Potassium hydrogen phosphonate

Potassium hydrogen phosphonate	Last updated: 12/06/2024
(Also known as: monopotassium phosphite; monopotassium phosphonate)

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate	Ecotoxicity	Human health
Environmental fate High alert: Persistent; GUS: High leachability	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate	Human health Moderate alert: Reproduction/development effects

GENERAL INFORMATION

Description

An inorganic potassium salt that has fungicidal properties and used to control Pythium and Phytophthora on a variety of fruit and ornamental crops. It is usually used in a reaction mixture with dipotassium phosphonate.

Example pests controlled

Pythium spp.; Phytophthora spp. including root rot

Example applications

Fruit including avocados, apples, grapes; Ornamentals; Trees

Efficacy & activity

Appearance and life cycle

Availability status

Current

Introduction & key dates

1997, introduced USA

Taxonomic classification

UK regulatory status

UK COPR regulatory status

Approved (as potassium phosphonates)

Date COPR inclusion expires

30/09/2026

UK LERAP status

Crop over 5m - See Authorisation for Crop LERAP Details

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved (as potassium phosphonates)

Dossier rapporteur/co-rapporteur

France

Date EC 1107/2009 inclusion expires

31/01/2026

EU Candidate for substitution (CfS)

Listed in EU database

Yes

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece
✓	✓	✓	✓	✓	✓	✓	✓	✓
ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg
✓	✓	✓	✓	✓	✓		✓	✓
LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia
✓		✓	✓	✓	✓	✓	✓	✓

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway

Additional information

Known to be also used in the following countries

Australia

Chemical structure

Isomerism

None

Chemical formula

H₂KO₃P

Canonical SMILES

OP(O)[O-].[K+]

Isomeric SMILES

International Chemical Identifier key (InChIKey)

BZHCGFBZBPVRFE-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/K.H2O3P/c;1-4(2)3/h;1-2H/q+1;-1

2D structure diagram/image available?

Yes

General status

Biopesticide type

Fungicide

Substance groups

Inorganic compound

Minimum active substance purity

Known relevant impurities

Substance origin

Natural

Mode of action

Mixed mode of application including direct toxicity to plant pathogens reducing populations and promotion of plants natural defences

Substance source

Phosphonates occur naturally in biological cells

Substance production

There are various commercial production methods including; (1) from phosphonic acid, (2) using the Michaelis–Arbuzov reaction, and (3) from phosphorus trichloride

Uses

Crop protection

Target pests

Pythium spp.; Phytophthora spp. including root rot

Target host

Fruit including avocados, apples, grapes; Ornamentals; Trees

Farming system suitability

CAS RN

13977-65-6

EC number

604-162-9

CIPAC number

756

US EPA chemical code

076416

PubChem CID

23701737

CLP index number

No data found

Molecular mass

120.09

PIN (Preferred Identification Name)

IUPAC name

potassium hydrogen phosphonate

CAS name

potassium dihydrogen phosphite

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Examples of recorded resistance

Physical state

Deliquescent solid

Related substances & organisms

potassium phosphonates

disodium phosphonate

dipotassium phosphonate

Formulations

Property

Product

Manufacturer

Example products

Formulation and application details

Usually supplied as an aqueous solution with a variety of application methods used including foliar sprays, soil drenches and root dips

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

500000

High

Solubility - In organic solvents at 20 °C (mg l⁻¹)

Melting point (°C)

(as potassium phosphonates)

Boiling point (°C)

Decomposes before boiling

(as potassium phosphonates)

Degradation point (°C)

180

(as potassium phosphonates)

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

Not applicable

Log P

Not applicable

(as potassium phosphonates)

Not applicable

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.65

(as potassium phosphonates)

Dissociation constant pKa) at 25 °C

2.0

(as potassium phosphonates)

PKa(2) = 6.59

Vapour pressure at 20 °C (mPa)

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

142

(as potassium phosphonates)

Persistent

DT₅₀ (lab at 20 °C)

142

as phosphonic acid

Persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

381

as phosphonic acid

Very persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies for phosphonic acid DT₅₀ range 88-196 days, DT₉₀ range 319-442 days

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

10.7

as phosphonic acid

Moderately mobile

K_oc (mL g⁻¹)

453.6

Notes and range

EU dossier K_d range 3.1-18.96 mL g⁻¹, K_oc range 228-972 mL g⁻¹, Soils=5

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

phosphoric acid

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

> 1997

Unknown species Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2250

Colinus virginianus as phosphonic acid

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5620 mg kg feed⁻¹

Colinus virginianus as phosphonic acid

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

149.04

Colinus virginianus NOEC

Moderate

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 1000

Eisenia foetida as phosphonic acid

Low

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

182.5

Eisenia foetida as phosphonic acid

Low

Soil micro-organisms

Nitrogen mineralisation: Minor transient effects
Carbon mineralisation: Minor transient effects

Dose: up to 26.99 mg posphonic acid/kg soil 28 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 145

as potassium phosphonates

Low

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps) as % Mortality at dose 2.02 kg ha⁻¹

12.82

Aphidius rhopalosiphi as phosphonic acid

Beneficial insects (Predatory mites) as % Mortality at dose 2.02 kg ha⁻¹

10.8

Typhlodromus pyri as phosphonic acid

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 118

Oncorhynchus mykiss as phosphonic acid

Low

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

100

Oncorhynchus mykiss as phosphonic acid

Low

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

> 118

Daphnia magna as phosphonic acid

Low

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

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)

100

Chironomus riparius as phosphonic acid

Low

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

146.7

Scenedesmus subspicatus as phosphonic acid

Low

Mesocosm study data

NOEAEC mg l⁻¹

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

4000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.05

Rat

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

3.9

as phosphonic acid

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

None allocated

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

None allocated

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

None allocated

Dermal penetration studies (%)

100

default

Dangerous Substances Directive 76/464

Exposure Routes

Public

Negligible risks identified for proposed uses

Occupational

Negligible risks identified for proposed uses

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

No further information available

Handling issues

Property

Value and interpretation

General

Not oxisiding or explosive
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

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Name

English

potassium hydrogen phosphonate

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Record last updated:	12/06/2024
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242