Assessment and Comparison of Microplastic Contamination in Atlantic Navigation Routes with Known Uncertainty.

Microplastics (MP) have been found in various environments worldwide. However, not many studies focus on the open ocean due to logistical restraints. Between January and May 2020, the NRP Sagres sampled 123 linear paths of subsurface water of the Atlantic Ocean, passing by Cape Verde, the east coast of South America, and the west coast of Africa. The water was sampled through the ship's water system. The membranes were analyzed by the Hydrographic Institute of Portugal and the Norwegian Institute for Water Research by micro-FTIR. The contamination levels were reported with uncertainty, for 99% confidence level (CL), normalized for filtered water volume and the distance traveled during sampling. Uncertainties were calculated through a detailed ″bottom-up″ evaluation. MP were found in about a third of the stations (48 out of 123), and most of those stations (43 out of 48) presented concentrations below 1 m-3 km-1. The sites where higher concentrations were registered were the port of the island of Santiago (Cape Verde) ((5.9 ± 5.2) m-3 km-1), the Guanabara Bay in Rio de Janeiro (Brazil) ((41 ± 27) m-3 km-1), and close to South Africa ((4.9 ± 2.4) m-3 km-1). Most MP found were polyamide, polyester, polyethylene, ethylene vinyl acetate, and poly(methyl methacrylate). The estimated contamination levels cannot be directly compared with information obtained in other studies due to differences in how MP were determined and the unknown uncertainty of their measured values. This article presents a relevant and reliable contribution to understanding the MP distribution in the Atlantic Ocean.

Determination of microplastic contamination levels and trends in vast oceanic sediment areas with uncertainty.

Small plastic particles, designated as microplastics, are known vehicles of several contaminants desorbed from their surface after being ingested by marine organisms. The monitoring of the levels and trends of microplastics in oceanic areas is essential to identify relevant threats and respective sources whose management should be improved to protect the environmental resources. However, the assessment of contamination trends in large oceanic areas is affected by contamination heterogeneity, sampling representativeness, and the uncertainty of collected sample analyses. Only contamination variations not justifiable by system heterogeneity and their characterisation uncertainty are meaningful and should be taken seriously by the authorities. This work describes a novel methodology for the objective identification of meaningful variation of microplastic contamination in vast oceanic areas by the Monte Carlo simulation of all uncertainty components. This tool was successfully applied to the monitoring of the levels and trends of microplastic contamination in sediments from a 700 km2 oceanic area from 3 km to 20 km offshore Sesimbra and Sines (Portugal). This work allowed concluding that contamination has not varied between 2018 and 2019 (difference of mean total microplastic contamination between -40 kg-1 and 34 kg-1) but that microparticles made of PET are the major type of studied microplastics (in 2019, mean contamination is between 36 kg-1 and 85 kg-1). All assessments were performed for a 99 % confidence level.

Metrologically sound comparison of trace-metal levels in sea cucumber tissues from different species and habitats.

Sea cucumbers are indicators of metal contamination in sea bottoms due to their low mobility and feeding behaviour. Comparing contaminations of specimens from different locations, habitats, and/or organs allows understanding of contamination processes and differences. However, the interpretation of these data is affected by the variability of contamination levels in specimens, the uncertainty of tissue analyses, and the complex correlation of mass fractions estimated by using the same calibration of the used instrumental method of analysis. This work presents a novel tool for the sound comparison of contamination levels of biota where all mentioned factors are considered to produce reliable and undisputable information on the studied system. The Monte Carlo simulation of uncertainty components, affecting the determination of mean contamination levels observed in selected types of tissues, allowed simulating mean contamination differences and determining if these are meaningful. This tool was used to assess the levels of Cd, Cu, Ni and Pb of animals collected in different locations of Sesimbra-Portugal. It was concluded that specimens that selectively consume macroalgae have larger contamination levels than animals feeding on sediment. The gut is the most contaminated organ suggesting intake from feeding is dominant. Three of the analysed animals have Pb mass fractions larger than a maximum admissible value for human consumption of 3 mg kg-1 with a probability larger than 2.5%.

Bottom-Up Evaluation of the Uncertainty of the Quantification of Microplastics Contamination in Sediment Samples.

