Sampling Techniques for Microplastics PDF

MODULE FOUR SESSION 1 Sampling Techniques for Microplastics  Course overview This course will bring you: The objectives of microplastic sampling Microplastic sampling techniques in water, biota, and sediment  LEARNING OUTCOMES At the end of...

MODULE FOUR SESSION 1 Sampling Techniques for Microplastics  Course overview This course will bring you: The objectives of microplastic sampling Microplastic sampling techniques in water, biota, and sediment  LEARNING OUTCOMES At the end of the course, you should be able to: 1. Clearly define the objectives of microplastic sampling 2. Assessing contamination levels from microplastic sampling 3. Identify microplastic Source: EPC 2020 sampling techniques for water, biota, and sediment  Planning to commence sampling (A) Clearly define the objectives of the microplastic sampling Precision in Target Selection: Enhanced Data Relevance: – Prioritise microplastic size, type, or Clear objectives guide precise polymer composition. target selection during – This prioritisation ensures that data matches research aims. microplastic sampling, Improved Data Interpretation: identifying expected – Well-defined goals increase data contamination locations and interpretation. media. – Data contextualization for specified goals valid conclusions and plans. Optimized Sampling Strategies: Measure microplastic This ensures efficient resource contamination in the target utilization and avoids irrelevant environment. data collection. Optimized Locate microplastic entrance sampling strategies are points. developed accordingly. Assess microplastic distribution in the sampled region.  Planning to commence sampling (B) Assessing contamination levels in microplastic sampling Quantitative Analysis: Depth Profiling: Selection of quantitative techniques to Vertical dispersion: Measure measure microplastic content in a microplastic dispersion in water and sample. sediment layers. Standardisation: methods and Temporal Variability: Track standards for consistent and contamination levels at different comparable outcomes across research and locales. depths over time to discover vertical distribution patterns and reasons. Spatial Distribution: To capture geographic heterogeneity, Particle Characteristics: use a systematic and representative Size Class Distribution: Determine sample design. microplastic size class predominance Mapping Contamination: map by analysing size distribution. microplastic distribution patterns to Polymer Composition: Determine locate hotspots and explain dispersion in the studied environment. polymer kinds to understand origins and environmental persistence.  Planning to commence sampling (B) Assessing contamination levels in microplastic sampling Depth Profiling: Ecological Relevance: – Vertical dispersion: Measure – Ecotoxicological Studies: Integrate microplastic dispersion in water pollution data with ecotoxicological and sediment layers research to estimate risks to aquatic and terrestrial life. – Temporal Variability: Track – Food Web Analysis: Monitor contamination levels over time to microplastic transmission across the identify trends and causes. food chain to assess its effects on Particle Characteristics: higher trophic levels. – Size Class Distribution: Analyse Comparison with Baseline Data: size distribution to determine – Establishing Baselines: compare microplastic size class historical or pre-contamination dominance. data. – Polymer Composition: – Temporal Trends: analyse Determine polymer types for contamination levels over time to sources and environmental find patterns and evaluate pollution mitigation techniques. persistence.. Sampling Techniques Grab sampling involves collecting instantaneous vs samples at a specific Passive sampling involves location and time, the deployment of samplers providing a snapshot of over an extended period, the microplastic content Grab Passive allowing microplastics to in the sampled medium. accumulate gradually. Merits Merits Capturing microplastic changes over short periods. Long-term trends and seasonal changes data High Spatial Resolution: focused collecting. sampling at key places. Fieldwork and sampling are less frequent and Microplastic concentrations are need less human presence. monitored in real-time. Particle Type Integration: accumulation of several particle kinds throughout time. Choosing the Appropriate Method whether short-term or The specific Objective long-term trends are of characteristics of the Environment greater interest. sampling environment The available resources, For the understanding of including personnel, microplastic dynamics Combination Resources equipment, and budget. over different temporal and spatial scales. General sampling overview Sampling Techniques - Water (A) Grab sampling (B) Trawl sampling  Methodology  Methodology involves collecting water Uses nets or trawls towed through samples at specific locations the water to collect suspended and depths at a single point in microplastics. time.  Applications  Applications Effective for capturing surface suitable for capturing a water microplastics and larger snapshot of microplastic plastic debris, to provide presence in specific areas, information on size distribution offering high spatial resolution. and spatial variability.  