee-1) > 100 A5 Low
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) > 1000 A5 Low
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) - - -
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 - - -
% Effect 95 Mortality
Dose: 5 kg ha-1
A5 Aphidius rhopalosiphi
-
Other arthropod (2) LR50 g ha-1 - - -
% Effect 55 Mortality
Dose: 5 kg ha-1, 7days
A5 Typhlodromus pyri
-
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
A5
Dose: 5 kg ha-1
-
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for maleic hydrazide

General:
Property Click here for information on the parameters used to describe human health and protection issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with human health and protection data Interpretation Click here for information on the way in which we interpret human health and protection data
Threshold of Toxicological Concern (Cramer Class) Click here for a note on the limitations of the Cramer class High (class III) - -
Mammals - Acute oral LD50 (mg kg-1) > 2000 A5 Rat Low
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rabbit -
Mammals - Inhalation LC50 (mg l-1) > 3.2 A5 Rat (nose only) -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.25 A5 Rat, SF=100 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) None allocated A5 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.25 A4 Dog, 1 year, SF=100 -
Dermal penetration studies (%) 38 A5 -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public No unacceptable risks to bystanders identified
Occupational No unacceptable risks to operators or other workers identified
European MRLs Click here for the EU MRL pesticide database
Drinking Water Standards - - -
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant

Respiratory tract irritant Skin irritant Skin sensitiser Eye irritant Phototoxicant

General human health issues Potential liver toxicant
Possible mutagen
Ingestion might cause tremors and muscle spasms
IARC group 3 carcinogen

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found

Handling issues:
Property Click here for information on the parameters used to describe substance handling issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with data on handling issues Interpretation Click here for information on the way in which we interpret data on handling issues
General Click here for a description of the International Maritime Dangerous Goods (IMDG) codes IMDG Transport Code is usually 9
Not explosive or oxidising
CLP classification 2013 Health: H315, H319, H341, H335
EC Risk Classification Click here to view information omn the EU risk phrases Xi - Irritant: R36/37/38
EC Safety Classification Click here to view information omn the EU safety phrases S26, S36
WHO Classification U - Unlikely to present an acute hazard
US EPA Classification (formulation) III - Caution - Slightly toxic
UN Number Usually 3077
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group III (minor danger)


TRANSLATIONS

for maleic hydrazide

Language Name
English maleic hydrazide
French hydrazide maleique
German Maleinhydrazid
Danish maleinhydrazid
Italian idrazide maleica
Spanish hidrazida maleica
Greek -
Slovenian malein-hidrazid
Polish hydrazyd maleinowy
Swedish maleinhydrazid
Hungarian maleic hydrazide
Dutch maleine hydrazide

Record last updated: Wednesday 31 October 2018
Contact: aeru@herts.ac.uk
© University of Hertfordshire