Dear Anil Shankhwar , it is an interesting question.
Heavy metal toxicity has proven to be a major threat and there are several health risks associated with it.
The toxic effects of these metals, even though they do not have any biological role, remain present in some or the other form harmful for the human body and its proper functioning.
They sometimes act as a pseudo element of the body while at certain times they may even interfere with metabolic processes.
Few metals, such as aluminium, can be removed through elimination activities, while some metals get accumulated in the body and food chain, exhibiting a chronic nature.
Various public health measures have been undertaken to control, prevent and treat metal toxicity occurring at various levels, such as occupational exposure, accidents and environmental factors.
Metal toxicity depends upon the absorbed dose, the route of exposure and duration of exposure, i.e. acute or chronic. This can lead to various disorders and can also result in excessive damage due to oxidative stress induced by free radical formation.
The answer to your question is not simple. Every single ‘heavy’ (or light, like aluminium) has its own mechanism of human toxicity. And metalloids like arsenic are usually also included in the term ‘heavy metals’.
Please look at my ResearchGate page for our publications on aluminium, lead, bismuth, arsenic, mercury, uranium, and some more. You will find there full texts of our review articles as well.
If there is anything else I can do for you, please do not hesitate to get in touch.