Sources of Heavy Metal Exposure: A Clinical Guide

Written by Empire Medical Training Editorial Team

Medically reviewed by Peter Bongiorno, ND, LAc Naturopathic Doctor & Licensed Acupuncturist; Integrative & Functional Medicine

Updated June 2026 ·11 min read

When a patient turns up with elevated heavy metals, the first clinical question is not how do we chelate — it is where is this coming from? Removing the source is the single most important intervention in heavy metal medicine, and it is also where most of the work is. Heavy metals enter the body through five routes — ingestion of food and water, inhalation, skin absorption, eye contact, and injection or IV — but for the vast majority of patients the two that matter most are what they eat and drink and what they breathe.

This guide is part of Empire's heavy metal toxicity resource center. It maps the real-world sources of exposure metal by metal and setting by setting, drawn from the clinical teaching of Dr. Peter Bongiorno, ND, LAc. It is professional education, not medical advice, and it is written for clinicians building the environmental-history skills that make source identification possible.

Food and water

Food and water are, for most people, the dominant route of exposure. The metal that comes to mind first is mercury, and the source is fish and shellfish. Mercury accumulates up the food chain as methylmercury — the most toxic form — so the larger and longer-lived the fish, the higher the burden. The practical hierarchy matters: albacore tuna carries roughly 0.35 parts per million of mercury, nearly three times the level of chunk light or skipjack tuna, regardless of brand. Lower-mercury choices such as salmon and sardines are reasonable substitutes.

Dr. Bongiorno makes a point worth repeating to patients: mercury has no biological role in the human body, so there is no clearly safe level. The FDA's fish thresholds assume a tenfold safety factor, but in practice a daily-tuna habit can raise tissue mercury meaningfully — particularly in a patient who already has blood-sugar issues or cardiovascular risk. One of his long-standing patients developed cerebellar ataxia and depression while eating canned albacore every day; switching to canned salmon was part of a recovery. For the full picture, see our guide to mercury toxicity.

Arsenic is the second food-and-water story. Rice readily takes up arsenic from soil and water, and imported rice tends to carry more than domestically grown rice. Apple juice and some shellfish (cod, haddock) contribute as well, and historically pesticides and insecticides have been the highest-exposure sources of the more toxic inorganic form. Globally, contaminated drinking water is a major arsenic source — which is why filtering water is so central to reducing exposure. See arsenic toxicity for the clinical detail.

Water is also a route for lead (old pipes), and canned foods can leach aluminum and other metals — especially acidic and salty foods, which pull metal from their containers. The recurring lesson is that food is simultaneously a source of metals and, when chosen well, a tool for reducing them.

The mouth: dental amalgam

After fish, the most common mercury source Dr. Bongiorno sees is dental amalgam — the traditional silver-colored fillings that are roughly half elemental mercury by weight. Amalgam can slowly off-gas mercury vapor, which is readily inhaled and absorbed. The encouraging trend is that fewer dentists use mercury amalgam than in the past, but many adults still carry fillings placed decades ago.

This is a nuanced area clinically. Removal is not automatically indicated, and improper removal can release a burst of mercury vapor — so when it is pursued, it should be done by a dentist with the right equipment and air filtration to protect the patient. We cover the clinical reasoning, when removal is and isn't warranted, and how it fits a broader plan in dental amalgam and mercury.

The home

The home is a surprisingly rich source of heavy metals, and most of it traces to lead. The big-ticket items are old lead paint — still present in many pre-1978 buildings — and old lead pipes and solder, which leach lead into drinking water. Children are especially vulnerable: they are closer to the ground, ingest more dust relative to body weight, and absorb lead more efficiently than adults. Other household lead sources include building materials, older painted surfaces, and imported or traditional dishware. One of Dr. Bongiorno's patients had high lead from eating daily on culturally important leaded plates sent from family abroad — a reminder that the source is often hiding in plain sight and only emerges through a careful history.

The kitchen contributes its own metals. Aluminum cookware — including the classic stovetop moka pot — adds aluminum, particularly when cooking acidic or salty foods, as does aluminum foil and canned goods. Cadmium shows up in the home through certain batteries and consumer items. And iron cookware, while generally benign, can add small amounts of iron to food, which matters for the subset of patients prone to iron overload. The practical move for aluminum is switching to stainless steel.

Personal care and consumer products

Everyday consumer products are an underappreciated source. Antiperspirants are a common aluminum exposure — and because they also suppress sweating, they blunt one of the body's natural routes for shedding fat-soluble toxins. Cosmetics can contain metals used as preservatives; eyeliner and other eye makeup have historically carried mercury and lead, and they sit close to a sensitive absorption site.

