Assessment of anthropogenic pollution in Guanabara Bay (SE Brazil) through biogeochemical data and stable isotope mixing models.

This work intends to identify pollution sources along the margins of Guanabara Bay (GB; SE Brazil) through a multiproxy approach and Bayesian stable isotopic mixture model (BSIMM). For this purpose, 33 surface sediment samples were collected and analyzed for granulometry, geochemistry (heavy metals, total organic carbon-TOC, stable isotopes of carbon and nitrogen-δ13C and δ15N, Rock-Eval pyrolysis parameters-REPP), and physicochemical parameters. Metal concentrations (E) dissolved in water (EW), adsorbed by organic matter (EOM) and by Mn hydroxides (EMn), and total extracted concentrations (ET) were analyzed. Sampling was conducted in 2018 after an oil spill from Reduc Oil Refinery. Potential Ecological risk index (PERI), based on metals, classified 85% of the analyzed stations as having moderate to considerable ecological risk. The metals with the potential to cause the highest ecological risk were CdW, CdOM, PbOM, and HgOM. The combination of BSIMM and REPP data was an effective proxy for oil spill detection by indicating the presence of polycyclic aromatic hydrocarbons (PAHs). Relatively high TOC contents suggested that the analyzed stations are eutrophicated environments. BSIMM discriminated three groups of stations with different sources of organic matter (OM), endorsing the result previously shown by the cluster analysis: (A) Niterói region, Botafogo marina, Glória marina, Fiscal and Fundão islands with diffuse sources of OM, including marine phytoplankton and material of continental origin from highly polluted rivers and domestic sewage; (B) region near Fundão and Governador islands and Mangue Channel outlet with OM (≃70%) supplied by highly polluted streams and a small contribution of PAHs; (C) Duque de Caxias and Botafogo-Urca inlet with significant contributions of PAHs, materials from C-3 plants and rivers polluted by urban sewage. Results of linear regressions in conjunction with BSIMM indicate that HgMn and PbOM mainly affect Group A's stations. Although the eastern margin of GB (Niterói; Group A) showed greater oceanic interaction than the other groups, it presented substantial concentrations of metals, potentially harmful (i.e., Hg and Pb) to marine biota and human health.

Past environmental changes: using sedimentary photosynthetic pigments to enhance subtropical reservoir management.

The historical impacts of eutrophication processes were investigated in six subtropical reservoirs (São Paulo, Brazil) using a paleolimnological approach. We questioned whether the levels of pigment indicators of algal biomass could provide information about trophic increase and whether carotenoid pigments could offer additional insights. The following proxies were employed: organic matter, total phosphorus, total nitrogen, photosynthetic pigments (by high-performance liquid chromatography), sedimentation rates, and geochronology (by 210 Pb technique). Principal component analysis indicated a gradient of eutrophication. In eutrophic reservoirs (e.g., Rio Grande and Salto Grande), levels of lutein and zeaxanthin increased over time, suggesting growth of Chlorophyta and Cyanobacteria. These pigments were significantly associated with algal biomass, reflecting their participation in phytoplankton composition. In mesotrophic reservoirs, Broa and Itupararanga, increases and significative linear correlations (r > 0.70) between pigments and nutrients are mainly linked to agricultural and urban activities. In the oligotrophic reservoir Igaratá, lower pigment and nutrient levels reflected lesser human impact and good water quality. This study underscores eutrophication's complexity across subtropical reservoirs. Photosynthetic pigments associated with specific algal groups were informative, especially when correlated with nutrient data. The trophic increase, notably in the 1990s, may have been influenced by neoliberal policies. Integrated pigment and geochemical analysis offers a more precise understanding of eutrophication changes and their ties to human factors. Such research can aid environmental monitoring and sustainable policy development.

Five years after the collapse of the Fundão Dam: lessons from temporal monitoring of chemistry and acute toxicity.

