Using the urban environment to make a living: The principles of pollution and profits in urban
farming applied to the city of Cleveland
Alexander Hogan
4/23/2013
EEB 3256
Professor, Dr. Felix Coe
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ABSTRACT
The purpose of this paper is to examine the issues associated with farming in urban
environments, especially the city of Cleveland, including soil pollution, and how to make a profit
with sustainable farming methods. A review is made of heavy metal pollution in Cleveland
soils, techniques for remediating soils, and reasons and methods for growing organic foods in
urban areas. Future trends that are likely to promote increased practice of urban agriculture are
also discussed.
INTRODUCTION and BACKGROUND
Urban inhabitants are increasingly growing their own food plants. In the developed
world, urban inhabitants are most likely to grow plants for food security or to build a community,
but there are also enterprises seeking to monetize food grown in cities. The purpose of this paper
is to examine the issues associated with farming in urban environments, particularly the city of
Cleveland, Ohio, including soil pollution, and how to make a profit with sustainable farming
methods. In many cities in the United States, Cleveland included, soil contains heavy metals that
make exposure to the soil unsafe for inhabitants and unsuitable for growing food (McClintock
2012, Pfaff and Jennings 1996, Jennings et al. 2002, Petersen et al. 2006, Srinivas et al. 2009).
Lead is one of these contaminants, however lead containing soils may be treated to lessen the
risk of exposure (Ruby et al. 1994). When suitable land is found and cultivated, the method of
cultivation and marketing has an impact on the profits from the crops. Organic produce tends to
sell more readily than conventional produce to customers in urban areas, as reported by
managers of farmers’ markets (Kremen et al. 2004, Oberholtzer et al. 2008). Farmers can take
advantage of this trend, and expand it by engaging other urban inhabitants and teaching their
fellow city dwellers about agriculture and caring for plants. As the trend of sustainable farming,
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of which organic urban agriculture is a part, continues more farmers may turn to roofs for
growing space (Whittinghill and Rowe 2011), or consider human waste as a fertilizer
(Richardson 2012).
While the future for urban agriculture may be bright, the current reality is that there are
several difficulties in establishing and running a farm in an urban environment. Business based
on selling local food in a city must consider where to farm, and where and how to sell their
goods in addition to the concerns of raising healthy crops despite air and soil pollution. Some
companies have found success in urban agriculture (Cheney 2005), but Cleveland, along with
many historically industrial cities in the United States, still faces polluted soil and food deserts1.
Local urban farmers’ markets may be a step toward opening up access to healthy foods and
preventing the limited access that defines food deserts. The location of food deserts may guide
the location of markets, but the locations of farms follow other rules. Uncontaminated growing
media is necessary for a farmer to produce healthy crops. When growing crops in vacant lots,
this medium is soil. City inhabitants may turn to brownfields, “abandoned or underutilized
industrial properties for which concerns about environmental problems are assumed to increase
the difficulty of redevelopment,” (Jennings et al. 2002) when looking for free land to farm
(McClintock 2012). Unfortunately, these brownfields are subject to heavy metal contamination
deposited from heavy machinery discharge or particles in the air that originated in smelting
operations or traffic and from paints (Jennings et al. 2002). Other substances such as reactive
nitrogen, copper, and zinc also pollute the air and soil of cities and threaten to interfere with crop
quality (Zbieranowski and Aherne 2012, Srinivas et al. 2009). The above contaminants may be
in the soil, but remain nonhazardous. Creating soil that is within acceptable ranges of hazard
1
Food deserts are urban areas in which residents lack reasonable, spatial access to: fresh fruits and vegetables, food
from all the major food groups required for an adequate diet, and food items priced competitively compared to the
same item in a higher income neighborhood (Eckert and Shetty 2011).
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based on published environmental guidelines is the point of soil remediation. Some soil
remediation techniques rely on reducing the bioaccessibility of the hazardous material and
therefore the harm the materials can cause when humans are exposed to them (Ruby et al. 1994).
Other remediation techniques wash the hazardous material out of the soil but are costly because
the soil must be removed, treated, and then replaced (Pfaff and Jennings 1996).
