Santos Estuarine System Research Articles

Microplastics in marine sponges (Porifera) along a highly urbanized estuarine gradient in Santos, Brazil

Microplastics (MPs) are ubiquitously found in environmental matrices, particularly affecting aquatic systems. While several marine species have been widely used to assess MP contamination, sponges (Porifera) are less used. The MPs contamination was assessed in the sun sponge (Hymeniacidon heliophila) along a gradient at the Santos Estuarine System (Brazil). A 14-fold difference between concentrations (particles g−1) was verified between the most (1.40 ± 0.81) and least (0.10 ± 0.12) contaminated sites, confirming the local contamination gradient. The MPs found were primarily polypropylene, small (1.2–1000 μm), fibrous, and colored. Considering total concentrations, sizes and shapes these spatial patterns were similar those previously detected in molluscs obtained in the same sites. On the other hand, they differed in polymeric composition and color categories. Such findings give important initial insights into the potential role of marine sponges as putative sentinels of MPs contamination.

Microplastics in rocky shore mollusks of different feeding habits: An assessment of sentinel performance

Microplastics (MPs) accumulation in rocky shore organisms has limited knowledge. This study investigated MPs accumulation in filter-feeding oysters, herbivorous limpets and carnivorous snails to assess their performance as sentinel species in the MPs trophic transfer. The samples were obtained along a contamination gradient in the Santos Estuarine System, Brazil. All three studied species showed MPs concentrations related to the contamination gradient, being the oysters the species that showed the highest levels, followed by limpets and snails (average of less and most contaminated sites of 1.06–8.90, 2.28–5.69 and 0.44–2.10 MP g−1, respectively), suggesting that MPs ingestion rates are linked to feeding habits. MPs were mainly polystyrene and polyacetal. The polymer types did not vary among sites nor species. Despite minor differences in percentages and diversity of size, shape, and color classes, the analyzed species were equally able to demonstrate dominance of small, fiber, transparent, black and blue MPs. Thus, oysters, limpets, and snails are proposed as sentinels of MPs in monitoring assessments.

A framework to assess resilience attributes based on local knowledge

New coexistence scenarios have been imposed on fishermen in the Santos Estuarine System region, a coastal city located 75 km from the largest city in Latin America (São Paulo). Whether due to the expansion of port and industrial activities, or due to the environmental liabilities associated with other human activities, thousands of workers from fishing communities are compelled to seek new forms of subsistence in the face of the gradual reduction of their fishing territories. The objective of this investigation was to develop a methodological framework to assess, based on local knowledge, ecological and social attributes of resilience in socio-ecological systems of small-scale fisheries over the last decades. To experimentally test the application of the framework, pilot interviews with fishermen, master craftsman and local leaders of the Santos Estuarine System were carried out with questions on aspects concerning eleven attributes of resilience, for three different time periods (currently, 25 years ago, and 50 years ago). Scores were assigned to the responses according to the contribution of the aspect addressed to the resilience of small-scale fisheries in the face of the various disturbances suffered over the years. The attribute scores in each period were then compared in a multivariate manner and the results of this pilot evaluation showed a decrease in overall resilience in recent decades, according to the perceptions of interviewees. Ecological attributes showed a significant decrease in the same period associated with anthropic pressures with losses in the attributes diversity, modularity and variability. Social resilience attributes did not show significant variation, although there was an increase in the attributes recognition of slow variables, tight feedbacks and overlap in governance. Although the use of the framework proposed requires its application on a broader scale for the characterization of resilience of small-scale fishing communities, the present study demonstrated that the methodological framework is applicable and provides useful information on attributes of socio-ecological resilience based on local knowledge.

Negative Impacts of Trace Metal Contamination on the Macrobenthic Communities along the Santos Port Complex—Brazil

Port sites represent one of the most impacted coastal areas; this impact is due to intensive anthropogenic pressures. In addition to the port complex itself, associated activities, such as indiscriminate disposal of pollutants, including trace metals, affect the local ecosystem. Macroinvertebrate benthic communities are one of the most effective bioindicators of environmental health because of their importance as a primary food source for many fish, birds, and mammals, as well as their influence on sediment stability and geochemical composition. This article evaluates the benthic macrofauna in the Santos Estuarine System (SES), the location of the Santos Port Complex (SPC), linking trace metal levels to differences in microbenthic community structure and pollutant bioavailability. The distribution of Cd, Ni, and Pb was directly related to organic matter deposits, while Cu and Zn appeared to result from port activities. The SES contained a poor benthic macroinvertebrate community, resulting from the contaminated muddy sediments. A significant negative correlation was found between the macrobenthic diversity and concentrations of Cu in the soluble phase; this implied the pollution-induced degradation of the macrobenthos in SES.

