A colony of limpets attached to a diving mask, found washed ashore on a beach
The plastisphere consists of ecosystems that have evolved to live in human-made plastic
environments. All plastic accumulated in marine ecosystems serves as a
habitat for various types of microorganisms, with the most notable
contaminant being microplastics. There are an estimate of about 51 trillion microplastics floating in the oceans.
Relating to the plastisphere, over 1,000 different species of microbes
are able to inhabit just one of these 5mm pieces of plastic.
Microbes interacting with the surface of plastics.
Plastic pollution acts as a more durable "ship" than biodegradable material for carrying the organisms over long distances. This long-distance transportation can move microbes to different ecosystems and potentially introduce invasive species as well as harmful algae. The microorganisms found on the plastic debris comprise an entire ecosystem of autotrophs, heterotrophs and symbionts.
The microbial species found within plastisphere differ from other
floating materials that naturally occur (i.e., feathers and algae) due
to plastic's unique chemical nature and slow speed of biodegradation. In
addition to microbes, insects have come to flourish in areas of the
ocean that were previously uninhabitable. The sea skater, for example, has been able to reproduce on the hard surface provided by the floating plastic.
History
Global distribution of microplastics according to size in millimeters.
Discovery
The
plastisphere was first described by a team of three scientists, Dr.
Linda Amaral-Zettler from the Marine Biological Laboratory, Dr. Tracy
Mincer from Woods Hole Oceanographic Institution and Dr. Erik Zettler from Sea Education Association.
They collected plastic samples during research trips to study how the
microorganisms function and alter the ecosystem. They analyzed plastic
fragments collected in nets from multiple locations within the Atlantic
Ocean. The researchers used a combination of scanning electron microscopy and DNA sequencing to identify the distinct microbial community composition of the plastisphere. Among the most notable findings were "pit formers," crack and pit forming organisms that provide evidence of biodegradation. Moreover, pit formers may also have the potential to break down hydrocarbons. In their analysis, the researchers also found members of the genusVibrio, a genus which includes the bacteria that cause cholera and other gastrointestinal ailments.
Some species of Vibrio can glow, and it is hypothesized that this
attracts fish that eat the organisms colonizing the plastic, which then
feed from the stomachs of the fish. Studies carried out in the Baltic Sea and in the Mediterranean Sea, also found microorganisms of the genusVibrio, in plastic films and fragments, and in plastic fibres, respectively.
UN assessment of marine plastics litter
Anthropogenic sources
Plastic itself was invented in 1907 by Leo Baekeland using formaldehyde and phenol. Since then, the material has been used in anything from clothes to artificial heart valves. As a result, as of 2014 the use of plastic has increased twenty-fold since 1964, and it is expected to double by 2035. Despite efforts to implement recycling programs, recycling rates tend to be quite low. For instance, in the EU, only 29% of the plastic consumed is recycled.
The plastic that does not reach a recycling facility or landfill, will
most likely end up in our oceans due to accidental dumping of the waste,
losses during transport, or direct disposal from boats. In 2010, it was estimated that 4 to 12 million metric tons (Mt) of plastic waste entered into marine ecosystems.
The smaller, more inconspicuous microplastic particles have been aggregating in the oceans since the 1960s.
A more recent worry in the pollution of microplastics comes from the
use of plastic films in agriculture. 7.4 million tons of plastic films
are used each year to increase food production.
Scientists have found that microbial biofilms are able to form within
7–14 days on plastic film surfaces, and have the ability to alter the
chemical properties of the soil and plants that we are ingesting. Microplastics have been recorded everywhere, even the Arctic due to atmospheric circulation.
Research
Diversity
Large scale sequencing studies have found alpha diversities to be lower in the plastisphere relative to surrounding soil samples due to a decrease in species richness in the plastisphere.
Polymer film fragments affect microbes in different ways, leading to
mixed effects on microbial growth rates in the plastisphere.
Certain polymer degrading bacteria release toxic byproducts as a result
of the degradation of the plant fragment, serving as a deterrent to the
colonization of the plastisphere by susceptible species. Phylogenetic diversity is also decreased in the plastisphere relative to nearby soil samples.
The bacterial and microbial communities in the plastisphere are
significantly different from those found in surrounding soil samples,
creating a new ecological niche within the ecosystem. The specific growth of bacteria caused by film fragments is a primary cause for the creation of a unique bacterial community.
Changes in bacterial community composition over time in the
plastisphere have also been shown to drive changes in surrounding land.
In another study which looked at the factors influencing the
diversity of the plastisphere, the researchers found that the highest
degree of unique microorganisms tended to favor plastic pieces that were
blue.
A recent experiment carried across the Atlantic Ocean and the Mediterranean Sea aimed at studying the colonisation and genetic variety of plastics in the marine environment, identified tardigrades in in situincubated plastics for the first time.
Taxonomy
The
growth of specific bacteria in their plastisphere occurs because of the
ability of certain bacteria to degrade polymers. Phyla of bacteria that
have increased presences in the plastisphere relative to soil samples
without plastic micro-fragments include Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes, and Proteobacteria. Furthermore, bacteria of the order Rhizobiales, Rhodobacterales, and Sphingomonadales are enriched in the plastisphere. Interactions within the unique bacterial community composition in the plastisphere influence local biogeochemical cycles and ecosystems' food web interactions.
Community metabolism
The metabolism of bacterial communities in the plastisphere are enhanced.
KEGG Pathway enrichment analyses of plastisphere samples have also
demonstrated increases in genetic and environmental information
processing, cellular process, and organismal systems.
