Author Archive

Unconventional hydrocarbons – Understanding the Potential Environmental Impacts

In the continuing drive to meet the world’s future energy needs, few can have missed the increased recent prominence of unconventional hydrocarbons. The extraction of resources such as shale gas, using techniques like hydraulic fracturing (or fracking) has gained attention from around the world, both for its potential to fulfil our energy requirements, as well as due to concerns around possible environmental impacts.

Chemistry has a strong role to play in helping us to understand potential environmental impacts, particularly areas such as air and water quality. The Royal Society of Chemistry supports the research community examining these issues, as chemical sciences research can help to inform broader policy decisions on this issue. We publish papers and books across our portfolio of journals, including those that encourage scientific debate and have actively supported those in the research community to share knowledge and advance science. To mark the publication of a report that explores research questions in this area, we have gathered some of our best publications on this topic to share with readers.

Unconventional hydrocarbon extraction in different countries has evolved at different rates. In the US there has been rapid exploration that has led to commercial scale production, whilst in the UK we are at a much earlier stage of the debate. Examining the situation in places like the US, which has a comparatively more established shale gas industry, can help us to determine what is known about the potential environmental impacts and where research, including chemistry, can help to address unknowns.

In November 2015, the UK Natural Environment Research Council (NERC), the US National Science Foundation (NSF) and the Environment, Sustainability and Energy Division of the Royal Society of Chemistry brought together researchers from the US and the UK at a workshop on Improving the Understanding of the Potential Environmental Impacts Associated with Unconventional Hydrocarbons. The aim of the workshop was to share knowledge in this rapidly changing area, particularly with respect to identifying research gaps and areas where future research may be needed. The range of topics covered by the workshop was broad, including areas such as air quality and wastewater treatment, which have a direct link with the chemical sciences, through to seismicity and socioeconomic impacts.

Participants at the workshop had the opportunity to present current research in their field, taking into account the specific situation in their country.  Discussions at the workshop examined similarities and differences between the different nations, leading onto the identification of knowledge gaps and future research needs.

The workshop’s co-chairs, Professor Richard Davies of Newcastle University and Professor Danny Reible at Texas Tech used the discussions from the meeting to produce a report, Joint US-UK Workshop on Improving the Understanding of the Potential Environmental Impacts Associated with Unconventional Hydrocarbons. The report captures key research gaps and needs in a whole range of areas from community engagement, to human health to waste water management.

Professor Richard Davies commented: “This workshop represented a valuable opportunity to prioritise and tailor research questions that could help us to better understand any potential environmental impacts if unconventional hydrocarbon extraction were to take place in the UK. The report examines both near-term and long-term research priorities for the research communities working in this area”.

The report will be relevant to researchers working on unconventional hydrocarbon extraction, outlining future research opportunities and needs. You can watch Professor Fred Worrall, one of the UK workshop participants talk about some of the points covered at the workshop in his lecture Exploring the impact of the unknown: a potential UK shale gas industry. Fred’s work on monitoring emissions relating to onshore oil and gas operations is also the subject of a recent Education in Chemistry article.

We hope that you will enjoy reading about both recent research advances and future areas for investigation in an area that will likely continue to feature in both scientific and public discourse.

Books

Fracking
Editors: R E Hester, R M Harrison
Print publication date: 02 Sep 2014
DOI: 10.1039/9781782620556

Principles and Practice of Analytical Techniques in Geosciences
Editor: Kliti Grice
Print publication date: 11 Sep 2014
DOI: 10.1039/9781782625025

Reviews

Evolving shale gas management: water resource risks, impacts, and lessons learned
Brian G. Rahm and Susan J. Riha
Environ. Sci.: Processes Impacts, 2014,16, 1400-1412
DOI: 10.1039/C4EM00018H

Use of stable isotopes to identify sources of methane in Appalachian Basin shallow groundwaters: a review
J. Alexandra Hakala
Environ. Sci.: Processes Impacts
, 2014,16, 2080-2086
DOI:
10.1039/C4EM00140K

Unconventional oil and gas extraction and animal health
M. Bamberger and   R. E. Oswald
Environ. Sci.: Processes Impacts
, 2014,16, 1860-1865
DOI:
10.1039/C4EM00150H

