A multi-molecular marker assessment of organic pollution in shore sediments from the Río de la Plata Estuary, SW Atlantic

Concentrations, sources and risks of polycyclic aromatic hydrocarbons in sediments from the Parnaiba Delta basin, Northeast Brazil

The Parnaíba River is the main river in the Parnaíba Delta basin, the largest delta in the Americas. About 18 polycyclic aromatic hydrocarbons (PAHs) were identified and the environmental risk associated with the sediments was evaluated. The study found that PAHs levels ranged from 5.92 to 1521.17 ng g-1, which was classified as low to high pollution, and that there were multiple sources of pollution along the river, with pyrolytic sources predominating, mainly from urban activity such as trucking, although the influence of rural activity cannot be ruled out. PAHs correlated with black carbon and organic matter and showed high correlation with acenaphthylene, phenanthrene, pyrene, benzo(a)anthracene, chrysene, benzo(ghi)perylene, and ∑PAHs. The benzo(a)pyrene levels were classified as a risk to aquatic life because the threshold effect level and the probable effect level were exceeded. In addition, the sediments were classified as slightly contaminated with a benzo(a)pyrene toxicity equivalent value of 108.43 ng g-1. Thus, the priority level PAH exhibited carcinogenic and mutagenic activity that posed a potential risk to human health.

Insights about levels and sources of organic pollution in an urbanized Amazon estuary (Belém, PA, Northern Brazil)

Amazon aquatic systems have been affected by organic pollution from urbanized regions. This study was conducted to determine the levels, sources, and distribution patterns of 16 polycyclic aromatic hydrocarbons (PAHs) and 6 steroid markers in surficial sediments from an important urbanized Amazon estuarine system (Belém, PA, Northern Brazil). Total PAH concentration (∑PAH) ranged from 878.2 to 9905.7 ng g^-1, 3295.2 ng g^-1 on average, suggesting a highly contaminated environment. PAH molecular ratios and statistical analysis indicated that PAH originated from a mixture of local sources emissions, mainly related to the combustion of fossil fuels and biomass. Coprostanol levels (maximum concentration = 292.52 ng g^-1) could be compared to the mid-range reported in the literature. Studied stations, except for one, presented sterol ratio data indicating organic matter related to untreated sewage. Sterols indicative of sewage contamination showed a correlation with pyrogenic PAH amounts which are transported by the same channels where sewage is discharged.

Insights about levels and source appointment of petroleum hydrocarbons in Brazilian semi-arid coastal: baseline status assessment for ocean decade targets

The Ocean decade (2021-2030) for sustainable development proclaimed in 2017 by the UN, seeks to promote and conserve the sustainable use of oceans, seas, and marine resources. For this, the distribution of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and biomarkers, in sediments from the Fortaleza coastal zone (Mucuripe harbor (MH) and Inner Continental shelf (ICS)) were used to assess the impacts of anthropogenic activities in the area. The concentrations of total n-alkanes (Σ16 n-alkanes) in MH and ICS sediments varied from 35.9 to 94.9 and 17.9 to 197.3 μg g^-1, respectively, while the isoprenoids phytane and pristane in MH and ICS sediments ranged from 0.1 to 1.69 ug g^-1 and from 0.14 and 1.20 μg g^-1, respectively. Most of the sediment samples presented carbon preference index (CPI) values close to unity, indicating that the area is submitted to petroleum-related sources. The concentrations of Σ16 PAHs in MH and ICS sediments varied from 87.0 to 562.0 and 98 to 288.0 ng g^-1. This work presents the first investigation of the petroleum biomarkers hopanes and steranes in the Fortaleza coastal zone, in which ΣBiomarkers varied from 0.10 to 1.79 and 0.02 to 0.24 ug g^-1 in MH and ICS sediments, respectively. The presence at stations of biomarkers also indicates petrogenic input. The diagnosis of the distribution of pollutants in the investigated zones of the Fortaleza coast suggests contamination from urban areas and oil spills and vessel traffic.