Then there is the supplement aisle. This deserves candor: some supplements are themselves contaminated with heavy metals, particularly certain imported products. Dr. Bongiorno is direct that even good supplements can be laden with metals if a company isn't testing raw materials, batches, and finished product. The guidance is to choose manufacturers with genuine quality controls rather than assuming "natural" means clean. Imported products of any kind — foods, remedies, dishware, cosmetics — warrant extra scrutiny.

Cigarette smoke

Cigarette smoke is one of the major sources of cadmium, and it is worth singling out because it is both common and modifiable. The tobacco plant takes up cadmium from soil, and smoking delivers it straight to the lungs, where cadmium is especially damaging — it is a known human carcinogen with particular links to lung and prostate cancer, and it concentrates in and injures the kidneys. Secondhand smoke matters too. For any patient with unexplained kidney findings, bone demineralization, or lung issues, a smoking history is a key part of the cadmium picture. The full clinical profile is in our guide to cadmium toxicity.

Occupational and environmental sources

Beyond food and the home, the wider environment supplies a baseline of exposure that is largely outside any individual's control. Industry is the historical driver — smelting and refining, battery and paint manufacturing, muffler and metalwork — and it leaves a regional fingerprint. Industrial lead is concentrated in the Northeast and in mining regions, so geography is part of the clinical history.

Combustion is the other great dispersal mechanism. Coal-burning power plants release mercury that eventually rains down into oceans and soil; the encouraging news is that US power-plant mercury emissions fell roughly 90% between 2008 and 2020 under stricter regulation. But forest and structural fires are pushing the other way. As climate change drives more fires, more lead and other metals are released into the air — when the Notre-Dame cathedral burned, an estimated 400 tons of lead rained down across Paris. Soil, air, and contaminated water carry these metals into the food supply and into homes. The takeaway for clinicians is that some exposure is ambient and unavoidable, which is exactly why reducing the controllable sources matters so much.

Reducing your exposure: the most important intervention

If there is one principle to carry from this entire topic, it is this: removing the source is the most important intervention — more important than any chelator or supplement. Treatment that pulls metals out while the patient keeps eating, drinking, or breathing them in is working against itself. The reduction measures below are conceptual; the structured assessment that pins down a given patient's specific source is taught in Empire's course.

• Filter your water. A good-quality water filter is foundational. Where possible, test the water first to confirm it is a source. Reverse-osmosis systems are thorough (they also remove beneficial minerals, which then need replacing), and shower filters help with chlorine exposure.
• Choose lower-mercury fish. Favor salmon and sardines over albacore tuna; reserve high-mercury species for occasional use rather than daily meals.
• Eat organic where you can. Conventionally grown foods can carry more pesticide-related arsenic and more cadmium; choosing organic lowers both. Prefer domestically grown rice over imported.
• Replace aluminum cookware with stainless steel, and limit acidic or salty foods cooked or stored in aluminum, canned, or foil-wrapped form.
• Check the home for lead — old paint, pipes and solder, and imported or traditional dishware — especially where children live.
• Avoid cigarette smoke, first-hand and second-hand, to cut a major cadmium source.
• Scrutinize imported supplements and cosmetics, and favor manufacturers with verified quality testing.
• Support natural elimination — sweating and movement help the body shed fat-soluble toxins, which is partly why herbal deodorants are preferable to sweat-blocking antiperspirants. Antioxidant support such as glutathione is discussed in our overview of glutathione IV therapy.

A genuine caution belongs here. Significant acute heavy metal poisoning is a medical emergency, and treatment decisions should always begin with confirming that real, meaningful toxicity is present — through a careful source history, signs and symptoms, and appropriate testing — before any therapy. Source reduction is the safest, highest-value first move precisely because it carries no risk and addresses the actual problem. When in doubt, or when poisoning is severe, refer.

Training for providers

Identifying the source of a patient's heavy metal exposure is a learned clinical skill, not a guess. It depends on knowing which metals come from which settings, taking a thorough environmental and dietary history, and exercising the judgment to confirm real toxicity before acting. The same skill set distinguishes responsible practice from the unproven "detox" marketing that surrounds this field.

Empire's Heavy Metals & Chronic Illness training situates source identification within the broader science of heavy metal medicine — mechanisms, testing, and treatment — so clinicians can evaluate exposure honestly and counsel patients on the prevention measures that do the most good. Explore the full resource center or the Anti-Aging & Functional Medicine Academy to see how this fits a complete curriculum.