Practical measures for reducing the risk of environmental contamination in shale energy production
Paul Ziemkiewicz, John D. Quaranta and Michael McCawley
Environ. Sci.: Processes Impacts
, 2014,16, 1692-1699
DOI: 10.1039/C3EM00510K

Air quality concerns of unconventional oil and natural gas production
R. A. Field, J. Soltis and   S. Murphy
Environ. Sci.: Processes Impacts
, 2014,16, 954-969
DOI:
10.1039/C4EM00081A

Analysis

Deciphering the true life cycle environmental impacts and costs of the mega-scale shale gas-to-olefins projects in the United States
Chang He and   Fengqi You
Energy Environ. Sci.
, 2016,9, 820-840 DOI: 10.1039/C5EE02365C

Wells to wheels: water consumption for transportation fuels in the United States
David J. Lampert, Hao Cai and Amgad Elgowainy
Energy Environ. Sci.
, 2016,9, 787-802
DOI:
10.1039/C5EE03254G

Papers

Solid-phase extraction followed by gas chromatography-mass spectrometry for the quantitative analysis of semi-volatile hydrocarbons in hydraulic fracturing wastewaters
Julia Regnery, Bryan D. Coday, Stephanie M. Riley and  Tzahi Y. Cath
Anal. Methods
, 2016,8, 2058-2068
DOI:
10.1039/C6AY00169F

Partitioning of naturally-occurring radionuclides (NORM) in Marcellus Shale produced fluids influenced by chemical matrix
Andrew W. Nelson, Adam J. Johns, Eric S. Eitrheim, Andrew W. Knight, Madeline Basile, E. Arthur Bettis III, Michael. K. Schultz and   Tori Z. Forbes
Environ. Sci.: Processes Impacts
, 2016,18, 456-463
DOI:
10.1039/C5EM00540J

A liter-scale microbial capacitive deionization system for the treatment of shale gas wastewater
Casey Forrestal, Alexander Haeger, Louis Dankovich IV, Tzahi Y. Cath and   Zhiyong Jason Ren
Environ. Sci.: Water Res. Technol.
, 2016,2, 353-361
DOI:
10.1039/C5EW00211G

Detection of water contamination from hydraulic fracturing wastewater: a μPAD for bromide analysis in natural waters
Leslie J. Loh,a Gayan C. Bandara,a Genevieve L. Webera and  Vincent T. Remcho*a

Analyst, 2015,140, 5501-5507
DOI:
10.1039/C5AN00807G

Microbial capacitive desalination for integrated organic matter and salt removal and energy production from unconventional natural gas produced water
Casey Forrestal, Zachary Stoll, Pei Xu and  Zhiyong Jason Ren
Environ. Sci.: Water Res. Technol.
, 2015,1, 47-55
DOI: 10.1039/C4EW00050A

Stimuli-responsive/rheoreversible hydraulic fracturing fluids as a greener alternative to support geothermal and fossil energy production
H. B. Jung, K. C. Carroll, S. Kabilan, D. J. Heldebrant, D. Hoyt, L. Zhong, T. Varga, S. Stephens, L. Adams, A. Bonneville, A. Kuprat and   C. A. Fernandez
Green Chem.
, 2015,17, 2799-2812
DOI:
10.1039/C4GC01917B

Geo-material microfluidics at reservoir conditions for subsurface energy resource applications
Mark L. Porter, Joaquín Jiménez-Martínez, Ricardo Martinez, Quinn McCulloch, J. William Carey and Hari S. Viswanathan
Lab Chip
, 2015,15, 4044-4053
DOI:
10.1039/C5LC00704F

Shale gas-to-syngas chemical looping process for stable shale gas conversion to high purity syngas with a H2:CO ratio of 2:1
Siwei Luo, Liang Zeng, Dikai Xu, Mandar Kathe, Elena Chung, Niranjani Deshpande, Lang Qin, Ankita Majumder, Tien-Lin Hsieh, Andrew Tong, Zhenchao Sun and Liang-Shih Fan
Energy Environ. Sci.
, 2014,7, 4104-4117
DOI:
10.1039/C4EE02892A

Organic compounds in produced waters from shale gas wells
Samuel J. Maguire-Boyle and Andrew R. Barron
Environ. Sci.: Processes Impacts
, 2014,16, 2237-2248
DOI:
10.1039/C4EM00376D