Enhanced metabolic functions for communities in the plastisphere
include nitrogen metabolism, insulin signaling pathways, bacterial
secretion, organophosphorus compound
metabolism, antioxidant metabolism, Vitamin B synthesis, chemotaxis,
terpenoid quinone synthesis, sulfur metabolism, carbohydrate metabolism,
herbicide degradation, fatty acid metabolism, amino acid metabolism,
ketone body pathways, lipopolysaccharide synthesis, alcohol degradation,
polycyclic aromatic hydrocarbon degradation, lipid metabolism, cofactor
metabolism, cellular growth, cell motility, membrane transport, energy
metabolism, and xenobiotics metabolism.
Relationship to carbon, nitrogen, and phosphorus cycling
The
presence of hydrocarbon degrading species in the plastisphere proposes a
direct link between the plastisphere and the carbon cycle.
Metagenome analyses suggest that genes involved in carbon degradation,
nitrogen fixation, organic nitrogen conversion, ammonia oxidation,
denitrification, inorganic phosphorus solubilization, organic phosphorus
mineralization, and phosphorus transporter production are enriched in
the plastisphere, demonstrating the potential impact on biogeochemical
cycles by the plastisphere.
Specific bacterial phyla present in the plastisphere due to their
biodegradation abilities and their role in the carbon, nitrogen, and
phosphorus cycles include Proteobacteria and Bacteroidetes. Some carbon-degrading bacteria are able to use plastics as a food source.
Research in the South Pacific Ocean has investigated the plastisphere's potential in CO2 and N2O
contribution where fairly low greenhouse gas contributions by the
plastisphere were noted. However, it was concluded that greenhouse gas
contribution was dependent on the degree of nutrient concentration and
the type of plastic.
Significance to human health
KEGG
Pathway enrichment analyses of plastisphere samples suggest that
sequences related to human disease are enriched in the plastisphere. Cholera causing Vibrio cholerae, cancer pathways, and toxoplasmosis sequences are enriched in the plastisphere.
Pathogenic bacteria are sustained in the plastisphere in part due to
the adsorption of organic pollutants onto biofilms and their usage as
nutrition.
Current research also aims to identify the relationship between the
plastisphere and respiratory viruses and whether the plastisphere
affects viral persistence and survival in the environment.
Degradation by microorganisms
Some microorganisms present in the plastisphere have the potential to degrade plastic materials.
This could be potentially advantageous, as scientists may be able to
utilize the microbes to break down plastic that would otherwise remain
in our environment for centuries. On the other hand, as plastic is broken down into smaller pieces and eventually microplastics, there is a higher likelihood that it will be consumed by plankton and enter into the food chain. As plankton are eaten by larger organisms, the plastic may eventually cause there to be bioaccumulation in fish eaten by humans. The following table lists some microorganisms with biodegradation capacity.
Oftentimes the degradation process of plastic by microorganisms is quite slow. However, scientists have been working towards genetically modifying these organisms in order to increase plastic biodegradation potential. For instance, Ideonella sakaiensis has been genetically modified to break down PET at faster rates.
Multiple chemical and physical pretreatments have also demonstrated
potential in enhancing the degree of biodegradation of different
polymers. For instance UV or c-ray irradiation treatments, have been
used to heighten the degree of biodegradation of certain plastics.
A green-collar worker is a worker who is employed in an environmental sector of the economy. Environmental green-collar workers (or green jobs) satisfy the demand for green development. Generally, they implement environmentally conscious design, policy, and technology to improve conservation and sustainability.
Formal environmental regulations as well as informal social
expectations are pushing many firms to seek professionals with expertise
with environmental, energy efficiency, and clean renewable energy
issues. They often seek to make their output more sustainable, and thus
more favorable to public opinion, governmental regulation, and the
Earth's ecology.
There is a growing movement to incorporate social responsibility within the green industries. A sustainable green economy simultaneously values the importance of natural resources and inclusive, equitable, and healthy opportunities for all communities.
In the context of the financial crisis of 2007–2008,
many experts now argue that a massive push to develop renewable sources
of energy could create millions of new jobs and help the economy
recover while simultaneously improving the environment, increasing
labour conditions in poor economies, and strengthening energy and food security.
1976, Patrick Heffernan, “Jobs for the Environment — The Coming Green Collar Revolution”, in Jobs
and Prices in the West Coast Region: Hearing before the Joint Economic
Committee, Congress of the United States, Ninety-Fourth Congress, Second
Session, U.S. Government Printing Office, page 134,
1997, Geoff Mulgan, Perri 6 [sic] et al., The British Spring: A Manifesto for the Election After Next, Demos, page 26,
The United States, Canada, Germany, and Denmark are all generating hundreds of thousands of new 'green collar' jobs, especially for young people, achieving remarkable reductions in energy, water, waste disposal and materials costs.
2001, Diane Warburton and Ian Christie, From Here to Sustainability: Politics in the Real World, Earthscan, page 75,
Studies for the UK suggest that the more than 100,000 existing 'green collar'
workers in environmental occupations could be joined by many thousands
more, both in the private sector and in the 'social economy' of
community enterprises.
2007, U.S. Green Jobs Act
2007, U.S. Energy Independence and Security Act - Title X: "Green Jobs - Energy Efficiency and Renewable Energy Worker Training Program" (signed into law 2007-12-19)
2008, January 22 U.S. Federal Reserve Board unprecedented mid-term 3/4% interest rate cut to soon be followed by other economic stimulus to avoid recession and support new job development in green buildingconstruction, remodeling/weatherization, transportation (green vehicles) and green manufacturing
industry sectors. Widespread bipartisan, Administration and
Congressional support for immediate economic stimulus funding, with a
bias toward increasing sustainable green-collar jobs.