One of options in selling the crops grown in urban farms is a farmers’ market. Selling in
a farmers’ market is a popular option for urban farmers and gives the farmers almost complete
control over how their products are sold. Such markets are also more flexible for farmers who
may not be able to reliably supply a retail chain. Also, farmers’ markets give farmers a chance to
directly interact with customers which may help increase a customer’s likelihood of buying
sustainable products (Kremen et al. 2004). Organic farming is one of the main avenues to
sustainable farming, and is appropriate for urban farms and for urban farmers’ markets. The
avoidance of chemical pollution by petroleum-based fertilizers, the growing demand for
sustainable food (Woolverton and Dimitri 2010), and the ability to farm without great monetary
investment make organic farming a sensible choice for urban farmers (Kremen et al. 2004).
SOIL POLLUTION and REMEDIATION
Soil quality is important to consider when assessing the possibility for farming a plot of
land. Polluted soil is unsuitable for crops because crops will take up pollutants, and can spread
these pollutants to humans upon ingestion (Srinivas et al. 2009). Urban farms in particular must
consider soil pollution because city soils are often polluted with heavy metals and other
contaminants (Petersen et al. 2006, McClintock 2012). The occurrence of polluted soil in cities
restricts the possible location of urban farms. Another factor to consider in planning the location
of an urban farm is inhabitant access to fresh foods. While this consideration for food deserts is
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most important for planning markets, it affects farms because farm proximity to markets lessens
transportation. Unfortunately, the locations within a city that are most in need of fresh food from
farms are also often the most polluted (McClintock 2012). Farm locations that best influence the
health of the surrounding community, and may therefore earn sustainable profits, should be close
enough to sell food in food deserts, but cultivating soil that is free of soluble heavy metal
contamination. The goals of proximity to food deserts and land free from contamination may be
difficult to fulfill in Cleveland; many plots of available land in Cleveland are heavily
contaminated with heavy metals (Jennings et al. 2002, Petersen et al. 2006, Pfaff and Jennings
1996).
Another complicating factor in deciding whether urban land is suitable to farm is the
variation in acceptable concentrations of heavy metals in soil caused by differing local, state, or
national guidelines (Petersen et al. 2006). There are several possible methods to follow when
testing for soil contamination. The various procedures rely on different solvents, from H20 to HF
to extract heavy metals from soil, and the discovered concentrations may be graded at different
levels of hazard (Petersen et al. 2006). Because of this variation, different states permit different
concentrations of heavy metals in tested soils before requiring remediation. Some brownfields
containing heavy metal contamination may therefore be considered usable or unusable
depending upon the state regulations observed. In Cleveland, the acceptable levels of lead
contamination are 420 mg/kg for industrial soils and 400 mg/kg for residential soils (Petersen et
al. 2006). Other heavy metals the contaminate Cleveland soils
Land in Cleveland is especially at risk for lead. In a study of heavy metal contamination
in Cleveland brownfields, Jennings et al. found levels of lead in 53 out of 53 tested sites that
were at least double the background levels for lead in Ohio farm soils (2002). Thirty of the
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tested sites were even above the acceptable level of contamination of 400 mg/kg for residential
soils, a measure more appropriate when considering potential agricultural land. Other heavy
metal contaminants include cadmium, chromium, copper, nickel, and zinc (Jennings et al. 2002,
Petersen et al. 2006). However, the burden of lead is of particular interest because of the
Polluted soils often have a history of industry. Urban centers, land zoned for industry,
and land with old housing structures in Oakland, CA were shown to have greater concentrations
of lead than areas outside of industrial and urban centers and land with newer housing stock.
These spatial concentrations of lead support the conclusions that lead is deposited into soil from
industrial and automobile emissions as well as from lead based paint used especially on pre-1940
housing. Another factor that positively correlated with presence of lead contamination in soil
was proximity to an airfield. Recent replacement of soil for landscaping or fill lowered the
likelihood of finding lead contamination at a testing site (McClintock 2012). In a study of
Cleveland brownfield soils, the presence of a railway was noted as correlating with lead
contamination (Jennings et al. 2002). Both situations in which lead appeared more prevalent in
soil involve industrial use of land and suggest that special attention should be paid to testing the
soil of land in industrial centers before planning to farm such a plot.