Automated method for determining the flow of surface functionalized nanoparticles through a hydraulically fractured mineral formation using plasmonic silver nanoparticles
Samuel J. Maguire-Boyle, David J. Garner, Jessica E. Heimann, Lucy Gao, Alvin W. Orbaek and  Andrew R. Barron
Environ. Sci.: Processes Impacts
, 2014,16, 220-231
DOI:
10.1039/C3EM00718A

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Between a rock and a hard place: greenhouse gas storage and natural resource extraction

Humans are continuing to release increasing amounts of greenhouse gases to the atmosphere that have been implicated as key contributors to climate change. One major greenhouse gas is CO2. It is estimated that geological storage could result in a 17% reduction in atmospheric CO2 by 2050. Such projects aim to use sedimentary basins as they are believed to be the safest option for long-term storage of CO2 and other greenhouse gases. However, sedimentary basins are also valued for a range of extractable natural resources such as groundwater, oil and gas, and geothermal energy. Thus, there is a need to understand the potential interactions between these resources and subsurface storage of CO2 when targeting a particular site for CO2 storage.

A recently published study involving researchers from various institutes in Western Australia explain the potential risks involved with geological CO2 storage. Considering all the potential interactions between basin resource use and CO2 storage, the authors outline a Framework for Basin Resource Management Strategy (FBRMS) for optimizing interactions that may occur during the management of sedimentary basins.

Potential impacts of CO2 geological storage on other basin resources (reproduced from K. Michael
et al., EAGE Third Sustainable Earth Sciences 2015 Conference, DOI: 10.3997/2214-4609.201414262)

The initial stage of the FBRMS is an assessment of potential basins for CO2 storage based on containment potential of the subsurface. Optimal conditions include thick layers of low permeability rocks such as shales and anhydrites that can effectively cap the CO2. Lateral containment should be provided by lateral decreases in permeability, low permeability faults, or, in the absence of physical barriers, residual trapping, dissolution into water and mineral formation via reactions with the subsurface matrix. In addition to geologic characterization, modelling, monitoring and risk assessment are crucial for verifying long-term CO2 containment.

Also considered in the FBRMS are the two general means by which CO2 storage can affect other basin resources: migration and increasing basin pressure. Vertical or horizontal migration may result in contamination of natural gas or another currently used or potentially extractable resource.

Once CO2 is present in the subsurface, the future potential use of the injected area is instantly limited. An important concern associated with using shale basins is that shale may be used as an unconventional gas resource in future, and the methods for utilizing this resource negate its effectiveness as a long-term cap for CO2 storage. Though the probability is extremely low, increasing subsurface pressure from CO2 injection could also force saline water upwards along a wellbore or through existing fractures into groundwater resources, or may even cause fractures. Regardless of the likelihood, identifying all of these risks is an important facet of the FBRMS, presumably leading to relevant monitoring activities. On the other hand, increased pressure could also be beneficial in counteracting reduced pressure in mature oil or gas fields, low groundwater levels, or subsidence.

The FBRMS integrates all of these concerns to evaluate the likelihood of various basin resource-storage interactions, how beneficial or detrimental the interactions would be, and to determine how best to manage these interactions. It is intended to be used by various project stakeholders throughout the lifetime of a project, and may require intensive data collection or expert risk assessment depending on the individual project being assessed.


To read the full paper for free*, click the link below:

Framework for the assessment of interaction between CO2 geological storage and other sedimentary basin resources
K. Michael, S. Whittaker, S. Varma, E. Bekele, L. Langhi, J. Hodgkinson, and B. Harris
Environ. Sci.: Processes Impacts,
2016, 18, 164-175
DOI: 10.1039/C5EM00539F

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About the webwriter

Abha Parajulee is a Ph.D. student at the University of Toronto Scarborough. She is interested in water resources and the behavior of organic contaminants in urban environments.

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* Access is free until 01/06/2016 through a registered RSC account.

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Sun, wind, and a crowd: Tough days in the life of a passive sampler?

Passive air samplers (PAS) have found great utility in monitoring environmental concentrations of semivolatile organic contaminants (SVOCs) all over the world. They provide a picture of longer-term average air concentrations of SVOCs while being relatively portable, low-cost and extremely low-maintenance. Knowing the deployment time, the amount of chemical accumulated in the passive sampling medium (PSM), and the sampling rate derived when a PAS is first calibrated before widespread use, a time-averaged volumetric air concentration can be calculated.