In November 2015, the Fundão Dam break released millions of tons of metal-rich tailings into the Doce River Basin (DRB), causing catastrophic damage and potential ecological effects that reached the Atlantic Ocean. This study aimed to evaluate the geochemistry and toxicity of water and sediments collected in the DRB from 2015 to 2019 and to determine the spatial and temporal trends. Water and sediment samples were analyzed for metals and As by inductively coupled plasma optical emission spectrometry (ICP-OES), and acute toxicity for Daphnia similis or D. magna. Results were explored using geochemical indices and correlation analyzes. Overall, higher concentrations of metals and As in water and sediments were observed immediately after dam breakage, but the levels exhibited a decreasing trend over time, although the levels of some elements such as As and Mn remained high in the upper DRB. The geochemical indices indicated mostly low to moderate contamination, and the enrichment factor (EF) demonstrated a higher enrichment of Mn in the upper DRB. Acute toxicity to water fleas (D. similis and D. magna) was occasionally observed in waters and sediments, but the reference samples were toxic, and the short-term effects were not correlated with metals and As. Overall, the results showed limited bioavailability of metals and As and a decreasing trend in their concentrations, indicating an ongoing recovery process in DRB. These results are important to decision-making regarding the disaster and actions for environmental restoration.

Spatial-temporal variations of metals and arsenic in sediments from the Doce River after the Fundão Dam rupture and their bioaccumulation in Corbicula fluminea.

The rupture of the Fundão dam in Brazil released tons of mining tailings into the Doce River Basin (DRB). This investigation aimed to determine the bioaccumulation of metals in soft tissues of the bivalve Corbicula fluminea exposed to sediments collected in the DRB in four periods (just after, 1, 3, and 3.5 years after the dam rupture). In the exposure bioassays, the concentrations of Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in sediments and bivalve soft tissues were quantified. The concentration of some elements (As, Cd, Mn, and Al) in sediments exceeded the federal limits or regional backgrounds at some sampling sites, but their concentrations tended to decrease over time. However, higher concentrations of many elements were detected in the winter of 2019. Several elements were detected in C. fluminea soft tissues, but the bioaccumulation factors were generally low or not related to those elements associated with the ore tailings, evidencing that the bioavailability of metals to bivalves, in laboratory conditions, was limited. Integr Environ Assess Manag 2024;20:87-98. © 2023 SETAC.

Emergent properties of free-living nematode assemblages exposed to multiple stresses.

Biological communities are currently facing multi-stressor scenarios whose ecological impacts are challenging to estimate. In that respect, considering the complex nature of ecosystems and types and interaction among stressors is mandatory. Microcosm approaches using free-living nematode assemblages can effectively be used to assess complexity since they preserve the interactions inherent to complex systems when testing for multiple stress effects. In this study, we investigated the interaction effects of three stress factors, namely i-metallic mixture of Cu, Pb, Zn, and Hg (control [L0], low, [L1] and high [L2]), ii- CO2-driven acidification (pH 7.6 and 8.0), and iii- temperature rise (26 and 28 °C), on estuarine free-living nematode assemblages. Metal contamination had the greatest influence on free-living nematode assemblages, irrespective of pH and temperature scenarios. Interestingly, whilst the most abundant free-living nematode genera showed significant decreases in their densities when exposed to contamination, other, less abundant, genera were apparently favored and showed significantly higher densities in contaminated treatments. The augmented densities of tolerant genera may be attributed to indirect effects resulting from the impacts of toxicity on other components of the system, indicating the potential for emergent effects in response to stress. Temperature and pH interacted significantly with contamination. Whilst temperature rise had potentialized contamination effects, acidification showed the opposite trend, acting as a buffer to the effects of contamination. Such results show that temperature rise and CO2-driven acidification interact with contamination on coastal waters, highlighting the importance of considering the intricate interplay of these co-occurring stressors when assessing the ecological impacts on coastal ecosystems.

Biogeochemical and oceanographic conditions provide insights about current status of an Antarctic fjord affected by relatively slow glacial retreat.

Understand the origin, transport, and character of organic matter entering Antarctic fjords is essential as they are major components of the global carbon cycle and budget. Macromolecular pools of particulate organic matter, bulk organic geochemistry, major and trace elements in surface sediments from Collins Bay were analysed as source indicators. Oceanographic conditions, bathymetry (multibeam) and grain size were considered as environmental controlling factors. Sediment samples were taken with a van Veen grab, during the ANTAR XXV Peruvian expedition (February 2018), onboard the R/V "BAP Carrasco" from the Peruvian Navy. Biopolymeric composition revealed the predominance of fresh marine protein-rich organic matter in the seafloor of Collins Bay, denoting high quality food resource for marine benthic heterotrophs. Based on Igeo values (between 0 and 1) Collins Bay can be considered unpolluted with natural levels of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. Distribution of most of these elements with a gradient of decrease from the shallow inner fjord towards the outer deepest fjord, suggest their association with the deposition of detrital material and lithogenic particles supplied by Collins Glacier frontal ablation and runoff. This first comprehensive baseline information would assist in interpreting downcore sedimentary reconstructions and future climate-induce changes.