Sampling Techniques - Water (C) Surface water filtration (D) Integrated sampling devices Methodology:  Methodology Involves passing water through a Deployment of integrated samplers, fine mesh filter to capture such as sediment traps, sediment microplastics present on the cores, or sediment grabs, over a water's surface. specified period to accumulate Applications: microplastics. Ideal for quantifying floating microplastics, particularly in  Applications areas with high surface enables the collection of time- concentrations. integrated samples, providing data on long-term trends and variations in microplastic concentrations.  Sampling Techniques - Water (E) Passive sampling (F) Pump sampling  Methodology  Methodology deployment of samplers involves using pumps to draw designed to accumulate water through a filter, capturing microplastics over time, microplastics present in the water without active water pumping. column. Applications  Applications captures microplastics in a suitable for assessing manner that integrates their microplastics at different water presence over extended depths, to explain the vertical periods, suitable for assessing distribution. long-term trends and variations.  Sampling Techniques - Water (G) Size-Fractionated sampling (H) Automated sampling systems  Methodology  Methodology Segregation of water samples into implementation of automated size fractions using filters with devices equipped with sensors for different mesh sizes. continuous or programmed water  Applications sampling. Enables the assessment of size-  Applications specific microplastic allows for frequent and systematic concentrations, aiding in sampling, providing real-time or understanding size-related high-frequency data on ecological impacts. microplastic concentrations.  Sampling Techniques - Water (I) Bailer sampling  Methodology Deployment of bailers (closed tubes) to collect discrete water samples at specific depths.  Applications useful for studying vertical variations in microplastic concentrations, especially in water bodies with stratification. Source: Environmental test Products  Sampling Techniques - Biota Digestive Tract Dissection Filtration and Density Separation Method: Dissecting organisms to Method: Filtering digestive contents or access their digestive tracts, where homogenized tissues followed by density microplastics may accumulate. separation to concentrate microplastics. Application: Microplastic ingestion Application: Useful for separating research on fish, birds, and marine microplastics from organic matter, facilitating animals are common. microscopic analysis. Enzymatic Digestion Tissue Homogenization Method: Using enzymes to degrade Method: Homogenizing tissues to create a organic material and remove uniform sample for subsequent microplastic microplastics from tissues. extraction. Application: Used to decompose Application: Commonly used for analyzing tissues and separate microplastics for microplastics in various organs and tissues. examination.  Sampling Techniques - Biota Non-lethal Sampling Techniques Genetic Analysis Methods: Collecting samples without Methods: Implementing genetic harming the organism, such as techniques, such as DNA barcoding analyzing mucus, excrement, hair, or or metagenomics, to identify feathers. microplastics. Application: Suitable for species Application: Enhances traditional where lethal sampling is impractical methods by offering genetic-level or ethically challenging. identification and understanding of Epidermal Sampling Techniques microplastic sources. Method: Collecting samples from the Microscopy and Spectroscopy skin or outer surfaces of organisms. Methods: Utilizing various Application: Particularly useful for microscopy techniques (FTIR, SEM, studying microplastics in marine TEM) and spectroscopy for mammals and sea turtles. visualizing and identifying microplastics. Application: Essential for characterizing the size, shape, and composition of microplastics in biota samples.  Sampling Techniques - Biota Bioaccumulation Studies Method: Studying the concentration of microplastics in organisms over time. Application: Provides insights into the accumulation patterns, bioavailability, and trophic transfer of microplastics in ecosystems. Non-destructive Sampling Techniques Methods: Developing techniques that do not harm the organisms during the sampling process. Application: Preserves the integrity of the organism for additional studies and ethical considerations.  Sampling Techniques - Sediments  Methodology Elutriation Collection of sediment samples Method: Using water or a liquid from the water bed to analyze medium to separate microplastics from sediment particles based on their the presence and characteristics buoyancy. of microplastics.  Applications Application: Effective for extracting microplastics from fine sediments. reveals the accumulation of Coring with Subsampling microplastics in sediments, Method: Extracting sediment cores and providing insights into vertical subsampling at specific intervals for distribution and potential microplastic analysis. sources. Application: Provides detailed information on the vertical distribution of microplastics within sediment cores.  