Graphical Abstract

A key assumption underlying the calculation of PAS-derived air concentrations is that the passive sampling medium takes up chemicals uniformly. But this assumption has not been thoroughly tested so far and studies to date have indicated that the sampling rates of some commonly used PSM can differ with position inside a sampler housing. For example, sampling rates decreased with increasing distance from the opening at the bottom of a cylindrical sampler housing for the commonly used styrene-divinylbenzene copolymer or “XAD” resin.

In a study recently published in Environmental Science: Processes & Impacts, Zhang and co-workers at the University of Toronto Scarborough have put their XAD PAS to the test once more to determine if exposure to sunlight, wind, and the presence of multiple units of XAD-filled mesh cylinders in one PAS housing caused differential chemical uptake across the length of a single cylinder.

The chemicals of interest in this series of experiments, polychlorinated biphenyls (PCBs), were chosen because their environmental partitioning properties are inclusive of a range of SVOCs commonly measured in the environment. One indoor experiment included axially segmented PAS at four indoor locations, one of which also used fans to simulate the effect of wind. At one of the indoor locations, a similar experiment was conducted outdoors, where the effect of heat conduction resulting from sunshine was also tested. This involved using PAS with regular housings, housings painted black to enhance heat absorption, and housings shaded by a steel cover.

Two additional experiments varied the number of mesh cylinders inside each housing. One experiment deployed a pair of PAS containing one and four mesh cylinders at one outdoor and one indoor location. A final outdoor experiment attempted to incorporate a variety of temperatures and wind speeds by deploying PAS at nine locations on the Big Island of Hawaii. Each site had one PAS containing one XAD-filled mesh cylinder and another containing two.

Environmental Science: Processes & Impacts front cover image highlighting the article

In the first indoor experiment, the total amount of PCBs accumulated in all segments was not significantly different from the amount accumulated in a mesh cylinder that had not been segmented. In those cylinders that were axially segmented, the amount of PCBs accumulated in the bottom segments was significantly higher than in the upper two segments in office and storage areas, and assumed to have little activity and therefore air turbulence. But this difference was not significant in the mesh cylinder placed in a cargo-loading area, presumably because of the relatively higher level of activity and therefore air turbulence. Similarly, gradients within PAS deployed outdoors were also not as strong, and the samplers exposed to fans indoors showed no significant gradients – strong indications that increased air turbulence allows for more uniform uptake across the length of the sampler.

The effect of heat convection on total accumulation and axial distribution of PCBs was determined to be minor, as was the presence of multiple mesh cylinders within one housing, but only outdoors. Indoors, the amount of PCB accumulated per sampler was significantly lower in those PAS with four mesh cylinders, and the gradient was also steeper.

The final outdoor deployment across varying temperature and wind conditions in Hawaii, which measured accumulation of PCBs, pesticides, polycyclic aromatic hydrocarbons, and polybrominated diphenyl ethers, showed no significant difference in chemical accumulation in PAS with one versus two XAD-filled mesh cylinders. The finding that uptake of SVOCs by XAD PAS is affected very little by the presence of multiple mesh cylinders in one housing in a variety of outdoor conditions means that fewer housings can be used during a given sampling campaign that uses XAD PAS. This augments the low-maintenance nature of this monitoring method, and thus the value of this particular PAS as a tool for monitoring SVOCs in the environment.


To read the full Open Access article, click the link below:

Exploring the role of the sampler housing in limiting uptake of semivolatile organic compounds in passive air sampler
Xianming Zhang, Michelle Hoang, Ying D. Lei, and Frank Wania
Environ. Sci.: Processes Impacts,
2015, 17, 2006-2012
DOI: 10.1039/C5EM00447K

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About the webwriter

Abha Parajulee is a Ph.D. student at the University of Toronto Scarborough. She is interested in water resources and the behavior of organic contaminants in urban environments.

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Snow soaks up pollutants from engine exhausts

Scientists in Canada have shown that snow acts as a sink for nanosized particles and certain organic constituents from car exhausts.

Snow for the experiment was collected from a park in Montreal, where it snows for around 5 months of the year

Air pollution is recognised as a leading environmental driver of cancer deaths, which makes the fate of these toxic and carcinogenic aerosols from car exhausts important for informing changes in emissions and air quality regulations, and technologies, in countries with cold winters.

