5 Quantifying microplastics in beach sand and river sediment using thermal analytical methods
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Abstract
Microplastics are emerging contaminants that have gained significance in the recent years. To understand the generation, transport, and transformation of microplastics in the environment, it is important to be able to identify plastics by their type and quantify their levels in environmental matrices. This study reviewed existing thermal analytical techniques employed in microplastics research and discussed their advantages and limitations. As a case study, we examined microplastics in beach sand and river sediment samples collected at two locations in Massachusetts, USA using pyrolysis-gas chromatography- mass spectrometry (PY-GC-MS). Multiple-step pretreatment processing based on size fractionation, density separation, wet peroxide oxidation, and solvent extraction was necessary to remove inorganic constituents and natural organic matter in samples prior to PY-GC-MS analysis. Pretreatment sequence was optimized separately for beach sand and river sediment as the latter carried very high levels of plant debris and organic matter. PET was identified in the fine fraction (< 100 μm) of the beach sand at 8.1 mg/kg and it was not detected in the medium size fraction (100 μm - 1.2 mm). This suggests the degradation of macro-plastics on beach due to UV exposure and mechanical abrasion caused by water and sand. For the river sediment sample, PET was detected in both the fine and medium fractions and the mass concentrations were on the order of 1 mg/kg. PP was also detected in both fractions of the river sediment at 0.1 - 0.3 mg/kg. The results validate the ability of PY-GC-MS in conjunction with appropriate pretreatments to quantitatively analyze low levels of microplastics in the coastal and terrestrial environments.
Abstract
Microplastics are emerging contaminants that have gained significance in the recent years. To understand the generation, transport, and transformation of microplastics in the environment, it is important to be able to identify plastics by their type and quantify their levels in environmental matrices. This study reviewed existing thermal analytical techniques employed in microplastics research and discussed their advantages and limitations. As a case study, we examined microplastics in beach sand and river sediment samples collected at two locations in Massachusetts, USA using pyrolysis-gas chromatography- mass spectrometry (PY-GC-MS). Multiple-step pretreatment processing based on size fractionation, density separation, wet peroxide oxidation, and solvent extraction was necessary to remove inorganic constituents and natural organic matter in samples prior to PY-GC-MS analysis. Pretreatment sequence was optimized separately for beach sand and river sediment as the latter carried very high levels of plant debris and organic matter. PET was identified in the fine fraction (< 100 μm) of the beach sand at 8.1 mg/kg and it was not detected in the medium size fraction (100 μm - 1.2 mm). This suggests the degradation of macro-plastics on beach due to UV exposure and mechanical abrasion caused by water and sand. For the river sediment sample, PET was detected in both the fine and medium fractions and the mass concentrations were on the order of 1 mg/kg. PP was also detected in both fractions of the river sediment at 0.1 - 0.3 mg/kg. The results validate the ability of PY-GC-MS in conjunction with appropriate pretreatments to quantitatively analyze low levels of microplastics in the coastal and terrestrial environments.
Chapters in this book
- Frontmatter I
- About the series VII
- Contents IX
- List of contributing authors XI
- 1 Use of green chemistry for process development and improvement 1
- 2 Technoeconomic evaluation and life cycle assessment of biorenewable route to produce high-value aromatics 13
- 3 Green chemistry and catalysis 33
- 4 Green chemistry and environmental justice in the biochemistry classroom 45
- 5 Quantifying microplastics in beach sand and river sediment using thermal analytical methods 53
- 6 Outlook of undergraduate programs in sustainability and environmental studies in the United States 75
- 7 Likely energy solutions for reversing climate change 83
- 8 Carbon dioxide, climate change, and classroom connections 95
- Index 101
- De Gruyter Series in Green Chemical Processing 103
Chapters in this book
- Frontmatter I
- About the series VII
- Contents IX
- List of contributing authors XI
- 1 Use of green chemistry for process development and improvement 1
- 2 Technoeconomic evaluation and life cycle assessment of biorenewable route to produce high-value aromatics 13
- 3 Green chemistry and catalysis 33
- 4 Green chemistry and environmental justice in the biochemistry classroom 45
- 5 Quantifying microplastics in beach sand and river sediment using thermal analytical methods 53
- 6 Outlook of undergraduate programs in sustainability and environmental studies in the United States 75
- 7 Likely energy solutions for reversing climate change 83
- 8 Carbon dioxide, climate change, and classroom connections 95
- Index 101
- De Gruyter Series in Green Chemical Processing 103
