Beyond Remediation: Re-Thinking Hawaiʻi’s Contaminated Landscapes
Emily Sobolewski Knight May 2023
Beyond Remediation: Re-Thinking Hawaiʻi’s
Contaminated Landscapes
A capstone design research project submitted in partial fulfillment of the Plan B requirements for the degree of MASTER OF
LANDSCAPE ARCHITECTURE
May 2023
By Emily Sobolewski Knight
Capstone committee: Judith Stilgenbauer, Chairperson Phoebe White
Keywords: Phytoremediation, Pollution, Contamination, Urban Landscapes, In-Situ Design
Acknowledgments
This journey started long before this semester and I am so grateful for all the professors that have taught me so much over these last three years. I have had an immensely rewarding time at UH Mānoa all thanks to my fellow classmates, professors and coworkers.
Many thanks to my committee Judith Sitlgenbauer and Phoebe White for sharing new perspectives and pushing me to go beyond what I thought I was capable of.
A million thanks to my family for the constant words of encouragement and support. Mama, the shining light that you are makes even the toughest days less difficult. You inspire me daily with your kindness and patience.
Justin, the days that you were here were immensely better. Thank you for pushing me to work even when I don’t want to, and for demanding we celebrate the smallest accomplishments.
And finally, I owe much gratitude to my hairy illiterate support system: Kimo. Thank you for staying by my side late into the night and for being the quietest cheerleader. This capstone would have been much more stressful without you.
Contents:
\Introduction / 5
What Is Contamination? / 13
How Is Contamination Addressed? / 35
Contamination In Hawaiʻi / 49
What Is A Remediation Network? / 69
Beyond Remediation/ 135
Appendix A: Remediation Plant Guide / 143
“Waste
is everyone’s matter, and it’s no one’s. It is a private matter that becomes a public matter. It is a private problem deferred to the public, ballooning from a relatively minor and simple undertaking to the individual to a major and complex one for collective society”
- Mira Engler
01. Introduction
Contamination significantly threatens humans, living organisms, and the environment. As a byproduct of the Anthropocene era, contamination can no longer be separated from the human experience. Pollutants come from all facets of life: agriculture, industry, households – the list goes on. Indeed, their ubiquity implies that pollutants are part and parcel of any urban area. Urban landscapes are inextricably linked to historic pollution and pose harmful effects on humankind, ecology, and natural resources. Currently, 4.4 billion people live in cities (World Bank, 2023). According to the United Nations, almost 60% of the world’s population will live in cities by 2050. Cities have always been cornerstones of development, industry, and commerce, so it is not surprising that, as evidenced by mass migrations into urban areas, cities are becoming the preferred living situation of people across the globe. Migrations to urban areas are happening in both the developing and developed world, a fact ultimately attributable to the proximity to jobs and shops, access to services and goods, and the presence of different people and cultures. The problems of waste, pollution, and contamination are not new introductions to the urban landscape. Sickness and disease in cities have historically stemmed from mismanaged waste and unhygienic conditions. While conditions have improved substantially in the last 100 years, the forms of contamination have transformed to challenge our innovations and technologies. In many of today’s urban environments, the byproducts of human activity/anthropocen-
Contamination: introduction of unnatural elements into an environment that cause adverse change
Pollution: the presence in or introduction into the environment of a substance or thing that has harmful or poisonous effects.
tric processes tend to exceed nature’s capacity to break down pollutants. These polluted landscapes are often perceived negatively and, as such, tend to fall by the wayside as wasted landscapes.
Despite its location in the center of the Pacific Ocean, the Hawaiian archipelago has not been spared from the impacts of contamination. Throughout Hawaiʻi’s history, contamination has built up over time due to agricultural practices, military activities, industry, and urban living. Hawaiʻi’s limited land for expansion will soon require a response to polluted landscapes throughout the islands.
While there are methods to remediate pollution, such as soil replacement, capping, or chemical treatments, bioremediation offers an organic approach to clean pollutants on-site. Phytoremediation, using plants to clean contaminants from the environment, provides a low-cost and visually appealing in-situ remediation strategy (US EPA, n.d.). Using plants to remove, degrade, or immobilize pollutants on-site from soil and water reduces the risk of exposure to harmful contaminants (US EPA, n.d.). Hawaiʻi’s tropical climate offers a year-round growing season, enabling phytoremediation to be a practical and effective strategy for continuous pollutant remediation.
Contamination is often seen as an artificial introduction into the environment, pollutants and harmful environmental elements naturally occur within the environment. For example, volcanoes release toxic gasses and debris that can upset the equilibrium of ecosystems. Natural ʻpollutionʻ disperses itself throughout the environment over time, allowing the organic restoration of the ecosystem’s balance. Phytoremediation offers a similar approach for naturally restoring ecological balance in artificially polluted landscapes.
Thesis
This capstone project intends to establish a toolkit for in-situ phytoremediation in Hawaiʻi, prioritizing native and other non-invasive plant species to clean contaminated sites. Beyond the toolkit, this capstone explores how phytoremediation can be built into the fabric of the neighborhood. The transformation of disturbed landscapes into a remediation network re-imagines a community’s connection to the process of cleansing contaminated sites via phytoremediation.
Archipelago: a group or cluster of island chains, the Hawaiian Islands
phytoremediation: using plants to clean contaminants from the environment
Invasive: an introduced, nonnative organism that begins to spread or expand its range from the site of its original introduction and that has the potential to cause harm to the environment, the economy, or to human health
Research Question
How can well developed and established in-situ phytoremediation principles be used to create an adapted toolkit for Hawaiʻi’s contaminated urban landscapes?