Anna Lea Rantalainen, an environmental chemist at the University of Helsinki, Finland, says the work raises further questions: ‘It seems that snow is efficient at removing aerosol particles from the air, but what happens after the snow has melted?’ If the sink is temporary, pollutant emissions could increase rapidly in industrialised areas when snow melts. ‘This is not just important for Canada, but other industrial regions like China that emit very diverse compounds, which are subject to transport around the globe,’ cautions Ariya.

Please visit Chemistry World to read the full article.

Role of snow and cold environment in the fate and effects of nanoparticles and select organic pollutants from gasoline engine exhaust*
Yevgen Nazarenko, Uday Kurien, Oleg Nepotchatykh, Rodrigo B. Rangel-Alvarado and   Parisa A. Ariya
Environ. Sci.: Processes Impacts, 2016, Advance Article
DOI: 10.1039/C5EM00616C

*Access is free through a registered RSC account until 25 February 2016 – click here to register

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New Editor-in-Chief for Environmental Science: Processes & Impacts

We are pleased to announce that Professor Kris McNeill (ETH Zürich) will be taking on the role of Editor-in-Chief for Environmental Science: Processes & Impacts from 2016. Professor McNeill has been an active member of the Editorial Board of Environmental Science: Processes & Impacts for several years.

His research focuses on environmental chemistry in aquatic systems, particularly regarding reaction mechanisms. Kris takes over from Professor Frank Wania, who finished his term as Chair of the Editorial Board at the end of 2015.

Read Kris’ most recent work in Environmental Science: Processes & Impacts below:

Aquatic photochemical kinetics of benzotriazole and structurally related compounds, Elisabeth M. L. Janssen, Emily Marron and Kristopher McNeill, Environ. Sci.: Processes Impacts, 2015, 17, 939–946, DOI:  10.1039/C5EM00045A

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Teasing out the relative importance of controls on the production of a bioaccumulative neurotoxin

Environmental Science: Processes & Impacts cover highlights this research (issue 9)

Monomethylmercury (MeHg) is a chemical of great concern due to its neurotoxic nature and its efficient bioaccumulation in aquatic systems, eventually reaching humans through fish consumption.

MeHg is produced by the action of bacteria that transform the most commonly found species of mercury in aquatic environments. Remediation of mercury-contaminated sites requires insight into factors that facilitate the action of these mercury methylators. For example, anaerobic conditions and relatively large quantities of total and dissolved organic carbon both enhance production of MeHg.

The original speciation of mercury is also important, as some forms of mercure are more bioavailable to mercury methylators than others. Past work has traditionally focused on the influence of these factors individually; however, under environmental conditions these factors likely work in concert to affect mercury methylation.

Kucharzyk and co-workers at Duke University take the next step forward with their recent study published in Environmental Science: Processes & Impacts which aims to assess the relative influence of microbial productivity and mercury speciation on MeHg production. The researchers enriched cultures of mercury methylating bacteria found in two different marine sediments containing similar, elevated mercury concentrations. The cultures were determined to contain mostly one type of anaerobic bacteria known to methylate mercury.

For each of the two cultures, microbial growth was varied by adding different amounts of carbon substrate, and mercury speciation was varied with the addition of either dissolved or nanoparticulate mercury. The cultures were then incubated for 64 hours, during which two or three replicates were analyzed for various chemical and biological parameters at several time points across the incubation period.

In both cultures, mercury methylation increased with increasing concentrations of carbon substrate for a given type of mercury. When carbon substrate concentration was kept constant, the percentage of mercury that was methylated was 3 to 4 times lower in cultures amended with nanoparticulate mercury relative to those containing dissolved mercury instead. This could not have been due to differences in bacterial growth rates as the observed cell growth was the same across both types of added mercury, implying that the differences are probably a result of lower bioavailability of nanoparticulate mercury versus dissolved mercury.

The differences in microbial productivity between cultures spiked with the two different types of mercury became smaller with decreasing levels of carbon substrate. Interestingly, this data suggest there may be a threshold in the activity of mercury methylating bacteria, below which net MeHg production is controlled by the availability of carbon substrate, and above which the bioavailability of mercury becomes more important. However, further study including lower levels of carbon substrate is required to better confirm the existence of this threshold in microbial methylation activity.


