Coastal plastic pollution: A global perspective.

Coastal ecosystems have ecological importance worldwide and require control and prevention measures to mitigate human pollution. The objective of this study was to perform a systematic review to provide a comprehensive overview of the global issue of coastal plastic pollution. 689 articles were eligible for qualitative synthesis and 31 were considered for quantitative analysis. There was an exponential increase in articles addressing coastal plastic pollution over the past 50 years. Studies were mainly carried out on beaches, and plastic bottles were the most found item, followed by cigarette butts. Polyethylene was the predominant plastic polymer, and white microplastic fragments stood out. China published most articles on the topic and Brazil had the highest number of sites sampled. Meta-analysis had significant effect sizes based on the reported data. These findings carry significant implications for environmental policies, waste management practices, and targeted awareness campaigns aimed at mitigating plastic pollution.

Meta-analysis of the thermal pollution caused by coastal nuclear power plants and its effects on marine biodiversity.

The rise in seawater temperature due to industrial activities is one of the main threats to marine biodiversity. In nuclear power plants, large volumes of water are used for their operation, returning to the ecosystem at higher temperatures. A global meta-analysis was performed to evaluate the thermal effects caused by coastal nuclear power plants on marine organisms. We found 853 articles of which, 99 were included in the qualitative analysis and 75 in the meta-analysis. The meta-analysis showed an increase of 4.38 °C in water temperature near the outfall, and the temperature variation of each study was found to be associated with the power plant latitudes. The main effects on organisms were related to changes in the structure and composition of aquatic communities, with species abundance, distribution, dominance, and density being the most cited ones. Among the affected groups, photosynthesizing microorganisms were the most cited, potentially contributing to shifts in ecosystem dynamics.

Chironomus sancticaroli (Diptera: Chironomidae) in ecotoxicology: laboratory cultures and tests.

Chironomus sancticaroli is a tropical species, easy to grow and to maintain in laboratory cultures. It has a fast reproduction cycle, under adequate conditions, around 30 days, allowing it to have many generations per year, an important criterion for selecting a test organism in ecotoxicology. Its life stages include: eggs, four larval instars (one planktonic and three benthic), pupa and adult (midges) This study aimed to: (1) review the methods for C. sancticaroli cultivation and its use in ecotoxicological tests, (2) establish a laboratory culture of C. sancticaroli, presenting the difficulties and discussing the ways to overcome them. Early 4th instar larvae was the most used in acute studies, while the 1st instar larvae (early 1st instar) was the most used in chronic studies; 96 h and 28 days were the most frequent durations in acute and chronic studies, respectively. The most common endpoints evaluated were organisms' survival and development, and most of the ecotoxicological studies using C. sancticaroli were performed in laboratory. Most of the tested contaminants were pesticides and these had the most adverse effects on organisms. Most mesocosms with environmental contaminated samples did not show adverse effects on C. sancticaroli. Chronic and field studies as well as those testing the effects of the mixture contaminants on C. sancticaroli were still deficient. Keeping the laboratory environment and equipment effectively sanitized was important as well as maintaining stabilized conditions of temperature, photoperiod, physical, chemical and biological water quality in cultures.

Glyphosate concentrations in global freshwaters: are aquatic organisms at risk?

Glyphosate is the most used herbicide worldwide. Many studies have reported glyphosate risks to aquatic organisms of different trophic levels. Moreover, evidence suggests flaws in countries' legislation that may imply the non-protection of aquatic species exposed to glyphosate. Therefore, we aimed to investigate glyphosate concentrations in freshwater ecosystems worldwide based on a systematic literature review, to discuss the results considering each country's legislation, and to assess the relative tolerance and risk for aquatic species. Only articles providing in situ concentrations of glyphosate in freshwater systems were included in our study. In total, 73 articles met the inclusion criteria and were used in our analysis. The studies comprised freshwater ecosystems from 21 countries. Most countries evaluated (90%) did not have restrictive legislation for aquatic glyphosate concentrations, resulting in a potential non-protection of aquatic organisms. Glyphosate may pose a moderate to high risk in 95% of the countries investigated, reaching a maximum concentration of 105 mg L-1. Additionally, the risk analysis showed that glyphosate concentrations below 0.1 µg L-1 represent a low risk, whereas glyphosate concentrations above 1 µg L-1, which is below the limit established by some countries' legislation, represent a high risk to aquatic organisms. Therefore, we strongly recommend a revision of the countries' legislation for glyphosate concentration in freshwater systems.