Pollution has negative effects on macrozoobenthic trait diversity in a large subtropical estuary

Changes in species composition and relative abundance caused by pollution might have an impact on the community dynamics and ecosystem functioning. Macrobenthos are widely used as indicators of marine environmental health due to their sensitive to disturbance. The present study aims to evaluate spatial and temporal variability of functional diversity of macrobenthos of the Montevideo and Canelones coastal zone along a pre-established pollution gradient, based on Biological Traits Analysis, and functional diversity indices. Body-size", "Feeding-mode", "Habitat", and "Indicator-role" were useful proxies to detect changes in environmental conditions in organically enriched habitats. FRic, FEve and FDis detected temporal variations but only FRic registered spatial variations. Differences among surveys would mainly reflect environmental variability caused by the 2009-2010 El Niño-Southern Oscillation event. Finally, negative correlations between FEve and FDis with AMBI suggest both indices as useful proxies of benthic environmental health, with potential to be used in monitoring and quality assessment programs.

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.

Sterol and PAHs fingerprint analysis of organic matter at Southeast Brazilian Bay

Southeast Brazilian bays have been increasingly degraded by untreated organic loads. Therefore, to assess fecal contamination status, sediment quality regarding polycyclic aromatic hydrocarbons (PAHs), and sources of organic matter (OM), we have determined fine-grained and total organic carbon (TOC) content and concentrations of PAHs and sterols in twenty-six surface sediment samples in Sepetiba Bay. The fine-grained (1-26 %), TOC (0.20-3.45 %), PAHs (<LQ - 78.27 ng g^-1) and sterols (0.10-21.58 μg g^-1) results showed a decreasing trend from the internal to the external sector of the study area. The diagnostic ratios of selected PAHs and sterols indicated a mixture with significant contribution from continental and pyrolytic OM in all stations. The fecal contamination is significant to the internal sector of Sepetiba Bay. Considering a site-specific sediment quality guidelines (SQGs) the PAHs levels with more restricted benchmark values indicate the harbor and the internal sector as contaminated.

An integrated assessment to reconstruct the history of changes influenced by multiple anthropogenic activities (City of Fortaleza, Ceará, Brazil)

In this study, the multi-marker approach was used for the first time with a highly urbanized lake located in the city of Fortaleza, Brazil, to provide a comprehensive view of temporal trends in sources of pollutants and evaluate the relation between the influence of anthropogenic activities and socioeconomic development. Total concentrations of the markers analyzed ranged from 21.0 to 103.8 ng g^-1, 450.2 to 2390.2 ng g^-1, and 233.8 to 9827.3 ng g^-1 for ∑_PAHs, ∑_n-alk, and ∑_sterols, respectively. Concentrations and patterns of PAH, AH, and sterol ratio distribution changed over time and may be associated with different episodes in the history of the city of Fortaleza. The marker ratio distribution in the sediment core revealed an overlap of natural and anthropogenic sources, with degraded oil, biogenic inputs, pyrogenic processes, and fecal contamination from humans and animals in the past changing to petroleum fossil inputs and high contamination from sewage in the present day. The distribution of markers and the chronological history of Fortaleza revealed two distinct periods related to human activities during the development of the city. In the first period (prior to the 1950s), the main human activities were animal breeding and the use of biomass for domestic activities, public and cargo transportation, and commercial activities, especially food production. In the second period (after the 1950s), expansion of the city occurred due to the so-called Brazilian economic miracle and the main human activities were industrialization and urbanization processes, involving deforestation, paving, sewage discharge, and petroleum combustion.

Dealing with complex contamination scenarios: using a multi-geochemical approach to assess environmental quality and identify pollution sources in a semi-arid estuary from Brazil

The Jundiaí-Potengi Estuary (EJP) is located on the semi-arid coast of northeastern Brazil and is influenced by multiple sources of contamination. The sediment quality of EJP was assessed by using a multi-geochemical approach during the dry and wet seasons. Sediments were analyzed for concentrations of nutrients, metals, polycyclic aromatic hydrocarbons (PAHs), pesticides, hormones (natural and synthetic), and sterols. The results were integrated by multivariate methods. The sediment was altered by the presence of contaminants from anthropogenic and natural sources. The middle and lower estuarine areas were considered more degraded in both seasons. In these regions, metals, hormones, sterols, and PAHs were found, indicating that these regions are severely affected by industrial, sanitary and aquaculture effluents, combustion of fossil fuels, and oil spills. The upstream region was contaminated by pesticides. The contamination pattern along the EJP shows the prevalence of local sources which continuously release the chemicals into the estuary. Worse conditions occurred during the rainy season, when the runoff from urban and rural areas is more intense and carries a greater load of contaminants to the EJP.