Despite the presence of heavy metals, soil may be safe for growing plants. There is some
uncertainty in the relationship between lead occurring in the soil and plants taking up lead. Of
four tested plants, lady’s finger (Abelmoschus esculentus Linn., Malvaceae) and capsicum pepper
(Capsicum annum Linn., Solanaceae) contained more lead when grown in soil with 15 mg/kg
lead rather than soil with 48 mg/kg lead. Tomato (Lycopersicon esculentum Mill, Solanaceae)
and bimli (Hibiscus cannabinus Linn, Malvaceae) contained more lead when grown in the more
highly contaminated soil (Srinivas et al. 2009). When considering concentrations of lead greater
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than 400 mg/kg, a 30 mg/kg difference in soil lead concentration does not seem that great.
However, it is important to consider that phosphate soil remediation reduced dissolved lead in
soil pore water from 6500 μg/L to 0.12 μg/L (Ruby et al. 1994). The drastic reduction of soluble
lead obtained through phosphate soil remediation may lead to soil that is appropriate for growing
plants. It is uncertain what dry weight concentration a pore water concentration of 0.12 μg/L
represents, but it may bring the concentration of lead into a range more appropriate for farmland
rather than a range typical of contaminated urban soil.
Because of the discrepancy in plant matter lead concentrations, an important
consideration for the assessment of risk is the bioavailability of the contaminants, and there are
strategies for minimizing the bioavailability of lead in contaminated soils. Phosphorous and
chlorine remediation produced the reduction in soluble lead cited above. The process of adding
phosphorous and chlorine to lead contaminated soil stimulates the formation of pyromorphite
compounds (Ruby et al. 1994, Yang et al. 2001). The most effective way of introducing
phosphorous into soil in order to bind lead into pyromorphite compounds was found to be
rototilling rather than pressure injection or undisturbed surface application (Yang et al. 2001).
Introducing phosphorous into soil in order to immobilize lead is a method of remediating a soil
in situ. In order to pull the lead out of the soil, ex situ methods of remediation are more
effective. Despite the greater effectiveness in removing pollutants, ex situ methods are not
always as practical because the required removal, transportation, and replacement of soil is
expensive and time consuming (Pfaff and Jennings 1996). In order to treat soil effectively and
prepare for growing crops, it is important to test soil and remediate effectively for the level of
contamination found.
AIR POLLUTION
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Deposition of particulates from the air affects agricultural practices in measurable ways
(Zbiernowski and Aherne 2012, Zbiernowski and Aherne 2013, Srinivas et al. 2009). Although
air particulate presence did not correlate as strongly with pollutant presence in plant material as
pollutant presence soil correlated with contaminated plant material, air pollution still affects
plant growing conditions because substances settle out of the air into soil (Srinivas et al. 2009,
Zbiernowski and Aherne 2012). Air pollution is not unique to urban environments, but the
difference between urban and air pollution in traditional agricultural fields is great enough for
some consideration.
The presence of heavy traffic is a major factor that affects urban air and creates a
situation different from rural environments. One of the measurable differences that may be
caused by the environmental difference is a greater presence of reactive nitrogen in urban air
compared to rural air (Zbiernowski andAherne 2013). Reactive nitrogen is essential for plant
growth because most crops cannot integrate atmospheric nitrogen (N2) into plant structures.
Instead, plants require ammonia (NH3), nitrogen dioxide (NO2), nitric acid (HNO3), or some type
of organic matter containing nitrogen as sources of one of the essential building blocks of life. In
cities, reactive nitrogen often occurs as nitrogen dioxide, and at concentrations about five times
greater than agricultural environments (Zbiernowski and Aherne 2012). Ammonia occurred
more often in air in an agricultural location, but only produced a median difference of 1.06
μg/m3, rather than the 20.72 μg/m3 difference in nitrogen dioxide concentration (Zbiernowski
and Aherne 2012). Despite the increased presence of reactive nitrogen, urban farms still require
more fertilizer than rural plots (Whittinghill and Rowe 2012).
ORGANIC FOOD and FARMERS’ MARKETS
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Organic farming should be the primary method of agriculture in urban areas. Farming
organically avoids the necessity of spreading petrochemicals in the soil, and the pollution from
conventional farming is inappropriate for the dense population of a city (Richardson 2012).