1983, U.S. Senate Subcommittee on Forestry, Water Resources, and Environment, Cultivation of Marihuana in National Forests: Hearing Before the Subcommittee on Forestry, Water Resources, and Environment, […], U.S. Government Printing Office, page 32,
American [marijuana] growers, who have more recently become known as America's "green-collar" workers because of the bright green color of their product, […]
2004, Martin Heidenreich et al., Regional Innovation Systems: The Role of Governances in a Globalized World, Routledge UK, page 394,
Al Gore states that economists across the spectrum — including Martin Feldstein and Lawrence Summers
— agree that large and rapid investments in a jobs-intensive
infrastructure initiative is the best way to revive the economy in a
quick and sustainable way.
Center for American Progress
A report from the Center for American Progress
concludes that a $100 billion federal investment in clean energy
technologies over 2009 and 2010 would yield 2 million new U.S. jobs,
cutting the unemployment rate by 1.3% and put the nation on a path
toward a low-carbon economy. The report, prepared by the Political Economy Research Institute at the University of Massachusetts Amherst,
proposes $50 billion in tax credits for energy efficiency retrofits and
renewable energy systems; $46 billion in direct government spending for
public building retrofits, mass transit, freight rail, smart electrical
grid systems, and renewable energy systems; and $4 billion for federal
loan guarantees to help finance building retrofits and renewable energy
projects. The Center believes that clean energy investments would yield
about 300,000 more jobs than if the same funds were distributed among
U.S. taxpayers. The clean energy investments would also have the added
benefits of lower home energy bills and reduced prices for non-renewable
energy sources, due to the reduced consumption of those energy sources.
Worldwatch Institute/UNEP
Global efforts to tackle climate change could result in millions of "green" jobs over the coming decades, according to a 2008 study prepared by the Worldwatch Institute with funding from the United Nations Environment Programme
(UNEP). The study found that the global market for environmental
products and services is projected to double from $1.37 trillion per
year at present to $2.74 trillion by 2020, with half of that market in efficient energy use. In terms of energy supply, the renewable energy industry will be particularly important. Some 2.3 million people have found renewable energy
jobs in recent years, and projected investments of $630 billion by 2030
would translate into at least 20 million additional jobs.
U.S. Conference of Mayors
Also
in 2008, the U.S. Conference of Mayors released a report that finds the
U.S. economy currently generates more than 750,000 green jobs, while
over the next 30 years, an emphasis on clean energy
could result in a five-fold increase, to more than 4.2 million jobs.
Engineering, legal, research, and consulting jobs currently dominate the
green jobs in the United States and could grow by 1.4 million by 2038,
while renewable electricity production will create 1.23 million jobs,
alternative transportation fuels will add 1.5 million jobs, and building
retrofits will create another 81,000 jobs. The report notes that most
of today's jobs are in metropolitan areas, led by New York City;
Washington, D.C.; Houston, Texas; and Los Angeles, California.
Green-Collar Work in China
Background
In China,
green-collar work is defined as “employment in industries, professions,
departments and enterprises that on an average social level have low
input, high output, low consumption, low emissions, recyclability, and
are sustainable".
With this definition, the main goal of green-collar work is to increase
productive efficiency while minimizing resources used in production,
including energy, while being environmentally conscious. This framework
for green development maintains the current Chinese economic paradigm
that has prioritized economic growth. As a general rule, green jobs
include jobs in low-carbon development and environment protection.
For some examples: environmental protection has existed in China since
the 1970s, tree planting commenced in China every year since the PRC was
established, and the solar power industry has been producing on a large scale since its beginning in the 1990s.
Policy decisions
Since 1979, many pieces of legislation have been passed in China regarding environmental protection, including:
Laws regarding pollution: Solid Waste Pollution Prevention and
Control Law, Water Pollution Prevention and Control Law, Air Pollution
Prevention Law, Water Pollution Control Regulation, The Energy
Conservation Law.
Laws regarding recycling and clean production: Clean Production
Promotion Law, Renewable Energy Law, Circular Economy Promotion Law.
China has also passed a number of laws for developing renewable
energy and optimizing China’s energy structure, including: Energy
Conservation Law, Eleventh Five-Year Plan
– Outline for Economic and Social Development, Plan of Energy
Efficiency and Emissions Reduction, Eleventh Five-Year Plan for
Environmental Protection, National Climate Change Program, Climate
Change Policies and Actions, and the New Energy Development Plan.
These policies aim to develop innovations and optimizations for
various power generation technologies, including thermoelectric,
hydroelectric, solar, wind, biofuel, and nuclear. In addition, the
“policies promote the clean usage of coal, the use of coal-bed and
coal-well gas”.
In 2007, the state council also issued the Comprehensive Plan to
Save Energy and Reduce Emissions, giving 45 policy measures to save
energy and reduce emissions. The measures related to technological
innovation of traditional industries are as follows:
“Accelerate the desulphurization
of current facilities for thermal power units, enhancing desulphurized
unit’s capacity to 213 million kW. Newly built or expanded coal power
plants must build desulphurized facilities and reserve places for
denitration. Further promote projects in coal washing and clean-burning
coal technologies. Strengthen the paper making, brewing, chemical,
textile and dyeing industry’s waste water and pollution management and
technological innovation”.
The Chinese government has also implemented measures to promote
recycling pilot projects, achieve clean production, and reduce emissions
with the Promotion of Clean Production Law, the Solid Waste Pollution
Prevention Law, the Promotion of Recycling Law, Rules on Managing Daily
Waste, Regulations on Recycling and Handling Electronic Products, as
well issuing the Interim Provisions on Promoting Industrial Structure
Adjustment, Opinions on Accelerating the Development of the Recycling
Economy, Guiding Opinions on the Comprehensive Use of Resources during
the Eleventh Five-Year Plan, the Notice of Energy Conservation and
Emission Reductions, the Eleventh Five-Year Plan for National
Environmental Protection, and Policies and Actions Addressing Climate
Change, etc.