Chronostratigraphy elucidates environmental changes in lacustrine sedimentation rates and metal accumulation.

All changes taking place in a watershed have repercussions on lacustrine environments, being these, the sink of all activities occurring in the basin. Lake Titicaca, the world's highest and navigable lake, is not unfamiliar with these phenomena that can alter the sedimentation dynamics and metal accumulation. This study aimed to identify temporal trends of sedimentation rates by employing a geochronological analysis (210Pb, 137Cs) and to propose metal background values in Puno Bay, as well as to identify metal concentrations (As, Ba, Ca, Cr, Cu, K, Mg, Mo, Ni, Pb, Zn) in the projected timeline to propose, for the first time, background values in Puno Bay. Two sediment cores were collected from the outer and inner bays. Sediment rate (SR) was calculated through the excess of 210Pb (210Pbxs) applying the Constant Flux Constant Sedimentation (CFCS) model. Results show that SR in the outer bay was 0.48 ± 0.08 cm a-1 and for the inner bay was 0.64 ± 0.07 cm a-1. Sediment quality guidelines (SQGs) did not indicate toxicity was likely to occur, except for As. However, enrichment factors (EFs) indicated that all metal accumulation is geogenic. Climatic factors had a marked influence on sedimentation rates for the outer bay, and in the case of the inner bay, it was a sum of climatic and human-based factors.

Ocean warming and CO2-driven acidification can alter the toxicity of metal-contaminated sediments to the meiofauna community.

Interactive effects of trace metal contamination, ocean warming, and CO2-driven acidification on the structure of a meiofaunal benthic community was assessed. Meiofauna microcosm bioassays were carried out in controlled conditions in a full factorial experimental design which included three fixed factors: metal contamination in the sediment (3 levels of a mixture of Cu, Pb, Zn, and Hg), temperature (26 and 28 °C) and pH (7.6 and 8.1). Metal contamination caused a sharp decrease in the densities of the most abundant meiobenthic groups and interacted with temperature rise, exacerbating deleterious effects for Nematoda and Copepoda, but mitigating effects for Acoelomorpha. CO2-driven acidification resulted in increased acoelomorphs density, but only in sediments with lower levels of metals. Copepod densities, in turn, were lower in the CO2-driven acidification scenario regardless of contamination or temperature. The results obtained in the present study showed that temperature rise and CO2-driven acidification of coastal ocean waters, at environmentally relevant levels, interacts with trace metals in marine sediments, differently affecting the major groups of benthic biota.

Polycyclic aromatic hydrocarbons in a Natural Heritage Estuary influenced by anthropogenic activities in the South Atlantic: Integrating multiple source apportionment approaches.

Polycyclic aromatic hydrocarbons (PAHs) were analysed in the sediments of one of the most well-preserved estuaries in South Brazil, the Paranaguá Estuarine System (PES), using several source apportionment tools. The ∑PAH ranged from < DL to 125.6 ng g-1 dw (dry weight) (average 29.9 ± 26.1 ng g-1 dw), and the lowest levels detected were similar to those found in other protected areas of the world. In general, the PAH concentrations indicated excellent environmental quality for the entire estuary. Principal component analysis indicated that fine sediments and total organic carbon were the main factors controlling PAH concentrations in the PES. Multiple PAH sources were identified in the study area; biomass burning and fossil fuel combustion predominated but considerable amounts of petrogenic residues were also observed. We identified evidence of a contribution from an adjacent watershed resulting from the construction of interconnections between large rivers and from years of intense deforestation in the local Atlantic Forest.

Spatial distribution of arsenic and metals suggest a high ecotoxicological potential in Puno Bay, Lake Titicaca, Peru.

Spatial distribution and interpolation methods provide a summarized overview about the pollution dispersion, concerning the environment's quality. A high-altitude lake was taken as a model to assess the metalloid As and metals Cr, Cu, Ni, Pb, Zn distribution in superficial sediment and classify them according to their ecotoxicological potential in the aquatic environment. Surface sediments were collected from 11 sites along Puno Bay located at the western area of Lake Titicaca, Peru, and analyzed for pseudo total-metals. Sediment concentration data and quality were plotted using the Inverse Distance Weighting (IDW) as an interpolation method. High concentrations of As were found especially in the outer bay (81.73 mg.kg-1). Spatial heterogeneity was evidenced for metal by the coefficient of variation, although no significative differences were observed between the two bays applying a Kruskall Wallis test (p < 0.05, df = 1). Sediment quality classification showed that most metal values were below TEL and toxicity was unlikely to occur, only As exceeded threefold PEL values, which categorized sediment as "Very Bad", indicating a rather high ecotoxicological potential to the aquatic environment. In conclusion, spatial analysis connected to interpolation methods demonstrated the superficial sediment heterogeneity in Puno Bay.