The quantification and comparison of microplastic contamination of sediments are affected by sample heterogeneity and the systematic and random effects affecting sample analysis. The quantification and combination of these components in the measurement uncertainty allows the objective interpretation of analysis results. This work presents the first detailed evaluation of the uncertainty of microplastic contamination quantification in sediments. The random and systematic effects affecting microplastic counts are modeled by the Poisson-lognormal distribution with inputs estimated from duplicate sediment analysis and the analysis of sediments spiked with microparticles. The uncertainty from particle counting was combined with the uncertainty from the determination of the dry mass of the analytical portion by the Monte Carlo method. The developed methodology was implemented in a user-friendly spreadsheet made available as the Supporting Information. The contamination of sediment samples collected in various inland Portuguese waters was determined, ranging from [0; 160] to [361; 2932] kg-1 for a 99% confidence level, and compared by assessing if the difference between contamination levels is equivalent to zero for the same confidence level. Several samples proved to have metrologically different microplastic contamination. This work represents a contribution to the objectivity of the assessment of environmental contamination with microplastics.

Microplastics contamination in sediments from Portuguese inland waters: Physical-chemical characterisation and distribution.

Plastics are the major constituent of waste accumulated in inland waters and subsequently transferred to the ocean. The smaller plastic particles, typically obtained from the fragmentation of larger pieces, are vehicles for food chain accumulation of plastic components and contaminants sorbed to these particles through their ingestion by small organisms. The monitoring of the level and trends of the contamination by microplastics is essential to determine the relevance and potential sources of this contamination necessary to define strategies to reduce this threat. This work presents microplastic contamination levels and trends of sediments of four Portuguese inland waters, namely Ria de Aveiro, Ria Formosa, Mira river, and Mondego river, between 02/2019 and 09/2020. The contamination is classified considering the type of polymer and size, shape, and colour of particles. Polymers are identified by micro-ATR-FTIR with true and false identification rates larger and lower than 95% and 5%, respectively. Duplicate analysis results are used to quantify contamination heterogeneity subsequently applied to assess if a specific contamination trend is not meaningful for a 99% confidence level. The analytical procedure is described in detail to clarify the scope of the analysis. Tests' quality is controlled by following strict quality control measures. Results from sixty-three sediment samples proved the ubiquitous presence of microplastic (MP) in these inland waters with contamination levels ranging between 20 MP kg-1 and 1090 MP kg-1, excluding six samples not contaminated with these particles. Overall, more than 86% of the microplastics were fragments lower than 1000 µm, and 33% were identified as polyethylene or polypropylene. A large diversity of microplastic colours was observed. For the Mondego River and Ria de Aveiro locations monitored for consecutive years, no significant variations of microplastic contamination were observed for a 99% confidence level.

Validated spreadsheet for the identification of PE, PET, PP and PS microplastics by micro-ATR-FTIR spectra with known uncertainty.

The monitoring of microplastics in the environment is crucial to determine the relevance and trends of this contamination necessary to plan environmental protection policies. Monitoring data reliability is essential for this purpose. This work describes a methodology for the reliable identification of the most abundant polymer types in aquatic sediments (polyethylene, PE, polypropylene, PP, polyethylene terephthalate, PET, and polystyrene, PS) by micro-ATR-FTIR. Identifications with true and false result rates greater than 95% and lower than 5% are performed, respectively. The analysis is based on defining spectra requirements regarding characteristic and interfering bands intensity and selecting optimal assessed wavenumber range, signal processing, and algorithm to quantify the match/agreement between particle and reference spectra. It is also defined the minimum match value, P5¼P, for reliable identifications. Examinations are performed in two stages where in the first stage PE and PP, PE&PP, are distinguished from other microplastics by taking the [4000-500] cm-1 spectra and various Match Methods and P5¼P depending on the polymer type. PE and PP are distinguished by quantifying weighted or unweighted Pearson correlation coefficients against a reference spectrum in the [3000-2800] cm-1 range. The defined P5¼P are above the 0.6 value considered in many references that do not quantify identification uncertainty. The MS-Excel files used in method development and validation are made available as Supplementary Material being applicable to other spectral techniques and analytical fields.

Monte Carlo bottom-up evaluation of the uncertainty of complex sample preparation: Elemental determination in sediments.

