Monocrotophos (The killer insecticide)

Monocrotophos is an organophospate insecticide mainly used on on citrus, olives, rice, maize, sorghum, sugar cane, sugar beet, peanuts, potatoes, soya beans, vegetables, ornamentals and tobacco and cotton. This highly toxic insecticide is prohibited in many countries.

English: A sign warning about pesticide exposure.
English: A sign warning about pesticide exposure. (Photo credit: Wikipedia)

Monocrotophos has oral, dermal and inhalation toxicity. This has resulted in death due to accidental exposure and suicides. Symptoms after oral exposure includes but not limited to excessive sweating, headache, weakness, giddiness, nausea, vomiting, hypersalivation, abdominal cramps, diarrhea, blurred vision and slurred speech. Inhalation and dermal routes may not show initial symptoms.

Severe poisoning will affect the central nervous system, producing inco-ordination, slurred speech, loss of reflexes, weakness, fatigue, involuntary muscle contractions, twitching, tremors of the tongue or eyelids and eventually paralysis of the body extremities and the respiratory muscles. In severe cases there may also be involuntary defecation or urination, psychosis, irregular heart beat, unconsciousness, convulsions and coma. Ingestion of 120 mg monocrotophos can be fatal.

Many incidents in developing countries have been linked to monocrotophos.  Monocrotophos has been pointed to as a cause, in the following:

Brazil, Parana State Monocrotophos caused 107 of 412 reported incidents analysed in 1990, and the toxicology centre and health clinics also noted 1,650 incidents involving monocrotophos between 1982 and 1991.

Paraguay In a region where monocrotophos is one of the most commonly used active ingredients there have been numerous cases of pesticide poisoning; monocrotophos was identified as the cause of paralysis in children in cotton-growing areas by the Ministry of Public Health and Welfare which found that 2–3 weeks of frequent exposure caused paralysis in children and acute poisoning in adults.

Egypt In a cotton growing region of Egypt the health of 14 farmers who spray was compared with a control group from the same region. Monocrotophos is widely used and 61% of those surveyed showed symptoms of chronic pesticide poisoning.

Philippines, Cordillera region Monocrotophos was one of the pesticides widely used by farmers in a survey that found all farmers suffered some adverse health effects.

Indonesia In observations of 906 spray operations of 214 farmers commonly using monocrotophos and other OPs, over a three-month period, researcher found a significant increase-from two to fiftyfold-in the symptoms of pesticide toxicity during the spraying period. Of these spray operations, 21% brought on three or more neurobehavioural and intestinal signs of poisoning.

India The 2013 incident where 23 schoolchildren in north-eastern India died from eating a contaminated school lunch is believed to have been caused by cooking oil stored in a container formerly used to store monocrotophos.

(Above quoted from Wikipedia)

English: Monsanto pesticide to be sprayed on f...
English: Monsanto pesticide to be sprayed on food crops. Français : Remplissage d’un épandeur (Photo credit: Wikipedia)

Transport regulation classifies Monocrotophos pesticides under class 6.1, toxic substances, packing group II or III depending on the products’ toxicity level.

BETSY, LAURA & PESTICIDES

Close up yellow rose

Laura’s garden is infested with insects and she kept wondering why her next door neighbor Betsy’s garden is not having this problem.

One day morning while going out Laura meets Betsy hurrying to catch her regular bus.

Laura: Good Morning!

Image of Cleobora mellyi, authority Mulsant, c...

Betsy: Good Morning Laura!

Laura:  Betsy! My garden is full of insects, dear; tell me which insecticide I should use. I can see your garden blooming.

Betsy: “Just go to any shop which sells gardening stuff and ask for 2-ethyl-3,7-dimethyl-6-[4-(trifluoromethoxy)phenoxy]-4-quinolyl methyl carbonate

And off goes Betsy her way. What did she say? Two times ethyl and six times dimethyl?

Chemical names of pesticides are not short and are very complex to remember. In order to simplify ISO has issued common names for pesticides. These names can be used in scientific publications as well throughout the industry.

Now let’s hear what Betsy said again

Betsy: “Just go to any shop which sells gardening stuff and ask for flometoquin

Easier to remember what she said? This is the reason for ISO common names.