Sampling Techniques - Sediments Artificial Substrates Pore Water Sampling Method: Deploying artificial substrates, Method: Collecting water from sediment pore spaces to analyze the presence of such as trays or panels, in sediments to microplastics. assess microplastic colonization. Application: Provides information on Application: Offers insights into the potential leaching or exchange of microplastic interactions with benthic microplastics between sediments and communities. water. Biological Sampling Benthic Traps Method: Studying benthic organisms, such Method: Placing traps on the seafloor or as bivalves or worms, and analyzing their riverbed to collect settling particles, associated sediments for microplastics. including microplastics. Application: Explores the potential for Application: Captures microplastics in bioturbation and biodegradation of areas with dynamic sedimentation microplastics in sediments. patterns.  Sampling Techniques - Sediments Remote Sensing Method: Utilizing remote sensing techniques, such as aerial surveys or satellite imagery, to identify areas with potential microplastic accumulation. Application: Complements traditional sampling methods by providing a broader spatial perspective. Depth Profiling Method: Collecting sediment samples at different depths to assess vertical variations in microplastic concentrations. Application: Useful for understanding how microplastics are distributed within sediment profiles.  MODULE FOUR SESSION 2 Sample Preparation and Microplastics Analysis  Course overview This course will bring you: The importance of sample preparation in studying freshwater microplastics Analytical procedures/techniques for the identification and quantification of microplastics in water Data interpretation, results expression and reporting  LEARNING OUTCOMES At the end of the course, you should be able to: 1. Understand the importance of sample preparation in studying freshwater microplastics 2. Understand analytical procedures/techniques for the identification and quantification of microplastics in water 3. Understand data interpretation, results expression and reporting  Separation of microplastics in sediment Density Separation Cost and Environmental Exploits the density differences Considerations between MPs and sediment particles. While ZnCl₂ and NaI solutions are Involves isolating MPs from effective, they can be relatively other materials by using a expensive and unsafe for the solution with a density greater environment, especially in than 1.6 g/cm³ developing countries Considering efficiency, cost, and environmental impact, NaCl solution was selected as a practical choice Extraction using NaI, ZnCl₂, and NaCl solutions results in higher recovery rates (ranging from 37% to 97%) compared to CaCl₂ (which yielded 28% to 83% recovery).  Settling and Decanting Settling Decanting After collecting the water Gently pour off the clear water sample containing from the top of the container, microplastics, allow it to stand leaving the settled microplastics undisturbed in a container undisturbed. Gravity will cause the heavier Use a pipette or a similar tool to microplastic particles to settle extract the water without to the bottom of the container disturbing the sediment. The settling time can vary The decanted water can be depending on the sample discarded or further processed volume and the concentration for analysis. of microplastics The remaining sediment Once settled, the water above contains the concentrated microplastics. the sediment contains fewer microplastics  Settling and Decanting Selective Digestion  Separation: Solution is filtered or  Sample Preparation: Before centrifuged to separate the plastic selective digestion, the sample is particles from the digested organic typically processed to remove large matter and other debris. debris and homogenized to ensure  Plastic particles, being resistant to representative subsampling.  Digestion Solution: Chemicals digestion, are retained on the filter or in the sediment pellet, while the that selectively digest organic soluble organic matter passes matter while leaving plastic through particles intact. Include concentrated acids, enzymes, or  Rinsing and Drying: Retained combinations. plastic particles are rinsed with  Digestion Process: Sample is solvent (e.g., water, alcohol) then immersed in the digestion solution dried before further analysis. and subjected to controlled  Microplastic Analysis: Using conditions, such as temperature, microscopy, spectroscopy, or other agitation, and duration, to facilitate analytical techniques to characterize the breakdown of organic their size, shape, color, polymer materials. type, and other properties.  Settling and Decanting  Advantages in Microplastic Analysis Limitations  Selective Removal: selective  Method Optimization: The choice of removal of organic matter and digestion solution and conditions must other non-plastic materials be optimized to ensure effective improvs the efficiency and digestion of organic matter without causing degradation or alteration of accuracy of microplastic plastic particles. identification and quantification.  Risk of Contamination: Selective  Reduced Interference: By digestion procedures can introduce removing background materials, contamination if not properly selective digestion minimizes controlled. Careful handling and use of interference from non-plastic clean laboratory equipment are particles, allowing for more essential to minimize contamination.  