Are fire suppressants “nontoxic”? Acute toxicity, DNA damage and lipid peroxidation in fish (Poecilia reticulata) exposed to low concentrations

During an emergency in the Port of Santos (Brazil), large volumes of Aqueous film forming foams (AFFFs) were used, producing an effluent containing a mixture of AFFFs, gasoline and ethanol, which reached the Santos Estuarine System and caused massive fish deaths. This investigation aimed to study the toxicity of three AFFFs (Agefoam; Cold Fire; and F500 Fire) used in the fire fighting on the fish Poecilia reticulata. Acute toxicity tests were conducted using adult individuals, and the lethal concentration to 50% organisms (LC50) was calculated after 96 h, together with the low observed (LOEC) and the no observed effect concentrations (NOEC). Gills and liver from the exposed fish were analyzed for DNA damage and membranes’ lipoperoxidation (LPO). All the AFFFs caused significant fish mortalities, and the LOECs were 0.01% for Agefoam® and 0.001% for F500® and Cold Fire®. Toxicity thresholds were determined for F500® (LC50–48 h = 0.01%), Agefoam® (LC50–96 h = 0.008621%) and the Cold Fire® (LC50–96 h = 0.001221%). Fish exposed to 0.01% and 0.001% of Agefoam® and Cold Fire® did not showed significant effects on DNA damage, while those exposed to F500® presented significantly reduced damages at 0.00001%. The exposed fish presented reduced levels of LPO in most concentrations, excepting those exposed to Cold Fire® (gills) and Agefoam® (liver). The results suggest that the fish deaths were likely caused by direct action of the tensoactives and not by the oxidation induced by reactive oxygen species.

Emerging Contaminants in Sediments as Markers of Anthropogenic Inputs in Santos Estuarine System: Analytical Method and Occurrence Data

The occurrence of emerging contaminants (ECs) in the aquatic systems under influence of urban areas have been considered as an environmental marker of anthropogenic contamination. In this study 10 ECs were investigated in sediment samples from Santos Bay using a quick, easy, cheap, effective, rugged, and safe method with determination by liquid chromatography tandem mass spectrometry. The method showed acceptable accuracy (51-116%) and precision (relative standard deviation (RSD) ≤ 9), limits of quantification in ng g-1 levels and matrix effect lower than 29%. Environmental occurrence of benzophenone-3, caffeine, ketoconazole and triclocarban was detected in two campaigns (2015 and 2019), with concentrations ranging from < 1 to 470 ng g-1. Caffeine and triclocarban were the most abundant target chemicals occurring in up to 71 and 100% of the sample point, respectively. The results indicated that ECs in sediment samples came from diffused sources as the discharge of treated and untreated sewage in the estuary.

Pollutants potential mobilization in Santos bay/Brazil: subsidies for the environmental management of a highly anthropized estuary

Understanding the dynamics and spatial variation of subaquatic sediment contamination in the Santos Estuarine System has been of interest to the scientific community and environmental managers; the hazardous contaminant compounds, either individually or synergistically, can affect the health of the local community. In the present study, water column salinity and sediment geochemical properties (calcium and organic matter content, grain size) of the Santos Estuarine System were correlated with heavy metal concentrations (As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn and Fe) in order to elucidate the relationship between the toxic elements and the dynamics of water mixing. To assess the potential relationships, Spearman’s correlation test and Principal Component Analysis (PCA) between were applied. The heavy metal concentrations were also evaluated by calculating Contamination Factor, Geoaccumulation index and Enrichment Factor. Results revealed extremely heterogeneous particle sizes within the sampling stations. Most of the heavy metal concentrations were not at critical levels. The only exception was arsenic, which reached levels above the threshold effect. The statistical analysis allowed the influence of organic matter and grain size on the dynamics of heavy metal accumulation to be demonstrated. The values between these binding matrices and metals were mostly significant. Bottom water salinity, on the other hand, showed no apparent influence on the distribution of metals. However, the various pollution indices used were contradictory, with certain cases presenting critical results. The Geoaccumulation Index presented the Mn as highly polluting at all sampling stations and classified the environment as moderately polluted by Zn. The same pollution pattern was not found by the other contamination indexes.

