Chemical contamination affecting filter-feeding bivalves in no-take marine protected areas from Brazil.

Marine protected areas (MPAs) are zones geographically delimited under pre-defined management goals, seeking to reduce anthropogenic threats to biodiversity. Despite this, in recent years reports of MPAs affected by chemical contamination has grown. Therefore, this study addresses this critical issue assessing legacy and current chemical contamination in filter-feeder bivalves obtained in very restrictive no-take MPAs from Brazil. The detected pollutants encompass polycyclic aromatic hydrocarbons (PAHs), linear alkylbenzenes (LABs), and persistent organic pollutants (POPs) like dichlorodiphenyltrichloroethane (DDTs) and polychlorinated biphenyls (PCBs). Despite protective measures, bivalves from nine MPAs exhibited high LABs (13.2-1139.0 ng g-1) and DDTs levels (0.1-62.3 ng g-1). PAHs were present in low concentrations (3.1-29.03 ng g-1), as PCBs (0.7-6.4 ng g-1), hexachlorobenzene (0.1-0.2 ng g-1), and Mirex (0.1-0.3 ng g-1). Regardless of the sentinel species, MPAs and management categories, similar accumulation patterns were observed for LABs, DDTs, PAHs, and PCBs. Based on the limits proposed by Oslo Paris Commission, the measured levels of PAHs, PCBs and were below the environmental assessment criteria. Such findings indicate the no biological effects are expected to occur. However, they are higher considering background conditions typically measured in remote or pristine areas and potential simultaneous exposure. Such findings indicate an influence of anthropogenic sources, emphasizing the urgency for monitoring programs guiding strategic management efforts to safeguard these areas.

Microplastic in clams: An extensive spatial assessment in south Brazil.

Microplastic pollution is becoming a continuously growing environmental concern, while bivalve mollusks are particularly vulnerable due to their sessile habits and feeding through water filtration processes. Microplastic incidence in soft tissues of the clam Amarilladesma mactroides was assessed along unconsolidated substrates distributed in extensive coastal regions of southern Brazil. Influence of urbanization levels, distance to rivers and local hydrodynamics on microplastic accumulation by the clam was tested. The average concentration of microplastics was high (3.09 ± 2.11 particles.g-1), considering 16 sampled sites. Particles were mainly composed by polyamide, polyethylene and polyethylene terephthalate, while were mainly smaller, fibrous and colorless. High urbanization and closer proximity to rivers insured higher contamination, which is a trend observed globally. No influence of coastal hydrodynamics was seen. Considering obtained findings, A. mactroides presents good potential to be used as a valuable tool to assess microplastic contamination in unconsolidated substrates of beach areas.

High levels of anthropogenic litter trapped in a mangrove area under the influence of different uses.

The contamination of mangroves by anthropogenic litter has increased in recent decades. Notably, Brazil occupies a prominent status within Latin America, boasting the second-largest mangrove areas globally. In Santos-São Vicente Estuarine System (SESS), mangroves coexist with a preeminent port complex and substantial urbanization rates. Nevertheless, the anthropogenic litter occurrence and distribution in this ecosystem remains unknown. This study aimed to comprehensively assess anthropogenic litter across 13 strategically positioned sites in the SESS. The total litter density (Mean ± SD) was 22.84 ± 36.47 (0.00-142.00) items·m-2, putting the SESS among the top four most contaminated mangrove ecosystems worldwide. Residential zones accumulated more litter than uninhabited areas and significant correlation was seen with human modification index. Plastic was the prevalent material (70.4 %), measuring mostly between 2.5 and 30 cm (41.1 %). It is imperative that local authorities adopt comprehensive strategies to mitigate contamination, while also curtailing the litter inputs to the SSES mangrove ecosystem.

PAH residues and toxicity levels two years after an extensive oil spill on the northeast Brazilian coast.