A review on advances in removal of endocrine disrupting compounds from aquatic matrices: Future perspectives on utilization of agri-waste based adsorbents

In the recent past, a class of emerging contaminants particularly endocrine disrupting compounds (EDCs) in the aquatic environment have gained a lot of attention. This is due to their toxic behaviour, affecting endocrine activities in humans as well as among aquatic animals. Presently, there are no regulations and discharge limits for EDCs to preclude their negative impact. Furthermore, the conventional treatment processes fail to remove EDCs efficiently. This necessitates the need for more research aimed at development of advanced alternative treatment methods which are economical, efficient, and sustainable. This paper focusses on the occurrence, fate, toxicity, and various treatment processes for removal of EDCs. The treatment processes (physical, chemical, biological and hybrid) have been comprehensively studied highlighting their advantages and disadvantages. Additionally, the use of agri-waste based adsorption technologies has been reviewed. The aim of this review article is to understand the prospect of application of agri-waste based adsorbents for efficient removal of EDCs. Interestingly, research findings have indicated that the use of these low-cost and abundantly available agri-waste based adsorbents can efficiently remove the EDCs. Furthermore, the challenges and future perspectives on the use of agri-waste based adsorbents have been discussed.

Levels, source appointment, and ecological risk of petroleum hydrocarbons in tropical coastal ecosystems (northeast Brazil): Baseline for future monitoring programmes of an oil spill area

We reviewed 20 years of levels, sources, and environmental risks related to the main petroleum hydrocarbons in the northeast region of Brazil. The aim of this study was to conduct a systematic review to serve as a comprehensive baseline for future monitoring programmes related to the oil spill disaster in 2019/2020. Most contamination levels of both PAHs and AHs were classified as low, except those in specific areas influenced by human activities, such as ports, highly urbanised mangroves, or rivers of medium-sized cities with inadequate liquid and solid waste treatment. Most hydrocarbons were linked to natural sources and burning processes, except in regions of extraction activities and petrochemical facilities as well as highly urbanised areas, where degraded petroleum and oil hydrocarbons predominated. Only 2.5% of the samples exceeded threshold effect levels for ∑_16-PAHs and no samples exceeded probable effect levels. When regional threshold levels were used, however, the probable effect for the ∑_16-PAHs measured was high, ranging from 5.8 to 6.1%. The few studies reporting biological responses showed that hydrocarbons from anthropogenic sources can induce adverse effects on marine organisms even at low to moderate levels. As the region has recently received a considerable quantity of crude oil, studies should be prioritised for a more precise assessment of the impact of this oil spill.

Occurrence and source apportionment of organic pollutants in deep sediment cores of the Venice Lagoon

In this study, recent and aged inputs of five classes of organic contaminants (i.e. PCBs, OCPs, PCDD/Fs, PAHs, and n-Alkanes) were evaluated in eight deep sediment cores of the Venice Lagoon, collected along the path of a new waterway whose excavation is under evaluation by local authorities, to assess the environmental quality status of the area. Diagnostic indices were calculated for identifying pollutant distribution patterns and their major emission sources, whose relative contribution was quantified by a Positive Matrix Factorization source apportionment model. Sedimentary depth profiles highlighted higher contamination in the top layer, mainly related to ship traffic combustion and vehicular/industrial emissions from the mainland. Nevertheless, a significant level of pollution has been detected also in the deeper layers, probably due to the transport of particulate matter through the aquifers underlying the lagoon seabed. The results underlined the threat posed by the possible resuspension of pollutants in the water column during contaminated sediment dredging.

Marine protected areas in Latin America and Caribbean threatened by polycyclic aromatic hydrocarbons

The present study is a literature-based analysis investigating occurrence and the possible consequences of polycyclic aromatic hydrocarbons (PAH) in marine protected areas (MPAs) of Latin America and Caribbean. The approach using overlapping of georeferenced MPA polygons with data compiled from peer-reviewed literature, published during the last 15 years, showed 341 records of PAH in 9 countries. PAH was reported to occur within the boundaries of 36 MPAs located in Argentina, Brazil, Colombia, Mexico, Nicaragua and Uruguay. According to quality guidelines, low to moderate impacts are expected in MPAs categorized in different management classes. Considering sediment samples, 13% of the records presented concentrations enough to cause occasional toxicity. Such level of risk was also seen in Ramsar sites and in Amazonian MPAs. In addition, based on concentrations reported in biota, occasional deleterious effects on organisms from Biosphere Reserves might occur. Diagnostic ratios pointed out petrogenic and pyrolytic processes as PAH predominant sources, and were mainly attributed to the proximity to ports, industries and urban areas. MPAs located in the vicinity of impact-generating areas may be under threat and require government attention and action, mainly through implementation of contamination monitoring programs.

