Desmetryn (Ref: G 34360)	Last updated: 23/12/2020
(Also known as: desmetryne; semeron)

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SUMMARY

Desmetryn is a herbicide that is not approved for use in the EU. It has a high aqueous solubility and is volatile. Based on its chemical properties it is not expected to leach to groundwater. It is not usually persistent in soils but may persist in water under some conditions. Desmetryn is moderately toxic to mammals. It is moderately toxic to birds, most aquatic organisms and earthworms. It is relatively non-toxic to honeybees.

GENERAL INFORMATION

Description	A methylthiotriazine herbicide used to control annual broad-leaved weeds and some grasses
Example pests controlled	Fathen; Lambsquarter; Nettleweed; Nightshade; Pigweed
Example applications	Brassicas; Onions and leeks; Fodder rape
Efficacy & activity	-
Availability status	Obsolete
Introduction & key dates	1962, frist reported

UK regulatory status

UK COPR regulatory status	Not approved
Date COPR inclusion expires	Expired
UK LERAP status	No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status	Not approved
Dossier rapporteur/co-rapporteur	Not applicable
Date EC 1107/2009 inclusion expires	Expired
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

Also used in

Also used in	-

Chemical structure

Isomerism	-
Chemical formula	C₈H₁₅N₅S
Canonical SMILES	CC(C)NC1=NC(=NC(=N1)NC)SC
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	HCRWJJJUKUVORR-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C8H15N5S/c1-5(2)10-7-11-6(9-3)12-8(13-7)14-4/h5H,1-4H3,(H2,9,10,11,12,13)
2D structure diagram/image available?	Yes

General status

Pesticide type	Herbicide
Substance group	Methylthiotriazine
Minimum active substance purity	>95%
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Selective, absorbed by leaves and roots, photosynthetic electron transport inhibitor
CAS RN	1014-69-3
EC number	213-800-1
CIPAC number	147
US EPA chemical code	080810
PubChem CID	13904
Molecular mass	213.30
PIN (Preferred Identification Name)	N2-methyl-6-(methylsulfanyl)-N4-(propan-2-yl)-1,3,5-triazine-2,4-diamine
IUPAC name	N2-isopropyl-N4-methyl-6-methylthio-1,3,5-triazine-2,4-diamine
CAS name	N-methyl-N'-(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine
Other status information	-
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	C1
Herbicide Resistance Classification (WSSA)	5
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	-
Physical state	White crystalline powder

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Semeron
Example products using this active	Syngenta Novartis Ciba-Geigy
Formulation and application details	Usually supplied as a wettable powder

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		580	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	High
Solubility - In organic solvents at 20 °C (mg l⁻¹)		300000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Methanol	-
		230000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Acetone	-
		200000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Toluene	-
		2600	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source n-Hexane	-
Melting point (°C)		84	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Boiling point (°C)		339	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	2.40 X 1002	Calculated	-
	Log P	2.38	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Low
Bulk density (g ml⁻¹)		1.18	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source	-
Dissociation constant pKa) at 25 °C		4	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source	-
		Weak base
Vapour pressure at 20 °C (mPa)		1.30 X 10-01	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		4.89 X 10-05	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source	Non-volatile
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)	9	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Non-persistent
	DT₅₀ (lab at 20 °C)	9	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Non-persistent
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	Other literature quotes DT₅₀ soil 50 days (L3)
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	-	-	-
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	Stable	W4 W = French database provided by ARVALIS-Institut du Végétal 4 = Verified data	Stable
	Note	-
Water-sediment DT₅₀ (days)		34	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data	Moderately fast
Water phase only DT₅₀ (days)		-	-	-

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	B3 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 3 = Unverified data of known source	Moderately mobile
	Koc	150
	Notes and range	-
Freundlich	Kf	-	-	-
	Kfoc	-
	1/n	-
	Notes and range	-
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		1.74	Calculated	Low leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	2.37 X 10-02	Calculated	-
	Note	-
Potential for particle bound transport index		Low	Calculated	-
Potential for loss via drain flow		Moderately mobile	Calculated	-

ECOTOXICOLOGY

Property		Value	Source; quality score; and other information	Interpretation
Bio-concentration factor	BCF (l kg⁻¹)	21	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source Estimated	Low potential
	CT₅₀ (days)	Not available		-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		1390	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source Rat	Moderate
Mammals - Short term dietary NOEL	(mg kg⁻¹)	-	-	-
	(ppm diet)	-		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		> 10000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Coturnix japonica	Low
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		2.2	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Oncorhynchus mykiss	Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		45	K3 K = Research datasets, e.g. Pandora, Demetra 3 = Unverified data of known source Daphnia magna	Moderate
Aquatic invertebrates - Chronic 21 day NOEC (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)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)		-	-	-
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		0.025	F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment ) 3 = Unverified data of known source Ankistrodesmus falcatus	Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		-	-	-
Honeybees (Apis spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	> 101	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Low
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	> 197	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Low
	Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
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 pollinators (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other pollinators (2)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		160	K4 K = Research datasets, e.g. Pandora, Demetra 4 = Verified data Ensenia foetida	Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)		-	-	-
Other soil macro-organisms	Acute LC₅₀ (mg kg⁻¹)	-	-	-
	Chronic NOEC (mg kg⁻¹)	-	-	-
Other arthropod (1)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	Harmless	AA2 AA = IOBC Database on classification of side effects to beneficial organisms, 2005 2 = Unverified data of unknown source Chrysoperla carnea	-
Other arthropod (2)	LR₅₀ g ha⁻¹	-	-	-
	% Effect	-	-	-
Soil micro-organisms		-	-	-
Mesocosm study data	NOEAEC mg l⁻¹	-	-	-
	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)		1390	V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM ) 3 = Unverified data of known source Rat	Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		2000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		-	-	-
Other Mammal toxicity endpoints		-	-	-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)		-	-	-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)		-	-	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)		-	-	-
Dermal penetration studies (%)		-	-	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Routes	Public	-
	Occupational	-
European MRLs		EU MRL pesticide database
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l⁻¹)		-	-	-

Health issues

Specific human health issues		Carcinogen Genotoxic Endocrine disruptor XNo, known not to cause a problem A0 A = Chromosome aberration (EFSA database) 0 = No data ; B0 B = DNA damage/repair (EFSA database) 0 = No data ; C0 C = Gene mutation (EFSA database) 0 = No data ; D0 D = Genome mutation (EFSA database) 0 = No data ; E0 E = Unspecified genotoxicity type (miscellaneous data source) 0 = No data No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant No data found XNo, known not to cause a problem XNo, known not to cause a problem Respiratory tract irritant Skin irritant Skin sensitiser No data found XNo, known not to cause a problem No data found Eye irritant Phototoxicant   XNo, known not to cause a problem No data found
General human health issues		No further information available

Handling issues

Property	Value and interpretation
General	No information available
CLP classification 2013	Health: H302, H312 Environment: H400, H410
EC Risk Classification	Xn - Harmful: R21/22 N - Dangerous for the environment: R50, R53
EC Safety Classification	S2, S36/37, S60, S61
WHO Classification	III (Slightly hazardous)
UN Number	-
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	desmetryn
French	desmétryne
German	Desmetryn
Danish	desmetryn
Italian	desmetrina
Spanish	desmetrina
Greek	desmetryn
Polish	desmetryna
Swedish	-
Hungarian	-
Dutch	desmetryn

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Record last updated:	23/12/2020
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