The most extensive oil spill ever recorded in tropical oceans occurred between August 2019 and March 2020, affecting approximately 3000 km of the Brazilian coast. This study assessed the chemical contamination and toxicity of sediments collected from affected reef areas during two sampling surveys conducted 17 and 24 months after the peak of oil slick inputs. Our results indicated that neither PAH levels nor measured toxicity showed a significant contribution from the spilled oil, with concentrations and biological effects indistinguishable from those in unaffected areas. Similarly, no differences were observed between seasons. Furthermore, there was no discernible relationship between sediment toxicity results and the measured PAH concentrations. Therefore, while biological responses indicated toxicity in most assessed areas, these responses are likely related to other local sources. This evidence suggests a natural oil attenuation process contributing to local environmental recovery. Nonetheless, further investigation is needed for other areas affected by oil spills.

Toxicity of antifouling biocides on planktonic and benthic neotropical species.

Organotin-based (OTs: TBT and TPT) antifouling paints have been banned worldwide, but recent inputs have been detected in tropical coastal areas. However, there is a lack of studies evaluating the toxicity of both legacy and their substitute antifouling booster biocides (e.g., Irgarol and diuron) on neotropical species. Therefore, the acute toxicity of four antifouling biocides (TBT, TPT, Irgarol, and diuron) was investigated using the marine planktonic organisms Acartia tonsa and Mysidopsis juniae, the estuarine tanaid Monokalliapseudes schubarti (water exposure), and the burrowing amphipod Tiburonella viscana (spiked sediment exposure). Results confirmed the high toxicity of the OTs, especially to planktonic species, being about two orders of magnitude higher than Irgarol and diuron. Toxic effects of antifouling compounds were observed at levels currently found in tropical coastal zones, representing a threat to planktonic and benthic invertebrates. Furthermore, deterministic PNECmarine sediment values suggest that environmental hazards in tropical regions may be higher due to the higher sensitivity of tropical organisms. Since regulations on antifouling biocides are still restricted to a few countries, more ecotoxicological studies are needed to derivate environmental quality standards based on realistic scenarios. The present study brings essential contributions regarding the ecological risks of these substances in tropical and subtropical zones.

Oysters and mussels as equivalent sentinels of microplastics and natural particles in coastal environments.

Filter-feeder organisms such as oyster and mussels are exposed to particles like microplastics (MPs). Although widely used to monitor MPs contamination, little is known about their performance as sentinels, which are biological monitors accumulating contaminants without significant adverse effects. This study comparatively evaluated the quantitative and qualitative accumulation of MPs by oysters (Crassostrea brasiliana) and mussels (Perna perna) along a gradient of contamination in a highly urbanized estuarine system of Brazil. In the most contaminated site, both species presented the worst status of nutrition and health, and also one of the highest MPs levels reported for molluscs to date (up to 44.1 particles·g-1). Despite some inter-specific differences, oysters and mussels were suitable and showed an equivalent performance as sentinels, reflecting the gradient condition demonstrated for other contaminants in the region. The similarity in MPs accumulation was also observed for qualitative aspects (polymer composition, sizes, shapes and colors). Particles were mostly <1000 µm, fibrous, colorless and composed by cellulose and polymethyl methacrylate (PMMA). Thus, despite small variations, the usage of C. brasiliana and P. perna is recommended and provides reliable information for environmental levels of microplastics.

Antifouling booster biocides in Latin America and the Caribbean: A 20-year review.

This review summarized booster biocides studies from Latin America and the Caribbean during the last two decades. Studies were focused on six countries, with most of them in Brazil. In water and sediment, diuron and Irgarol were the most abundant and frequent biocides, probably due to their former intense use. Antifouling paint particles were also reported and had mainly DCOIT, which is currently the most used booster biocide. Toxicity of individual booster biocides was tested in laboratory, and most effects were related to chlorothalonil, DCOIT, dichlofluanid, and Irgarol, including, but not limited to DNA damage, fertility decrease, and mortality at different trophic levels. This review highlighted the need for further studies on environmental occurrence of booster biocides in Latin America and Caribbean associated to ecotoxicological studies. Such information is essential to determine the potential ecological risks and to create directives regarding safe limits of booster biocides in aquatic systems.

A global snapshot of microplastic contamination in sediments and biota of marine protected areas.