The influence of dredging on estuarine hydrodynamics: Historical evolution of the Santos estuarine system, Brazil

We assess changes in estuarine hydrodynamics due to the deepening of navigation channels by dredging. A validated numerical hydrodynamic model (Delft3D) was used to analyze scenarios (historical bathymetry data from 1876 to 2014) and applied to assess the hydrodynamic evolution of the Santos estuarine system (SES), Brazil. During the studied period, the SES underwent significant morphological changes, mainly related to the dredging of the Santos harbor navigation channel. The unprecedented results of the hydrodynamic evolution of the SES show that the gradual process of deepening the channels by dredging resulted in modified estuarine circulation parameters such as tidal propagation and stratification of the water column, as well as the residual water and materials transport through the SES channels. Channel deepening resulted in greater saline intrusion, a decrease in the volume of water transported through the Santos channel, an increase in the influence of the tide in the system and an increase in its asymmetry over the years in the upper estuary.

Heavy Metal And Hydrocarbons Bioaccumulation By Two Bivalve’s Species From Santos Bay, Brazil

ABSTRACT Contaminants compounds like Heavy Metals and Polycyclic Aromatic Hydrocarbons (PAH’s) are primarily sourced from industrial and urban areas. As pollutants, these chemical elements and compounds are potentially toxic and present the capacity to negatively impact the ecosystem, especially the most sensitive ones such as estuaries. Bivalves’ species have been successfully utilized as monitoring tools to evaluate pollutants bioaccessibility around the globe. The present study assessed heavy metals (Zn, Cd, Ni, Fe, Cr, Cu and Pb), As and PAH’s levels in two mollusk species (Perna perna and Crassostrea rhizophorae) from Santos Estuarine System, in São Paulo State, in order to compare the effectiveness of each species in the biomonitoring process. According to the obtained data, Perna perna mussels may be better indicators of environmental pollution than Crassostrea rhizophorae oysters for some metals (Iron and Nickel) and hydrocarbons. On the other hand, in the present study, oysters had a higher capacity for retaining zinc, copper, and cadmium, due to their peculiar physiological characteristics.

Mollusc shell shape as pollution biomarkers: Which is the best biological model?

Alterations in mollusc shells have been proposed contamination biomarkers. We used geometric morphometrics analyses associated with analytical determinations of contaminants to select suitable biological models among species widely distributed on coastal zones. The study was carried out using Lottia subrugosa (herbivore limpet), Crassostrea brasiliana (filter-feeder bivalve), and Stramonita brasiliensis (carnivore gastropod) obtained along a marked contamination gradient at Santos Estuarine System (Brazil). L. subrugosa and S. brasiliensis presented distinct shapes along the gradient, while no significant differences in shell form were seen for C. brasiliana. Indeed, limpets and snails presented morphometric parameters consistent with measured contamination levels hazardous substances. Based on cross-validation models, the reliability of morphometric responses was over 75% for the herbivore and carnivore species. In addition, for S. brasiliensis, a 95.2% confidence was detected in most contaminated sites. Therefore, shell alterations on carnivorous gastropods should be further investigated, seeking to be effectively employed as pollution biomarkers.

Contamination gradient affects differently carbonic anhydrase activity of mollusks depending on their feeding habits.

