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MERCURY and mercury compounds have long been known to be toxic to humans, other organisms and the environment.

Considering that mercury increases in concentration at each feeding level (bio-accumulates) in the ecosystem, its adverse impacts on the environment were evident in countries like Japan causing the Minamata disease as well as the Niigata Minamata disease.

The negative impacts of mercury gave rise to the promulgation of the Minamata Convention on Mercury of October 2013.

The convention is an international treaty designed to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.

The convention was a result of international action aimed at managing mercury in an efficient, effective and coherent manner, while member states work towards the subsequent reduction in the use of mercury and adoption of technologies to substitute the use of mercury.

Milestone has been achieved globally in the medical industry where the use digital technology has substituted mercury in the case of thermometers.
Zimbabwe is one of the 128 countries, which signed the convention and is working towards ratification.

The document obliges member states to ensure there is informed consent from the receiving state in relation to the trade in mercury or mercury based products.

Trade in mercury or mercury based products will be restricted to allowed purposes under the instrument and also domestic law, and only in quantities needed for those purposes.

In the mining sector there is a need for the development and adoption of sustainable technologies to extract gold in preparation for the subsequent reduction in the use of mercury.

Once ratified, the main benefit of the document is that it will be a reference point or provide direction on how national legislation can be developed to tackle the on-going problem of controlling the use and influx of mercury into the country and prevent the possibility of Zimbabwe being a dumping ground of such hazardous substances.

Miners are at risk since they do not use appropriate personal protective equipment when handling mercury.

They further put communities surrounding mining areas at risk when the openly burn the mercury-gold amalgam to recover the gold.

The hazardous substance is not well labelled and miners lack knowledge on the health risk associated with exposure to mercury considering that its effect is not acute but chronic.

Emerging evidence indicate that artisanal and small-scale gold mining related mercury contamination in Africa is contributing to serious health and ecological impacts and has raised concern among environmentalists.

UNEP estimates that 3, 5 million people are at risk of health impacts in artisanal and small-scale gold mining sector of which 2, 5 million are in Africa.

The health effects of mercury on humans

The mercury in household products is trapped and usually does not cause any health problems.

However, when a thermometer breaks, a significantly high exposure to mercury through breathing will occur for a short period of time while it vaporises.

This can cause harmful effects, such as nerve, brain and kidney damage, lung irritation, eye irritation, skin rashes, vomiting and diarrhoea.

Mercury has a number of effects on humans that can all of them be simplified into the following main effects:

Disruption of the nervous system

Damage to brain functions

DNA and chromosomal damage

Allergic reactions, resulting in skin rashes, tiredness and headaches

Negative reproductive effects, such as sperm damage, birth defects and miscarriages

Damaged brain functions can cause degradation of learning abilities, personality changes, tremors, vision changes, deafness, and muscle in coordination and memory loss.

Chromosomal damage is known to cause Down syndrome. Most people can continue to look to fish as a healthy, low fat source of protein and other nutrients.

However, pregnant women, women who may become pregnant within the next several years, children less than six years old and people who consume unusually large quantities of freshwater fish, may be impaired by mercury.

What Zimbabwe has done towards ratifying the Minamata Convention?

Zimbabwe has established a Mercury Initial Assessment Project Steering Committee comprising of government line ministry officials.

The committee will spearhead citizens’ education and awareness of on mercury issues as well as to inform the nation on how to manage mercury.

All their efforts will help Zimbabwe to make an informed decision when ratifying the minamata convention.