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Muscle fatty acid profiles and PCB contents of the detritivorous species Prochilodus lineatus and its diet (stomach contents, settling particles and sediments) were analysed from reference and polluted areas of the Paraná-Rio de la Plata basin, to evaluate the alterations produced by opportunistic feeding on sewage discharges. Overall muscle fatty acid composition was dominated by saturated and monounsaturated 16 and 18 carbon (18 C- FA) components with reduced long-chain polyunsaturated fatty acids ( LC-PUFA). Compared to sediments, settling particles and stomach contents were enriched in lipids and had a similar fatty acid composition. Opportunistic feeding on sewage detritus at Buenos Aires resulted in enhanced PCB and triglyceride accumulation, with higher proportions of 18 C- FA and lower proportions of 16:1 and LC-PUFA compared to fish from northern pristine reaches of the basin. Mid-Paraná showed intermediate values reflecting mixing of the North stock with migrating Buenos Aires P. lineatus identified by their lipid and contaminant profile. According to multivariate analyses, this geographical variation of fatty acid composition was strongly influenced by PCB concentration. Prochilodus lineatus assimilates the energy subsidy of sewage inputs through enhanced lipogenesis with dominant 18 C- FA and significant amounts of valuable LC-PUFA. This lipid alteration facilitates the bioaccumulation of PCBs which in turn may reinforce the adipogenic effect of sewage feeding. [ABSTRACT FROM AUTHOR]

A comparative analysis of bioaccumulation behavior of dioxin-like polychlorinated biphenyls (dlPCBs) and polybrominated biphenyl ethers (PBDEs) was conducted involving simultaneous measurements in settling particles and a detritivorous fish (Sabalo, Prochilodus linneatus) collected in the sewage impacted Buenos Aires coastal area. Focalization of dlPCBs and PBDEs along the detritus food chain is reflected by a 30-40-fold increase of dry weight PBDE and dlPCB concentrations from settling particles to fish (1.8 ± 1.0 to 58 ± 31 and 6.8 ± 3.9 to 281 ± 155 ng g dry weight (dw), respectively). In this transference, dlPCB congeners presented more conservative patterns than those of PBDEs, basically due to debromination of BDE 99 and 153 to BDE 47 in fish. Lipid/organic carbon-based biota-sediment accumulation factors (BSAFs) ranged between 5 and 20 (7.3 ± 3.0 and 16 ± 8.0 for PBDEs and dlPCBs). Congener-specific BSAF of dlPCBs suggested a lower bioavailability of more planar non-ortho-PCB versus mono-ortho-PCB suggesting higher affinity to organic matter. BSAFs of PBDEs differed markedly among bromine homolog groups, supporting the biotransformation-formation from higher brominated to lighter congeners. The log BSAFs-log K relationship of dlPCBs and PBDEs presented a parabolic pattern maximizing at log K 6-7, but PBDE curve differs reflecting biotransformation processes. [ABSTRACT FROM AUTHOR]

Settling particles and bottom sediments collected at 1, 2.5, and 4 km off the metropolitan Buenos Aires coast in the Río de la Plata were analyzed to evaluate the sources and toxicity of resolved (PAHs) and unresolved (AROUCM) aromatic hydrocarbons. PANs (0003-2.1 μg g-1) and AROUCM (0.01 -78 μg g-1) presented the highest concentrations near the Buenos Aires port and sewer and decreasing values up- and downstream and along on- and offshore gradients. Sediment traps deployed in the Central area revealed large aromatic fluxes (1.3 ± 1.5 and 31 ± 47 mg m-2 day-1 for PAHs and AROUCM). The composition of sedimentary PAHs was dominated by uniformly distributed high molecular weight pyrogenic PANs (53 ± 11% fluoranthene, pyrene, and heavier PAHs), followed by diagenetically derived perylene more abundant in less polluted sites (29 ± 15%) and lower molecular weight petrogenic PANs (18 ± 7.1% phenanthrene, anthracene, and methylated compounds), which covaried inversely with perylene. PAH diagnostic ratios indicated a stronger influence of petrogenic discharges close to the shore and the prevalence of combustion of fossil fuels and vehicle emissions over wood in offshore sediments. Sediment cores showed sustained hydrocarbon levels with decreasing proportion of petrogenic PAHs and relative enrichment of pyrogenic components and perylene down to 20-cm depth. PAH toxicity assessment by sediment quality guidelines (SQG) and dioxin-equivalent factors (PAH TEQ: 0.08-395 pg g-1 dw) identified 1-2.5 km sediments close to the port and sewer as the most affected area. According to SQG, dibenz[a,h]-anthracene and pyrene were the most critical PAHs, followed by benzo[a]pyrene, benz[a]anthracene, and chrysene. In contrast, PAH TEQs were dominated by indeno[1,2,3-cd]- pyrene, benzo[k]fluoranthene, benzo[a]pyrene, perylene, and benz[a]anthracene which accounted for an average 86 ± 5.7% of total TEQs. [ABSTRACT FROM AUTHOR]

