Toxicity – IMDG Code Compliance Centre

Mercury (Hg)

We all know mercury is a silvery metal in liquid form. Probably most of us first saw it in childhood at the mirror like shining bulb end of thermometer when doctor pushed the thermometer in to our mouth .

In ancient days mercury was thought to have medicinal properties which will prolong life !! 🙂 Qín Shǐ Huáng Dì, Emperor of China, died due to drinking a mercury and powdered jade mixture formulated by Qin alchemists thinking he will attain immortality. The Emperor’s tomb contained flowing mercury models of rivers in china. Ancient Egyptians and Greeks used mercury in cosmetics and other ointments.

Mercury is highly corrosive to aluminium and is classified as Corrosive Substances (Class 8) in model regulations. Recent study of corrosive effect of Mercury on Aluminium states that heavy and sudden corrosion will take place leading to pitting and cracking which increases by presence of humidity. On mild steel the corrosion rate is.25mm/year.

Mercury is traditionally sold in flasks measuring about 2.5 litres (34.5 kg or 76 lb.). This weight is equal to one Spanish quintals; Spain was one of the biggest producers of mercury. Mercury is having high density of 13.54562 g/cm³

For sea transport IMDG Code list mercury under UN 2809 MERCURY Class 8 with special instruction prohibiting transport by hovercraft and other ships constructed of aluminium. IMDG Code allows flasks up to 3L for transporting Mercury by sea, including the empty flask the total gross mass per flask may be around 45-50 kg.

There is a new convention by United Nations named Minamata Convention for protecting human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.

If you are shipping Mercury or any article containing Mercury by Sea it is a mandatory requirement that you receive training to handle same as per IMDG Code.

For details of training click here Click here for Elearning

IMDG Code e-learning (shashikallada.com)
UNEP Minamata Convention (cardinalenvironment.wordpress.com)
Global Treaty Demands Mercury Reduction in Mining, But Not in Vaccines or Dental Fillings (govtslaves.info)
Mercury Treaty Signed in Minamata (ictsd.org)
There’s Mercury In Your Mascara, And The UN Is OK With That (huffingtonpost.com)
Guyana unveils 5-year plan to reduce mercury use (kaieteurnewsonline.com)
UN sees mercury use phase-out within 3 decades (boston.com)

what is LD50?

In many Material Safety Data Sheets we see LD₅₀ , What is LD₅₀?

Definition of LD50 given in IMDG Code is “LD50 (median lethal dose) for acute oral toxicity is the statistically derived single dose of a substance that can be expected to cause death within 14 days in 50 per cent of young adult albino rats when administered by the oral route. The LD50 value is expressed in terms of mass of test substance per mass of test animal (mg/kg).”

Which means the amount of a substance required to kill at least 50% test animal when administered orally (in above case) with respect to their body weight.

LD₅₀ is issued for toxicity in oral and dermal route and LC₅₀ is used for toxicity in inhalation route.

Let us see some examples of LD50 which can kill 50% of adult albino rats compared to humans

LD50 for paracetamol is 1.944g , over dosage may cause death due to liver failure.

However this is not an absolute figure some may be killed with much less dosage than LD50 and some may survive much higher dosage. These LD50 figures assist the experts in predicting toxicity giving a safe margin in practical applications.

LC50 – Lethal Concentration is also measured in same way for inhalation toxicity.

Dermal

LD50 for acute dermal toxicity is that dose of the substance which, administered by continuous contact for 24 hours with the bare skin of the albino rabbit, is most likely to cause death within 14 days in one half of the animals tested. The number of animals tested shall be sufficient to give a statistically significant result and be in conformity with good pharmacological practices. The result is expressed in milligrams per kilogram body mass.

Inhalation

LC50 for acute toxicity on inhalation is that concentration of vapour, mist or dust which, administered by continuous inhalation to both male and female young adult albino rats for one hour, is most likely to cause death within 14 days in one half of the animals tested. A solid substance shall be tested if at least 10% (by mass) of its total mass is likely to be dust in the respirable range, such as the aerodynamic diameter of that particle fraction is 10 microns or less. A liquid substance shall be tested if a mist is likely to be generated in a leakage of the transport containment. For both solid and liquid substances, more than 90% (by mass) of a specimen prepared for inhalation toxicity testing shall be in the respirable range as defined above. The result is expressed in milligrams per litre of air for dusts and mists or in millilitres per cubic metre of air (parts per million) for vapours.

Toxicity Classification for Sea Transport

Refer IMDG Code chapter 2.6 for classification criteria of toxic substances for sea transport.

Dangerous Goods Classes, Divisions, Marine Pollutants, Packing Groups and Wastes

In dangerous goods transport regulations⁺ of sea, IMDG Code, substances (including mixtures and solutions) and articles are assigned to one of the classes 1 to 9 according to the hazard or the most predominant of the hazards they present. Some of these classes are subdivided into divisions.

These classes or divisions are as listed below:

Class 1: Explosives

Division 1.1: substances and articles which have a mass explosion hazard

Division 1.2: substances and articles which have a projection hazard but not a mass

explosion hazard

Division 1.3: substances and articles which have a fire hazard and either a minor

blast hazard or a minor projection hazard or both, but not a mass

explosion hazard

Division 1.4: substances and articles which present no significant hazard

Division 1.5: very insensitive substances which have a mass explosion hazard

Division 1.6: extremely insensitive articles which do not have a mass explosion

Hazard

Class 2: Gases

Class 2.1: flammable gases

Class 2.2: non-flammable, non-toxic gases

Class 2.3: toxic gases

Class 3: Flammable liquids

Class 4: Flammable solids; substances liable to spontaneous combustion; substances which, in contact with water, emit flammable gases

Class 4.1: flammable solids, self-reactive substances and solid desensitized

Explosives

Class 4.2: substances liable to spontaneous combustion

Class 4.3: substances which, in contact with water, emit flammable gases

Class 5: Oxidizing substances and organic peroxides

Class 5.1: oxidizing substances

Class 5.2: organic peroxides

Class 6: Toxic and infectious substances

Class 6.1: toxic substances

Class 6.2: infectious substances

Class 7: Radioactive material

Class 8: Corrosive substances

Class 9: Miscellaneous dangerous substances and articles

The numerical order of the classes and divisions is not that of the degree of danger.

Marine Pollutants

As per IMDG Code any substance which are subject to the provisions of Annex III of

MARPOL 73/78, as amended is a MARINE POLLUTANT. These substances or articles are identified as such in column 4 of Dangerous Goods List in Volume 2 of the said Code.

Packing Groups

For packing purposes, substances* are assigned to three packing groups in accordance with the degree of danger they present:

Packing group I: substances presenting high danger;

Packing group II: substances presenting medium danger; and

Packing group III: substances presenting low danger.

*classes 1, 2, 5.2, 6.2 and 7, and self-reactive substances of class 4.1 are not assigned with Packing Groups

Wastes

While transporting wastes by sea the goods shall be assigned to the class or division considering their properties and shall be consigned as per the relevant rules. However when wastes not subject to any criteria of IMDG Code but belonging to the notification requirement of BASEL Convention may be transported as Class 9

⁺Based on UN Model Regulations, for latest edition click here

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