Aquatic organisms that inhabit coastal areas are often exposed to several contaminants. It is known that the bioaccumulation of contaminants can be amplified according to the species feeding habits and contaminant properties. As a consequence, species can experience different effects to contaminant exposure even if they inhabit the same area. The present study aimed to investigate the activities of carbonic anhydrase (CA), Ca2+-ATPase, and Mg2+-ATPase in different tissues (soft tissue, mantle, and gill) of three mollusk species (Lottia subrugosa, Stramonita brasiliensis, and Crassostrea brasiliana) with different feeding habits (herbivore, carnivore, and filter-feeder, respectively) which were sampled within a known contamination gradient at Santos Estuarine System (Southeastern Brazil). From the three enzymes tested, only CA was affected by the presence of contaminants within the contamination gradient evaluated. In general, the CA activity from the three species were lower in contaminated sites when compared to the reference site. The contrasting CA activity response observed in S. brasiliensis compared to L. subrugosa and C. brasiliana could be related to the tissue-specificity of this enzyme activity and species feeding habits (filter-feeders can accumulate more contaminants than herbivores and even carnivores). Results indicated that C. brasiliana mantle is the most suitable tissue for the use of CA analysis as a biomarker.

Anthropogenic litter composition and distribution along a chemical contamination gradient at Santos Estuarine System—Brazil

Anthropogenic litter (AL) distribution was assessed on beaches presenting different levels of urban occupation at Santos Estuarine System. Plastics and cigarette butts were the items most found at sampling sites. Plastic items sub-categories, such as cotton buds, lids, microcentrifuge tubes, pellets, and polystyrene foam, presented sources related to industrial, tourism and port activities, and sewage discharges. The contamination gradient already reported for hazardous chemical levels was also observed for AL. Litter categories related to local and allochthonous sources presented a gradient of spatial distribution. Although touristic activities are an impactful and variable factor, the number of inhabitants was positively correlated with most AL categories. The semi-urban beach (S1) was classified as extremely dirty, and it was mostly covered by hazardous AL. The semi-remote (S2) and remote (S3) beaches were classified as moderate and clean with some or few hazardous AL, respectively. Therefore, urban and hydrodynamic gradients drive marine litter distribution on studied zone.

A TIE Approach to Identify Substances Causing Sediment Pore Water Toxicity After a Major Fire at Fuel Storage Tanks in the Port of Santos (SE, Brazil).

The major fire at the fuel storage tanks of a Chemical Terminal in April 2015 at the Port of Santos (SP), SE Brazil, potentially caused significant environmental impacts to the Santos Estuarine System (SES). The aim of the study was to identify the classes of substances causing pore water toxicity in the SES sediments in the vicinity of the port terminal before and after the incident using the TIE approach. Our results suggest that nonpolar compounds (e.g. PAHs, BTX, oil and grease) from the storage tanks that burned, and surfactants present in the formulation of foam fire extinguishing agents were the responsible for the sediment toxicity observed in the vicinity of the incident site. The contribution of metals to the toxicity related to the incident was ruled out. A long-term monitoring of the environmental effects of the incident is recommended since substances for which evidence of toxicity was found are toxic, persistent and can accumulate in the biota.

Geochemistry of the upper estuarine sediments of the Santos estuary: provenance and anthropogenic pollution

Major and trace element geochemistry of the upper estuarine sediments of the Santos estuary has been used to characterize sediment geochemistry, classification, distribution, and possible sources of industrial pollution. The vertical sediment cores were collected on the margin of the Cubatão, Perequê, Mogi, Piaçaguera and Jurubatuba rivers, the main effluents of the Santos estuarine system. Samples of selected basement rocks (n=12), industrial waste (n=2) and one weathering profile (organic soil, residual soil and saprolite rock) were also analyzed. The sedimentary deposits showed interbedding of medium, fine, and very fine sands in the upper portion of the estuary and subordinate silt-clay units derived from lower energy in swamp/mangroves deposits in the lower estuary. Marked geochemical differences occurred among these fluvial sediments. The calculated indices of chemical weathering, such as Chemical Index of Alteration (CIA) and A-CN-K ternary diagram indicate that the estuarine sediments display a wide range of weathering effects, from unweathered derived of Proterozoic gneiss and granitic rocks to intensely weathered site in the swamp deposits of the Piaçaguera River. Phosphogypsum waste stored in the catchment area of the Mogi River showed high concentrations of S, La, Ce, Ca, Sr, Nd, Nb, U, Ba, P, Y and F when compared with the regional rocks, soils and fluvial sediments samples analyzed in the study area, which make it a potential source of environmental contamination. The UCC-normalized patterns, geoaccumulation indexes (Igeo), robust linear regression (RA) and principal component analysis (PCA) were used to identify geochemical anomalies and discuss their probable sources. The principal component scores exhibited strong spatial association with anthropogenic sources. The principal component loading allowed to separate heavy metal elements (Cr, Cu, Ni, Pb and Zn) from the elements related to phosphogypsum waste (e.g., Ce, La, Nd and F). The geochemical anomalies of Ce, La, Nd and F in the fluvial sediments of the Mogi downstream River may be related to phosphogypsum waste in the catchment area, whereas the Cr, Cu and Ni anomalies may be related to fossil fuel, chemical industries and industrial waste deposits which occur near the Pereque and Cubatão rivers.