ISO common name for for 2-ethyl-3,7-dimethyl-6-[4-(trifluoromethoxy)phenoxy]-4-quinolyl methyl carbonate is flometoquin.

IMDG Code –

For package marking and documentation purpose which ever Dangerous Goods entry in IMDG Code assigned with special provision 274 must have a technical or chemical group name.

The technical name shall be a recognized chemical or biological name, (for those assigned with special provision 318), or other name currently used in scientific and technical handbooks, journals and texts.

In the case of pesticides, only ISO common name(s), other name(s) in the WHO Recommended Classification of Pesticides by Hazard and Guidelines to Classification, or the name(s) of the active substance(s) may be used.

Trade names must not be used for this purpose.

Helix pomatia, common names the Burgundy snail...

If interested you may download WHO publication here

One of the best internet site which lists out pesticide common names is http://www.alanwood.net/pesticides/

CLASSIFICATION OF PESTICIDES BY HAZARD

Spraying pesticide in California

Pesticides are used to destroy, repel, or mitigate any pests from crops, warehouses,  homes etc.

Various types are there in the market some of which are listed below

Pesticide Target
Algicides or Algaecides Algae
Avicides Birds
Bactericides Bacteria
Fungicides Fungi
Insecticides Insects
Miticides or Acaricides Mites
Molluscicides Snails
Nematicides Nematodes
Rodenticides Rodents
Virucides Viruses

Some of the pesticides are plant derived and some are chemicals

Lets look at the WHO guidelines for classification of pesticides and related Transport regulations for pesticides by ocean going vessels ( IMDG Code )

THE WHO RECOMMENDED CLASSIFICATION OF PESTICIDES BY HAZARD
was approved by the WHO in 1975 and the guidelines were first published first in 1978 and renewed there after every few years.

In 2002, the United nations committee of Experts on Transport of Dangerous goods and the UNCETDG/GHS issued a document called “The Globally Harmonized System of Classification and Labelling of Chemicals”. This document provide guidance for a globally harmonized system to address the classification of chemicals, labelling and safety data sheets.

Basis above, GHS, WHO hazard classes had to be aligned as per GHS Acute Toxicity  for acute oral or dermal as the triggering point for allocating pesticides to WHO Hazard Class.

The revised Document is published by WHO as  The WHO Recommended Classification of Pesticides by Hazard and  Guidelines to Classification 2009

Click here to download above document.

Structure of  The WHO Recommended Classification of Pesticides by Hazard and Guidelines to Classification 2009

PART I RECOMMENDED CLASSIFICATION OF PESTICIDES BY HAZARD

This part sets out the basis of classification considering acute risk to health , single or multiple  exposures, that might be encountered by any person handling the product as per the manufactures guidelines.

Basis of Classification

The Classification is based primarily on the acute oral and dermal toxicity to the rat as this is the standard procedure in toxicology.

In practice, the majority of classifications will be made on the acute oral LD50 value. However, dermal toxicity must always be considered since it has been found that, under most conditions of handling pesticides, a high proportion of the total exposure is dermal. Classification based on dermal data in a class indicating a great risk is necessary when the dermal LD50 values indicate greater hazard than oral LD50 values. ( Source WHO )

Revised criteria for classification (Triggered by GHS )

WHO Class LD50 for the rat
(mg/kg body weight)
Oral                 Dermal
Ia Extremely hazardous < 5 < 50
Ib Highly hazardous 5–50 50–200
II Moderately hazardous 50–2000 200–2000
III Slightly hazardous Over 2000 Over 2000
U Unlikely to present acute hazard 5000 or higher 5000 or higher
PART II GUIDELINES TO CLASSIFICATION OF PESTICIDES BY HAZARD

This  part is consists of 5 tables

Table 1 EXTREMELY HAZARDOUS (Class Ia) active ingredients (technical grade) of pesticides

Table 2 HIGHLY HAZARDOUS (Class Ib) active ingredients (technical grade) of pesticides

Table 3 MODERATELY HAZARDOUS (Class II) active ingredients (technical grade) of pesticides

