210Pb-derived history of PAH and PCB accumulation in sediments of a tropical inner lagoon (Las Matas, Gulf of Mexico) near a major oil refinery

Abstract

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in a sediment core from the tropical freshwater inner lagoon of Las Matas, near the petroleum industrial area of Minatitlán-Coatzacoalcos, in the Gulf of Mexico. A 210 Pb-derived chronology was used to reconstruct the historical PAH and PCB accumulation in the site during one century . Both geochemical and sedimentological data indicated that a major change occurred in 1947 ± 4, including a shift to coarser sediments and a significant decrease of Al, Li, Fe, organic C and total N contents. This was likely due to the changes in hydrology caused by the confinement of Las Matas Lagoon due to the construction of the Trans-Isthmus road in 1946. PAHs in these samples show relatively low concentrations (259-1176 ng g À1 ), and the congener relative abundances indicate the influence of pyrogenic (petroleum combustion) sources. Total PCB concentrations in the sediments ranged from 24 to 77 ng g À1 , and are composed by low chlorinated PCBs, with 3-and 4-CB as the prevalent species (51-65% and 29-40%, respectively). PAHs and PCBs were detected at depths corresponding to the early 1900s, when Minatitlán refinery started operations, although their time evolution appears to be influenced by different accumulation processes. The PCB background is most likely produced by the combustion of natural organic matter, and an industrial contribution can be recognized when normalizing with OC contents. We concluded that atmospheric deposition is the most significant source of PAHs and PCBs for this water body. This study also provided evidence of the alteration of the wetlands surrounding this industrial area due to urbanization; the fragmentation and alteration of Las Matas Lagoon hydrology contributes to the gradual loss of the wetlands in the zone.

Distribution of persistent organic pollutants (PAHs, Me-PAHs, PCBs) in dissolved, particulate and sedimentary phases in freshwater systems

“…Our results showed a linear correlation between PCB153 and S 16 PAHs concentrations (R 2 ¼ 0.83, p < 0.01), suggesting similar sources of emission. Therefore, PCB153 most likely also originated by pyrolysis processes such as coal, wood and peat combustion (Rose et al, 2004;Ruiz-Fern andez et al, 2012).…”

Organic pollution in surficial sediments of Tripoli harbour, Lebanon

“…Among the principal classes, there are the aromatics compounds, including parent and alkyl-substituted polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and polychlorinated biphenyls (PCBs). Due to their physicochemical properties, their ubiquitous, their persistence, their transportability, and fat-solubility (Jones and Voogt, 1999), these compounds tend to bioaccumulate in fatty tissue and have potential adverse effects on aquatic ecosystems and human health via food chains (Jones and Voogt, 1999;Fleeger et al, 2003;Manodori et al, 2006;Fernández et al, 2012). Moreover, these contaminants are known or suspected as mutagenic and carcinogenic (Jones and Voogt, 1999;Qiao et al, 2006;Chen et al, 2012) and their endocrine disrupting activities in humans and wildlife have been recently reported for PAHs and PCBs (Clemons et al, 1998;Jones and Voogt, 1999;Brun et al, 2004).…”

Exploring the possibility to detect recent temporal changes in highly disturbed sedimentary records through sampling repetitions and core comparisons of porosity and sand content

“…3 and a basic statistical data treatment can be used. Indeed, the Pearson product-moment correlation coefficient (r) is a measure of the linear dependence (correlation) of two variables and is generally used in geochemistry studies (e.g., Romano et al 2012;Ruiz-Fernández et al 2012;Bellucci et al 2013;Giuliani et al 2015) to verify if two sedimentary parameters are linked to each other (and, by extension, if their variability in sediments is guided by the same depositional processes) or not. It varies between +1 (total positive correlation) and −1 (total negative correlation), with 0 as an indication of no variable dependence.…”