Microplastics (MPs) become ubiquitous contaminants in Marine Protected Areas (MPA) that have been planned as a conservation strategy. The present study provides a comprehensive overview of the occurrence, abundance, and distribution of MPs potentially affecting MPA worldwide. Data on MP occurrence and levels in sediment and biota samples were collected from recent peer-reviewed literature and screened using a GIS-based approach overlapping MP records with MPA boundaries. MPs were found in 186 MPAs, with levels ranging from 0 to 9187.5 items/kg in sediment and up to 17,461.9 items/kg in organisms. Peaked MPs concentrations occurred within multiple-use areas, and no-take MPAs were also affected. About half of MP levels found within MPA fell into the higher concentration quartiles, suggesting potential impacts on these areas. In general, benthic species were likely more affected than pelagic ones due to the higher concentrations of MP reported in the tissues of benthic species. Alarmingly, MPs were found in tissues of two threatened species on the IUCN Red List. The findings denote urgent concerns about the effectiveness of the global system of protected areas and their proposed conservation goals.

Key issues for bio-based, biodegradable and compostable plastics governance.

Among global efforts facing plastic pollution, their gradual replacement with alternative materials has gained strength during the last decade. We identified five stakeholders and their respective key participation in the chain of bio-based, biodegradable and compostable plastics (BBCP), which have contributed to several flaws on governance of these materials. The widespread unfamiliarity of the consumers about biodegradability concepts has been leading to misguided purchase decisions and disposal practices, along with possible littering behavior. Simultaneously, the adoption of greenwashing practices by stores and manufacturers contribute to disseminating misguided decisions on plastic consumption. Such issues are further aggravated by the lack of certification standards concerning the impact of littering, including the assessment of persistency and toxicity, also covering those made with biodegradable plastics.". Moreover, even though such alternative polymers were originally conceived as a strategy to minimize plastics pollution, the almost inexistence of specific regulatory frameworks in different political scales may convert them in a relevant part of the problem. Therefore, the governance systems and management strategies need to incorporate BBCP as potentially hazardous waste as they do for conventional plastics.

Organotin contamination in seafood from the Yucatán Peninsula, Mexico: Is there a potential risk for the health of consumers?

Since seafood is considered an important source of organotin compounds (OTCs), the present study assessed the potential risk to human health of ingesting butyltins (BTs) and phenyltins (PhTs) along with this type of food. Seafood samples were collected at five fishing sites in the Yucatán Peninsula (Mexico) during February and March 2018. In general, organotins were detected in all samples, suggesting a widespread occurrence of these compounds in the investigated region. The average concentration of total organotins in the muscle of demersal fish (Lutjanus synagris, Lutjanus campechanus, Calamus pennatula, Haemulon plumierii, Rhomboplites aurorubens), pelagic fish (Euthynnus alletteratus, and Opisthonema oglinum), gastropods (Melongena bispinosa and Strombus pugilis), oyster (Crassostrea virginica) and shrimp (Penaeus duorarum) was 146.7 ± 76.2, 93.1 ± 92.6, 61.0 ± 53.0, 76.7 ± 2.6, and 28.8 ± 2.7 ng Sn g-1 dry weight, respectively. Overall, MPhT among PhTs was the dominant compound in fish, while TBT among BTs was the dominant compound in shellfish. Regarding the toxic OTCs, TBT followed by DBT were the predominant compounds in all seafood species, while TPhT was below the quantification limit in most samples. The estimated daily intake values were lower than the tolerable daily intake (TDI) for the sum of organotins established by the European Food Safety Authority (EFSA). Furthermore, the hazard quotients (HQ) and hazard indices (HI) values were all lower than 1, suggesting that daily exposure to these levels of organotins is unlikely to cause any harm to the human health of seafood consumers at the Yucatán Peninsula. Thus, consumers may not be at risk through the inclusion of these investigated seafood species in their normal diet. However, due to the increasing coastal urbanization, maritime activities, and the likely illegal use of tin-based paints in Mexico, additional monitoring is needed to assess organotin levels in other regions along the Mexican coastal zone and using other seafood species.

Chemical contamination in coastal areas alters shape, resistance and composition of carnivorous gastropod shells.