Many chemical analyses involve a complex sample preparation, and some, based on an instrumental method of analysis such as spectrometric or chromatographic methods, are affected by matrix effects. The objective interpretation of the results of these analyses performed in the framework of a research or a conformity assessment requires quantifying the measurement uncertainty. This work presents a novel methodology for the bottom-up modelling of the performance of complex analytical operations, such as sample digestion or extraction, by the Monte Carlo simulation of their performance independently of the performance of the other analytical steps. The simulation of between-days precision of complex sample preparation and mean measurement error observed from the analysis of various reference materials and their combination with models of instrumental quantification performance allow the detailed modelling of the measurement uncertainty. The developed methodology adapts to the complex distribution of observed measurement performance data avoiding the under evaluation of the measurement uncertainty by assuming the normal distribution of systematic and random effects. The developed methodology was successfully applied to the determination of total or acid-extractable As (following OSPAR or EPA 3051A methods, respectively) in sediments where measurement trueness was assessed from the analysis of one Certified Reference Material and two spiked samples. The evaluated uncertainty is fit for environmental monitoring considering performance criteria defined for Quasimeme proficiency tests. The developed measurement models were successfully cross-validated by randomly extracting data from the validation set subsequently used to check the compatibility between estimated and reference values for 95% or 99% confidence level. The observed success rate of these assessments is compatible with the confidence level of the tests.

Microplastics identification by infrared spectroscopy - Evaluation of identification criteria and uncertainty by the Bootstrap method.

The assessment of microplastic contamination in an environmental compartment involves identifying and counting microplastics in a representative fraction of the compartment. Microplastics can be identified by µFTIR spectroscopy where spectra are manually examined for characteristic polymer bands or by an automatic comparison of particle spectrum with reference spectra of polymers. The automatic spectra comparison can involve calculating a correlation coefficient, CC, between particle and reference spectra where a minimum correlation above which identification is adequately reliable should be defined. Correlation can be calculated from original or transformed signals, such as taking the first derivative, and by using unweighted or weighted CC. Weighted CC can highlight the spectral features more relevant to distinguish polymers. This work describes a methodology for setting the minimum CC, P5¼P, associated with a true positive result rate, TP, of 95% and for checking if this threshold allows identifications with a false positive result rate, FP, not greater than 5%. This methodology was successfully applied to the use of various CC determined from original or transformed spectra for the identification of polyethylene, PE, and polypropylene, PP, microplastics in river sediments by µFTIR. The analytical portions of sediments were digested with H2O2 and microplastics separated from the remaining particles by density using a saturated NaCl solution. Pearson's, Spearman's and Alternative unweighted and weighted correlation coefficients were studied. The P5¼P was estimated by the Bootstrap method that resamples spectra CC between a reference material and microparticle of the same polymer collected from the environment. This resampling allows simulating CC distribution required to estimate its 5th percentile (i.e. P5¼P). The FP was estimated from the probability of a particle not from the same polymer type of the reference material producing a CC greater than P5¼P. Some unweighted and weighted CC determined from original or transformed spectra were successfully used to identify PE or PP particles in river sediments. More particle spectra need to be collected to ensure performance is assessed from a representative diversity of aged polymers with different additives. The spreadsheets used for CC calculations and Bootstrap simulations are made available and can be used for the validation of the identification of other polymer types by µFTIR or ATR-FTIR spectroscopy.

Monte Carlo bottom-up evaluation of global instrumental quantification uncertainty: Flexible and user-friendly computational tool.

Many instrumental methods of analysis require the daily collection of calibrator signals to calibrate their response. The quality of quantifications based on these calibrations depends on calibrators quality, instrumental signal performance and regression model fitness. Linear Ordinary Least Squares (LOLS), Linear Weighted Least Squares (LWLS) or Linear Bivariate Least Squares (LBLS) regression models can be used to calibrate and evaluate the uncertainty from instrumental quantifications, but require the fulfilment of some assumptions, namely, constant signal variance (LOLS), high calibrators quality (LOLS and LWLS) and linear variation of instrumental signal with calibrator values. The LBLS is flexible regarding calibrator values uncertainty and correlation but requires the determination of calibrator values and signals covariances. This work developed a computational tool for the bottom-up evaluation of global instrumental quantifications uncertainty which simulates calibrator values correlations from entered calibrators preparation procedure and simulates calibrators and samples signals precision from prior precision data, allowing accurate uncertainty evaluation from a few replicate signals of the daily calibration. The used signal precision models were built from previously observed repeatability variation throughout the calibration interval adjusted to daily precision condition from a residual standard deviation adjustment factor. This approach was implemented in a user-friendly MS-Excel file and was successfully applied to the analysis of As, Cd, Ni and Pb in marine sediment extracts by Absorption Spectroscopy. Evaluations were tested by the metrological compatibility of estimated and reference values of control standards for confidence levels of 95% and 99%. The success rates of the compatibility tests were statistically equivalent to the confidence level (p-value>0.01).