Settling particles and underlying sediments collected at 1, 2.5 and 4 km off the metropolitan Buenos Aires coast were analyzed to evaluate the sources and accumulation of resolved (RES), unresolved (UCM), and biomarker aliphatic hydrocarbons. Sedimentary aliphatic concentrations (RES 0.11-14 μg·g-1; UCM 0.1-80 μg·g-1) included variability associated with north-south gradients and an exponential offshore reduction. Highest concentrations were registered close to Buenos Aires port and sewer, compared to cleaner northern stations and southward sites affected by a seaward residue transport. Sediment traps deployed in the sewer area revealed large hydrocarbon (38 and 319 mg·m-2day-1, RES and UCM) and total organic carbon fluxes (29 ± 26 g·m-2day-1). The composition of RES and hopanes evaluated by principal component analysis indicated a consistent offshore gradient defined by the relative contribution of lower vs higher molecular weight components. Distant sites showed decreasing proportions of petrogenic n-C17-26 alkanes, isoprenoids, and C20-.27 terpanes and relative enrichment of n-C27,29,31,33 terrestrial plant alkanes and C31-33 homohopanes. Sediment hydrocarbon profiles showed an average 2-fold reduction down to 20 cm depth with preferential removal of lower molecular weight components and enrichment of n-C23-35 alkanes and hopanes. Sediment inventories and trap depositional fluxes indicate the accumulation of 5800- 9700 tons of aliphatic hydrocarbons in the top 0-5 cm sediments with a strong interfacial alteration and selective preservation of refractory components: n-C13-22 (1.0%) < isoprenoids (3.2%) < n-C23-35 (6.1%) < hopanes (47%) ∼UCM (50%), compared to intermediate stability of organic carbon (12%) and quantitative preservation of polychiorinated biphenyls (PCBs) (91%). [ABSTRACT FROM AUTHOR]

Atmospheric Polychlorinated Biphenyls (PCBs: ∑ 42 congeners) collected by polyurethane passive samplers (PAS-PUFs) in 29 stations from July 2010 to February 2014 (n=141) in the most productive and populated Southern Rio de la Plata area in Argentina were evaluated to assess concentration gradients, potential sources and compositional profiles related to different land use and urbanization. On a global scale, total airborne PCBs concentrations are low/very low (below detection limit to 937pgm -3 ) and show a significant potential correlation with urban scale increasing 2.5 times each 10 times increase of population reflecting the primary role of urbanization controlling PCB emissions. Compositional patterns evaluated by principal component analysis (PCA) of individual congeners indicated that highly populated atmospheres are enriched in lighter, more volatile tri, tetra and penta chlorine congeners of lighter Aroclor mixtures (from 1242 to 1254) suggesting actual emission of fresh PCBs signatures from sealants, combustion and/or electrical equipment. Sub urban and rural sites show a gradual transition to heavier Aroclor mixtures (from 1254 to 1260) with predominance of more persistent hexa and hepta PCBs indicating an aged background signal resulting from long range transport and/or re-emission from historic reservoirs such as soils., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In order to evaluate the impact of intensive agriculture on air quality in the most productive and populated Argentina's Pampas, a comprehensive assessment of airborne Endosulfan (∑Endo) was performed using polyurethane passive samplers deployed from 2010 to 2013 covering the critical period of Endosulfan restrictions at twenty nine sites in the Rural Pampa and Great Buenos Aires Metropolitan Area (GBA: Horticultural and Urban subareas). ∑Endo concentrations were very high and variable (0.01-63 ng m(-3)), exceeding worldwide reported maxima at Horticultural GBA and Rural Pampa with lowest values at Urban GBA (geometric means: 3.1, 1.1 and 0.53 ng m(-3), respectively). The composition was relatively fresh with strong predominance of Endo I (72 ± 18%) over Endo II (23 ± 15%) and Endo SO4 (5 ± 10%). Airborne ∑Endo was significantly correlated to annual soybean crop in Rural Pampa. ∑Endo concentrations showed a temporal pattern defined by consistent peaks enriched in Endo I during summer application periods, cold temperature minima with higher proportions of Endo SO4 and a general exponentially declining trend over time related to incipient control policies., (Copyright © 2015 Elsevier Ltd. All rights reserved.)