Baia Mare

Cyanide and Heavy Metals

Cyanide comes in many forms, the most lethal being that of hydrogen cyanide, HCN, which is lethal to humans at 1.1 mg/kg in the blood. In the plume that swept through the river, Cyanide most likely formed complexes with heavy metals associated with it. Even though free floating Cyanide is readily degradable when it forms into a complex, dilution and degradation become complicated.


Heavy metals do not break down and are “bio-accumulative” in plants, animals and the environment. This means that the level of toxins builds up in an organism over time, increasing its toxicity and threat to local ecosystems. Toxins may also be passed on to other species if a toxic organism is eaten. Therefore, living organisms face high risks with long-term and chronic exposure to heavy metals.

Sources and Sinks of Heavy Metals

To read more about the quantitative distribution of heavy metals and cyanide in the rivers and sediments in the Baia Mare area, please click on Environmental Impacts.