The levels of lead and mercury in the sea reduce noticeably following concrete actions to limit their release, recent research at the IAEA using nuclear techniques has shown. The banning of leaded petrol and the closure of a mercury discharging plant have led to decreases in pollution levels over 10-15 years.
This is the case for lead, which when consumed by fish which is in turn eaten by people, can cause damage to the human nervous system and internal organs. Many different activities such as mining or smelting in metallurgy and the burning of coal as well as lead’s use in batteries, paint, ceramics and other everyday items can release it into the environment. The biggest source of lead pollution in the last century was related to the use of leaded petrol.
As part of efforts to develop new methods to determine the source and levels of lead pollution, researchers at the IAEA Environment Laboratories analysed sediments from the Baltic Sea and the Caribbean Sea. In mapping the pollution history in a sediment core from the Baltic coast of Germany, researchers could clearly observe that within 10 to 15 years of phasing out lead in petrol by 1996, lead pollution levels in the sea had decreased..
In addition, IAEA researchers have successfully developed methods to use lead isotope ratios to determine the source of lead pollution and assess whether it is naturally present or the result of anthropogenic activities, since natural and anthropogenic lead sources will show different isotopic fingerprints and isotope compositions....
IAEA scientists' analysis of a dated sediment core in a Caribbean bay shows total mercury (Hg) levels rapidly decreased after the closure of a discharging plant...Mercury was used in an alkali plant there as a catalyser, and in the 1970s, high concentrations were found in water, sediments and marine organisms as a result of discharges from the plant. Years later, after the plant had been closed, IAEA researchers showed, by analysing sediment core taken from the bay, that levels of total mercury had started to decrease. While remnants of this pollution are still buried in the sediment, acute toxicity has been greatly reduced.
Excerpts from World Oceans Day 2018: Regulating Lead and Mercury Releases has Decreased Marine Pollution, IAEA Press Release, June 8, 2018