Factsheet #2: Dissolved lead

Lead (Pb) occurs naturally in the environment as a trace element. Lead major natural sources include volcanoes and weathering of rocks. Human activities, including mining, coal combustion, addition to gasoline and waste incineration, have greatly increased the distribution and abundance of lead in the environment. Increased usage and then phasing-out of leaded-petrol since the mid-70s yielded a decrease of this contamination.

Lead can enter the ocean by atmospheric deposition and fluvial freshwaters are common to other trace metals. Therefore, lead provides a proxy of trace metal inputs to the ocean. Isotopic ratios of Pb can be applied to determining the source material (ie. gasoline, coal) or the source location (ie. Asia, North America) of Pb inputs.

By measuring lead concentrations and isotopes GEOTRACES scientists reveal for the first time that natural lead can be detected again in the surface water of the North Atlantic. Indeed, significant proportions of up to 30–50% of natural Pb, derived from mineral dust, are observed in Atlantic surface waters off the Sahara. This clearly reflects the success of the global effort to reduce anthropogenic Pb emissions. Indeed, the increased usage and then phasing-out of leaded petrol since the mid-70s yielded a decrease in this pollution.

Atlas

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Atlantic Ocean:

Indian Ocean:

Data

Data is available to download after registration here: https://geotraces.webodv.awi.de/login

Discoveries include:

Spatial and temporal variability of bioactive trace metals, speciation and organic metal-binding ligands in the eastern Gulf of Mexico

Mellett and Buck present the concentrations of bioactive trace metals (Fe, Cu, Mn, Zn, Co, Ni, Cd, and Pb), Fe-and Cu-binding organic ligands, and electroactive Fe-binding humic substances in the eastern Gulf of Mexico.

About the decoupled fates of aluminium, manganese, cobalt and lead in the North Pacific Ocean

Did you know that each of these tracers could follow its own marine story, quite decoupled from the others?

Testament of the efficiency of environmental policies

Bridgestock and his co-workers reveal for the first time that natural lead can be detected again in the surface water of the North Atlantic.

Study of North Atlantic Ocean reveals decline of leaded petrol emissions, September 2016

Nature Communications (September 2016) Bridgestock, L., van de Flierdt, T., Rehkämper, M., Paul, M., Middag, R., Milne, A., Lohan, M.C., Baker, A.R., Chance, R.,, Khondoker, R., Strekopytov, S., Humphreys-Williams, E., […]

Decreasing of the industrial lead contamination in the Amundsen Sea area

Since the phasing-out of leaded automobile gasoline, the imprint of industrial lead is decreasing everywhere. 

Lead isotopes tracks leakage of Indian Ocean seawater into the Atlantic Ocean

Stable lead isotopes have been measured by Maxence Paul and co-workers along 40°S during the first and second legs of the UK GEOTRACES cruise (GA10) in the Atlantic Ocean. They […]

A new method to measure lead isotopes in the ocean with an outstanding precision

A new method for the determination of seawater lead (Pb) isotope compositions and concentrations was developed, which combines and optimizes previously published protocols for the separation and isotopic analysis of […]

Analyzing rapidly, precisely and semi-automatically lead isotopes on variable volumes of seawater (up to 1000 ml)

Zurbrick and co-authors present a relatively fast (2.5–6.5 hours), semi-automated system to extract lead (Pb) from seawater, with few chemicals yielding low blanks. They also demonstrate that subsequent Pb isotopic […]

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