What does this mean for the field of landscape architecture and beyond?
in-situ: on site, in place
With all the problems associated with contamination, landscape architecture has attempted to respond to the issues which contamination implies. Within the field of landscape architecture, nationally and globally, phytoremediation is a recognized process that can be incorporated into the design of contaminated sites. The frequency with which phytoremediation is incorporated into the landscape design process shows the potential to use plants to address historical and immediate sources of contamination. That being said, this capstone has identified a fundamental gap in available research. Landscape Architecture in Hawaiʻi has not truly begun to use phytoremediation as a method in design. Some projects have used plants and other living elements to respond to contaminants, but the projects are either no longer being supported or are at a pilot test scale.
In other parts of the United States, in-situ remediation projects are affected by shorter growing seasons. The climate in Hawaiʻi allows for phytoremediation systems to work year-round. Furthermore, due to Hawaiʻi’s warmer climate, the increased soil temperature can naturally accelerate the phytoremediation process (Paquin et al., 2006, p. 127).
Methods
In order to develop an in-situ phytoremediation system for Hawaiʻi’s urban landscapes, this capstone will conduct an in-depth literature review, an analysis of phytoremediation precedent studies, empirical research, and conduct site analysis specific to Honolulu.
The literature review consists of dissecting scientific publications relating to the phytoremediation process, landscape architecture and design perspectives on phytoremediation, the impacts of contaminated landscapes, and the ecological and environmental relationship within urban
landscapes.
Precedent research will look specifically at phytoremediation projects implemented globally, nationally throughout the United States, and locally (in Hawaiʻi), highlighting the scales, plants used, scope, and remediation timeframe. Since there have been few in-situ phytoremediation projects in Hawaiʻi, this capstone looks beyond planted phytoremediation projects and will also look at the full spectrum of bioremediation efforts.
This capstone’s empirical research gathers Geographic Information Systems data to spatialize the foundational structural elements within a watershed. GIS data is used in conjunction with policy analysis and systems analysis for how contaminants and pollutants are addressed
LITERATURE REVIEW
- Scientific research relating to phytoremediation in the United States and Hawaiʻi
- Review of landscape architecture and design focused texts relating to contaminated and disturbed landscapes
- Academic and peer-reviewed journals addressing urban environmental problems and their impacts on humans and ecology.
Precedent: existing complete projects
PRECEDENT STUDIES EMPIRICA RESEARCH
- Documentation and design analysis of site-specific precedent projects to understand scale
- Strategy analysis of precedent projects that employ a larger framework to phytoremediaion strategies
- GIS and spatial watersheds with to potential contaminants.
- Policy analysis and Hawaiʻi
- Systems analysis water and waste ment strategies
currently. Policy analysis will be on a national, state, and city & county level to show how different tiers of governance address the problems. Systems analysis for waste management, contaminant processing, and pollutant identification will focus on the City & County of Honolulu.
Within this capstone’s identified site boundaries, site analysis will consist of GIS data to establish the foundational structure of the site, in-person observation and cataloging, and historical and present narration. The selected sites, located within a larger framework of the City of Honolulu, are dynamic and ever-changing. The foundation of the site analysis is to identify pollutants and their movement and how humans and non-human participants interact with and are affected by the pollutants.
EMPIRICAL RESEARCH
SITE ANALYSIS
APPLIED
DESIGN
RESEARCH
spatial analysis of with connection contaminants. analysis for the U.S. analysis of current waste managestrategies in Hawaiʻi
- Large scale analysis tracing contaminants and movement through a watershed.
- Ephemeral impacts to selected sites with their relationship to growing conditions
- Human and ecological interactions with selected sites
- Historic uses of selected sites.
“Pollution is man’s way of giving something back to the environment that he lives in.”
- Anthony T. Hincks
Contamination: the process of making something dirty or poisonous or the state of containing unwanted or dangerous substances
Particulate matter: are microscopic particles of solid or liquid matter suspended in the air
02. What Is Contamination?
Contamination is the process of making something dirty or poisonous or the state of containing unwanted or dangerous substances (Cambridge Dictionary, 2023).
Pollution is the introduction of harmful materials into the environment (National Geographic, 2023).
The contaminants present were historically regulated and monitored by the government with the foundation of the Environmental Protection Agency (EPA). The 1960s brought public awareness to the ramifications of pollution on the environment. Air and water quality were not being monitored and were harming people and animals who lived nearby. Founded by Richard Nixon on December 2, 1970, as a response to the growing environmental concerns raised by citizens, the EPA’s goals were to research and respond to pollutants in the environment.
How does contamination move?
Pollutants and contaminants are transmitted via water, air, soil, and human intervention. From the point where the contaminant is introduced into the environment, pollutants can “move” by the natural elements they become attached to.
Contaminants released into the air in the form of particulate matter can travel long distances on air currents. Dispersal of contaminants through the air can also lead to dissipation or reduction of concentration in the atmosphere. Pollution in the air can be visible (e.g. smog,
Environmental Protection Agency: protects people and the environment from significant health risks, sponsors and conducts research, and develops and enforces environmental regulations.
smoke, ash, etc.) but oftentimes is invisible to the naked eye. While air pollution comes mostly from man-made resources, some forms of air pollution present in Hawaiʻi have natural origins; volcanic smog, also known as VOG, is a natural byproduct of volcanoes erupting.
The sources of soil contamination are often directly linked to spills and leaks. When exposed to soil, pollutants absorb into the ground and can bind with soil molecules. Soil contamination is one of the most common site development problems and can be one of the most difficult problems to address.
Contamination also has the potential to move across surfaces and through soil until it makes contact with water. Consequently, when in contact with contamination, water
Source: EPA
VOG: form of air pollution that results when sulfur dioxide and other gases and particles emitted by an erupting volcano react with oxygen and moisture in the presence of sunlight
Soil contamination: presence of chemicals within a natural soil environment.
becomes a vector for pollution to spread through streams, rivers, lakes, and the ocean. Contamination can also settle into the sediment and stay within the body of water indefinitely.