Morphological, structural and compositional alterations in shells of molluscs have been proposed as putative biomarkers of chemical contamination in coastal zones. Despite this, few studies were carried out using top predator gastropods which tend to be more susceptible to contamination exposure. Thus, the present study assessed disturbances on shells of Stramonita brasiliensis considering compression resistance and organic and mineralogical matrix composition, related to morphometric alterations. Results showed reductions in compression resistance and organic matrix content associated with higher contaminated sites. In addition, a predominance of calcite polymorphs was seen in shells obtained in polluted areas. Such outputs were consistent with local contamination levels which may have induced the observed alterations. Thus, changes in mollusc shells showed good performance as potential biomarkers of coastal contamination, being probably observed in other species of carnivorous gastropods around the world.

Cigarette butts in two urban areas from Brazil: Links among environmental impacts, demography and market.

Environmental impacts are currently linked to smoking cigarette behavior, as cigarette butts (CBs) represent the most common litter item in natural areas. Despite this, even the best ranked Brazilian cities, in terms of urban cleaning, have no information about urban littered CBs. Thus, CBs were monitored in Santos and Niterói cities, aiming to assess contamination, Cigarette Butt Pollution Index (CBPI) and the illegal market size. CBs were collected in 36 walkways considering different land usage types and urban density levels. The CBPI was calculated, and brands were used to identify the size of the illegal market. CBs contamination in Santos (0.25 CBs/m2) was three times higher than Niterói (0.08 CBs/m2) and their occurrence and distribution presented no relationship with land usage types and urban population densities levels. CBPI = 17.6 was severe and the highest so far reported. A total of 28 cigarette brands were found both studied cities. Further, illegal cigarette consumption in Santos and Niteroi was estimated, based on brands of collected CBs, at 25.2% and 36.8%, respectively. Such data may be valuable for implementation of logistic reverse actions seeking to environmentally sustainable and socially resilient cities. Cigarette consumption threatens human life and the environment, and tobacco companies should be accountable for the pollution they generate.

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.

COVID-19-related personal protective equipment (PPE) contamination in the highly urbanized southeast Brazilian coast.

This study aimed to report personal protective equipment (PPE) contamination in Santos beaches (Brazil) using standardized procedures for the first time while comparing two periods to understand the progression of PPE contamination. The occurrence of PPE items was ubiquitous in all sampled sites, although the densities were relatively low compared to those in other parts of the world. Unlike previous studies, reusable face masks were the most common type of PPE. PPE density in the studied areas was similar in both sampling seasons, probably because of the influence of tourism, urbanization, and local hydrodynamic aspects. PPE items can release microfibers into the aquatic environment and pose entanglement hazards to marine biota. A wider monitoring of PPE pollution, accompanied by surveys on PPE usage and behavior, as well as chemical characterization of the discarded PPE items, is needed to fully understand this unprecedented form of plastic pollution.

The most extensive oil spill registered in tropical oceans (Brazil): the balance sheet of a disaster.

This article presents a synthesis of information about the massive oil spill in Brazil (2019/2020). The event affected 11 states; however, the majority of the oil residue was collected (~ 5380 tons) near nine states (99.8%) in northeastern Brazil. This spill was not the largest in volume (between 5000 m3 and 12,000 m3) recorded in tropical oceans, but it was the most extensive (2890 km). This spill develops an overwashed tar that remains mostly in the undersurface drift (non-floating oil plume) below 17 m of depth while on the continental shelf. Ten ecosystems were impacted, with potentially more severe effects in mangroves and seagrasses. Certain negative effects are still understudied, such as effects on tropical reefs and rhodolith beds. A total of 57 protected areas in seven management categories were affected, most of which (60%) were characterized as multiple-use regions. The spill affected at least 34 threatened species, with impacts detected on plankton and benthic communities. Acute impacts were reported on echinoderms, coral symbionts, polychaetes, and sponges with evidence of oil ingestion. Socioeconomic impacts were detected in food security, public health, lodging, gender equality, tourism, and fishing, with reduced sales, prices, tourist attractiveness, gross domestic product, and employment. Moreover, chemical contamination was detected in some states by toxic metals (Hg, As, Cd, Pb, and Zn) and polycyclic aromatic hydrocarbons (acenaphthalene, fluoranthene, fluorene, naphthalene, and phenanthrene). This summary aims to aid in the design of science-based strategies to understand the impacts and develop strategies for the most extensive spill observed in tropical oceans.