Inferring the ecological quality status based on living benthic foraminiferal indices in transitional areas of the Guanabara bay (SE Brazil).

Using benthic foraminifera, we evaluate the ecological quality status (EcoQS) of transitional waters of the Guanabara Bay (SE Brazil) by applying the diversity-based index exp (H'bc) and the sensitivity-based Foram-AMBI for the first time in South America. The Guanabara Bay was selected for this study as it is one of the largest transitional ecosystems in the State of Rio de Janeiro and has been severely impacted by anthropogenic activities. Concentrations of potentially toxic elements (PTEs) were assessed by sequential chemical extraction in three phases (i.e., dissolved in water, adsorbed on organic matter, and Mn oxy-hydroxides). Total organic carbon, total nitrogen, and stable isotope (δ13C and δ15N) signatures of organic matter were analyzed to trace environmental stress. The Ammonia/Elphidium ratio suggests hypoxic conditions at most of the sampled sites. Principal component analysis identifies the first component as environmental stress underlying organic matter and PTE enrichment (in all three phases), which is positively related to Foram-AMBI and negatively to exp (H'bc). The exp (H'bc) and Foram-AMBI indices reveal that stations near the Governador Island and Niterói margin have the worst EcoQS, showing medium to extreme pollution. Additionally, Foram-AMBI and exp (H'bc) provide a congruent EcoQS classification for ∼64% of the sites. Although these results are promising, they suggest that a significant effort should be made to obtain better knowledge of foraminiferal ecological requirements to employ benthic foraminifera as a biomonitoring and management method.

Bioaccumulation of heavy metals in estuaries in the southwest Atlantic Ocean.

The southwestern Atlantic Ocean is home to highly productive regions, composed of a mosaic of both protected and anthropogenically impacted areas, including the estuaries of Paranaguá, Cananéia, and Santos. In this study, concentrations of metals were measured in sediments and in marine organisms, collected from these three Brazilian estuaries. The higher concentrations of metals in the sediments from the Santos estuary are due to having the greatest intensity of anthropogenic activities. There is bioaccumulation of As, Cu, Ni, and Pb in benthic invertebrates, As in fish, and Se and Zn in all studied trophic groups. Comparing the biota among estuaries, levels were highest for Cr, Cu, Pb, Se, and Zn in Paranaguá, As in Cananéia, and Ni in Santos; results justified due to anthropogenic activities, natural sources, and geochemical and hydrodynamics characteristics of each region that affect the bioavailability of metals. The results showed that these regions of the Atlantic present higher levels of metals in the biota than several coastal regions worldwide, and signal that food security may be compromised. Highlighting the need for better impact assessment, monitoring, and managing is deemed necessary as these regions are globally recognized as hotspots of biodiversity and are considered priority areas for conservation.

Historical mercury contamination in a major Latin American industrial and port complex: The case of the Santos estuary, Southeastern Brazil.

The present study determined total mercury (Hg) in four 210Pb dated sediment cores to assess the historical anthropogenic Hg accumulation in the Santos estuary, Southeastern Brazil. Background levels were identified using the deepest sections of the cores, corresponding to pre-industrial ages. Mercury distribution in the sediment cores (0.02-2.64 mg kg-1) presented a large spatial and temporal variation. Contamination is highest in the upper estuary and indicates that the industrial hub, especially a chlor-alkali plant is the primary source of Hg. A contaminant trap effect is observed in this area associated with high fine sediment accumulation and Hg fluxes. The contamination pattern indicates that the regions not affected by direct inputs are influenced by reworking, resuspension, and transport of contaminated sediments by tidal flows. The Hg enrichment in the upper layers of the sediment cores demonstrates that the environmental actions fulfilled in the 1980s were insufficient to control Hg pollution in the Santos estuary.

Unusual natural polycyclic aromatic hydrocarbons in sediment cores of an Amazon estuary.