Hawaiʻi’s volcanic history is responsible for producing today’s remarkable hydrological conditions. The watersheds present throughout the islands are concentrated in a small geographic area. Large elevation differences throughout the Hawaiian Islands create circumstances in which water moves quickly to the ocean: a drop of water that falls high in the mountains can be traced down to where it is released into the ocean by streams, canals, or storm drains. The historic goals of development in Hawaiʻi have been to move water as fast as possible. (Civil
Hydrology: the study of of the earth’s water and its movement in relation to land
Beat, 2023) This led to the channelization of streams all throughout the islands. The impacts of urbanization, the high percentage of impervious surfaces, and the lack of meaningful green stormwater infrastructure only magnify the issue by preventing water from absorbing into the groundwater and depositing polluted sediment onto reefs and other near-shore habitats.
Who addresses contamination?
The contaminants present were historically regulated and monitored by the government with the foundation of the Environmental Protection Agency. The 1960s brought public awareness to the ramifications of pollution on the environment. Air and water quality were not being monitored, and harmed people and animals living near polluted areas. Founded by Richard Nixon on December 2, 1970, as a response to the growing environmental concerns raised by citizens, the EPA’s goals were to research and respond to pollutants in the environment.
Locally, the Hawaiʻi Department of Health has a Hazard Evaluation and Emergency Response (HEER) Office responsible for monitoring, processing, and cleaning hazardous materials and sites. The HEER Office is divided into three sections that oversee all issues regarding contaminated sites: Emergency Preparedness & Response (EP&R); Site Discovery, Assessment, and Remediation (SDAR); and Hazard Evaluation.
The following are the current policies in place for regulating and processing contaminated sites in the United States and Hawaiʻi:
• The Clean Air Act of 1970 is a federal law in the United States that regulates air emissions from stationary and mobile sources to protect human health and the environment. (US EPA, 2022)
• The Clean Water Act of 1972 is a federal law regulating the discharge of pollutants into the nation’s surface waters, including lakes, rivers, streams, and wetlands, to restore and maintain their chemical, physical, and biological integrity. (US EPA, 2022)
HEER: Hawaiʻi Department of Health’s Hazard Evaluation and Emergency Response
• The Endangered Species Act of 1973 is a federal law that aims to protect and recover endangered and threatened species and their habitats and to prevent their extinction. (NOAA, 2020)
• The Resource Conservation and Recovery Act of 1976 is a federal law regulating the management of hazardous and non-hazardous solid waste from generation to disposal to protect human health and the environment. (US EPA, 2022)
• The Nuclear Waste Policy Act of 1982 is a federal law that establishes a comprehensive national program for the safe, permanent disposal of highly radioactive waste, including spent nuclear fuel, from commercial nuclear power plants. (US EPA, 2022)
• The Comprehensive Environmental Response, Compensation, and Liability Act of 1986, also known as Superfund Law, is a federal law that provides a framework for responding to and cleaning up hazardous waste sites and holds responsible parties liable for the costs of cleanup. (US EPA, 2022)
• The Emergency Planning and Community Right-toKnow Act of 1986 is a federal law that requires state and local governments, and certain industries, to develop emergency response plans and to disclose information about hazardous substances in their communities. (US EPA, 2023)
• The Federal Pollution Prevention Act of 1990 is a federal law that establishes a national policy to promote pollution prevention, reduce or eliminate waste at the source, and conserve natural resources. (US EPA, 2022)
• The Hawaiʻi Environmental Policy Act (HEPA) of 1970 is a state law that requires environmental impact statements for any actions that significantly affect the quality of the environment in Hawaiʻi. (State of Hawaiʻi, 2014)
• The Hawaiʻi Environment and Resource Protection Amendment 23 of 1978 is a state constitutional amendment that establishes the duty of the state and counties to conserve and protect Hawaiʻi’s natural beauty and resources for future generations. (Hawaiʻi State Judiciary, 2023)
What are the types of contaminants?
In this capstone, contaminants are categorized by origin as well as chemical construction. Contaminants can either be organic or inorganic. Organic contaminants are pollutant compounds that typically contain bonds of carbon, oxygen, and nitrogen (Kirkwood and Kennen, 2015). In comparison, inorganic contaminants are elemental pollutants that can be found within the periodic table (Kirkwood and Kennen, 2015).
Contaminants can be further categorized according to the following:
• Pesticides control pests such as weeds, insects, and other wildlife.
• Chlorinated solvents are chemical compounds that are used in industrial activities. Chlorinated solvents are most commonly known as cleaning or degreasing agents and are used in dry cleaners, refrigerants, and other industrial activities.
• Petroleum hydrocarbons are one of the most prevalent contaminants throughout the world. Petroleum is an organic compound used for fuel, plastics, and other uses.
• Persistent organic pollutants are a group of contaminants, including pesticides and industrial chemicals, and can be released during combustion. POPs are known as forever chemicals due to their persistence in the environment for generations.
• Explosives are man-made chemical compounds that can react violently and release a great amount of energy. They can contaminate soil and groundwater and pose a threat to humans and the environment.
• Salts are compounds of ions that can occur naturally or be introduced to the environment through human activities. In Hawaiʻi, the most common salt contamination comes from the Pacific Ocean.
• Nutrients such as nitrogen and phosphorus are essential for plant growth, but excessive levels can lead to eutrophication in bodies of water, resulting in stresses on the environment.
Eutrophication: the process where a body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus
organic contaminants: typically contain bonds of carbon, oxygen, and nitrogen inorganic: elemental pollutants
Forever Chemicals: Peristent organic chemicals that don’t break down in the environment or in our bodies
Sym.
