In our first blog post about mercury, we promised to share with you more information about how mercury affects human health. But then we diverted a bit to satisfy a request for more information on the findings of the Minamata Initial Assessment (MIA) that we mentioned in the first post. Rest assured that we have not forgotten our promise! In this blog we will provide you with more information on what should matter the most to us all, our health. After all, as the saying goes, ‘No Health, No Wealth’!
What are the impacts of Mercury on humans?
Before we get into the nitty gritty details about how mercury affects humans, we first need to clarify a few things. We first need to understand that mercury is an element that exists naturally in our environment. Just like copper, iron, silver and zinc. In fact, remember the Periodic Table of the Elements that most of us were introduced to when we began studying science in Secondary School? Hopefully the one below will refresh your memory. On this table, mercury is element number 80 with the mercury symbol, Hg. Just like the symbol for water is H20, mercury also has a symbol which is Hg.
According to the World Health Organisation’s (WHO) website “mercury exists in various forms: elemental (or metallic) and inorganic (to which people may be exposed through their occupation); and organic (e.g., methylmercury, to which people may be exposed through their diet)”.
WHO’s website also states the following:
- Exposure to mercury – even small amounts – may cause serious health problems, and is a threat to the development of the child in utero and early in life.
- Mercury may have toxic effects on the nervous, digestive and immune systems, and on lungs, kidneys, skin and eyes.
- The inorganic salts of mercury are corrosive to the skin, eyes and gastrointestinal tract, and may induce kidney toxicity if ingested.
How are we exposed to mercury?
I am sure you will agree that to prevent something from entering our homes we must first know how it enters so that we can block the entry points. The same goes for our bodies. Earlier it was mentioned that people can be exposed to organic mercury through their diets. In the previous post, we considered several sources of mercury in Saint Lucia. But what we did not consider was the fact that some of the foods that we consume also contain mercury!
What are some of those foods? According to the brochure on the major findings of the MIA in Saint Lucia, “fish from the sea or freshwater systems can be a major source of methylmercury exposure to humans. The brochure also states that “methylmercury, the organic form of mercury, is toxic to humans because it can biomagnify in food webs and bioaccumulate over time in organisms that may be frequently consumed”. The image below may help to explain this concept better. We can also illustrate it this way: imagine mercury is cholesterol, the more foods you eat with high cholesterol the higher your cholesterol levels will be.
Therefore, it is better to eat small short-lived fish than fish that grows to a larger size because it is very likely that they have consumed several fish species that were exposed to methylmercury and therefore their concentration of mercury can be high. This increases the level of mercury that you are exposed to if you consume them. The brochure provided the following list of healthier and riskier seafood choices below as a guide:
Seafood with lower mercury levels (<0.22 ppm, ww; healthier choices):
- Small grouper, snapper, shrimp, tilapia, oysters, mahi mahi, salmon
Seafood with higher mercury levels (>0.22 ppm, ww; riskier choices):
- Atlantic blue marlin, barracuda, large grouper, king mackerel, swordfish, many tuna species, wahoo (peto)
Therefore, we are not saying that fish is not good but rather what we need to be weary of is how much of the fish which may contain mercury that consume. Thus, we can have unlimited amounts of the less risky fish choices but try to limit the frequency with which we consume the riskier sea food choices.
We encourage you to learn more about the Minamata initiative in Saint Lucia and how you can protect yourself from unnecessary exposure to mercury by contacting the Sustainable Development and Environment Division at 451-8746.
We also urge you not to keep all this knowledge to yourself. Please share our posts with your friends and family. You can follow and share this blog on our facebook page as well and don’t forget to like us too!
We also encourage you to read our previous Mercury blog posts: