How do we ingest/absorb them?

How we ingest /absorb Heavy Metals?

Heavy Metals Toxicity and the Environment

" In many areas of metal pollution, chronic low dose exposure to multiple elements is a major public health concern."

This study looks at Arsenic,Lead, Mercury, Cadmium and Chromium.

Read study >> https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4144270/

Sources and routes of Lead exposure

People can become exposed to lead through occupational and environmental sources.

This mainly results from:

inhalation of lead particles generated by burning materials containing lead, for example, during smelting, recycling, stripping leaded paint, and using leaded gasoline or leaded aviation fuel; and
ingestion of lead-contaminated dust, water (from leaded pipes), and food (from lead-glazed or lead-soldered containers).

An additional source of exposure is the use of certain types of unregulated cosmetics and medicines. High levels of lead have, for example, been reported in certain types of kohl, as well as in some traditional medicines used in countries such as India, Mexico and Viet Nam. Consumers should therefore take care only to buy and use regulated products.

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time.

source for above: WHO - http://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health

Also see - Lead exposure in Ireland