Category of Pollutants
Organic / Inorganic Types
Pesticides Organic
Chlorinated Solvents
Herbicides, Insecticides and Fungicides
Organic TCE, PCE, and organic compounds with a chlorine component
Petroleum Organic Oil, Gasoline, Benzene, Touline, PAHs, and additives such as MBTE
Persistent Organic Pollutants
Explosives
Organic DDT, DDE, PCBs, Aldrin, Chlordane
Common Sources
Agricultural and landscape applications, railway and transportation corridors, residential spraying for termites and pests
Dry cleaners, military activities, industrial uses
Organic
RDX, TNT, HMX
Salts
Inorganic
Sodium, Chloride, Magnesium, Calcium
Fuel spills, petroleum extraction, underground leaky storage tanks, industrial uses, railway corridors, automobile related sites
Agriculture and landscape applications of historic pesticides (pre-1970s), former industry, atmospheric deposition
Military activities, munitions manufacturing and storage
Nutrients
Inorganic
Nitrogen and Phosphorus
Agricultural activities, roadways (snowy climates), mining, industrial uses, ocean
Wastewater, Stormwater, agriculture and landscape applications, landfill leachate
Radionuclides
Inorganic
Radioactive Isotopes: Cesium 127 and Strontium 90
Military activities, energy production, coal burning sites
Metalloids / Metals
Inorganic
Arsenic, Cadmium, Selenium, Nickel, Lead, Aluminum, Boron, Chromium, Copper, Iron, Mercury, Zinc, plus many others
Source: Kennen & Kirkwood, 2015
Mining, Industrial uses, agriculture applications, roadways, landfill leachate, pigments, lead paint, emissions
• Radionuclides are radioactive elements that are present on the periodic table. They can occur both naturally in the environment and can be manmade.
• Metals or metalloids are naturally occurring elements on the periodic table. They can be emitted into the environment through mining, industrial activities, and improper disposal of waste. Metals do not break down and can accumulate in the food chain.
What are the impacts of pollutants and contaminants on people, the environment, and resources?
Contamination threatens natural resources, humans, and the environment regardless of the type. Soil and water that are contaminated can harm any living organism that comes into contact with the polluted resource.
People are regularly interacting with the contaminants that are dispersed throughout the environment. Either through breathing in particulates in the air, drinking or interacting with polluted water, eating food grown in contaminated soil, or interacting with the landscape, people can come in contact with harmful pollutants. Countless studies examine the relationship between environmental contaminants and their impacts on nearby populations, and the results clearly reveal a host of detrimental effects of pollution on a local population, ranging from physical and mental health problems (e.g. cancer and depression) to a loss of the economic and cultural viability of a landscape (no farming; no fun).
Other living things are not immune to the impacts of contamination either. It is especially documented in ocean food chains. Small plankton and microorganisms will consume and absorb pollutants released into the environment. As one progresses through the food chain, the pollutants bioaccumulate and become exponentially more prevalent in higher level predators. Naturally this should be of concern to anyone who is not particularly fond of mercury in their salmon, but perhaps of greater concern is the fact that this progressive concentration of contamination is disrupting, with the violence that only a vicious cycle can provide, the ability of entire ecosystems of species to exist and thrive in their native environments.
Particulate matter: are microscopic particles of solid or liquid matter suspended in the air
Remediation Strategies
Chemical Methods
Biological Methods
03. How Is Contamination Addressed?
What are the forms of remediation?
Remediation of contaminated landscapes can be done in a multitude of ways. When a project responds to contamination, the methods used can be physical, chemical, or biological. The physical ways in which contamination can be dealt with are through soil replacement or capping. Soil replacement is “using clean soil to replace or partly replace the contaminated soil to dilute the pollutant concentration, increase the soil environmental capacity, and thus remediate the soil” (Yao et al.). Soil replacement is a very intensive process that requires a great deal of energy to move soil from the polluted site. The soil that is removed will either need to be stored or processed to clean out the contaminants.
The second physical way in which contaminants can be prevented from moving away from a site is through capping. Soil capping is physically containing and isolating contaminants within the soil. Caps are a protective barrier surrounding the polluted soil to reduce interaction with the environment, people, and water. Capping is the traditional process used in landfills and other waste storage facilities. While caps are successful at containing contaminants, frequent monitoring and maintenance need to occur to ensure no failures of the physical barriers installed. Similar to the soil replacement process, no steps are being taken to treat and clean the contaminants from the soil.
Chemical remediation includes the process of cleaning contaminated soil with additives or chemicals. An
Remediation: the removal of pollution or contaminants from environmental media such as soil, groundwater, sediment, or surface water
Capping: placing a cover over contaminated material; the addition of a physical barrier
on-site chemical remediation method is soil immobilization or encapsulation. Similar to soil capping, soil encapsulation reduces the mobility of the contaminants. By injecting the soil with stabilizers such as cement, lime, or concrete, the contaminated soil is frozen in place to prevent the movement of pollutants. The goal of immobilization/encapsulation is to prevent contaminated soil from leaching into the surrounding water bodies or into the air. The challenge with soil encapsulation is that once the additives have been added into the soil, the land becomes nearly unusable for any natural growth. Another chemical remediation process that aims to restore the viability of the land is soil washing, whereby contaminated soil is transplanted to a processing facility where it can be cleaned. The treatments for the contaminated soil can be thermal or chemical. In thermal treatments, the soil is heated to the contaminant’s evaporation point to release and contain it. Chemical treatments put the soil through a washing process to capture contaminants, using water combined with other chemicals to flush contaminants from the soil. After the treatment is complete, the water solution is stored until processing takes place for disposal. While relatively effective, soil washing requires
Immobilization / Encapsulation: prevention of movement of contaminants
Stabilizer: the addition of chemicals and additives to soil to render pollutants immobile.
costly off-site locations for the processing of contaminated soil, and, as of the writing of this capstone, there are currently no established ex-situ processing sites in Hawaiʻi for the treatment of contaminated soil.
Bioremediation is a process in which natural and living elements decompose, disperse and store introduced contaminants. The ʻbioʻ in bioremediation can take the form of bacteria and microorganisms found in the soil, fungus, and plants. Bioremediation can take place both ex-situ and in-situ. The benefit of using living elements to remediate sites is that “the plants are doing the dirty work” (Halbur, 2010). Instead of the labor-intensive strategies applied in traditional remediation processes, the cleaning is done by living elements.