Potential Bias: Selective digestion accurate detection of may selectively remove certain types of microplastics. plastics or degrade particles of certain  Sample Enrichment: Selective sizes, leading to potential bias in digestion can concentrate microplastic analysis results. microplastics in the sample, making them easier to detect and analyze.  Sieve Analysis  Sample Collection and Preparation:  Particle Collection and Environmental samples are collected from Weighing: Particles are then dried the field using appropriate sampling to remove moisture and weighed techniques. Before analysis, the sample using a precision balance. The undergoes pretreatment - drying, sieving to mass of particles retained on each remove large debris, and homogenization sieve is recorded.  Sieve Setup: sieves with different mesh  Data Analysis: The mass of sizes are selected based on the expected size particles retained on each sieve is range of microplastics in the sample. used to calculate the percentage Arranged in ascending order of mesh size, of particles within each size the coarsest sieve at the top and the finest at fraction relative to the total the bottom. sample mass. Generate particle  Sample Sieving: A known mass of the distribution curve to visualize the prepared sample is placed on the top sieve distribution of microplastics across of the stack. Use a mechanical sieve shaker different size ranges. or manual shaking to facilitate the  Characterization: Microplastics separation of particles based on size. retained on each sieve can be further characterized using microscopy, spectroscopy, or other analytical techniques.  Sieve Analysis  Advantages  Limitations  Simple and Cost-effective: Does not  Size Limitation: Sieve require specialized equipment. analysis is limited to particles  Quantitative: Provides quantitative larger than the mesh size of data on the size distribution of the finest sieve used in the microplastics in the sample. analysis. Smaller microplastics  Versatility: Sieve analysis can be may not be captured by the applied to a wide range of sample sieves and could be types and sizes, including sediment, overlooked. soil, water, and biological samples  Particle Aggregation: Aggregation of particles during sieving may affect the accuracy of size measurements and lead to underestimation of microplastic abundance.  Sample Loss: Fine particles may adhere to sieve surfaces or be lost during handling,  Elutriation  Sample Preparation: gather field sediment or  Fraction Collection: As particles settle, soil samples using proper collection methods. fractions of the suspension are collected pretreatment—drying, sifting big debris, and from different levels of the elutriation homogenization for representative column at specific time intervals or when subsampling. certain conditions are met.  Elutriation Setup: A column or vessel filled  Particle Concentration: The collected with water or surfactant solution is used for fractions are then processed further (e.g elutriation. The sample is suspended in liquid, filtration, centrifugation) to concentrate generating a slurry. Elutriation columns may microplastics. feature exits or valves to gather particle Microplastic Analysis: The concentrated fractions by density and size. microplastic samples are analyzed using  Density Stratification: When gently swirled, microscopy, spectroscopy, or other slurry particles become suspended in the analytical techniques to characterize their liquid. Lighter particles stay suspended or size, shape, color, polymer type, and other settle slowly, whereas heavier particles settle properties. quickly. This method stratifies particles by density.  Elutriation  Advantages  Limitations  Selective Separation: It allows for the  Particle Aggregation: Aggregation of selective separation of microplastics from particles during elutriation may affect the sediment or soil based on their density and accuracy of size measurements and lead to size, enabling the isolation of microplastics underestimation of microplastic abundance. from other particles.  Labor-intensive: Elutriation can be labor-  High Efficiency: Elutriation can process intensive and time-consuming, particularly relatively large sample volumes and for large sample volumes or samples with concentrate microplastics efficiently, complex matrices. making it suitable for environmental  Contamination Risk: There is a risk of monitoring studies.  Non-destructive: Elutriation is a non- contamination during sample handling and processing, which may affect the accuracy destructive technique that preserves the and reliability of results. integrity of microplastic particles, allowing for subsequent chemical and physical characterization  Filtration  Sample Collection and Preparation:  Particle Retention: Particles bigger than Homogenization and representative the filter medium's pores are kept on its subsampling of obtained samples before surface or matrix. Solid microplastics are transfer. captured by the filter.  Selection of Filter Medium: Depending on  Washing and Rinsing: Washed with water the sample and microplastic size range. Filter or alcohol to eliminate organic residues membranes or meshes with micrometer-to-  Drying and Storage: Drying the filter tens-micrometer pores are prevalent. before examination removes moisture.  Filtration Setup: Under regulated Clean, dry filter storage prevents particle circumstances, sample passes through filter contamination and deterioration. media. Achieved via vacuum, gravity, or  Microplastic Analysis: Microscopy, pressure filtration. spectroscopy, or other analytical methods are used to detect and characterise microplastics by size, shape, colour, polymer type, and other physical features in the filter.  