Three-bestseller pesticides in Brazil: Freshwater concentrations and potential environmental risks.

Agricultural production in Brazil is favored by weather conditions and by the large amount of available land. Therefore, currently, Brazil is the second largest exporter of agricultural products globally. Pesticides are widely used in Brazilian crops due to their high efficiency, their low cost, and permissive legislation. However, pesticides tend to reach water resources threatening organisms and the water quality. Thereby, we aimed to review the surface freshwater concentrations of the three-bestseller pesticides in Brazil (glyphosate, 2,4D, and atrazine), and discuss the results with sales, legislation, toxicity and potential risks. For that, we performed a systematic review of quantitative studies of glyphosate, atrazine, and 2,4D in Brazilian freshwater and included monitoring data provided by the Brazilian Ministry of Health in our analysis. Finally, we calculated the risk assessment for the three pesticides. Only a few scientific studies reported concentrations of either of the three-bestseller pesticides in Brazilian freshwaters. Between 2009 and 2018, an increase in the sales of 2,4D, atrazine, and glyphosate was observed. It was not possible to evaluate the relation between concentrations and sales, due to limited number of studies, lack of standard criteria for sampling, individual environmental properties, and type of pesticide. Atrazine showed a higher toxicity compared to 2,4D and glyphosate. Regarding the environmental risks, 65%, 72%, and 94% of the Brazilian states had a medium to high risk to 2,4D, atrazine, and glyphosate, respectively. Finally, 80% of the Brazilian states evaluated showed a high environmental risk considering a mixture of the three pesticides. Although most of the environmental concentrations registered were below the allowed limits according to the Brazilian legislation, they are already enough to pose a high risk for the aquatic ecosystems. We, therefore, strongly recommend a revaluation of the maximum allowed values in the national surface freshwater Brazilian legislation.

Acaricidal activity of (E)-cinnamaldehyde and α-bisabolol on populations of Rhipicephalus microplus (Acari: Ixodidae) with different resistance profiles.

This study aimed to investigate the acaricidal activity of (E)-cinnamaldehyde and α-bisabolol on populations of Rhipicephalus microplus with different resistance profiles. The adult immersion test (AIT) was used to characterize the susceptibility of tick populations (50 field populations) to synthetic acaricides: deltamethrin, amitraz, and chlorfenvinphos. The larval packet test (LPT) was used to determine the LC50 values for (E)-cinnamaldehyde (populations 1-25) and α-bisabolol (populations 26-50) at the concentrations of 0.31, 0.62, 1.25, 2.0, 2.5, 5.0 and 10.0 mg/mL. The susceptible strain Porto Alegre (POA) was used as a reference for calculating the resistance ratio (RR). In the AIT, deltamethrin did not show efficacy >95 % for any of the populations, whereas amitraz and chlorfenvinphos have presented efficacy >95 % for three (6 %) and 15 (30 %) populations, respectively. In the LPT, the LC50 values of (E)-cinnamaldehyde and α-bisabolol varied from 0.23 to 2.36 mg/mL and 1.57-3.01 mg/mL, respectively. The RR50 for (E)-cinnamaldehyde showed 20 (80 %) populations with values <1.0 and no population with values>1.5. As for α-bisabolol, only two (8%) populations have presented RR50 <1.0, whereas three (12 %) populations showed incipient resistance to this sesquiterpene (RR50 between 1.5 and 2.0). The results indicate that all studied tick populations showed low susceptibility to at least one of the commercial acaricides tested. In addition, comparison between the LC50 values of (E)-cinnamaldehyde and α-bisabolol for the field populations and the susceptible strain POA suggests that there is no cross-resistance of (E)-cinnamaldehyde and α-bisabolol for the tick populations evaluated, and that the differences in the LC50 values are due to population variations.

Ciliates as model organisms for the ecotoxicological risk assessment of heavy metals: A meta-analysis.

