How natural and anthropogenic factors should drive microplastic behavior and fate: The scenario of Brazilian urban freshwater.

Brazil maintains its position at the top of the global ranking of plastic producers, yet recycling efforts have been incipient. Recent data reveals an annual production of approximately 14 million tons of plastic waste, not accounting for the surge in the usage of plastic masks and related materials due to the COVID-19 pandemic. However, what remains largely unreported is that over half of post-consumer plastic packaging in Brazil is managed without any monitoring, and it remains unclear how this will contribute to the occurrence of plastic waste and microplastics in Brazilian freshwaters. This scenario requires the consideration of several other crucial factors. Studies have been carried out mainly in marine and estuarine waters, while data on freshwaters are lacking. Brazil has continental dimensions and the highest water availability on the planet, yet the demand for water is greatest in regions with medium to low supply. Many densely populated Brazilian urban areas face chronic flood problems, possess inadequate levels of wastewater treatment, and display inadequate solid waste management practices. Consequently, urban freshwater with tropical characteristics in Brazil presents an intriguing scenario and is complementary to the most commonly studied marine environments. In this study, we explore the nuances of pollution in Brazilian urban freshwater and discuss how various parameters, such as organic matter, suspended solids, temperature, and pH, among others, influence the behavior of microplastics and their interactions with organic and inorganic contaminants. Furthermore, we address how microplastic conditions, such as biofouling, the type of plastic, or degradation level, may impact their behavior. By analyzing how these conditions change, we propose priority themes for investigating the occurrence of microplastics in Brazilian urban freshwater systems under different degrees of human impact. Ultimately, this study aims to establish a network dedicated to standardized monitoring of microplastic pollution in Brazilian urban freshwaters.

Multilayered iron oxide/reduced graphene oxide nanocomposite electrode for voltammetric sensing of bisphenol-A in lake water and thermal paper samples.

A multilayered iron oxide/reduced graphene oxide (ION-RGO) nanocomposite electrode is reported for the voltammetric sensing of bisphenol-A (BPA). Structural characterizations reveal the nanocomposite features RGO sheets decorated with nanometric spherical ION in a mixture of maghemite and magnetite phases. ITO substrate modified with the ION-RGO multilayered film exhibits strong electrocatalytic effect toward BPA oxidation, which is made possible by Fe(III) catalysts generated at the ION's surface after scanning the electrode potential from below 0 V (vs Ag/AgCl) and followed by the RGO phase conducting the transferred electrons. Under optimized differential pulse voltammetry conditions, the proposed sensor shows three linear working ranges 0.09-1.17 (r2 = 0.999), 1.17-3.81 (r2 = 0.995) and 3.81-8.20 (r2 = 0.998), with the highest sensitivity equaling 7.76 µA cm-2/µmol L-1 and the lowest limit of detection of 15 nmol L-1. A single electrode can be used for at least twenty consecutive runs loosing less than 15% of sensitivity, whereas electrodes fabricated in different bacthes exhibit almost identical perfomances. Determination of BPA in a thermal paper sample shows no difference (at 95% confidence level) between the proposed sensor and HPLC/UV. The sensor is neither influenced by the matrix composition nor by other emerging contaminants.

Method Development for Assessing Carbamazepine, Caffeine, and Atrazine in Water Sources from the Brazilian Federal District Using UPLC-QTOF/MS.

About 3.0 million people living under a typical tropical savannah climate in the Brazilian Federal District (FD) have faced an unprecedented water crisis. Considering the need for indirect reuse of wastewater for public supply, this work aimed to investigate FD water sources regarding the presence and risks of three contaminants of emerging concern: caffeine, carbamazepine, and atrazine. Samples from two current water sources (Descoberto and Santa-Maria Lakes) and two future water sources of the FD (Paranoá and Corumbá Lakes) were analyzed by solid-phase extraction followed by liquid chromatography coupled to hybrid quadrupole-time-of-flight mass spectrometry (UPLC-QTOF/MS). Method precision and accuracy were satisfactory and limits of quantification ranged from 0.37 to 0.54 ng/L. Higher concentrations were observed for caffeine in the future water sources (39 to 180 ng/L) followed by carbamazepine (5.4 to 25 ng/L) and atrazine (3.9 to 15 ng/L). The less-impacted water sources, in current use in the FD, present caffeine concentrations ranging from 4.8 to 32 ng/L and atrazine levels varying between 2.4 and 5.5 ng/L. Carbamazepine was not detected in these reservoirs. Environmental risk assessment indicates a possible risk for carbamazepine and atrazine, evidencing the need for further studies. No human health risk was depicted within the results.

A preliminary nationwide survey of the presence of emerging contaminants in drinking and source waters in Brazil.

This is the first nationwide survey of emerging contaminants in Brazilian waters. One hundred drinking water samples were investigated in 22 Brazilian state capitals. In addition, seven source water samples from two of the most populous regions of the country were evaluated. Samples were collected from June to September of 2011 and again during the same period in 2012. The study covered emerging contaminants of different classes, including hormones, plasticizers, herbicides, triclosan and caffeine. The analytical method for the determination of the compounds was based on solid-phase extraction followed by analysis via liquid chromatography electrospray triple-quadrupole mass spectrometry (LC-MS/MS). Caffeine, triclosan, atrazine, phenolphthalein and bisphenol A were found in at least one of the samples collected in the two sampling campaigns. Caffeine and atrazine were the most frequently detected substances in both drinking and source water. Caffeine concentrations in drinking water ranged from 1.8ngL-1 to values above 2.0µgL-1 while source-water concentrations varied from 40ngL-1 to about 19µgL-1. For atrazine, concentrations were found in the range from 2.0 to 6.0ngL-1 in drinking water and at concentrations of up to 15ngL-1 in source water. The widespread presence of caffeine in samples of treated water is an indication of the presence of domestic sewage in the source water, considering that caffeine is a compound of anthropogenic origin.

Determination of antibiotics in Brazilian surface waters using liquid chromatography-electrospray tandem mass spectrometry.

A liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) method for the determination of antibiotics in water was developed and applied to Brazilian surface waters. Amoxicillin, ampicillin, cefalexin (CEF), ciprofloxacin (CIP), norfloxacin (NOR), sulfamethoxazole, tetracycline (TET), and trimethoprim were selected as target compounds due to their high consumption pattern in Brazil. LC and MS conditions were optimized to produce the maximum analytic response for each compound. Anion exchange and polymeric solid-phase extraction cartridges, in series, were employed during the extraction procedures. Recovery, linear range, limit of detection (LOD), and limit of quantification were calculated. LOD varied from 0.13 ng L(-1) for CIP and NOR to 0.76 ng L(-1) for TET. Surface water samples from the Atibaia watershed (São Paulo State, Brazil) were analyzed. Results showed that seasonal and anthropogenic aspects dictated the levels of antibiotics in the samples. An overall frequency of detection of 55% was observed during the rainy period, whereas a higher percentage (88%) was noticed for samples collected during the dry season. In the Atibaia River, sample concentrations ranged from 29 ng L(-1) for CEF to 0.5 ng L(-1) for NOR. In a sewage-affected stream, however, concentrations up to 2422 ng L(-1) CEF were found.