A sub-category of bioremediation, phytoremediation, is using plants to clean up contaminated environments (US EPA, 2023). In comparison to other forms of remediation, phytoremediation is an aesthetic and ecological approach to contamination. Certain plants, when in contact with contaminated soil or water, will take up pollutants. When plants uptake pollutants, they will either
Bioremediation: the process where living organisms are employed for removing environmental pollutants from air, water, or soil
break them down into less harmful forms, store them within the plant’s structure, or lock them in place (US EPA, n.d.).
Plants with deeper roots are able to uptake contaminants that are deeper in the soil. “Hydraulic control” is another result of phytoremediation; plants have the capability to slow groundwater to prevent it from contaminating clean water sources (US EPA, n.d.).
Phytoremediation is not an effective solution in extremely contaminated soils where no vegetation can grow, or where the concentration of pollutants is so great as to render the process of remediation extremely inefficient.
Phytoremediation: the use living plants to clean up soil, air and water contaminated with hazardous contaminants
Hydraulic control: reduces the movement of contaminated groundwater toward clean areas offsite
Many forms of plants can support the extraction and degradation of contaminants from the soil and groundwater.The different components that make up a plant can respond to the presence of contamination in different ways. Leaves and vegetation break down contaminants and can either store them within the cells or release them into the environment in a less toxic form. While the roots and microbial elements of soil extract, filter and break down contaminants.
Source: Wikimedia Commons
Image Source: UW Press Blog
Image Source: UW Press Blog
Image
Landschaftspark Duisburg-Nord
Firm / Group: Latz + Partner
Location: Duisburg-Meiderich, Germany
Date: 1991
Description: Designed by Latz + Partner and opened in 1991, this former coal and steel plant was transformed into a public park. The design of this contaminated site preserved many visual clues of the history associated with the former plant. In-situ phytoremediation was used as a tool to clean the contaminated soils on site, as well as sequestering and capping the highest toxicity soils. The historic remnants were transformed with new uses and have become a key hybrid-type public space in Duisburg-Meiderich, Germany.
Gas Works Plant
Firm / Group: Richard Haag Associates
Location: Seattle, WA
Date: 1975
Description: Gas Works Park is a former gasification plant run by Seattle Gas Light Company on Lake Union. The plant was operational from 1906 - 1956 and was purchased by the City of Seattle with its closure. The park preserves the visual history of the gasification plant and blends new uses around the old remnants. The soil and groundwater showed traces of contamination. Haag and Associates excavated and capped all the contaminated soil to respond to the contaminants. In addition to the capping, the topsoil was mixed with enzymes and other living organisms to break down contaminants.
Fresh Kills Park
Firm / Group: James Corner Field Operations
Location: New York, US
Date: 2012
Description: Fresh Kills Park in New York is a well-known, recent design project that addresses contamination. Fresh Kills was the site of a landfill that was used by New York City. After September 11, 2001, many of the remnants of the destroyed World Trade Center buildings were relocated to the Fresh Kills Landfill. While the park does not employ phytoremediation as a design strategy, the history and former use are tied into the design. James Corner Field Operations capped the contaminants with an impermeable layer while remediation of any running water with bioswales and retention basins.
Ala Wai Canal Phytoremediation Project
Firm / Group: Marine Agritech
Location: Oʻahu, HI
Date: 2006
Description: In an effort to clean contaminated stormwater that runs into the ala wai canal, Marine Agritech installed floating beds of ‘Akulikuli (Sesuvium portulacastrum). The project was canceled due to a lack of funding but showed successful uptake of heavy metals and nutrients. The largest challenge to the project’s success was weather events disrupting the floating gardens. This local project demonstrated the success of native plants in a remediation application.
Bioreactor Gardens
Firm / Group: Ridge to Reef
Location: Oʻahu, HI
Date: Ongoing
Description: Ridge to Reef, a non-profit organization based on O’ahu, has implemented bioreactor gardens as a solution to reduce the impact of agricultural runoff on the environment. The gardens consist of interconnected chambers filled with plants, sand, and rocks that work together with bacteria to filter nutrients and contaminants. This process results in clean and filtered water that can safely be released into the ocean.
Del Monte Superfund Site
Firm / Group: Del Monte Corp
Location: Oʻahu, HI
Date: 1996
Description: Del Monte’s historic pineapple fields on the island of O’ahu were assessed to have high levels of pesticides and nutrients, leading to the site being designated as a superfund site by the US EPA in 1994. To remediate the contaminants in the soil, a pilot project was developed in 1996 using Koa haole (Leucaena leucocephala), an invasive species, which successfully removed a significant portion of the identified pollutants. Koa haole is one of the only known plants in Hawaiʻi that are capable of extracting pesticides from the soil, making it a valuable component in phytoremediation projects. However, despite the pilot project’s success, the site remains a superfund site due to other contaminants in the soil and groundwater. (US EPA, n.d.)
Image Source: Golder Associates
Image Source: Honolulu Star Advertiser
Image Source: Ridge to Reef
www.histategis.maps.arcgis.com/apps/webappviewer/index.html?id=98d287050aa8497d9e577 9506ad816e9
03. Contamination In Hawai
How is contamination documented?
The Hawai’i State Energy office partnered with the Hawaii Department of Health’s Hazard Evaluation and Emergency Response Office (HEER), the US Environmental Protection Agency (EPA), and the National Renewable Energy Laboratory (NREL) to collect and distribute a database of “Previously developed or disturbed sites in Hawai’i”. Called the Brightfields Initiative, this program is meant to highlight potential sites for renewable energy purposes. The contaminated sites can serve as locations for climate-friendly renewable energy generation. There has been a nationwide program called the National Brightfields Initiative, which focused on addressing three challenges: “climate change, urban revitalization, and toxic waste cleanup.” (Brightfields, 2023) Initially, the National Brightfields Initiative aimed at identifying sites that could be repurposed for photovoltaic energy generation.
