From lead paint chips to trace parts per billion (ppb) in cookies, exposure to heavy metals has decreased in recent decades. Heavy Metal Exposure in the Past vs. TodayLead, mercury, arsenic, and cadmium are naturally occurring elements — part of the Earth’s crust, air, and water. LMNTSource: Assessment of trace metals in five most-consumed vegetables in the US: Conventional vs. organicAre We Safer From Heavy Metals Today? Q: Are heavy metals in food worse now than before? A: No, heavy metal exposure from just about all sources is much lower now than in recent history.