Fish are the major source of exposure to methylmercury.
A heavy metal present opinion the earth’s crust and exists in organic and inorganic forms.
Coal combustion and gold mining are the two main sources of mercury pollution.
Coal contains mercury which vapor rises during combustion, entering the atmosphere and precipitates in lakes, rivers, and oceans.
In aqueous environments, metallic and inorganic mercury convert to highly toxic methylmercury.
In aqueous environments, metallic and inorganic mercury convert to highly toxic methylmercury.
It is suspected that the conjugation of mercury to sulfhydryl groups of proteins throughout the body may inactivate enzymes and increase oxidative stress, inflammation, cytotoxicity, apoptosis, and auto immunity.
The toxic manifestations of mercury depend on its form, dose, route, and duration of exposure.
Chronic low-level mercury exposure causes measurable neurodevelopmental delay in infants.
Women of childbearing in each, pregnant or nursing mothers and infants and young children should eat no more than two servings of fish per week, And should avoid species of fish with high methylmercury content ( FDA).
Among 51,529 men and 121,700 women whose toenail clippings were evaluated for mercury and selenium concentrations there was no evidence of adverse effects of mercury exposure on coronary heart disease, stroke, or total cardiovascular disease (Mozaffarian D et al).
Exposure to inorganic mercury that includes mercury salts occurs in certain industries – mining, chemical, and metal processing, and by ingestion of mercury containing medications or the use of skin lightning agents.
Mercury levels in skin lightning products are greater than 1000 ppm, but should not exceed 1 ppm according to the WHO.
Methyl mercury in aquatic environments accumulates in the food chain and is consumed by humans, this is especially true of tuna fish.
Methyl mercury has long been known to be a neurotoxicant and associated with a dose dependent increase in the risks of deaths from Cardiovascular disease and non-fatal myocardial infarction.
Some individuals with chronic exposure to inorganic mercury salts are asymptomatic, even with high levels of mercury, while others develop symptoms with effects on their kidneys and CNS.
Symptoms may manifest months to years after initial mercury exposure.
Mercury deposition in the kidneys can cause nephrotic syndrome due to membranous nephropathy and neuropsychiatric effects that are common and include headache, dizziness, insomnia, vision changes, depression, anxiety, tremors, paresthesias, and ataxia.
Differential diagnosis includes: systemic lupus, nephrotic syndrome, polyneuropathy, pheochromocytoma, depression, and dementia.
Diagnosis is made on the basis of clinical suspicion and elevated levels of mercury in urine or whole blood.
Chelation therapy with dimercaptosuccinic acid or D-penicillamine is indicated for symptomatic patients with confirmed elevation of urine or blood mercury levels.