Interaction Between Endocrine Disruptors and Polyethylene Nanoplastic by Molecular Dynamics Simulations.

Nanoplastics (NPs) can come into contact with humans through different means such as ingesting contaminated food or exposure to contaminated air. Recent research indicates that these NPs can act as vectors for other contaminants. Further research is still needed to determine the effects of these interactions and whether they are significant under environmental conditions. Bisphenol A (BPA) and benzophenone (BZP) are possible contaminants that could be cotransported with NPs. Even in low concentrations, BPA and BZP can act as endocrine disruptors and have been linked to several diseases. In this study, we used molecular dynamics simulations to obtain the potential of mean force (PMF) profile between a polyethylene NP and a BPA/BZP molecule. The PMF shows a minimum of -8.0 kJ mol-1 for the BPA, whereas it is -23.5 kJ mol-1 for the BZP, meaning BZP has a much greater attractive potential to polyethylene than BPA. We can infer that the higher quantity of BPA's hydrogen bonds with the water contributes to the difference between BZP and BPA. The results indicate the need to address the possibility of NPs playing a role in the cotransport and bioaccumulation of contaminants in aquatic ecosystems.

Charge Inversion in 1:1 Electrolytes: Analyzing the Energetics.

The effects of bulk concentration, surface charge density, ionic diameter, and bulk dielectric constant on charge inversion in 1:1 electrolyte systems are investigated. The framework of the classical density functional theory is used to describe the mean electrostatic potential and the volume and electrostatic correlations, which combine to define the adsorption of ions at a positively charged surface. Our results show that a decrease in the dielectric constant, in particular, creates charge inversion for 1:1 electrolytes by amplifying both the electrostatic potential and the screening component (which is generally much larger than the excluded-volume component). Local electrical potential inversion can occur even for moderate concentrations and surface charges. These findings are especially significant for ionic liquids and systems with organic molecules as solvents, as these generally have a dielectric constant much smaller than water.

Surface charge regulation using classical density functional theory: the effect of divalent potential determining ions.

The charge regulation approach has been used to describe the charge of surfaces susceptible to the presence of protons and other ions. Conventionally, this model is used with the Poisson-Boltzmann equation, which generally neglects the finite size of the ions and the electrostatic correlations. Recently, progress has been made by coupling charge regulation with classical density functional theory (DFT), which explicitly includes these correlations. However, little is known about charge regulation at surfaces with both acid-base equilibria and complexation with multivalent ions. The main purpose of this work is to investigate the role divalent ions play in charge regulation. Using DFT, we show that the size of the divalent ion has significant consequences on the surface charge density and it should not be neglected. For the surface reactions investigated, the larger the size of the divalent cation, the greater the charge on the surface due to higher divalent concentration there. At low divalent concentration, the ion correlations play a second-order but non-negligible role; using Poisson-Boltzmann theory with point ions cannot recover the DFT surface charge. At high concentrations, ion correlations play a dominant role by creating charge inversion.

Pollution caused by nanoplastics: adverse effects and mechanisms of interaction via molecular simulation.

The continuous increase in the production of synthetic plastics for decades and the inadequate disposal of plastic waste have resulted in a considerable increase of these materials in aquatic environments, which has developed into a major environmental concern. In addition to conventional parameters, the relevance of the environmental monitoring of microplastics (MPs) and nanoplastics (NPs) has been highlighted by the scientific community due to the potential adverse effects these materials pose to the ecosystem as well as to human health. The literature has registered an increasing interest in understanding the mechanisms, at the molecular level, of the interaction between NPs and other compounds using molecular simulation techniques. The present review aims to: (i) summarize the force fields conventionally used to describe NPs by molecular simulations; (ii) discuss the effects of NPs in the structural and dynamical properties of biological membranes; (iii) evaluate how NPs affect the folding of proteins; (iv) discuss the mechanisms by which NPs adsorb contaminants from the environment. NPs can affect the secondary structure of proteins and change the lateral organization and diffusion of lipid membranes. As a result, they may alter the lipid digestion in the gastrointestinal system representing a risk to the assimilation of the nutrients by humans. The adsorption of contaminants on MPs and NPs can potentiate their harmful effects on human health, due to a possible synergism. Therefore, understanding the mechanisms involved in these interactions is crucial to predict dangerous combinations and outline action strategies that reduce negative impacts on ecosystems and human health. Depending on the chemical properties of contaminants and NPs, electrostatic and/or van der Waals interactions can be more relevant in explaining the adsorption process. Finally, we conclude by highlighting gaps in the literature and the critical aspects for future investigations.

[Analysis of the coverage of supply and of the water quality distributed in different regions of Brazil in 2019]. / Análise da cobertura de abastecimento e da qualidade da água distribuída em diferentes regiões do Brasil no ano de 2019.

