Event Date: 11 May 2015 04:00 AM - 11 May 2015 05:00 AM

Event Venue: CREATE Theatrette, CREATE Tower (Level 2)

Chronology of lead concentrations and isotopes in coastal environments near rapidly growing cities in the Middle East, South and South-East Asia and South America

Seminar Abstract
Lead is a trace metal that is closely related to anthropogenic activity, mainly via leaded gasoline and coal combustion. The study of lead concentrations and isotopes in seawater, sediments, corals and aerosols allows for a systematic look at its sources and their time evolution in a natural environment. Here I will present results from recent projects the Boyle group at MIT has been involved with. These projects studied the Middle East, South and South-East Asia, and South America, regions that have seen quick socio-economical changes over the past half-century that have left environmental signals.

The specific study sites are Kuwait, south Vietnam, western Sumatra, Singapore, and Rio de Janeiro, with preliminary data from near Boston as well. I will go into the details of each specific site, and I will conclude with a comparison that focuses on concentration factors, potential sources and their magnitude, and other relevant factors that can give us a general idea about the environmental state of these coastal regions from a Pb perspective as they are affected by urban conglomerates.

These results highlight the usefulness of the method, show the complexity of these systems as they show the relative influence of natural and anthropogenic sources in different media, and point to the need for a continuous monitoring of anthropogenic trace metals in the small-medium coastal scale to be able to assess the larger scale effects of human activity.

Speaker’s Biography
Gonzalo Carrasco joined CENSAM in 2014 after a postdoc at MIT in Ed Boyle’s group, where he studied the sources and chronology of a range of pollutant and micronutrient trace metals (including Pb, Zn, Cd, Ag, U) in coastal environments near densely-populated urban areas in the Arabian Gulf, Brazil, and the Gulf of Maine. He was also working on extending the directions of his PhD work on temporal decay of Zn complexing ligands along global ocean water masses in the North Atlantic and North Pacific.

For his MS and PhD in Oceanography (Old Dominion University, 2007 and 2010) he studied the sources, chemical speciation and bioavailability of pollutant and micronutrient trace metals Zn, Cd and Cu in natural and polluted environments in the North Atlantic, North Pacific, and the Chesapeake Bay. Previously he had investigated the sources of Cr in a polluted river-soil-plant ecosystem in a major city in Peru as part of his BS in Pharmacy and Biochemistry (Universidad Catolica Santa Maria, 1994).

He has participated in international research programs including GEOTRACES, SCOR, and C-MORE. He is in the process of publishing results presented in several international conferences, and has reviewed several publications concerning trace metals and their chemical speciation.