Table 4 SLIGHTLY HAZARDOUS (Class III) active ingredients (technical grade) of pesticides

Table 5 Active ingredients unlikely to present acute hazard in normal use

In addition, the following tables show the details stated:

Table 6 Active ingredients not included in the Classification and believed to be obsolete or discontinued for use as pesticides

Table 7 Pesticides subject to the prior informed consent (PIC) procedure
Table 8 List of gaseous or volatile fumigants not classified under the WHO Recommended classification of pesticides by hazard

ANNEX How to find the hazard class of a formulation
INDEX by CAS number
by name of active ingredient

Lets look at one of the table and understand what each column is indicating

Table 1. Extremely hazardous (Class Ia) technical grade active ingredients in pesticides

WHO TABLE 1

Column 1 : Common Name  [ISO] denotes  common name of the active ingredient approved by the International Organization for Standardization

Column 2 : CAS Registry number

Column 3 : UN Number as per UN Recommendations on the transport of dangerous goods, Eleventh revision     (1999) . UN Number is given only in tables 1,2,3 & 4

Column 4 : Chemical type

Below are the codes and corresponding chemical types

AS Arsenic compound                                

BP Bipyridylium derivative                           

C Carbamate

CO Coumarin derivative

OT Organotin compound
CU Copper compound

HG Mercury compound

NP Nitrophenol derivative 

OC Organochlorine compound

OP Organophosphorus compound

PZ Pyrazole
PY Pyrethroid
T Triazine derivative
TC Thiocarbamate

Column 5 :  Physical state. Refers only to the active ingredient. L denotes liquid, including
solids with a melting point below 50oC; oil denotes oily liquids and S solids, including waxes.

Column 6 : Main use

AC acaricide                                           L larvicide
AP aphicide                                            M molluscicide
B bacteriostat (soil)                                 MT miticide
FM fumigant                                           N nematocide
F fungicide, other than for seed                 O other use for plant pathogens
treatment                                               PGR plant growth regulator
FST fungicide, for seed treatment              R rodenticide
H herbicide                                             RP( ) repellant (species)
I insecticide                                           -S applied to soil: not used with herbicides
IGR insect growth regulator or plant growth regulators
Ix ixodicide (for tick control)                      SY synergist


Column 7: GHS: This column indicates the classification of the pesticide according to
“The Globally Harmonized System of Classification and Labelling of Chemicals” (GHS).

WHO Classification

See http://www.unece.org/trans/danger/publi/ghs/ghs_rev03/03files_e.html. The categories for oral and
dermal routes are used

Column 8 : LD50 :

The LD50 value is a statistical estimate of the number of mg of toxicant per kg of body weight required to kill 50% of a large population of test animals: the rat is used unless otherwise stated.

Column 9: Remarks. This column is used to indicate cases in which the classification of a
technical product has been adjusted (i.e., the oral LD50 value is not directly used as the basis
of classification); Major irritant properties are also noted although they do not affect the
classification.

Publications mentioned in column 9 can be found at http://www.who.int/ipcs/

IMDG Code Requirements

Apart from meeting all the requirements of IMDG Code, when applicable, pesticides requiring technical name to supplement the proper shipping name  ISO common name(s), other name(s) in the WHO Recommended Classification of Pesticides by Hazard and Guidelines to Classification, or the name(s) of the active substance(s) may be used.

Details of classification of pesticides for sea transport can be found in section 2.6.2.4 of IMDG Code

Entry in Dangerous Goods List may have been assigned with Special Provision in which case the stakeholders shall read, understand and ensure consignment meets all the relevant requirements of IMDG Code.

International Code of Conduct on the Distribution and Use of Pesticides, FAO (2003), available at
http://www.fao.org/docrep/005/Y4544E/y4544e00.HTM;

Guidelines on Good Labelling Practice for Pesticides, FAO (1995), available at  http://www.fao.org/ag/AGP/AGPP/Pesticid/Code/Download/label.pdf
 http://www.unece.org/trans/danger/publi/ghs/ghs_rev03/03files_e.html. The categories for oral and
dermal routes are used.

Ensure use and disposal of pesticides are carried out in the correct recommended manner and follow all applicable regulations and guidelines.

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