Polycyclic aromatic hydrocarbons (PAHs) most likely derived from natural sources were observed in two sediment cores covering the last 100 years in an Amazon estuarine region. A considerable change in the PAHs main source was observed in the 1960s. Before the 1960s, the sources of PAHs seem to be related to biogenic and/or early-diagenetic processes. Concentrations of perylene were higher before the 1960s and suggest that its primary source to the sediments in the Amazon region is linked to a short-term diagenetic transformation of their biogenic precursors. The natural formation of alkylated PAHs in sediments was linked to the methylation of the parental aromatic hydrocarbons due to sediment maturation processes and the dehydrogenation of sterols in the sediments. The relatively rapid reaction occurring in recent sediments of the Amazon region suggests the importance of the microbial community in the transformation of biogenic precursors to alkylated-PAHs in the sediments.

Genotoxic effects of silver nanoparticles on a tropical marine amphipod via feeding exposure.

Silver nanoparticles (AgNP) are widely used in several applications including as antifouling agents; therefore, they can end up in estuarine and marine environments. These nanoparticles tend to aggregate and to deposit in the sediment, where many organisms feed and reproduce. Parhyale hawaiensis is an epibenthic amphipod globally distributed in tropical zones, and has been considered a potential model for ecotoxicology. The aim of this study was to evaluate genotoxic effects of AgNP and Ag salt via feeding, as P. hawaiensis lives in the sediment where nanoparticles tend to accumulate. Organisms were cultivated in the laboratory, and adults were exposed to food containing both AgNP and Ag salt. We collected hemolymph after different times of exposure, and analysed the hemocytes for nuclear abnormalities (including micronuclei) and DNA damage using the standard alkaline comet assay. Conditions of both assays were developed/optimized to allow their successful application in marine invertebrates. Increased frequencies of micronuclei, nuclear buds and total abnormalities were detected in relation to concentration and time in organisms exposed to AgNP and Ag salt in comparison to the controls. No DNA damage was detected when the alkaline comet assay was applied. After 5 days of exposure, we observed higher micronuclei frequencies in Ag salt treatment in comparison with AgNP. After 13 days, micronuclei frequencies were similar for both silver forms. We believe that the Ag, in its ion form, is causing the mutagenic effect; therefore, more time would be needed for the release of the ion from AgNP, explaining the delayed mutagenic effect.

Assessment of crabs from Trindade, a Brazilian remote island: Support to marine studies.

Trindade is a remote island far from 1170 km of the Brazilian coast in the Atlantic Ocean, between South America and South Africa. The island has great biodiversity and scientific studies on the fauna and flora of Trindade are still scarce. Accordingly, since crustacean species of the island are also little known, this research features an unprecedented data set, which provides information on the level of potential toxic elements in two crab species: the Grapsus grapsus (herbivore) and the endemic species Gecarcinus lagostoma (omnivorous) which is in threatened status. Although Trindade has experienced contamination from human activities, mainly plastic debris, the element levels found in the samples suggest that there are no relevant inorganic sources into the island. Since minor and trace elements accumulated by marine invertebrates does not present a pattern behavior, our results can support other studies focused on the impact of global warming to the marine ecosystem.

Geochemistry and sedimentary photopigments as proxies to reconstruct past environmental changes in a subtropical reservoir.

Sediment cores were used to establish past environmental impacts associated with eutrophication, erosion and metal contamination in the subtropical Atibainha reservoir (São Paulo State, Brazil). We hypothesize that: (1) the levels of nutrients, determined by a spectrophotometric method, reflect the contributions of these elements over time and (2) changes in sedimentation rates, determined by 210Pb geochronology, and metal flows, determined by ICP-AEOS, are related to anthropic activities. Stratigraphic changes in the analysed variables were used to divide the sediment cores into three intervals, according to PCA and cluster analysis (Euclidian distances, Ward's method). Interval I, composed by the period prior to operation of the reservoir, was influenced by organic matter levels. Interval II, between 1967 and 1993 (PC2: 14.94% of the total variability), a period of minor impacts, was mainly influenced by Mn (eigenvalue of 0.71) and Zn (0.74). Interval III, which included sediment deposited between 1993 and 2015 (PC1: 60.28% of the total variability), was influenced by the highest levels of the pigments lutein (0.86), zeaxanthin (0.90) and fucoxanthin (0.65), together with total nitrogen (0.78) and sedimentation rate (0.91), suggesting changes in the phytoplankton community composition probably associated to the intensification of eutrophication and erosion processes. Despite the limitations of applying paleolimnological techniques in reservoirs and the use of pigments as proxies in regions with higher temperatures, it was observed that the anoxic conditions and the aphotic environment in the hypolimnion acted to preserve pigments associated with the groups Chlorophyta (lutein), Cyanobacteria (zeaxanthin) and Bacillariophyta (fucoxanthin). The isolated analysis of nutrients was not sufficient to make conclusive inferences regarding the eutrophication history, since the levels of TP tended to decrease over time, in contrast to an increase in the levels of TN. Despite intensification of eutrophication and erosion, associated to anthropic activities, no signs of metal contamination were recorded.

