Unless you physically work with inorganic mercury or its various salts, I don't think you have much to worry about. Playing with elemental mercury was a pretty big fad in the 1960s.
IMHO, mercury's low melting point has nothing to do with the covalent bonds it makes with methyl, ethyl or other organic groups in, e.g. dimethyl mercury, diethyl mercury, etc. Humans need to worry about consuming too much fish and shellfish or they can accumulate too much dimethyl mercury or diethyl mercury. I don't think it matters if they come from fresh or salt water.
Most of mercury gets in the atmosphere from burning coal. Its one of the main medical reasons that they want to kill coal. Inorganic mercury comes down wherever it rains. Various organisms convert to the toxic diethyl and dimethyl forms, and it gets more concentrated as it goes up the food chain.
The following links a fairly recent review article:
Mercury is a toxic heavy metal which is widely dispersed in nature. Most human exposure results from fish consumption or dental amalgam. Mercury occurs in several chemical forms, with complex pharmacokinetics. Mercury is capable of inducing a wide range of clinical presentations. Diagnosis of mercury toxicity can be challenging but can be obtained with reasonable reliability. Effective therapies for clinical toxicity have been described.
>> Most of mercury gets in the atmosphere from burning coal. Its one of the main medical reasons that they want to kill coal. <<
Your science is accurate, but your politics are not. Present policies are already greatly reducing mercury emissions, and they can be reduced far further, largely ending the problem, without having to “kill coal.”
Coal is domestic, and hence inevitably commoditized; there’s no profit. The big oil industries and the OPEC nations want to kill coal because our reliance on foreign oil from dictatorships makes it impossible to commoditize.