Lets start by listing the sources of mercury in our reality:
Dental Amalgams (Liquid Mercury and Metal Alloy);

Seafood ( Bio-accumulated methyl mercury);

Air (Mercury oxide from coal burning, gold mining etc);

Water (Gold mining wastewater, Urban wastewater, Mercury Gas precipitation)

Vaccines before 2000s(Thimerosal)

Amalgams. One source of mercury in humans is dental amalgams. They contain mercury, which is released as a gas, each time we chew. You can double check this by typing in “Smoking Tooth” in youtube. This means that everyone, that has had or has an amalgam, has a certain amount of mercury accumulation in his body. But beware, rushing to remove these amalgams with any type of dentist may be the worst decision in your life. You need to make sure that the dentist is specialized and you do not swallow or inhale mercury.

Seafood. Another source of mercury in humans is Seafood. Fish bio accumulate it. The larger the fish, the larger the amount of mercury. If we consume large fish like tuna, shark, swordfish on a daily basis, we will become mercury toxic. Seafood contains the most damaging type – methyl mercury.

Air. Even the air we breathe in busy cities contains some amount of mercury. Coal combustion releases mercury oxide in the air. Gold mining uses mercury to extract gold and the end process is burning the mercury and turning it into gas.

Water. Mercury ends in water via the Gold mining wastewater, Urban wastewater and Mercury Gas precipitation (mercury in the air).

Here is a short doc. on mercury pollution and gold mining:

We all know mercury is a toxin and we need to be careful. It is a neurotoxin, which means that it slowly degenerates the human nervous system. All of us have mercury in our bodies. Hair tests for heavy metals always reveal a certain level of mercury. But why is that? Because we’ve polluted mother Earth. There is a saying in English “Mad as a hatter”, which comes from a historic event, where people used mercury in the hat making industry. The result was that these workers inhaled mercury gas and became mentally ill.
The effects of mercury on the human body are extremely, extremely bad. Mercury can be the cause of anxiety, depressive disorders, as well as physical nephropathy or diseases of the nervous system . It bio-accumulates and the natural process of detoxification is very difficult. This process might just redistribute the mercury across the body, rather than detox it. And that is the case if we live in a toxic environment, such as a big city. Your natural detox system – Glutathione, will be depleted, as you are under constant assault by toxins, such as the Lead in the air from exhausts, Aluminium, dust particles, agro-chemicals, as well as pesticides, herbicides and fungicides in food. The human detox pathway will be overloaded and the only way to protect the body is to store mercury in fat, usually, rather than eliminate it. If the body is carrying a toxic load, the capacity to connect to your higher-body will be lessened. The capacity to conduct emotions and feel yourSelf will be obstructed.

One day it might turn out that there is no such thing as disease in a human body, which does not contain any toxins. Or in other words, our evolution in technology, has brought these diseases onto ourselves. How sad is that the number one source of mercury pollution is the great greed for GOLD. Conventional medicine manages depression and anxiety with chemical pills, but never looks deeper than that.. We are poisoning ourselves, the planet and the animals.

On a positive note. The body is capable of dealing with anything, given the proper resonance between body and mind. But this body is our temple. We Must clean the temple. And there are ways to do that. It is not easy and we must read and learn as much as possible on this topic.
The least you can do is Stop eating large-sized seafood, or stop eating seafood in general. Remove your dental amalgams only with a dentist, who is specialized in such an operation, or you risk severe poisoning, if done conventionally. As for detox, some types of clay can bind to mercury in the gut. Zeolite and Bentonite. That might be a good start for you to research. As for the mercury in the cells and the brain, this is an ongoing battle and maybe soon we will have the answer.

Bless and Love!