Ciliates are key components of aquatic ecosystems, significantly contributing to the decomposition of organic matter and energy transfer to higher trophic levels. They are considered good biological indicators of chemical pollution and relatively sensitive to heavy metal contamination. In this study, we performed a meta-analysis of the available toxicity data of heavy metals and ciliates to assess: (1) the sensitivity of freshwater ciliates to different heavy metals, (2) the relative sensitivity of ciliates in comparison to the standard test species used in ecotoxicological risk assessment, and (3) the difference in sensitivity across ciliate taxa. Our study shows that the tolerance of ciliates to heavy metals varies notably, which is partly influenced by differences in methodological conditions across studies. Ciliates are, in general, sensitive to Mercury > Cadmium > Copper > Zinc > Lead > Chromium. Also, this study shows that most ciliates are more tolerant to heavy metal pollution than the standard test species used in ecotoxicological risk assessments, i.e., Raphidocelis subcapitata, Daphnia magna, and Onchornyncus mykiss. Threshold concentrations derived from toxicity data for these species is expected to confer sufficient protection for the vast majority of ciliate species. Our data analysis also shows that the most commonly tested ciliate species, Paramecium caudatum and Tetrahymena thermophila, are not necessarily the most sensitive ones to heavy metal pollution. Finally, this study stresses the importance of developing standard toxicity test protocols for ciliates, which could lead to a better comprehension of the toxicological impact of heavy metals and other contaminants to ciliate species.

Responses of Leptinaria unilamellata (Gastropoda: Subulinidae) to Novel Micro-Environmental Conditions: Shift in Shell Morphology and the Balance between Protection against Desiccation and Reproductive Success.

In the present study, we observed that Leptinaria unilamellata responds to changes in microclimatic conditions through shifts in shell morphology. Over three laboratory generations, shell differences between two populations, representing distinct morphotypes, became less evident. Only F1 generations from both populations showed shell morphometry very similar to the field parental snails, suggesting maternal effect. Snails from the locality with higher values of rainfall, relative humidity and evaporation index and smaller values of temperature and insolation produced more and larger hatchlings. Snails from the locality with less favorable climatic conditions presented shells traits that offer protection against desiccation, but reduce reproductive success. These snails showed smaller offspring production and faster response to a desiccation regime, through changes in conchiometrics. In addition, the results of the present study suggest that the spire index plays a less important role in determining protective properties of the shell of L. unilamellata, in response to desiccation risk, compared to aperture dimension. As shell aperture dimension is an important trait related to resistance to desiccation, and at the same time to reproduction, plastic responses to environmental conditions promoting the balance between survival and reproductive success are critical for the species adaptive success.

Sediment drying-rewetting cycles enhance greenhouse gas emissions, nutrient and trace element release, and promote water cytogenotoxicity.

Increased periods of prolonged droughts followed by severe precipitation events are expected throughout South America due to climate change. Freshwater sediments are especially sensitive to these changing climate conditions. The increased oscillation of water levels in aquatic ecosystems causes enhanced cycles of sediment drying and rewetting. Here we experimentally evaluate the effects of induced drought followed by a rewetting event on the release of carbon dioxide (CO2), methane (CH4), nutrients (nitrogen and phosphorus), and trace elements (iron, manganese, and zinc) from the sediment of a tropical reservoir in southeastern Brazil. Furthermore, we used bulb onions (Allium cepa) to assess the potential cytogenotoxicity of the water overlying sediments after rewetting. We found peaks in CO2 and CH4 emissions when sediments first transitioned from wet to dry, with fluxes declining as sediments dried out. CO2 emissions peaked again upon rewetting, whereas CH4 emissions remained unaltered. Our experiment also revealed average increases by up to a factor of ~5000 in the release rates of nutrients and trace elements in water overlying sediments after rewetting. These increased release rates of potentially toxic compounds likely explain the lower replication of Allium cepa cells (up to 22% reduction) exposed to water overlying sediments after rewetting. Our findings suggest that increased events of drought followed by rewetting may lead to a range of changes in freshwater ecosystems, including nutrient enrichment, increased toxicity following resuspension of contaminants, and higher emission of greenhouse gases to the atmosphere.