Top-down evaluation of matrix effects uncertainty.

Many measurements in chemistry are affected by matrix effects responsible for larger deviation between results from the analysis of various matrices than observed from the replicate analysis of the same matrix. The identification of cases where matrix effects are relevant is useful to know if measurement robustness to matrix effects can significantly reduce the measurement uncertainty, e.g. by performing time-consuming standard addition calibrations or additional matrix clean-up. This work presents a methodology to estimate the percentage contribution of matrix effects to the measurement uncertainty by comparing the intermediate precision estimated from the analysis of a sample with the dispersion of analyte recovery observed form the analyses of samples with different matrices. The measurement model was divide in two intervals of the studied quantity: Interval I between the limit of detection and two times the limit of quantification, where the absolute measurement uncertainty is constant, and Interval II above or equal to two times the limit of quantification where the relative measurement uncertainty is constant. The division of measurements scope in these intervals allowed the comparison of information collected at different values of the studied quantity. The developed methodology was successfully applied to the analysis of total Cr, Cu, Li, Mn and Zn using a procedure developed by OSPAR and acid extractable Ni and Pb according to the EPA3051A standard in marine sediments. Matrix effects are responsible for 7.7 to 79% of the global uncertainty. For Interval II, the relative expanded uncertainty ranged from 12% to 25% and is fit for the environmental monitoring of sediments according to the way the performance of laboratories is assessed in QUASIMEME proficiency tests. The developed measurement uncertainty models produced results compatible with reference values of one Certified Reference Material and 65 proficient test samples independent of the ones used to estimate the measurement uncertainty. The used data and performed calculations are presented in a user-friendly MS-Excel spreadsheet, available as Electronic Supplementary Material, that can be used for other determinations.

As relações sociais entre jovens soropositivos: um novo desafio / Social relationships among young HIV positive: a new challenge

Vivemos hoje com a primeira geração de jovens infectados pelo HIV, estamos vivenciando uma nova fase da epidemia, a juvenilização. Com a garantia do direito ao acesso às terapias anti-retrovirais (TARVs), constata-se que crianças infectadas pelo HIV por modo de transmissão vertical estão chegando à vida adulta. Este estudo teve como objetivo investigar a rede de apoio social e familiar dos jovens soropositivos atendidos no ambulatório do Instituto de Infectologia "Emílio Ribas" (IIER), identificar se os jovens atendidos no ambulatório do IIER estão inseridos no mercado de trabalho. O estudo realizou-se com dez jovens na faixa etária entre 18 e 24 anos, infectado por modo de transmissão vertical, matriculados no ambulatório do IIER, atendidos por médico infectologista. O presente estudo foi conduzido, por meio de levantamento bibliográfico e pesquisa qualitativa e quantitativa. O instrumento utilizado foi o questionário com questões abertas e fechadas dirigidas a atingir aos objetivos propostos. Foi realizada uma entrevista aberta com perguntas norteadoras sobre: projeto de vida, relações sociais e serviço de saúde. Dentre os principais achados destaca-se que a metade dos participantes estão inseridos no mercado de trabalho. Quanto à rede de apoio sócio-familiar, identificamos que os jovens têm seus familiares como principal referência de apoio. Consideramos ainda que, o vínculo de confiança entre o profissional e paciente é de suma importância para o processo de tratamento/ adesão. É importante destacar que os resultados da pesquisa mostraram que jovens soropositivos têm os mesmos desejos e sonhos como qualquer outro jovem. Os jovens com HIV/Aids têm o direito de sonhar, planejar e construir o futuro. Espera-se que o estudo contribua para o enfrentamento de novas condutas profissionais diante da demanda apresentada pelos jovens soropositivos. Um desafio para melhorar a compreensão, atendimento e tratamento dos jovens