Mexican paradise under threat: The impact of antifouling biocides along the Yucatán Peninsula.

Levels of booster biocides (Irgarol, diuron, chlorothalonil, dichlofluanid and DCOIT), organotins (TBT, DBT, MBT, TPhT, DPhT and MPhT) and antifouling paint particles (APPs) were assessed in sediments of sites under the influence of maritime activities along the coastal zone of the Yucatán Peninsula, Mexico. Imposex incidence and organotin levels were also evaluated in seven caenogastropod species. The incidence of imposex was detected in five species from sites nearby fishing harbors and marinas, including the first reports to Gemophos tinctus and Melongena bispinosa. Butyltins levels were higher than phenyltins in gastropod tissues, sediments, and APPs. Regarding booster biocides, chlorothalonil was the most frequently detected compound and DCOIT was the most abundant biocide in sediments. DCOIT levels were registered in APPs from fishing harbors and marina areas. In addition, the highest levels of TBT, Irgarol, diuron and DCOIT exceeded the threshold limits set by international sediment quality guidelines, indicating that toxic effects could be expected in some of the studied areas, thus being a potential threat to marine life. Based on such outputs, Mexico urgently needs to adopt restrictive actions aiming at conserving the rich biological heritage of the Yucatán Peninsula.

Does pH variation influence the toxicity of organic contaminants in estuarine sediments? Effects of Irgarol on nematode assemblages.

Natural pH values in coastal waters vary largely among locations, ecosystems, and time periods; still, there is an ongoing acidification trend. In this scenario, more acidic pH values can alter bioavailability of organic contaminants, to organisms. Despite this, interactive effects between pH and chemical substances are not usually considered in Ecological Risk Assessment protocols. This study investigated the effects of pH on the toxicity of a hydrophobic organic compound on a benthic community using a microcosm experiment setup to assess the response of nematode assemblages exposed to environmentally relevant concentrations of Irgarol at two natural pH conditions. Estuarine nematode assemblages were exposed to two concentrations of Irgarol at pH 7.0 and 8.0 for periods of 7 and 35 days. Lower diversity of nematode genera was observed at the highest tested Irgarol concentration (1281 ± 65 ng.g-1). The results showed that the effects of Irgarol contamination were independent of pH variation, indicating no influence of acidification within this range on the toxicity of Irgarol to benthic meiofauna. However, the results showed that estuarine nematode assemblages are impacted by long-term exposure to low (but naturally occurring) pHs. This indicates that estuarine organisms may be under naturally high physiological pressure and that permanent changes in the ecosystem's environmental factors, such as future coastal ocean acidification, may drive organisms closer to the edges of their tolerance windows.

Biocides in antifouling paint formulations currently registered for use.

Antifouling paints incorporate biocides in their composition seeking to avoid or minimize the settlement and growing of undesirable fouling organisms. Therefore, biocides are released into the aquatic environments also affecting several nontarget organisms and, thus, compromising ecosystems. Despite global efforts to investigate the environmental occurrence and toxicity of biocides currently used in antifouling paints, the specific active ingredients that have been used in commercial products are poorly known. Thus, the present study assessed the frequencies of occurrence and relative concentrations of biocides in antifouling paint formulations registered for marketing worldwide. The main data were obtained from databases of governmental agencies, business associations, and safety data sheets from paint manufacturers around the world. The results pointed out for 25 active ingredients currently used as biocides, where up to six biocides have been simultaneously used in the examined formulations. Cuprous oxide, copper pyrithione, zinc pyrithione, zineb, DCOIT, and cuprous thiocyanate were the most frequent ones, with mean relative concentrations of 35.9 ± 12.8%, 2.9 ± 1.6%, 4.0 ± 5.3%, 5.4 ± 2.0%, 1.9 ± 1.9%, and 18.1 ± 8.0% (w/w) of respective biocide present in the antifouling paint formulations. Surprisingly, antifouling paints containing TBT as an active ingredient are still being registered for commercialization nowadays. These results can be applied as a proxy of biocides that are possibly being used by antifouling systems and, consequently, released into the aquatic environment, which can help to prioritize the active ingredients that should be addressed in future studies.

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.