The online Hawai’i database provides assessment information, renewable energy potential, present contaminants, historic site uses, land ownership, tax map key (TMK), and more. All data is available publicly and accessible either through an online portal or geospatial data.
Honolulu Harbor and its Impacts on urban surroundings
The Honolulu Harbor has been a key maritime trade and commerce location since the early 1800s. With the discovery of Hawai’i by international traders, the port became a critical stopping point for ships traveling between North America and Asia. In the 19th and early 20th centuries, the harbor was a major hub for the whaling and sandalwood industries, with sandalwood in particular being one of the largest economic resources of Hawai’i. The use of the harbor expanded to be an agricultural and industrial port, with exports of sugarcane and pineapple quickly becoming the two chief monocrops that would engender so much agricultural contamination on the island.
New facilities around the harbor, such as shipyards, food processing, manufacturing, fuel storage and maintenance, were introduced. These new industries brought employment opportunities and housing demands, but also, along with them, of course, new sources of pollution.
During World War II, Honolulu Harbor played a critical role in the Pacific Theater for the United States military, serving as the logistics hub for much of the Pacific Fleet. Furthermore, infrastructure design, owing to the compelling demands of the war, tended to focus on shoot-first-ask-later efficiency that neglected the long term sustainability of the harbor. After the end of the war, the military continued to expand and advertise its presence, with the military’s design preferences often taking priority over more socially
One of the original indicators for contaminated sites is the designation of ʻSuperfundʻ. In 1980, congress established the Comprehensive Environmental Response, Compensation, and Liability Act, or CERCLA. CERCLA enabled the EPA to identify and clean up contaminated sites. The EPA will require responsible parties to clean up the contamination. If no responsible party exists, the EPA will take responsibility. There have been four designated Superfund sites in Hawaiʻi, and one has been removed due to remediation (US EPA, 2023).
While Superfund sites catalyzed contamination remediation, more contamination is present throughout Hawaiʻi. The National Brightfields Initiative enabled the identification of contaminated sites, or brownfields, and consolidated the information into a database. This database is publicly accessible and is updated regularly. One of the challenges with the information is the documentantion of present contaminants. The online data is incomplete but provides information on some contaminant specifics.
Brownfield: land that is abandoned or underutilized due to pollution from industrial use
Existing Urban Conditions
Brightfields Sites
and environmentally responsible alternatives. This tendency, along with the continued industrialization of Honolulu Harbor, which saw an unprecedented number of contamination sources emerge quite rapidly, yielded a troubling situation: an extremely polluted hotspot seemingly without the wherewithal to clean up its own act.
Neighborhood Profile: Kalihi-Palama
The Kalihi-Palama neighborhood is located within Honolulu’s Primary Urban Center (PUC) on the island of Oʻahu. The neighborhood is bordered by the Airport, Moanalua, Kalihi Valley, Liliha/Alewa, and Downtown-Chinatown neighborhoods. The Kalihi- Palama neighborhood lies in the Moku of Kona and encompasses three ahupuaʻa: Kahauiki, Kalihi, and Kapalama. The neighborhood spans Kalihi, Kapalama, and Nuʻuanu watersheds.
According to the US Census in 2010, the population of the Kalihi-Palama neighborhood is 43,805 residents living in an area of 2,765 acres. The population density is 10,139 persons per square mile. 22% of the population is under 18, while 14% is over 65 (US Census, 2010). The Kalihi-Palama neighborhood has one of the lowest median incomes of $46,483 in relation to the remainder of the PUC Development Plan of Honolulu (2019). The neighborhood is primarily industrial, with industry taking up 37% of the land, while residential and commercial land use takes up 20% (PUC Development Plan, 2019). No resorts are in the neighborhood, and only 1% of the area is open space.
The neighborhood has faced a number of challenges, including poverty, crime, and inadequate housing. According to the health trends released by the PUC Development Plan in 2019, Kalihi-Palama has the highest poverty rates, scores highest on the hardship index, has the highest percentage of people with diabetes and stroke mortality, and has the highest percentage of the population participating in food assistance programs compared to other neighborhoods in the PUC. Kalihi-Palama has the highest rates of Native Hawaiian/Pacific Islanders living within the PUC (PUC Development White Paper Report, Public Health Trends, 2019).
“Places of waste are not doomed permanently due to intrinsic physical properties. Unpopular and devalued places can become popular and valuable and vice-versa. Their qualitative value is the result of social valuation, not the cause. ”
- Mira Engler
04. Remediation Network
A remediation network is a phytoremedaiton focused system that is worked into the fabric of the community. Through establishing a system of interconnected landscapes and agents collaborating to respond to contaminants throughout the neighborhood, The network acknowledges existing land uses while envisioning an adapted future that aims to rebuild native ecosystems.
A remediation network aims to provide residents an opportunity to participate in the revitalization of contaminated landscapes. Moreover, an in-situ phytoremediation network in Urban Honolulu showcases the potential of ecological design solutions for complex urban problems. This network develops sustainable and community-driven contamination remediation solutions that can serve as a model for other neighborhoods in Hawaiʻi and beyond. A remediation network consists of three parts: Phyto Hubs, Phyto Sites, and Phyto Corridors.
Phyto Hub
Phyto Hubs are centrally located sites within a neighborhood that support phytoremediation methods in close proximity. These hubs provide opportunities for ex-situ treatment of contaminated soil of sites incapable of in-situ phytoremediation and promote the growth of the remediation network. Remediation networks can expand their potential by testing new and adapted plant species to respond to contamination. Testing new plants can help
expand the plant species available for in-situ phytoremediation. Also taking place in a Phyto Hub is a plant nursery, where climate-adapted plants for in-situ treatment are grown. The sites that can best support Phyto Hubs are identified brownfields or potential brownfields.