Besides the environmental and health concerns, there is a significant economic motivation for
farming city plots organically. Organic food products are gaining popularity with producers and
handlers, with more companies supplying organic materials (Oberholtzer et al. 2008). Also,
consumers, particularly those shopping in farmers’ markets seek organic food (Woolverton and
Dmitri 2010, Kremen et al. 2004).
Farmer’s markets in the United States provide a venue for farmers to sell their products in
a place where the farmer has control. Without a retailer or wholesaler in between the producer
and consumer, the farmers are responsible for selling their goods to the customers and
occasionally managing the market. There is a complex of factors making farmers’ markets
perhaps the best option for selling food produced in urban farms. One factor is that many urban
growers do not produce the volume of crops necessary for retail establishments. Retail stores
offer greater security and the benefit of allowing a farmer to focus exclusively on farming.
However, farmers’ markets offer greater control and require lower initial capital. Because urban
farmers sell to a population of consumers in poverty stricken areas, minimizing cost is an
important approach to urban agriculture (McClintock 2012). Selling products at a farmers’
market allows farmers to invest their time to sell their products instead of money (Oberholtzer et
al. 2008).
According to Kremen, Greene, and Hanson (2004) the farmers who sell well in a farmer’s
market are those that sell high quality goods, provide goods that are difficult to find elsewhere,
and treat their customers well by speaking with them and appearing regularly at the market.
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Another aspect that positively influenced the sales of organic farmers was customer interest in
agricultural issues. The correlation between customer education of agricultural issues and
customer demand for organic, local food was strong enough to prompt the conclusion that,
education about agricultural practices and how to properly handle food was the element most
likely to increase consumer demand for organic products (Kremen et al. 2004). Another trend
that correlates with higher sales is locating a market near a community building. A community
building such as a university, church, or holistic health care center may help a group of people to
identify with the market and encourage the customers to consider agriculture a part of their lives.
The interest in agriculture that will probably be stimulated by this identification also increases
the likelihood that customers will purchase food grown sustainably.
As businesses grow, there are now models for growth that can illuminate a path of
economic growth that also respects sustainable farming practices. The importance of remaining
sustainable arises from consumer demand for organic products and transparency. A growing
company often becomes difficult for consumers to understand, but with some effort, green
companies can maintain their sustainable practices and consumer image as they grow
(Woolverton and Dmitri 2010).
CONCLUSION
Organic, local foods will probably become more available as more consumers educate
themselves about agricultural issues and take more responsibility for finding sustainably grown
food. The movement for sustainably grown food may have numerous effects on urban and rural
cultures and the lives of people around the world. Urban agriculture in particular, bringing the
production of food into densely populated areas, is one of the practices rising with the increased
demand and supply of sustainable agricultural products, and more sustainable lives in general, at
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least in the developed world. There are at least seven government projects around the world
aimed at providing food in an urban environment. The projects considered in Europe include Pig
City, Skyland, Plantagon Greenhouse, Cultivating the city, Tour Vivante, and Urban Farm; a
project titled Agro-housing is also being developed in China (Torreggiani et al. 2012). Some
developing parts of the world are also integrating agriculture into urban settings as cities grow.
These movements in the developing world are also refining the use of human waste as fertilizer,
especially in Africa (Richardson 2012). Experiments in Sweden have also measured the efficacy
of human waste as a fertilizer, with some success (Berndtsson 2006).
As more and more urban inhabitants learn about and support local agriculture, there are
several urban legislative and cultural changes likely to be effected. Currently, land in urban
settings is expensive, and may not be regularly observed by owners (McClintock 2012).
Increased use by farmers of urban that has been abandoned by industry may increase the
attention given to land rights and zoning laws in urban areas. As urban farmers build upon
experience and grow more prevalent and successful, there will likely be more formal recognition
of agriculture as an urban endeavor (Torreggiani et al. 2012, Whittinghill and Rowe 2012). The
trend of sustainable consumption has already influenced food producers and created an increase
in organic food production, and the more informed a population is about agricultural issues, the
more likely it is to seek sustainable products (Kremen et al. 2004), so as the organic industry
grows and becomes more visible, it is likely to cause increased conversion to organic. There is
likely a maximum growth point that will be reached, but it is not yet in the near future.
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