Additionally, Chapter six of the Eleventh Five-Year Plan for national
economic and social development describes a plan for developing China’s
recycling industry, based on energy saving to mobilize the whole society
to recycle.
Another policy focus for green-collar work in China lies in
comprehensive resource utilization to achieve speedy development of
resource utilization industries, which aims to improve the efficiency of
resource use and increase usage for industrial waste.
China has also made policies to develop the environmental
protection industry with the Eleventh Five-Year plan. The plan proposed
to develop large-scale high efficiency clean power generating facilities
and equipment for environmental protection and the comprehensive use of
resources. The Plan also proposed to develop equipment manufacturing
for environmental protection based on the needs of key environmental
protection projects; to actively develop a service industry prioritizing
environmental impact assessment, environmental project service;
environmental technology research and development; and environmental
venture investment.
The Chinese government has also set up a fund for environmental
management and supported a number of key projects in ecological
management and pollution management through national bonds.
These projects include controlling sandstorms in Beijing and Tianjin,
setting up environmental protection facilities in west region, control
pollution in three rivers and lakes, recycle waste water, industrialize
of recycled waste and treated water, engage in environmental pollution
management in Beijing, and subsidize programs that benefit forest
ecology.
Subsidies have also been introduced to facilitate the growth of
green-collar work. These subsidies include electricity price subsidies
for desulphurization processes, ecological construction projects (such
as climate adaptation measures), clean production projects, environmental research, and production of eco-friendly projects.
China has introduced numerous tax policies to encourage
green-collar work. First, the government has introduced tax policies
that waives and reduces value-added tax (VAT) for enterprises that
comprehensively use resources, that recycle and on-sell waste materials,
that buy in waste and recycled products, that create clean energy, that
produce environmental protection products, and that process
waste-water. For example, since 2001, administrative agencies at all levels have waived VAT for waste-water fees collected by water plants.
There have also been reforms for taxes on oil products, which has the
effect of encouraging development of low-consumption cars and new-energy
cars.
Income taxes are also waived and reduced for enterprises that use waste
material as raw materials in production and that are producing
environmental protection facilities and products.
A tax credit for investment and accelerated depreciation policy has
also been introduced for environmental protection facilities.
China also introduced a resource tax in 1988 that has since been
expanded to include: a carbon tax; tax refund recissions for enterprises
that export resource-based products such as refined mineral products
and crude oil; reductions in the tax refund rate on copper, nickel,
ferroalloy, coking coal and hard coke; and reduced tax refund rate for
enterprises with high energy consumption and high pollution.
Financial policies have also been enacted to promote the
development of green-collar work in China. In 2007, former SEPA, in
cooperation with the China People’s Bank, and CBRC issued Opinions
Regarding the Implementation of Environmental Policies and Regulations
requiring the People’s Bank and CBRC to work with environmental agencies
to guide financial institutions at all levels to introduce different
credit policies for enterprises that are forbidden, have been shut down
or have restrictions. In particular new loans could not be provided for projects which have not met environmental approvals.
Later that year in December 2007, the Ministry of Environmental
Protection and CIRC jointly issued the Opinions Regarding Environmental
Pollution Liability Insurance, formally launching the green insurance
system.
Additionally, China has put forth documents detailing their
forestry plans, including: National Afforestation and Greening Plan
(2016–2020), National Forest Management Plan (2016–2050), Action Plan
for Climate Change in Forestry in the 13th Five-Year Plan, Action Plan
for Forestry to Adapt to Climate Change (2016–2020).
Working Conditions
Workers in Green-collar jobs in China generally enjoy better job security and benefits compared to other industries due to the difficulty in outsourcing this kind of work.
These benefits include housing and transportation subsidies, health
checks, social security, as well as unemployment and workplace injury
insurance. However, in green energy
production particularly, overtime and long shifts are very common,
largely due to the fact that green energy industries are growing faster
than qualified labor is able to be trained.
While these workers were typically compensated with overtime pay or
supplementary leave, long working hours generally reduce a worker’s
performance, makes them more susceptible to occupational hazards, and
reduce the quality of family life.
However, green energy-production work in China is generally less
hazardous than non-green energy production work, such as coal mining.
But there are still notable hazards associated with green-collar jobs,
particularly in power generation systems, such as blade ejection, tower
collapse, overheating, the use of high voltage electricity, the use of
rotating machinery, working at significant heights, the handling of
heavy equipment, etc.
Many workers in green energy-production jobs in China report that they belonged to labor unions, and that representatives were able to participate in companies’ management.
The unions also help carry out support programs for employees, which
have contributed to the stability and satisfaction of the green-energy
workforce. However, it is unclear how representatives influence
decisions in management, and whether or not workers’ voices can be truly
reflected in the representatives, since representatives are not always
produced through direct elections.
It is also worth noting that Chinese workers are not entitled to
organize independent trade unions, and that all trade unions must be
affiliated with the All-China Federation of Trade Unions (ACFTU), and the formation of competing unions is prohibited. Whether state or privately owned, most trade union representatives are elected by management, rather than by workers, meaning that workers’ voices often go unheard.
Current State of Green-collar jobs in China
China
has been increasing investment in infrastructure and environmental
protection facilities to create demand within environmental protection
industries. Many recent efforts and developments in green-collar work in China have focused on the circular economy, recycling of waste materials, and eradication of high-waste and high-pollution industries.
In 2004, there were 1.595 million workers employed in the environmental
protection industry. Green employment still is in its early stages in
China, accounting for a very little percentage of China’s workforce.
The overall caliber of workers is still particularly low, and the
phasing out of outdated facilities will bring about some job loss.
The transformation of some jobs that come with adopting green measures
will pose a new challenge to workers who will need to update their
skills.