Click on the link below to read the full article for free*:
Relative contributions of mercury bioavailability and microbial growth rate on net methylmercury production by anaerobic mixed cultures
Katarzyna H. Kucharzyk, Marc A. Deshusses, Kaitlyn A. Porter and Heileen Hsu-Kim
Environ. Sci.: Processes Impacts, 2015, 17, 1568-1577
DOI: 10.1039/C5EM00174A

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About the webwriter

Abha Parajulee is a Ph.D. student at the University of Toronto Scarborough. She is interested in water resources and the behavior of organic contaminants in urban environments.

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* Access is free until 18/11/2015 through a registered RSC account.

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Most accessed Environmental Science: Processes & Impacts articles in June 2015

In June 2015, our most downloaded Environmental Science: Processes & Impacts articles were:

Christopher Exley
DOI: 10.1039/C3EM00374D

Lu Lu, Hongguang Cheng, Xiao Pu, Xuelian Liu and Qianding Cheng
DOI: 10.1039/C4EM00502C

B. D. Shoener, I. M. Bradley, R. D. Cusick and J. S. Guest
DOI: 10.1039/C3EM00711A

Identification of polymer types and additives in marine microplastic particles using pyrolysis-GC/MS and scanning electron microscopy
Elke Fries, Jens H. Dekiff, Jana Willmeyer, Marie-Theres Nuelle, Martin Ebert and Dominique Remy
DOI: 10.1039/C3EM00214D

Brian G. Rahm and Susan J. Riha
DOI: 10.1039/C4EM00018H

Weile Yan, Hsing-Lung Lien, Bruce E. Koel and Wei-xian Zhang
DOI: 10.1039/C2EM30691C

Interesting read? Let us know your thoughts.

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Decomposition pathways of oceanic plastic debris

Bisphenol A, phtalates, PCBs and other organic pollutants often embedded in plastics have been under the spotlight for a while. However, very few people have studied the degradation pathways of oceanic plastic debris. An article recently published in Environmental Science: Processes & Impacts critically reviews this topic.

Plastics have been widely used since the 1940s. In 2013, global plastic production reached 300 mega tonnes (50 times the Great Pyramid of Giza). We discard most of the plastic right away, within 3 years of its production. Yet, it is engineered to last for hundreds or even thousands of years. Thus, tonnes of plastic debris accumulate in the environment.

Scientists are especially concerned about plastic debris accumulating in the oceans. By 2050, 99% of all seabirds will have ingested, at least, one small piece of plastic. Nowadays, plastics represent more than 60% of all the floating debris in the oceans. All these pieces of plastic may release organic pollutants to the sea, either additives or adsorbed substance. Despite their high stability, plastics might also decompose by the action of different factors, releasing potentially dangerous chemicals.

Graphical abstract - pathways of plastic degradation

Polymer degradation is, technically, a decline of its original properties. Usually it can be easily spotted by observing the colour changes or cracking of the surface. Small plastic particles decompose faster, due to their higher surface to volume ratio. Depending on the structure of their backbone, plastics can degrade in very different ways. Plastic with carbon-carbon backbones (i.e. PE, PP, PS, PVC) often suffer abiotic decomposition, usually initiated by UV radiation or thermal processes. Plastics with heteroatoms in their backbones (i.e. PU, PET) may also suffer abiotic decomposition, but in this case hydrolysis is the most common process. Furthermore, enzymes may also break amide and ester bonds, therefore these plastics are also exposed to biodegradation.

If you want to better understand the different degradation pathways, I strongly recommend that you go over this Environmental Science: Processes & Impacts Critical Review where all the mechanisms are carefully examined and explained.


Click on the link below to read the full article for free*:

Pathways for degradation of plastic polymers floating in the marine environment
Berit Gewert, Merle M. Plassmann and Matthew MacLeod
Environ. Sci: Processes Impacts, 2015, 17, 1513-1521
DOI: 10.1039/C5EM00207A

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About the webwriter

Fernando Gomollón-Bel is a PhD Student at the ISQCH (CSICUniversity of Zaragoza). His research focuses on asymmetric organic synthesis using sugars as chiral-pool starting materials towards the production of fungical transglycosidase inhibitors.

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* Access is free through a registered RSC account.

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