Bearing in mind that universal access to sanitation services is one of the objectives of the Brazilian Plan for Basic Sanitation and one of the sustainable development goals (SDG), this research sought to evaluate the coverage of supply and of the quality of water distributed in Brazil in 2019. Data from the National Sanitation Information System (SNIS) and Water Quality for Human Consumption Surveillance Information System (Sisagua) databases were evaluated. It was found that 82% of the population has access to Water Supply Systems (WSS), this percentage only being lower in the North (58%) and Northeast (74%) regions. Most of the population is served by WSS; however, in the North region, 6.6% of the population is served by WSS and 7.2% by Collective Alternative Solution (CAS) without treatment. For the Total Coliforms parameter, 21.9% of CAS samples from the North region were outside the potability standard, while for the residual disinfectant agent, 40.6% of WSS from the Northeast region was outside this standard (with 19% of the samples having a concentration of the disinfectant agent above 5.0 mg/L, and 81% of the samples presenting concentration lower than 0.2 mg/L. The conclusion drawn is that part of the population may be vulnerable to water quality-related risks.

Tendo em vista que a universalização dos serviços de saneamento é uma das metas do Plano Nacional de Saneamento Básico (PLANSAB) e um dos objetivos de desenvolvimento sustentável (ODS), esta pesquisa objetivou-se avaliar a cobertura do abastecimento e a qualidade da água distribuída no Brasil em 2019. Foram utilizados os dados do Sistema Nacional de Informações sobre Saneamento (SNIS) e do Sistema de Informação de Vigilância da Qualidade da Água para Consumo Humano (Sisagua). Verificou-se que 82% da população foi atendida por serviços de água, sendo este percentual ainda menor considerando apenas a região Norte (58%) e Nordeste (74%). A maioria da população é atendida por Sistemas de Abastecimento de Água (SAA); entretanto, na região Norte, 6,6% da população é atendida por SAA e 7,2% por Solução Alternativa Coletiva (SAC) sem tratamentos. Para o parâmetro Coliformes totais, 21,9% das amostras de SAC da região Norte estavam fora do padrão de potabilidade, enquanto para o residual de agente desinfetante, 40,6% de SAA da região Nordeste encontravam-se fora do padrão, sendo que deste total 19% das amostras apresentavam concentração do agente desinfetante acima de 5,0 mg/L e 81% das amostras apresentavam concentrações menores que 0,2 mg/L. Conclui-se que parte da população pode estar vulnerável aos riscos relacionados à qualidade da água.

Análise da cobertura de abastecimento e da qualidade da água distribuída em diferentes regiões do Brasil no ano de 2019 / Analysis of the coverage of supply and of the water quality distributed in different regions of Brazil in 2019

Resumo Tendo em vista que a universalização dos serviços de saneamento é uma das metas do Plano Nacional de Saneamento Básico (PLANSAB) e um dos objetivos de desenvolvimento sustentável (ODS), esta pesquisa objetivou-se avaliar a cobertura do abastecimento e a qualidade da água distribuída no Brasil em 2019. Foram utilizados os dados do Sistema Nacional de Informações sobre Saneamento (SNIS) e do Sistema de Informação de Vigilância da Qualidade da Água para Consumo Humano (Sisagua). Verificou-se que 82% da população foi atendida por serviços de água, sendo este percentual ainda menor considerando apenas a região Norte (58%) e Nordeste (74%). A maioria da população é atendida por Sistemas de Abastecimento de Água (SAA); entretanto, na região Norte, 6,6% da população é atendida por SAA e 7,2% por Solução Alternativa Coletiva (SAC) sem tratamentos. Para o parâmetro Coliformes totais, 21,9% das amostras de SAC da região Norte estavam fora do padrão de potabilidade, enquanto para o residual de agente desinfetante, 40,6% de SAA da região Nordeste encontravam-se fora do padrão, sendo que deste total 19% das amostras apresentavam concentração do agente desinfetante acima de 5,0 mg/L e 81% das amostras apresentavam concentrações menores que 0,2 mg/L. Conclui-se que parte da população pode estar vulnerável aos riscos relacionados à qualidade da água.

Abstract Bearing in mind that universal access to sanitation services is one of the objectives of the Brazilian Plan for Basic Sanitation and one of the sustainable development goals (SDG), this research sought to evaluate the coverage of supply and of the quality of water distributed in Brazil in 2019. Data from the National Sanitation Information System (SNIS) and Water Quality for Human Consumption Surveillance Information System (Sisagua) databases were evaluated. It was found that 82% of the population has access to Water Supply Systems (WSS), this percentage only being lower in the North (58%) and Northeast (74%) regions. Most of the population is served by WSS; however, in the North region, 6.6% of the population is served by WSS and 7.2% by Collective Alternative Solution (CAS) without treatment. For the Total Coliforms parameter, 21.9% of CAS samples from the North region were outside the potability standard, while for the residual disinfectant agent, 40.6% of WSS from the Northeast region was outside this standard (with 19% of the samples having a concentration of the disinfectant agent above 5.0 mg/L, and 81% of the samples presenting concentration lower than 0.2 mg/L. The conclusion drawn is that part of the population may be vulnerable to water quality-related risks.