Occurrence, distribution, spatio-temporal variability and source identification of n-alkanes and polycyclic aromatic hydrocarbons in water and sediment from Loskop dam, South Africa

In this study, the spatial and temporal variations in the levels of C8-C40 n-alkanes and 18 polycyclic aromatic hydrocarbons (PAHs) in water and sediment from Loskop Dam (Mpumalanga Province South Africa), were investigated between 2015 and 2017. In addition, their sources, which have not been well defined, were also studied over the period. This water body is sourced from a historically contaminated water body, the Olifants River, which flows through areas where a range of industrial and agricultural activities take place. Mass crocodile and fish mortalities have been recorded in this aquatic system, and contamination by organic pollutants were highlighted as a contributing factor. The total average n-alkane concentrations in water and sediments ranged from 0.574±00811 to 18.8±1.39 µg/L and 4760±243 to 30700±906 µg/kg, respectively. Similarly, PAHs were detected at total average concentrations of between 0.150±00494 and 49.8±6.86 µg/L in water and 61.6±5.95 to 2618±300 µg/kg. n-Alkane and PAH diagnostic ratios indicated a mixture of sources of these compounds, attributed to terrestrial, submerged and floating plant material, as well as petrogenic and pyrogenic combustion. Inlet, middle and upper segment site clustering was observed with non-metric multidimensional scaling (NMDS) and hierarchical cluster analysis (HCA), mainly driven by the prevalence of PAHs at the inlet sites and n-alkanes in the upper reaches. By using indicator compounds, the sources of contamination could be predicted. The strategy described here can be applied to any water body for continuous long-term monitoring of pollutant levels and to identify sources attributing to water pollution.

Data on hydrocarbons in sediment samples, and its body burden levels in tissues of Anomalocardia flexuosa from toxicity testing

The analysis of hydrocarbons in terms of individual compounds is relevant to understand the origin and source of these substances, as well as its distribution in environmental compartments, including sediments and biota. Hydrocarbons concentrations were determined in sediments and in whole-body soft tissues of the tropical clam Anomalocardia flexuosa in sediment toxicity testing using samples of Mucuripe bay (Ceará State, NE Brazil) collected in 2011 during dredging events [1]. Data of target compounds included aliphatic (AHs) and aromatic hydrocarbons (PAHs), and linear alkylbenzenes (LABs). AHs compounds were determined on gas chromatography with flame ionization detector (GC-FID), while PAHs and LABs were determined on gas chromatography coupled to a mass spectrometer (GC/MS) in a selected ion mode (SIM). The potential of this dataset is baseline information on hydrocarbons contamination in sediments from a semi-arid region and the bioaccumulation of organic contaminants in marine organisms that can be used as models in ecotoxicological studies.

Sedimentary record of hydrocarbons and sewage inputs from a highly populated region in South-Eastern Brazil

The environmental impacts of the urban expansion in Rio de Janeiro was evaluated based on the historical accumulation of black carbon (BC), aliphatic (AHs) and aromatic hydrocarbons (PAHs) and sterols in a sediment core retrieved from Botafogo Cove. BC related to oil combustion sources increased significantly since the 1990s. AHs were associated with petroleum inputs and revealed a high level of contamination. Multivariate statistical methods (a Principal Component Analysis associated with a linear multiple regression - PCA/LMR) applied to PAHs suggests changes in the sources in recent years. This can be ascribed to a reduction in pyrogenic emissions over the last four decades and to an increase in petrogenic inputs since the 1990s. The sterol dinosterol registered the increased eutrophication over the last three decades, but the sewage marker coprostanol was present at relatively low concentrations (0.40 to 1.16 μg g^-1) probably caused by enhanced bacterial activity in the sediment.