While these sites are productive and functioning places, there is an opportunity for people to be a part of the process. Education, public gathering place, and commercial sale of plants can support a private resident’s goals to remediate or capture contaminants from sites near their homes or businesses. The plant materials gathered from the site can be converted to inedible products, processed to consolidate contaminants, or converted into remediation-supporting materials, such as biochar.
Phyto Site
Phyto Sites can take many different forms throughout a neighborhood. Phyto sites are any sites that release contaminants into the environment. The goal of these sites within the remediation network is to capture and contain pollutants emitted from activities within the site bounds. These sites are adapted to respond to existing pollutants and contaminants that have the potential to make their way into the soil or waterways.
The plants and planting styles for each phyto site will differ depending on the use and contaminants present. The sites can either be adapted to maintain their function or to be transformed to become a new community-accessible site. Similar to the phyto hubs, the plants incorporated into the remediation process will be used beyond their on-site application.
Phyto Corridor
The purpose of the Phyto Corridor is to prevent contaminants from moving into the waterways and to capture non-point source pollutants emitted throughout the neighborhood. Phyto corridors can be located along roadways and waterways and can be incorporated into the neighborhood fabric.
Corridors can serve as a preventive checkpoint to capture contamination and extend and support pedestrian access throughout the neighborhood. These spaces will require components that perform as remediation spaces, but new hybrid public spaces can emerge depending on the site’s size.
All three sites follow the following design principles:
• Filter, uptake, and breakdown contaminants that are present in the environment
• Connection of people to the process of phytoremediation
• Re-establishment of the neighborhood ecology
Phyto Hub
The potential identified test site is a brownfield lot that is owned by Liliha Civic Center. (Brightfields Data, 2023) The site is located along Iwilei Rd and N King St. The nearest park is ʻAʻAla Park and the nearest river is Nuʻuanu stream. The site itself sits in between the Department of Human Services, Iwilei Senior Residence, Auto repair shops, and miscellaneous commercial and industrial shops. As documented by the Brightfields data, there are identified traces of PAHs, VOCs, lead, and other metals in soil. Assessment is currently ongoing for the site, but contaminant causes are linked to the Honolulu Harbor (Brightfields Data, 2023).
A multitude of different land uses surrounds the site. Nearby residential properties are single-family homes, a senior high-rise complex, and low-rise public housing. The road along the site’s eastern side is one of the main access points to Chinatown and is a main thoroughfare for commuters.
Historical uses of the site inform the potential contaminants present, as well as surrounding uses. Along the site’s boundaries, roadways release petroleum hydrocarbons and heavy metals into the atmosphere and onto the roadways.
The former rail line used for the transportation of pesticides and fertilizers for agriculture throughout O’ahu is likely still present in the soil strata. Nearby grocery stores, automotive repair shops, and industrial warehouses have the potential to release chlorinated solvents and persistent organic pollutants.
Exisiting: Phyto Hub
As highlighted in the existing section, the site has minimal tree canopy coverage and a high concentration of invasive and ruderal species. Physical barriers in the form of fences surround the border of the site. The site also has remnant concrete and asphalt that has not been removed from previous uses.
The existing ecology of the site is invasive species, such as the cattle egret, chickens, cardinals, and mongeese. As previously mentioned, the vegetation is also nonnative and ruderal.
Near Term: Phyto Hub
Shrub and ground cover plantings respond to contaminants that require the least amount of time for remediation (Chlorinated solvents, pesticides, and petroleum hydrocarbons). In order to respond the most efficiently, soil will be mounded into planted landforms.
The introduced canopy will respond to persistent organic pollutants, heavy metals, and petroleum, capturing, containing, and breaking down the most prevalent and impactful contaminants. While Koa haole is an invasive species, it is required to remediate present pesticides on-site.
To prevent the spread of the invasive species, the workers will monitor the plants through seed harvesting and routine removal. The seeds harvested can be used for lei and wood for woodworking.
In the near-term roadmap, the site will not be accessible to the public and will only be accessed to take soil and plant samples to ensure remediation and plant selection is successful. Plants in the phytoremediation process will have shorter lifespans. Plants that have reached the end of their life will be removed, processed, and replaced.
Long Term: Phyto Hub
Once the soil is mainly remediated, the established hub can be expanded for public access. Nearby residents and users can move around and through the site through a series of circulation paths, gardens, and a plaza.
As a productive space, Phyto Hubs can support ex-situ remediation efforts for contaminated soils from other sites in the neighborhood. Instead of conventional remediation methods that require off-island technologies, contaminated soil can be mounded and remediated. The mounds will be planted with plants adapted to remediate identified contaminants. To prevent human access, vegetative barriers will be installed. The increased canopy and vegetation will reduce urban heat island effects.
In addition to remediation, a plant nursery and testing site will support the expansion of the phytoremediation toolkit. The growth of native and non-invasive introduced species will ensure a steady stock of plants available for use around the neighborhood. Universities and schools can incorporate education and testing into the curriculum to educate students about the remediation process.
A key component of phyto hubs is the education of the public. By establishing on-site offices that manage the sale of plants and help residents clean up contaminants, phytoremediation will become an accessible method for anyone.
Phyto Site
The potential identified test site is an automotive repair business. Located on Dillingham Boulevard, the site is on a main thoroughfare and experiences high traffic. Nearby, surrounding land uses are Oʻahu’s Community Correctional Center, a convenience store, industrial parts suppliers, and single-family homes. While no identified contaminant specifics are listed in the Brightfields Data, the site has hazards that need to be remediated (Brightfields, 2023).
The site’s location along the High-Transit Corridor directly impacts users. Busy roadways and minimal sidewalks create an unfriendly pedestrian experience. In addition, nearby homes and industrial shops increase vehicular traffic.
Surrounding and existing land use provide a picture of potential contaminants on site. The site’s nearby roadways and automotive focus produce petroleum hydrocarbons, heavy metals, and chlorinated solvents. The nearby roadways also contribute to auto-related contamination. In addition, nearby residences contribute pesticides and nutrients from lawn care.