Filtration  Advantages  Limitations  Selective Separation: Filtration selectively  Size Limitation: The effectiveness of separates microplastics from other particles filtration depends on the pore size of the and dissolved substances based on their size filter medium, which may limit the and physical properties. detection of smaller microplastics or  High Efficiency: It can process relatively particles that adhere to organic matter. large volumes of sample quickly and  Contamination Risk: There is a risk of efficiently, making it suitable for contamination during sample handling and environmental monitoring studies. filtration, which may introduce artifacts or  Versatility: Filtration can be applied to a false positives in the analysis. wide range of sample types, including water,  Sample Loss: Fine particles may be lost sediment, soil, and biological tissues. during filtration, particularly if the filter is mishandled or damaged.  Water Volume Estimation  Direct Measurement   Flow Rate Measurement: Flow rate Directly measures sampled water volume.  measurement helps determine water Using calibrated flow meters, water samplers, or volumetric containers. volume in rivers and streams.   Water flow velocity is measured by flow Water volume is obtained during sampling and utilised in the microplastic analysis. meters or current meters, and stream or  Depth-Integrated Sampling: river cross-sectional area is measured to compute discharge or flow rate.  In aquatic situations, depth-integrated sampling calculates average water volume  Flow rate and sampling period determine across depths. water sample volume.  The water column is divided into depth  Tracer Dye Dilution Method: entails intervals and samples are taken from each introducing a known amount of tracer dye interval. to the sample site's water and monitoring its downstream concentration.  Remote Sensing Techniques: Satellite photography or aerial surveys can estimate water volume in lakes, reservoirs, and seas.  Analytical Procédures/Techniques for Identification & Quantification Identification and Characterization  FTIR Spectroscopy - Analyze the  Microplastic Imaging and Particle chemical composition of microplastics Counting - Advanced imaging techniques, by identifying specific functional such as scanning electron microscopy (SEM) and transmission electron groups present in the polymer microscopy (TEM), can provide detailed  Raman Spectroscopy - Provides info images of microplastic particles and help about molecular vibrations and can be quantify their abundance and distribution. used to identify different types of  Pyrolysis-Gas Chromatography-Mass polymers in microplastics Spectrometry (Py-GC-MS) - heating microplastics to high temperatures to break them down into their constituent molecules, which are then analyzed using gas chromatography-mass spectrometry to identify the polymer type  Data Interpretation, Results Expression and Reporting Data Interpretation Results Expression  Study of microplastic data for useful  Results expression involves presenting the conclusions. findings of the microplastic analysis in a  Needs knowledge of the study's clear, concise, and organized manner. background, sampling procedures, sample  Typically includes tables, figures, graphs, characteristics, and analytical and statistical analyses to illustrate key methodologies. findings and trends.  Classifies microplastics by size, shape,  Results expression should provide detailed colour, polymer type, and other factors. information on the abundance,  Determine microplastic quantity and distribution, size distribution, polymer dispersion in water, sediments, soil, air, types and biota.  Descriptive statistics  Compares findings to the literature,  Spatial and temporal variations in regulatory standards, or baseline data to microplastic contamination assess trends, patterns, and environmental  Presentation of results is consistent with impacts. the objectives of the study and effectively  Data interpretation also requires communicates the main findings to the microplastic contamination sources and intended audience route identification.  Data Interpretation, Results Expression and Reporting Reporting  Involves documenting the methodology,  Results - Presented using text, tables, results, interpretation, and conclusions of figures, and supplementary materials as the microplastic analysis in a written necessary to convey the findings accurately. format.  Discussion section interprets the results in  Structured into introduction, methods, the context of the study objectives, results, discussion, and conclusion sections. compares them with existing literature,  Introduction - researchers provide discusses limitations, and proposes future background information, research research directions. objectives, and hypotheses.  The conclusion section summarizes the key  Methods section - details the sampling findings, implications, and strategy, sample preparation, analytical recommendations. techniques, quality control measures, and  The report should be written in a clear, data analysis methods. concise, and scientifically rigorous manner, adhering to the guidelines of the target journal, institution, or funding agency.