First Characterization of PAH-degrading bacteria from Río de la Plata and high-resolution melting: an encouraging step toward bioremediation

The Río de la Plata, one of the most important estuarine environments in South America that sustains valuable fisheries, is affected by PAH contamination associated with oil industry and port activities. A total of 95 bacteria with potential to degrade phenanthrene were obtained from water samples using traditional culture methods. PCR-RFLP analysis of 16S rDNA partial fragments was used as a screening tool for reducing the number of isolates during diversity studies, obtaining 42 strains with different fingerprint patterns. Phylogenetic analysis indicated that they were affiliated to 19 different genera of Gamma- and Alpha-Proteobacteria, and Actinobacteria. Some of them showed an efficient phenanthrene degradation by HPLC (between 83% and 97%) and surfactant production (between 40% and 55%). They could be an alternative for microbial selection in the degradation of PAHs in this estuarine system. In order to detect and monitor PAH-degrading bacteria in this highly productive area, rDNA amplicons of the 33 isolates, produced by PCR real time, were tested by the high-resolution melting (HRM) technique. After analyzing the generated melting curves, it was possible to accurately distinguish nine patterns corresponding to eight different genera. HRM analysis allowed a differentiation at the species level for genera Pseudomonas, Halomonas and Vibrio. The implementation of this method as a fast and sensitive scanning approach to identify PAH-degrading bacteria, avoiding the sequencing step, would mean an advance in bioremediation technologies.

Influence of anthropogenic activities and risk assessment on protected mangrove forest using traditional and emerging molecular markers (Ceará coast, northeastern Brazil)

Anthropogenic molecular markers were used to assess chemicals inputs and ecological risks associated from multiple sources to sediments in one of the largest tropical mangrove forests of South America, with a particular focus on lesser studied compounds resulting from rural activities. Total concentrations ranged from 23.4 to 228.2 ng g^-1 for polycyclic aromatic hydrocarbons (∑_PAHs), 750.4 to 5912.5 ng g^-1 for aliphatic hydrocarbons (∑_AHs), 32.4 to 696.6 ng g^-1 for pesticides (∑_pesticides), 23.1 to 2109.7 ng g^-1 for coprostanol and sterols (∑_sterols), 139.3 to 580.2 ng g^-1 for naturals hormones (∑_{natural hormones}) and 334.1 to 823.4 ng g^-1 for synthetics hormones (∑_{synthetic hormones}). The PAHs and AHs used as traditional anthropogenic markers showed a mixture between natural and anthropogenic sources, related mainly to inputs from higher plants, phytoplankton and both, biomass and petroleum combustion. Rural activities linked to agricultural pest control are the predominant source of pesticides, although minor inputs from pesticides used in urban public health campaigns and household activities were also detected. Synthetic hormones levels are two to three orders of magnitude greater than natural hormones levels and no correlations were observed between the main sewage markers and synthetic hormone concentrations, rural activities such as animal husbandry, which use drugs in management, may be the predominant anthropogenic sources of these compounds in the region. Traditional markers failed to detect ecological risks in rural areas, where synthetic substances (e.g. pesticides and hormones) are widely used and introduced in the environment.

Distribution, sources and consequences of nutrients, persistent organic pollutants, metals and microplastics in South American estuaries

Estuarine pollution imposes rapid, increasing and lasting environmental modifications. In the present review, especial attention is given to estuaries in South America (SA), where legislation, policies and actions to guarantee environmental quality remain ineffective. There, the majority of estuaries face uncontrolled occupation of its margins by urban and industrial centres, agriculture and aquaculture expansion, water extraction and flow control. The lack of basic sanitation and poor environmental management (including territories within Marine Protected Areas) often lead to hydrological alterations, high nutrient loads, and the presence and dynamics of pollutants (nutrient loads, persistent organic pollutants (POPs), metals and plastic debris) along the entire estuarine ecocline. Organic enrichment has increased dissolved oxygen consumption, with wide spatio-temporal variability along latitudes and estuarine gradients. The toxicity, biogeochemistry and availability of metals and POPs depend on the annual fluctuations of salinity, water renewal, dissolved oxygen levels, suspended particulate loads, sediment mobility, grain size and composition at the sink. Plastic debris from land sources are widespread in estuaries, where they continue to fragment into microplastics. River basins are the main contributors of plastics to estuaries, whose transportation and accumulation are subjected to interannual water flow variations. Although some systems seems to be in a better condition in relation to others around the world (e.g. Goiana and Negro estuaries), many others are among the most modified worldwide (e.g. Guanabara Bay and Estero Salado System). We propose that, estuarine conservation plans should consider year-round fluctuations of the ecocline and the resulting cycles of retention and flush of environmental signals and their influence on trophic webs over the whole extent of estuarine gradients.