Exisiting: Phyto Site
As a functioning business, the site has very minimal vegetation. The barriers to differentiate between public and private spaces are chain link fences. There are no ways to capture water or runoff from the site, leaving no barrier for the contaminants to make their way down the roadway.
Near Term: Phyto Site
Unlike other proposed designs, Phyto Sites will be accessible in the near-term processes. Physical barriers will be replaced with vegetative ones to adapt the business to preserve visual presence as requested by the business owners.
Plant selection prioritizes contaminants from current site activities. Near building footprints and roadways, depressed planters will be installed to capture runoff. The site owners are responsible for the removal of plant material and disposal. However, HEER or other state/city & county entities will be available to test soil and plant materials.
Long Term: Phyto Site
Phyto sites have the potential to continue functioning as businesses and residences in the neighborhood, but there is an opportunity to transform these once-contaminated lots into new public spaces.
With the transition away from fossil fuels, automotive-focused sites will no longer be as demanded by residents and can be converted to open space to support multimodal transportation. Because of its location along a transportation thoroughfare, this site will be transformed to become a new bus shelter for residents and commuters.
In addition to the shelter, new circulation will cut through the site, removing users from the dangerous high-frequency roadway. Canopy and groundcover planting will respond to remnant contaminants on-site and other contaminants from nearby houses. Increased tree canopy will also reduce urban heat island effect. Introduced paving will be permeable to direct water off the streets and away from further contamination.
Phyto Corridor
Phyto corridors are located along roadways and waterways to capture non-point source contaminants. The potential identified test site is a waterfront lot along the Kapalama Canal. The site is currently being used as a methane distribution center for the island of Oʻahu. Historically, the site was used to house petroleum storage tanks. The site is located along N Nimitz Highway and is on Pier 38. Brightfields data has identified petroleum, heavy metals, and methane in the soil.
The site itself is in the highly industrial waterfront area of the Honolulu Harbor. It is currently being used as a methane distribution hub. Adjacent to the distribution site is a brownfield that once housed petroleum storage tanks. The Pier is a tourist destination for visitors and is surrounded by parking lots. Across the Kapalama Canal, there is one of the main distribution centers for Matson, bringing imports to Hawaiʻi.
Apart from the present petroleum and heavy metals from historical and current surrounding uses, the site is impacted by nearby industrial warehouses. These industrial warehouses release chlorinated solvents, along with previously identified pollutants. In addition, the site location along the harbor introduces salts from impacted brackish groundwater and ocean connection. Waters running downstream are likely filled with nutrients from runoff throughout the watershed.
Exisiting: Phyto Corridor
The current waterfront conditions enable rapid movement of contamination while preventing pedestrian access. The largest barrier between the site and the road is a large concrete wall, a remnant of previous use as a petroleum storage site. The shoreline is eroding and is overrun with invasive mangroves.
There is some existing vegetation on the site of Hau and coconut palms. Besides the canopy, the ground cover is comprised of ruderal and invasive species.
The only site users currently are security staff, employees of the methane company, and ship workers that dock at the adjacent pier.
Near Term: Phyto Corridor
In order to create immediate checkpoints for contaminants and runoff from the roadways, the shoreline will be reconstructed to feature remediation terraces. The terraces will be planted with sedges and native wetland species that begin to remediate contaminants requiring a shorter remediation time (chlorinated solvents and nutrients). The terraces have a sunken center to capture water and prevent runoff before being absorbed into the soil.
Canopy will be introduced to begin the remediation processes of the contaminants that require longer timeframes for removal. All plants selected for this test site are salt-tolerant due to the proximity to the ocean and the brackish groundwater.
Near-term responses will limit public access to preserve the health of users. University faculty, HEER Staff, or City & County of Honolulu Parks workers will monitor all remediation sites in the initial remediation processes. Soil testing, plant testing, and plant maintenance will occur regularly to ensure the design’s success.
Long Term: Phyto Corridor
Phyto corridors can become hybrid spaces of remediation and public activity. Constructed wetlands will be introduced to capture contaminated runoff while providing a habitat for native wetland species. All planting will be salt tolerant and can handle wet soils.
New wooden boardwalks will be incorporated throughout the site to expand pedestrian waterfront access and connect the roadway to Honolulu Harbor. Due to its proximity to a tourist landmark, the new proposed site will offer a plaza to be used by workers and visitors (not pictured). Vegetative barriers will be incorporated to protect park users from plants that potentially have a higher concentration of contaminants in their structure. The terraces will be maintained but not directly accessible to the public. The only access point is a boardwalk viewing platform. All sites will be monitored and tested to ensure remediation success. All removed plant material will be processed to consolidate contaminants and prevent re-introduction into the environment.
“We stand now where two roads diverge...The road we have long been traveling is deceptively easy, a smooth superhighway on which we progress with great speed, but at its end lies disaster. The other fork of the road — the one less traveled by — offers our last, our only chance to reach a destination that assures the preservation of the earth.”
- Rachel Carson
05. Beyond Remediation
The remediation network proposed aims to provide residents an opportunity to participate in the revitalization of contaminated landscapes. Moreover, an in-situ phytoremediation network in Urban Honolulu showcases the potential of ecological design solutions for complex urban problems. This capstone project contributes to developing sustainable and community-driven contamination remediation solutions that can serve as a model for other neighborhoods in Hawaiʻi and beyond.
There is potential for remediation to be something other than a niche or scientific practice reserved for removed locations. While different stakeholders will still need to be involved in the remediation process, this new proposed network will introduce the public and residents to the remediation process. Community involvement cements that the path to healing the earth will be a priority.
As a society, we are responsible for repairing and restoring our contaminated landscapes, protecting residents’ health, and ensuring the health of neighboring ecologies. Remediation of contaminated sites will allow for re-establishing a healthy neighborhood and creating more livable and sustainable communities. Beyond remediation, this capstone proposes a new relationship with the land, prioritizing the future as much as the present.
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