Fuel exhaust PTEs and PAHs accumulation in coastal marine primary producers and their potential transfer along trophic webs

Potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) are persistent and ubiquitous pollutants in marine ecosystems, where their sources are primarily represented by local fuel exhausts and inputs from the coastline, and where they tend to preferentially accumulate in sediments and biota. Indeed, the capability of several organisms, especially primary producers, to accumulate PTEs and PAHs from the environment, allows the transfer of such contaminants through trophic webs and, in several cases, their biomagnification. These outcomes have been consistently viewed as a major environmental and human health concern, due to PTE and PAH toxicity and their effects on biodiversity and ecosystem functioning. To evaluate the potential input to marine trophic webs of both PTEs and PAHs mainly deriving from fuel exhausts (Fe, Cu and Zn, and phenanthrene and benzo(a)pyrene, respectively), we preliminarily investigated their distribution in sediments and in the main benthic producers, collected from six sites of the Cilento coast (southern Italy) differing in anthropogenic pressure. Over 57 species observed (1 Cyanobacteria, 16 Chlorophyta, 29 Rhodophyta, 9 Heterokontophyta, 2 Embryophyta), 18 species were analyzed (1 Cyanobacteria, 4 Chlorophyta, 6 Rhodophyta, 6 Heterokontophyta, 1 Embryophyta), according to their availability and abundance. Notwithstanding the different uptake mechanisms and phylogenetic position, the analyzed taxa showed comparable concentration ranges for most of the analyzed pollutants. Except for Fe, with the highest concentrations in sediments, all the contaminants were preferentially accumulated in the biota with concentrations up to one order of magnitude higher than those observed in sediments. In particular, the obtained results highlighted potentially hazardous concentrations, in relation to their availability to higher trophic levels, of Cu and Zn in Embryophyta, of phenanthrene in Heterokontophyta and of benzo(a)pyrene in Cyanobacteria, Rhodophyta, Heterokontophyta and Embryophyta.