Emerging and traditional organic markers: Baseline study showing the influence of untraditional anthropogenic activities on coastal zones with multiple activities (Ceará coast, Northeast Brazil)

Molecular markers are useful tools to characterize natural and anthropogenic impacts on coastal zones. Distribution of n-alkanes showed that the Pacoti River was predominantly influenced by terrigenous input. Distribution of polycyclic aromatic hydrocarbon (PAH) indices showed a mix of natural sources, especially pyrogenic influences. Sterol and hormone levels showed sewage discharge. Integrated geographic assessment showed that pyrogenic process and sewage discharge are predominant along the river because of natural and different anthropogenic activities. The upstream region is influenced by rural activities such as livestock and discharge from the sewage treatment plant, whereas the estuarine region is influenced by urban and industrial activities, predominantly the discharge of treated or untreated sewage, vehicle traffic, and manufacture of red ceramics. On the other hand, on the river mouth, there is the predominance of aquaculture activities. Traditional anthropogenic markers are not sufficient for producing a comprehensive assessment of anthropogenic impacts in areas with multiple activities.

Emerging and Traditional Organic Markers in Areas with Multiple Anthropogenic Activities: Development of an Analytical Protocol and Its Application in Environmental Assessment Studies

This work describes the development of an analytical protocol combining cleanup by liquid-solid extraction and GC-MS for the determination of emerging and traditional multi-molecular markers. The procedure was used for the environmental assessment of a coastal region with multiple human activities. Global recovery rates ranged from 45.49% to 119.4% for the 46 substances analyzed: pesticides (73.7%-97.7%), PAHs (52.5%-93.7%), sterols (66.7%-119.4%) and natural and synthetic hormones (45.5%-119.1%) and the rates were compared to those reported in studies on both individual classes and multi-classes of contaminants. The analytical protocol demonstrated satisfactory efficiency and could be used successfully in environmental assessments and source assignment studies. The environmental assessment study revealed that the Acaraú River in northeastern Brazil is influenced by the combination of urban and rural activities. The sources of PAHs are vehicular traffic and the burning of biomass; pesticides stem from pest control in agribusiness and public health campaigns; sterols and hormones stem from a combination of natural inputs, human sewage (treated and raw) and animal husbandry activities.

Sewage contamination of Amazon streams crossing Manaus (Brazil) by sterol biomarkers

Sewage pollution is a principal factor of decreasing water quality, although it has not been considered a real impact in Amazonia that is still considered a pristine environment around the world. Thus, this study aimed to assess the levels of sewage contamination in sediments from three streams crossing Manaus - a Brazilian city of 2,403,796 inhabitants in the heart of the Amazon rain forest. Cholesterol, cholestanol, brassicasterol, ergosterol, stigmasterol, β-sitosterol, campesterol, stigmastanol, coprostanol, and epicoprostanol levels were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS). The fecal indicator, coprostanol, was found in high concentrations (509-12 830 ng g^-1) and high relative proportions (21-54%) in all samples collected in the Mindu stream that crosses many heavily populated districts of the city, and in the Quarenta stream that crosses the Industrial District of Manaus. The sediments of the Tarumã-Açu stream also presented coprostanol; however, concentrations (<LOQ-142 ng g^-1) and relative proportions (0-7%) were much lower in this stream. Sterol ratios indicate a severe contamination of the urban streams (Mindu and Quarenta) and a low to moderate contamination of the partially urban stream (Tarumã-Açu). This is the first study evaluating the levels of sewage contamination of Amazon streams using sterol biomarkers and the results obtained herein indicate the need of an immediate implementation of effective sewage treatment strategies. Additionally, these findings may be considered as baseline concentrations for future monitoring programs of that globally important environment.

Hydrocarbon and sewage contamination near fringing reefs along the west coast of Havana, Cuba: A multiple sedimentary molecular marker approach

Organic contamination is a major environmental concern in coastal regions, and it can be evaluated by the determination of aliphatic hydrocarbons (AHs), polycyclic aromatic hydrocarbons (PAHs), faecal sterols and linear alkylbenzenes (LABs). The concentrations of these organic markers were obtained from nine surface sediment samples to evaluate a possible contamination near a fringing reef on the west coast of Havana, Cuba. The AH levels ranged from 1.24 to 135.6 μg g^-1, the PAH levels were up to 2133 ng g^-1, the faecal sterol levels ranged from 0.03 to 1.54 μg g^-1, and the total LAB levels were up to 22.7 ng g^-1. The highest concentrations were obtained at sites close to Havana Bay and at the sources of untreated sewage input. A decreasing concentration gradient was observed from Havana Bay to the outer sites. Although only two sites presented high levels of contamination, untreated sewage discharged close to the fringing reef may affect its environment.