Although new green jobs will be created, the number of new positions
will be limited compared to the amount of displaced workers who need
redeployment, and some industries will not be able to exit quickly due
to obligations to redundant workers.
Forestry Industry in China
Forests are one of the most economical carbon absorbers, with huge employment opportunities in three main areas: first, forestation and reforestation, restoration of degraded forests, and developing a joint system of forestry
and agriculture to improve the sustainable development of forests;
second, timber production and processing; third, sectors related to
forestry, such as forest-tourism, developing chemicals for forests,
forest machinery, forestry food, herbal medicines, etc.
In 2007, China’s total forestation was 2,680,000 hectares, with 980,000
workers registered across all natural forest conservation projects in
China.
At the same time, there were a total of 1,849,200 registered forestry
workers across those who worked in the fields of agricultural forestry
and fishery, the fields of public management and organization, in water
environment and facility management, and scientific research services.
According to the China Forestry Statistical Yearbook 2008, China had
over 1200 forest parks, directly or indirectly creating 3.5 million
jobs. The UN Food and Agriculture Organization estimates that forest restoration can create 10 million green jobs, particularly in organic farming and biofuel production.
Forestry efforts have received criticisms for being ineffective
and even exacerbating desertification and other ecological problems.
Many afforestation efforts have relied on monoculture style planting of
trees, without taking local ecology into account, in a style called 一刀切
(yi1dao1qie1), or “cutting everything with the same knife”.
Monoculture afforestation has a few problems ecologically: first, that
monoculture trees act as natural pumps that deplete groundwater and
intensifies desertification; second, that monoculture manufactures a
homogenized landscape that has little regenerative capacity; and third,
that monoculture forests are vulnerable to disease and makes for a poor
wildlife habitat.
Climate Analysis
With
power generation being a large source of emissions and inefficiency,
China’s push to develop renewable energy and shut down ‘backward’
industry has already led to increased energy saving and emission
reduction.
China currently plans to accelerate this change to renewable energy,
with the goal of having renewable energy sources supplying 40% of
China’s energy by 2050.
Additionally, forestry efforts in China have contributed to soaking up
carbon dioxide from the atmosphere. A 2015 study estimated that China’s
forests have absorbed more than 22 Gt of carbon since 1973, which is
equal to roughly seven years of carbon emissions.
Another 2016 study estimated that carbon storage in China’s forest
would reach 28 Gt by 2033, which is equal to roughly 9 years of carbon
emissions. Another 2018 study also found that each year, China’s forests sequester around 5% of the country’s CO2 emissions.
However, there are concerns that despite the forestry efforts,
consumption patterns simply encourage deforestation of other countries,
offsetting the benefits of forestry efforts in China.
The increase in timber demand and food imports suggest that the
environmental cost of consumption is being pushed off onto neighboring
countries who don’t share the same environmental goals as China. Although it is uncertain if the push for more green-collar work will be sufficient to combat the climate crisis, it begins to move in the right direction by reducing Greenhouse gas emissions caused by burning fossil fuels.
Scientific, environmental, and health justifications for green collar jobs
The Swedish utility Vattenfall
did a study of full life cycle emissions of Nuclear, Hydro, Coal, Gas,
Solar Cell, Peat and Wind which the utility uses to produce electricity.
The net result of the study was that nuclear power produced 3.3 grams
of carbon dioxide per KW-Hr of produced power. This compares to 400 for
natural gas and 700 for coal (according to this study). The study also concluded that nuclear power produced the smallest amount of CO2 of any of their electricity sources.
Claims exist that the problems of nuclear waste do not come anywhere close to approaching the problems of fossil fuel waste. A 2004 article from the BBC states: "The World Health Organization
(WHO) says 3 million people are killed worldwide by outdoor air
pollution annually from vehicles and industrial emissions, and 1.6
million indoors through using solid fuel." In the U.S. alone, fossil fuel waste kills 20,000 people each year. A coal power plant releases 100 times as much radiation as a nuclear power plant of the same wattage. It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as the Three Mile Island incident. In addition, fossil fuel waste causes global warming, which leads to increased deaths from hurricanes, flooding, and other weather events. The World Nuclear Association
provides a comparison of deaths due to accidents among different forms
of energy production. In their comparison, deaths per TW-yr of
electricity produced from 1970 to 1992 are quoted as 885 for hydropower,
342 for coal, 85 for natural gas, and 8 for nuclear.
While nuclear energy releases zero carbon dioxide into the atmosphere, there is dangerous waste
created that needs to be contained. Until safe, permanent disposal of
nuclear waste is created, society will likely remain reliant on fossil
fuels. The process used to store nuclear waste has room for improvement and will likely be advanced in the future.
Other uses
"Green collar" is used in the Metal Gear franchise to refer to members of the arms industry, mercenaries, and other individuals in the private sector involved in war and military activity, notably for profit.
"Green collar" is used in the Cannabis
culture to refer to a person who finds acceptance or enjoyment of
cannabis culture and cannabis products. The term is a play on the
traditional uses of the terms "white collar" and "blue collar," notably,
to indicate that there is broad acceptance and enjoyment of cannabis
culture that transcends socioeconomic stratifications.
Soil contamination, soil pollution, or land pollution as a part of land degradation is caused by the presence of xenobiotic
(human-made) chemicals or other alteration in the natural soil
environment. It is typically caused by industrial activity,
agricultural chemicals or improper disposal of waste. The most common chemicals involved are petroleumhydrocarbons, polynuclear aromatic hydrocarbons (such as naphthalene and benzo(a)pyrene), solvents, pesticides, lead, and other heavy metals. Contamination is correlated with the degree of industrialization
and intensity of chemical substance. The concern over soil
contamination stems primarily from health risks, from direct contact
with the contaminated soil, vapour from the contaminants, or from
secondary contamination of water supplies within and underlying the
soil. Mapping of contaminated soil sites and the resulting clean ups are time-consuming and expensive tasks, and require expertise in geology, hydrology, chemistry, computer modelling, and GIS in Environmental Contamination, as well as an appreciation of the history of industrial chemistry.