Predicting the Dispersal and Accumulation of Microplastic Pellets Within the Estuarine and Coastal Waters of South-Eastern Brazil Using Integrated Rainfall Data and Lagrangian Particle Tracking Models

Understanding how microplastic particles move and accumulate within estuarine and coastal waters requires consideration of the entry of primary inputs (e.g., raw materials from industrial zones) as well as secondary inputs resulting from fluvial processes (i.e., materials carried into coastal waters by rivers and streams). This study presents a novel approach to achieve this aim, by comparing the individual and combined ability of Particle Tracking Models (PTMs) and seasonal rainfall data, to explain observed inputs of microplastic pellets to the ocean beaches of Santos City (south-eastern Brazil). A Lagrangian (PTM) based on high-resolution hydrodynamic models was used to simulate seasonal patterns of pellet dispersal from five potential release points within the Santos Estuarine System (SES) and nearshore waters which are known contributors to the regions microplastic debris problem. Model outputs suggested that the debris field is likely to be small within the estuary (ranging from 3.6 to 8.1 km2), intermediate at the river mouth (mean 34 km2) and greatest for near- and offshore sites (ranging from 34 to 40 km2). The spatial footprints were strongly modulated by season (and rainfall), with simulations alone unable to reconcile daily inputs of pellets observed on the beaches of Santos Bay (ranging from 2 - 51 particles m2 ∙ d-1). Given this discrepancy, a Generalized Additive Modelling approach was employed to integrate the PTM outputs with rainfall data to improve predictions of beached particles. Results confirmed that fluvial processes, could indeed significantly improve the ability to predict rates of pellet accumulation (raising the explained deviance in observed inputs from 41% to 93%). Thus, the study highlights the potential to couple widely used dispersion models with metrics that describe fluvial forcing (rainfall and estuarine flushing) in order to better understand the spatio-temporal dynamics of microplastic debris transport and accumulation within dynamic coastal environments.

Biodegradation of diethyl-phthalate (DEP) by halotolerant bacteria isolated from an estuarine environment

Phthalates are widely used as plasticizers in many industrial products due to their chemical properties that confer flexibility and durability to building materials, lubricants, solvents, insect repellents, clothing, cosmetics, being widely distributed in the environment. Besides persistent, they are also considered endocrine-disrupting compounds (EDCs), causing a global concern about their release into the environment, once they can alter the reproductive and endocrine health of humans systems. Under natural conditions, photodegradation and hydrolysis rates of phthalates are often very slow; therefore, microbial degradation is a natural way to treat these pollutants. In this context, three bacterial consortia (CMS, GMS and GMSS) were isolated from environmental samples from the Santos Estuarine System (SES) and were able to grow on diethyl-phthalate (DEP) as an only carbon source. From the GMSS consortium, three different strains were isolated and identified as Burkholderia cepacia, Pseudomonas koreensis and Ralstonia pickettii by molecular and mass spectrometry (MALDI-TOF-Biotyper) techniques. Considering there are no reports about Ralstonia genus on phthalates degradation, this strain was chosen to proceed the kinetics experiments. Ralstonia pickettii revealed a great ability to degrade DEP (300mg/L) in less than 24 h. This is the first report implicating R. pickettii in DEP degradation.