Insights about sources, distribution, and degradation of sewage and biogenic molecular markers in surficial sediments and suspended particulate matter from a human-impacted subtropical estuary

The molecular markers sterols and linear alkylbenzenes (LABs) were analyzed in the surficial sediments and suspended particulate matter (SPM) of a subtropical estuary in South Atlantic (Paranaguá Estuarine System). The purpose of this study was identify the spatial distribution of sewage and the input of biogenic organic matter (OM) and to provide comparative insights about their behavior, compositions, and sources. The concentration of coprostanol ranged from < DL (detection limit) to 2.67 μg g^-1 in SPM and from < DL to 0.94 μg g^-1 in sediments. Total LABs ranged from 43.8 to 480.0 ng g^-1 in SPM and from < DL to 21.0 ng g^-1 in sediments. LABs homologs composition varied between the two matrices. The local hydrodynamic pattern may promote water column homogenization, dispersion, and dilution of sewage particles, and preferential sedimentation in fluvial and mixture zones. Results suggest that SPM is a good matrix for larger spatial and short time scale evaluation while sediments may help to define hot spot areas of input and final deposition of sewage particles. Marine sterols predominated in SPM while no dominance patterns of marine/terrestrial sterols occurred in surficial sediments. The higher degradation rates of sterols and LABs in the water column must be the main factor for the sharp drop in concentration towards the sediment and the variation of the preferential composition of these markers between compartments.

Trace Metals Bioavailability Approach in Intertidal Estuarine Sediments and Bioaccumulation in Associated Nereidid Polychaetes

Polychaetes that inhabit the sediments of estuaries are important prey to many species all around the world. Laeonereis acuta is a deposit feeder living in estuaries along the Atlantic coast of South America. Ragworms accumulate metals from the sediment, and represent a means of entry of sediment contaminants into the trophic network. The concentrations of Zn, Pb, Cu, Cr and Cd were determined in polychaetes and sediments (total and extractable) from six estuarine beaches of Río de la Plata. The associations between total and extractable concentrations in sediment and accumulated concentrations in L. acuta were analyzed. Sediments extracted by weak acid digestion appear to be a good proxy model of bioavailable metal fractions in the sediment. The association between metals in sediment and polychaetes denotes the role of L. acuta as an important link in metal trophic transfer from sediments to potential fish and bird predators of the worm.

Anthropogenic and natural variability in the composition of sedimentary organic matter of the urbanised coastal zone of Montevideo (Río de la Plata)

This study is aimed to identify the different sources of sedimentary organic matter (SOM) within Montevideo coastal zone (MCZ). To this end δ¹³C, δ¹⁵N and C/N ratio were analysed in surface sediments and a sediment core. Sediment core analysis showed that until ~1950CE SOM was mainly marine, observing a shift towards lower δ¹³C in recent sediments, evidencing an estuarine composition. This trend was associated to the climatic variability, which exerted a major influence on the SOM composition, leading to an increased input of terrigenous material and associated anthropogenic contaminants. Surface sediments collected during different El Niño South Oscillation (ENSO) phases did not show inter-annual variability in SOM composition, which was mainly marine in both eastern and western region of MCZ and estuarine in Montevideo Bay. This spatial pattern provides new insights on the dynamics and factors affecting organic matter sources available for primary consumers along the study region.

Unraveling the performance of the benthic index AMBI in a subtropical bay: The effects of data transformations and exclusion of low-reliability sites

We investigated the relationship between the AMBI index and different contamination proxies in an urbanized bay in South America (SE Brazil), and the effect of (a) abundance data transformation and (b) exclusion of low-reliability sites (high SD; low N) on the index' performance. Poor ecological quality and opportunistic species were related to an increase in contaminants concentrations and mud content. Good ecological status and sensitive species (EG I) were mainly related to increased hydrodynamics. Data transformation caused minimal changes to the overall relationships, but exclusion of low-reliability sites improved the relationship between ecological groups and contamination proxies. Our results show that AMBI is robust in detecting effects of different contaminants in the area and reinforce the importance of the index as a tool for coastal management, but local joint efforts are needed to improve and adjust local species classification in ecological groups to improve the index' performance.