In North America and Western Europe the extent of contaminated land
is best known, with many of countries in these areas having a legal
framework to identify and deal with this environmental problem.
Developing countries tend to be less tightly regulated despite some of
them having undergone significant industrialization.
Causes
Soil pollution can be caused by the following (non-exhaustive list):
E-waste processing in Agbogbloshie,
Ghana. Improper disposal of manufactured goods and industrial wastes,
often means that communities in the global south have to process goods.
Especially without proper protections, heavy metals and other
contaminates can seep into the soil, and create water pollution and air pollution.
Historical deposition of coal ash used for residential, commercial, and industrial heating, as well as for industrial processes such as ore smelting, were a common source of contamination in areas that were industrialized
before about 1960. Coal naturally concentrates lead and zinc during its
formation, as well as other heavy metals to a lesser degree. When the
coal is burned, most of these metals become concentrated in the ash (the
principal exception being mercury). Coal ash and slag may contain sufficient lead to qualify as a "characteristic hazardous waste", defined in the US as containing more than 5 mg/L of extractable lead using the TCLP procedure. In addition to lead, coal ash typically contains variable but significant concentrations of polynuclear aromatic hydrocarbons
(PAHs; e.g., benzo(a)anthracene, benzo(b)fluoranthene,
benzo(k)fluoranthene, benzo(a)pyrene, indeno(cd)pyrene, phenanthrene,
anthracene, and others). These PAHs are known human carcinogens
and the acceptable concentrations of them in soil are typically around
1 mg/kg. Coal ash and slag can be recognised by the presence of
off-white grains in soil, gray heterogeneous soil, or (coal slag)
bubbly, vesicular pebble-sized grains.
Treated sewage sludge, known in the industry as biosolids, has become controversial as a "fertilizer".
As it is the byproduct of sewage treatment, it generally contains more
contaminants such as organisms, pesticides, and heavy metals than other
soil.
In the European Union, the Urban Waste Water Treatment Directive
allows sewage sludge to be sprayed onto land. The volume is expected to
double to 185,000 tons of dry solids in 2005. This has good
agricultural properties due to the high nitrogen and phosphate
content. In 1990/1991, 13% wet weight was sprayed onto 0.13% of the
land; however, this is expected to rise 15 fold by 2005. Advocates say
there is a need to control this so that pathogenicmicroorganisms do not get into water courses and to ensure that there is no accumulation of heavy metals in the top soil.
Pesticides and herbicides
A pesticide
is a substance used to kill a pest. A pesticide may be a chemical
substance, biological agent (such as a virus or bacteria),
antimicrobial, disinfectant or device used against any pest. Pests
include insects, plant pathogens, weeds, mollusks, birds, mammals, fish,
nematodes (roundworms) and microbes that compete with humans for food,
destroy property, spread or are a vector for disease or cause a
nuisance. Although there are benefits to the use of pesticides, there
are also drawbacks, such as potential toxicity to humans and other
organisms.
Herbicides
are used to kill weeds, especially on pavements and railways. They are
similar to auxins and most are biodegradable by soil bacteria. However,
one group derived from trinitrotoluene
(2:4 D and 2:4:5 T) have the impurity dioxin, which is very toxic and
causes fatality even in low concentrations. Another herbicide is Paraquat. It is highly toxic but it rapidly degrades in soil due to the action of bacteria and does not kill soil fauna.
Insecticides are used to rid farms of pests which damage crops.
The insects damage not only standing crops but also stored ones and in
the tropics it is reckoned that one third of the total production is
lost during food storage. As with fungicides, the first insecticides used in the nineteenth century were inorganic e.g. Paris Green and other compounds of arsenic. Nicotine has also been used since 1690.
There are now two main groups of synthetic insecticides:
1. Organochlorines include DDT, Aldrin, Dieldrin
and BHC. They are cheap to produce, potent and persistent. DDT was used
on a massive scale from the 1930s, with a peak of 72,000 tonnes used
1970. Then usage fell as the harmful environmental effects were realized. It was found worldwide in fish and birds and was even discovered in the snow in the Antarctic.
It is only slightly soluble in water but is very soluble in the
bloodstream. It affects the nervous and endocrine systems and causes the
eggshells of birds to lack calcium causing them to be easily
breakable. It is thought to be responsible for the decline of the
numbers of birds of prey like ospreys and peregrine falcons in the 1950s – they are now recovering.
As well as increased concentration via the food chain, it is known to
enter via permeable membranes, so fish get it through their gills. As it
has low water solubility, it tends to stay at the water surface, so
organisms that live there are most affected. DDT found in fish that
formed part of the human food chain caused concern, but the levels found
in the liver, kidney and brain tissues was less than 1 ppm and in fat
was 10 ppm, which was below the level likely to cause harm. However, DDT
was banned in the UK and the United States to stop the further buildup
of it in the food chain. U.S. manufacturers continued to sell DDT to
developing countries, who could not afford the expensive replacement
chemicals and who did not have such stringent regulations governing the
use of pesticides.
2. Organophosphates, e.g. parathion,
methyl parathion and about 40 other insecticides are available
nationally. Parathion is highly toxic, methyl-parathion is less so and Malathion
is generally considered safe as it has low toxicity and is rapidly
broken down in the mammalian liver. This group works by preventing
normal nerve transmission as cholinesterase is prevented from breaking
down the transmitter substance acetylcholine, resulting in uncontrolled
muscle movements.