Trace element fluxes during the "Anthropocene" in a large South American industrial and port area (Santos and São Vicente estuarine system, SE, Brazil).

The worldwide evidence of human activities on the environment led the scientific community to recognize a new geologic time unit known as the "Anthropocene." Since the twentieth century, urbanization and industrialization needs driven by population and economic growth have impacted several ecosystems including the estuaries. To assess the contamination, provenance, and fluxes of trace elements (As, Cr, Cu, Ni, Pb, Sc, V, and Zn) over the last century, a geochemical and chemometric technique was employed in sediment cores of an industrial and port region of international importance, the Santos and São Vicente Estuarine System (SSVES). The results indicated low contamination, with the highest enrichment factors (EFs) for Cu (EF = 3.1), Pb (EF = 2.7), Zn (EF = 2.4), and As (EF = 2.3) found next to the harbor area. The Pre-industrial records confirm the relatively high concentrations of As and its naturally enriched occurrence on the Brazilian shelf. Sediment accumulation rates and trace element fluxes showed a general increase over the years, since the early 1960s, associated with the "Great Acceleration" of the mid-twentieth century. These alterations are human-induced and include urbanization and industrialization. Nonetheless, as the contents and enrichment of trace elements indicate that the region is not severely polluted, we hypothesize that the contamination in the SSVES is likely related to the drainage and erosion of the urbanized adjacent area, rather than direct disposal of inorganic contaminants from the industrial activity.

Sediment contamination and toxicity of Marine Protected Areas in southeastern Brazilian coast: A baseline for management planning.

Recent studies have shown that the effectiveness of establishing Marine Protected Areas (MPAs) is threatened by toxic effects of contaminants. São Paulo is the most economically developed state of Brazil, and its coast is protected by a system of MPAs, including the North Shore Marine Protected Area (NSMPA). The present study provides a first assessment of sediment quality in NSMPA and two reference sites. Concentrations of arsenic (As), metals (Al, Fe, Cd, Cr, Cu, Ni, Pb, and Zn) and polycyclic aromatic hydrocarbons (PAHs) and its sources were determined. Comparisons with sediment quality guidelines indicated low contamination, as confirmed by the Geoaccumulation Index, which classified the results as background levels. Whole-sediment exposures of the amphipod Tiburonella viscana were performed to estimate possible acute effects, but samples exhibited no toxicity. The results presented in this study represent a baseline for further monitoring programs of MPAs, supporting conservation actions of management plans.

Historical deposition of PAHs in mud depocenters from the Southwestern Atlantic continental shelf: The influence of socio-economic development and coal consumption in the last century.

Polycyclic aromatic hydrocarbon (PAH) concentrations were determined in four dated sediment cores collected in mud depocenters of the southern Brazilian continental shelf. Core dating results covered the interval between 1925 and 2017. The total PAH concentrations (ΣPAHs) ranged from 44.69 ng g-1 to 305.43 ng g-1 and were similar between the analysed cores. Fine-grained sediments and total organic carbon (TOC) results did not correlate with the ΣPAHs, indicating that the variations in PAH concentrations are mostly related to variations in sources and emissions. PAH source appointment indicated a high input of a natural compound (perylene) and the predominance of anthropogenic PAHs from coal, biomass, and fuel combustion. Alkylated PAHs presented high contributions throughout all cores. The historical deposition of PAHs was associated with different periods of the socio-economic and industrial development of near coastal cities and reflected very well the history of coal production and consumption in the southern region of Brazil. The low levels of ΣPAHs before 1945 in all analysed cores may be related to the beginning of the industrialization process and the lower urbanization degree in the region. Between 1945 and 1965, the gradual ΣPAHs increase reflects the establishment and enlargement of the southern Brazilian industrial sector. The interval between 1965 and 1990 corresponded to the highest ΣPAHs in three of the four analysed cores. After 1990, a relative decrease in the ΣPAHs was observed in most cores and may be related the multiple cuts of incentives to the industrial usage of coal, as well as to Brazil's efforts in environmental regulation for coal extraction and consumption.