Dr. Michael Martínez-Colón spent eight days (10/22/2021 – 10/30/2021) in Puerto Rico doing field work for a research project funded by Puerto Rico Sea Grant. One of the sampled estuaries, Guánica Bay, has been under the influence of anthropogenic pollution since the 1900 but more severely since the 1950. The waters of the bay receive raw sewage (point source) and fertilizers (non-point source). The surrounding soils are polluted with lead, mercury, and polychlorinated biphenyls (PCB). More importantly, PCBs have been found in fish tissue, bay sediments, and in human blood from the local residents. As of September 2021, EPA is including this bay as part of their Superfund National Priority List.
To have a better understanding of the history of pollution of the bay, a 52 cm core was collected to assess the levels of pollutants (sewage, persistent organic pollutants, and heavy metals) coupled with any changes in environmental health. A radiograph (x-ray) of the G8-core shows a noticeable change in sedimentation at 34 cm and at 26 cm depth. This is a key sedimentary marker given how much of the watershed and the estuarine sediments of Guánica Bay has been altered. Radiometric dating and if needed 14-C dating will be done to get an age of the sediment layers.
Dr. Martínez-Colón diving for core collection
Radiograph and visual description of sediment core G8