Agents of war
The
disposal of munitions, and a lack of care in manufacture of munitions
caused by the urgency of production, can contaminate soil for extended
periods. There is little published evidence on this type of
contamination largely because of restrictions placed by governments of
many countries on the publication of material related to war effort.
However, mustard gas stored during World War II has contaminated some sites for up to 50 years and the testing of Anthrax as a potential biological weapon contaminated the whole island of Gruinard.
Human health
Exposure pathways
Contaminated
or polluted soil directly affects human health through direct contact
with soil or via inhalation of soil contaminants that have vaporized;
potentially greater threats are posed by the infiltration of soil
contamination into groundwater aquifers
used for human consumption, sometimes in areas apparently far removed
from any apparent source of above-ground contamination. Toxic metals can
also make their way up the food chain through plants that reside in
soils containing high concentrations of heavy metals. This tends to result in the development of pollution-related diseases.
Most exposure is accidental, and exposure can happen through:
Ingesting dust or soil directly
Ingesting food or vegetables grown in contaminated soil or with foods in contact with contaminants
Skin contact with dust or soil
Vapors from the soil
Inhaling clouds of dust while working in soils or windy environments
However, some studies estimate that 90% of exposure is through eating contaminated food.
Consequences
Health
consequences from exposure to soil contamination vary greatly depending
on pollutant type, the pathway of attack, and the vulnerability of the
exposed population. Researchers suggest that pesticides and heavy metals
in soil may harm cardiovascular health, including inflammation and
change in the body's internal clock.
Chronic exposure to chromium, lead , and other metals, petroleum, solvents, and many pesticide and herbicide formulations can be carcinogenic, can cause congenital disorders,
or can cause other chronic health conditions. Industrial or human-made
concentrations of naturally occurring substances, such as nitrate and ammonia associated with livestock manure from agricultural operations, have also been identified as health hazards in soil and groundwater.
Chronic exposure to benzene at sufficient concentrations is known
to be associated with a higher incidence of leukemia. Mercury and cyclodienes
are known to induce higher incidences of kidney damage and some
irreversible diseases. PCBs and cyclodienes are linked to liver
toxicity. Organophosphates and carbonates can cause a chain of responses leading to neuromuscular blockage.
Many chlorinated solvents induce liver changes, kidney changes, and
depression of the central nervous system. There is an entire spectrum of
further health effects such as headache, nausea, fatigue, eye
irritation and skin rash for the above cited and other chemicals. At
sufficient dosages a large number of soil contaminants can cause death
by exposure via direct contact, inhalation or ingestion of contaminants
in groundwater contaminated through soil.
The Scottish Government has commissioned the Institute of Occupational Medicine
to undertake a review of methods to assess risk to human health from
contaminated land. The overall aim of the project is to work up guidance
that should be useful to Scottish Local Authorities in assessing
whether sites represent a significant possibility of significant harm
(SPOSH) to human health. It is envisaged that the output of the project
will be a short document providing high level guidance on health risk
assessment with reference to existing published guidance and
methodologies that have been identified as being particularly relevant
and helpful. The project will examine how policy guidelines have been
developed for determining the acceptability of risks to human health and
propose an approach for assessing what constitutes unacceptable risk in
line with the criteria for SPOSH as defined in the legislation and the
Scottish Statutory Guidance.
Ecosystem effects
This area is contaminated with stagnant water and refuse, making the environment unhygienic.
Not unexpectedly, soil contaminants can have significant deleterious consequences for ecosystems.
There are radical soil chemistry changes which can arise from the
presence of many hazardous chemicals even at low concentration of the
contaminant species. These changes can manifest in the alteration of metabolism of endemic microorganisms and arthropods
resident in a given soil environment. The result can be virtual
eradication of some of the primary food chain, which in turn could have
major consequences for predator or consumer species. Even if the chemical effect on lower life forms is small, the lower pyramid levels of the food chain
may ingest alien chemicals, which normally become more concentrated for
each consuming rung of the food chain. Many of these effects are now
well known, such as the concentration of persistent DDT materials for
avian consumers, leading to weakening of egg shells, increased chick mortality and potential extinction of species.
Effects occur to agricultural
lands which have certain types of soil contamination. Contaminants
typically alter plant metabolism, often causing a reduction in crop
yields. This has a secondary effect upon soil conservation, since the languishing crops cannot shield the Earth's soil from erosion. Some of these chemical contaminants have long half-lives and in other cases derivative chemicals are formed from decay of primary soil contaminants.
Potential effects of contaminants to soil functions
Heavy
metals and other soil contaminants can adversely affect the activity,
species composition and abundance of soil microorganisms, thereby
threatening soil functions such as biochemical cycling of carbon and
nitrogen.
However, soil contaminants can also become less bioavailable by time,
and microorganisms and ecosystems can adapt to altered conditions. Soil
properties such as pH, organic matter content and texture are very
important and modify mobility, bioavailability and toxicity of
pollutants in contaminated soils.
The same amount of contaminant can be toxic in one soil but totally
harmless in another soil. This stresses the need for soil-specific risks
assessment and measures.
Excavate soil and take it to a disposal site away from ready
pathways for human or sensitive ecosystem contact. This technique also
applies to dredging of bay muds containing toxins.
Aeration of soils at the contaminated site (with attendant risk of creating air pollution)
Thermal remediation by introduction of heat to raise subsurface
temperatures sufficiently high to volatilize chemical contaminants out
of the soil for vapor extraction. Technologies include ISTD, electrical resistance heating (ERH), and ET-DSP.
Interfacial solar evaporation to extract heavy metal ions from moist soilountry
Various
national standards for concentrations of particular contaminants
include the United States EPA Region 9 Preliminary Remediation Goals
(U.S. PRGs), the U.S. EPA Region 3 Risk Based Concentrations (U.S. EPA
RBCs) and National Environment Protection Council of Australia Guideline
on Investigation Levels in Soil and Groundwater.