Biometric and hematological indices of Mugil curema inhabiting two Neotropical estuaries

The present study aimed to evaluate the biometric and hematological indices in Mugil curema collected in two Neotropical estuaries in the south coast of Brazil, and to investigate if such variables can be influenced by seasonality and degree of anthropogenic influence. Differences between seasons and estuarine systems were observed, where the dissolved oxygen and salinity, together with the historical contamination of the Santos estuarine system (SES), seem to play an important role in the biological response. Fish from the SES presented, in general, high responses of the hematological variables (red and white series) and the hepatosomatic index, relative to those fish from Peruíbe estuarine system (PES), even with the remote contamination present at PES, while no erythrocytic abnormalities or micronucleus were observed in fish collected at SES and PES in both seasons. The present work demonstrated that M. curema collected at SES are experiencing hematological and metabolic perturbations that are not observed in fish collected at PES.

Adaptative responses of myenteric neurons of Sphoeroides testudineus to environmental pollution

Contamination in estuarine regions affects the local biota damaging the ecosystems and reaching humans. The gastrointestinal tract is a dynamic environment capable of obtaining nutrients and energy from food while it protects the host against harmful toxins and pathogens from the external environment. These functions are modulated by the enteric nervous system and changes in its structure can result in gastrointestinal disorders. The objective of this study was to evaluate if the environmental contaminants have effects on the myenteric neuronal plasticity of pufferfish Sphoeroides testudineus. Animals were collected in Barra do Una River, located at Jureia-Itatins Mosaic of Protected Areas (reference area – RA) and in the Santos Estuarine System (impacted area – IA). Morpho-quantitative analyses of the general and metabolically active myenteric neuronal populations of the proximal and distal intestine were made. Disarrangement was observed in the general organization of the myenteric plexus, with an expressive reduction of the neuronal groups (nodes) in the animals of IA. The vulnerability of the myenteric plexus was evidenced by a decrease in density and cellular profile of the general neuronal population, followed by an increase of the metabolism of the remaining neurons, which in turn was verified by a growth of the area of the cellular and nuclear profiles of the metabolically active neuronal population. Through these analyses, we concluded that animals inhabiting polluted regions present alterations in the myenteric neuronal plasticity, as a way of maintaining the functions of the gastrointestinal tract.

Natural factors and chemical contamination control the structure of macrobenthic communities in the Santos Estuarine System (SP, Brazil)

The Santos Estuarine System (SES) is a complex of bays, islands, estuarine channels, and rivers located on the Southeast coast of Brazil, in which multiple contaminant sources are situated in close proximity to mangroves and other protected areas. In this study, the composition and structure of the macrobenthic communities of SES were described and ninety-nine species were identified, with the predominance of polychaetes and bivalve mollusks. The benthic assemblages also showed strong signs of stress, as indicated by the low abundance, richness and diversity, and the dominance of opportunistic species. Integrated analysis including sediment characteristics related to natural and anthropogenic factors (e.g., sediment chemistry, and toxicity) indicated that benthic fauna from the inner portions of the SES and vicinities of the SSOS diffusers as Santos Bay were affected. Some locations at the mouths of Santos and Sao Vicente estuaries exhibited moderate disturbance. In other sites from the mouth of São Vicente and Bertioga channels, and Santos Bay, the benthic fauna were considered not degraded. Our results suggest that a combination of both environmental factors and contaminants were responsible for the benthic community structure.

Hexadecane biodegradation of high efficiency by bacterial isolates from Santos Basin sediments

The aim of the study was the investigation of bacterial diversity from sediments collected at Santos Estuarine System, regarding to their abilities for hexadecane biotransformation. Hexadecane is a medium-chain linear alkane, considered as a model molecule for hydrocarbon biodegradation studies. It is a component from aliphatic fraction of crude petroleum, commonly related to environmental contamination by diesel oil. Santos Basin is an area with historical petroleum contamination. In the present work, sediment samples from this area were inoculated in artificial seawater (ASW), containing hexadecane as carbon source. Six bacterial isolates were selected as resistant to hexadecane. Chromatographic results showed biodegradation indexes above 97%. After 48 h of culture, five of them could degrade >80% of the initial hexadecane added. These isolates were characterized by 16S rDNA gene sequencing analysis. The following species were found: Bacillus amyloliquefaciens, Staphylococcus epidermidis, Micrococcus luteus, Nitratireductor aquimarinus, and Bacillus pumilus.