Biomarker responses and PAH ratios in fish inhabiting an estuarine urban waterway

Many cities worldwide are established adjacent to estuaries and their catchments resulting in estuarine contamination due to intense anthropogenic activities. The aim of this study was to evaluate if fish living in an estuarine urban waterway were affected by contamination, via the measurement of a suite of biomarkers of fish health. Black bream (Acanthopagrus butcheri) were sampled in a small urban embayment and a suite of biomarkers of fish health measured. These were condition factor (CF), liver somatic index (LSI), gonadosomatic index (GSI), hepatic EROD activity, polycyclic aromatic hydrocarbon (PAH) biliary metabolites, serum sorbitol dehydrogenase (s-SDH) and branchial enzymes cytochrome C oxidase (CCO), and lactate dehydrogenase (LDH) activities. The biomarkers of exposure EROD activity, and pyrene- and B(a)P-type biliary metabolites confirmed current or recent exposure of the fish and that fish were metabolizing contaminants. Relative to a reference site, LSI was higher in fish collected in the urban inlet as was the metabolic enzyme LDH activity. CF, GSI, s-SDH, CCO, and naphthalene-type metabolites were at similar levels in the urban inlet relative to the reference site. PAH biliary metabolite ratios of high-molecular-weight to low-molecular-weight suggest that fish from the urban inlet were exposed to pyrogenic PAHs, likely from legacy contamination and road runoff entering the embayment. Similarly, the sediment PAH ratios and the freshness indices suggested legacy contamination of a pyrogenic source, likely originating from the adjacent historic gasworks site and a degree of contamination of petrogenic nature entering the inlet via storm water discharge. Biomarkers of exposure and effect confirmed that black bream collected in the Claisebrook Cove inlet, Western Australia, are currently exposed to contamination and are experiencing metabolic perturbations not observed in fish collected at a nearby reference site.

Historical economic and environmental policies influencing trace metal inputs in Montevideo Bay, Río de la Plata

Montevideo Bay is located in the middle zone of the Rio de la Plata, and since the foundation of the city, several key economic and environmental policies affected the industry, and thus, metal inputs into this ecosystem. The aim of this study is to evaluate the sedimentary geochemical record of Montevideo Bay, in order to determine the historical inputs of anthropogenic metals to the system. In addition, environmental and economic policies of the country were taken into account to infer the relationship between them and the historic metal input. Concentrations of aluminum, chromium, copper, lead, scandium and zinc were analyzed and the EF and SPI indices were calculated. The analysis showed that since Montevideo foundation, metal concentrations increased in accordance with industry development, and the indices as well as the metal concentration represent a reliable footprint of the history of different economic and environmental policies influencing historical industrial activities.

Complex spatial and temporal variation of subtropical benthic macrofauna under sewage impact

To better understand variation in sewage-impacted benthic macrofauna from subtropical tidal flats over time and space, we applied a five-factor linear model at a hierarchy of spatial (Condition - Contaminated or Non-Contaminated, Tidal Flat and Plot) and temporal scales (Season and Fortnight). The Contaminated site showed high levels of coprostanol and the presence of Paranais cf frici as markers or indicators of organic enrichment. Differences between Seasons were more pronounced for the faunal variation patterns than for the other parameters, with lower species richness and abundance in summer. There were significant interactions between Fortnight and Tidal Flat for most variables, reflecting marked heterogeneity within Tidal Flats. Benthic community has significantly changed over short periods of time. These rapid changes may lead to erroneous interpretations and mask the true sources of variation. Our results clearly demonstrate the need to better understand benthic temporal variability even at small scales.

Sewage contamination in a tropical coastal area (São Sebastião Channel, SP, Brazil)

Urban effluent discharges in Brazilian coastal areas are a chronic problem and often lead to changes in the quality of the marine environment. São-Sebastião-Channel (SSC) is an important aquatic ecosystem to be monitored for urban sewage contamination due to the intense urban activities in that region, as well as the relative high biodiversity of marine organisms. In the area are present three submarine sewage outfalls, a commercial harbour and also the biggest oil terminal in Brazil. Total organic carbon (TOC), total nitrogen (TN), total sulphur (TS), steroids and linear alkylbenzenes (LABs) were measured in sediment samples collected in three strategic locations of the SSC in order to monitor urban sewage contamination. Total LAB and total sterols levels ranged from below DL-51.3 ng g(-1) and below DL-10.40 μg g(-1), respectively. Samples collected near sewage outfall in the central part of the SSC had higher concentrations of urban sewage-associated contaminants.