People's Republic of China
The immense and sustained growth of the People's Republic of China since the 1970s has exacted a price from the land in increased soil pollution. The Ministry of Ecology and Environment
believes it to be a threat to the environment, to food safety and to
sustainable agriculture. According to a scientific sampling, 150 million
mu (100,000 square kilometres) of China's cultivated land have been polluted, with contaminated water
being used to irrigate a further 32.5 million mu (21,670 square
kilometres) and another 2 million mu (1,300 square kilometres) covered
or destroyed by solid waste. In total, the area accounts for one-tenth
of China's cultivatable land, and is mostly in economically developed
areas. An estimated 12 million tonnes of grain are contaminated by heavy
metals every year, causing direct losses of 20 billion yuan ($2.57 billion USD).
Recent survey shows that 19% of the agricultural soils are contaminated
which contains heavy metals and metalloids. And the rate of these heavy
metals in the soil has been increased dramatically.
European Union
According to the received data from Member states, in the European Union the number of estimated potential contaminated sites is more than 2.5 million
and the identified contaminated sites around 342 thousand. Municipal
and industrial wastes contribute most to soil contamination (38%),
followed by the industrial/commercial sector (34%). Mineral oil and
heavy metals are the main contaminants contributing around 60% to soil
contamination. In terms of budget, the management of contaminated sites
is estimated to cost around 6 billion Euros (€) annually.
United Kingdom
Generic guidance commonly used in the United Kingdom are the Soil Guideline Values published by the Department for Environment, Food and Rural Affairs (DEFRA) and the Environment Agency.
These are screening values that demonstrate the minimal acceptable
level of a substance. Above this there can be no assurances in terms of
significant risk of harm to human health. These have been derived using
the Contaminated Land Exposure Assessment Model (CLEA UK). Certain input
parameters such as Health Criteria Values, age and land use are fed
into CLEA UK to obtain a probabilistic output.
Guidance by the Inter Departmental Committee for the Redevelopment of Contaminated Land (ICRCL) has been formally withdrawn by DEFRA, for use as a prescriptive document to determine the potential need for remediation or further assessment.
The CLEA model published by DEFRA and the Environment Agency
(EA) in March 2002 sets a framework for the appropriate assessment of
risks to human health from contaminated land, as required by Part IIA of
the Environmental Protection Act 1990. As part of this framework, generic Soil Guideline Values (SGVs) have currently been derived for ten contaminants to be used as "intervention values".
These values should not be considered as remedial targets but values
above which further detailed assessment should be considered; see Dutch standards.
Three sets of CLEA SGVs have been produced for three different land uses, namely
residential (with and without plant uptake)
allotments
commercial/industrial
It is intended that the SGVs replace the former ICRCL values. The
CLEA SGVs relate to assessing chronic (long term) risks to human health
and do not apply to the protection of ground workers during
construction, or other potential receptors such as groundwater,
buildings, plants or other ecosystems. The CLEA SGVs are not directly
applicable to a site completely covered in hardstanding, as there is no
direct exposure route to contaminated soils.
To date, the first ten of fifty-five contaminant SGVs have been published, for the following: arsenic, cadmium,
chromium, lead, inorganic mercury, nickel, selenium ethyl benzene,
phenol and toluene. Draft SGVs for benzene, naphthalene and xylene have
been produced but their publication is on hold. Toxicological data
(Tox) has been published for each of these contaminants as well as for
benzo[a]pyrene, benzene, dioxins, furans and dioxin-like PCBs,
naphthalene, vinyl chloride, 1,1,2,2 tetrachloroethane and 1,1,1,2
tetrachloroethane, 1,1,1 trichloroethane, tetrachloroethene, carbon
tetrachloride, 1,2-dichloroethane, trichloroethene and xylene. The SGVs
for ethyl benzene, phenol and toluene are dependent on the soil organic matter
(SOM) content (which can be calculated from the total organic carbon
(TOC) content). As an initial screen the SGVs for 1% SOM are considered
to be appropriate.
Canada
As of February 2021, there are a total of 2,500 plus contaminated sites in Canada. One infamous contaminated sited is located near a nickel-copper smelting site in Sudbury, Ontario.
A study investigating the heavy metal pollution in the vicinity of the
smelter reveals that elevated levels of nickel and copper were found in
the soil; values going as high as 5,104ppm Ni, and 2,892 ppm Cu
within a 1.1 km range of the smelter location. Other metals were also
found in the soil; such metals include iron, cobalt, and silver.
Furthermore, upon examining the different vegetation surrounding the
smelter it was evident that they too had been affected; the results show
that the plants contained nickel, copper and aluminium as a result of
soil contamination.
In March 2009, the issue of uranium poisoning in Punjab attracted press coverage. It was alleged to be caused by fly ash ponds of thermal power stations, which reportedly lead to severe birth defects in children in the Faridkot and Bhatinda districts of Punjab.
The news reports claimed the uranium levels were more than 60 times the
maximum safe limit. In 2012, the Government of India confirmed that the
ground water in Malwa belt of Punjab has uranium metal that is 50%
above the trace limits set by the United Nations' World Health Organization
(WHO). Scientific studies, based on over 1000 samples from various
sampling points, could not trace the source to fly ash and any sources
from thermal power plants or industry as originally alleged. The study
also revealed that the uranium concentration in ground water of Malwa
district is not 60 times the WHO limits, but only 50% above the WHO
limit in 3 locations. This highest concentration found in samples was
less than those found naturally in ground waters currently used for
human purposes elsewhere, such as Finland. Research is underway to identify natural or other sources for the uranium.
