The rise of urban agriculture through municipal farms and gardens has provided a strategy to cope with the food needs of a rapidly growing population [1
]. In 2014, 54% of the world’s population lived in urban areas, and this proportion is projected to increase to 66% by 2050 [3
]. In 2008, roughly one million households in the United States were involved with some community gardening efforts [4
]. The use of local garden-grown food has also improved cost-savings by reducing the need to buy produce at grocery stores [5
]. Previous community-engaged studies have cited an increase in the consumption of fruits and vegetables and a decrease in the consumption of packaged foods among individuals with access to an urban garden [5
]. Shared gardens also provide an outlet for community members to engage with each other regularly as they share tools, cultures, and ideas. Previous studies have found that community gardeners often work collaboratively with each other and frequently share gardening tips and ideas among their network [5
However, because of the nature of cities, urban gardens are more likely than suburban and rural gardens to be near areas with high pollution, such as industrial sites and roads [12
]. Municipal soils typically have higher levels of heavy metal and metalloid (HMM) contaminants than non-municipal soils due to human activity, such as fossil fuel use, waste incineration, construction with lead-based paints, and mining and smelting [13
]. Lead, cadmium, mercury, and arsenic are four HMM often associated with soil contamination [15
]. Gardening increases individual exposure to these HMM through finger-to-mouth contact in children who have been playing in contaminated soils [16
]. Gardeners may also consume the produce grown in contaminated soils or track it into their house when they do not thoroughly wash their hands or clean their shoes [4
]. Ramirez-Andreotta et al. (2013) [18
] found home gardeners near mining sites were susceptible to lead contamination in their food and recommended that they test their soil and modify their behaviors to limit soil ingestion.
Lead has severe health consequences, especially for neurobehavioral-cognitive performance, such as irritability, memory loss, antisocial behavior, and reduced intelligence quotient (IQ), and attention span [19
]. Exposure to arsenic is linked to increased risk of cancer, neurological and behavioral conditions, diabetes, and hearing loss [22
]. Despite the health risks associated with HMM, community awareness of soil contaminant risks and remediation sources is limited, partially due to lack of educational resources [19
]. Kim et al. (2014) [12
] found that while most gardeners in Baltimore, Maryland were aware of lead as a soil contaminant, they were less aware of other HMM, such as arsenic and cadmium. In another interview-based study by Johnson et al. (2016) [24
], fewer than 50% of gardeners in predominantly African American and Latino communities were aware of and concerned about the potential health effects of lead in their soil.
Further exacerbating the issue, HMM can generally remain in soils indefinitely without degrading, and remediation techniques are often costly and difficult to carry out [25
]. Therefore, contaminated soils and crops must be treated and managed to remove HMM and reduce the risk of negative health effects for gardeners. For instance, through phytoremediation, certain plants grown in contaminated soils can extract and remove HMM from the soil [25
]. Other remedial management options include surface capping, encapsulation, electrokinetic extraction, soil flushing, chemical immobilization, bioremediation, and soil washing [27
]. These techniques employ both in-situ strategies, which treat soil on-site and are usually cheaper options, or ex-situ strategies, which require contaminated soil to be removed from its original site and transported to secure treatment facilities but at a higher cost [27
]. Remediation can take place through physical, chemical, electrical, thermal, or biological treatment options [27
]. Previous research from Tacoma, Seattle, and Kansas City found that urban gardeners had minimal confidence in their knowledge of and proper access to resources for soil contamination [28
]. Moreover, soil testing for urban gardeners is limited, and many urban gardeners lack appropriate knowledge regarding the methods for finding a soil contaminant testing lab [19
]. Without awareness of soil contamination risks, community gardeners may be unlikely to seek soil remediation.
Differences in exposure to environmental harms and unequal distribution of resources are two factors that influence the need for environmental justice. These differences may be due to variations in socioeconomic status, gender, race and/or ethnicity, age, and family structure [29
]. Differences in these areas may affect one’s ability to cope with environmental hazards, including hazards of soil contaminants in the built environment and improper industrial waste disposal in low-income communities. In many cities, HMM contaminants and industrial hazards have also afflicted certain racial groups disproportionately [30
]. For instance, predominantly low-income African American communities in Chicago, Illinois, and Flint, Michigan, have experienced exceptionally high levels of childhood lead poisoning [31
]. Improved food security and nutrition also reduce environmental health inequalities and promote environmental justice by providing a secure source of healthy produce to the often disadvantaged communities [33
The census shows that poverty has been substantially increasing in Atlanta [35
]. Additionally, neighborhoods in Atlanta are vulnerable to sources of HMM contamination. Deocampo et al. (2012) [36
] suggests that emissions near roads have resulted in high levels of lead in road dust. Atlanta has also historically been home to industrial sites, such as the Atlantic Steel Mill.
Peters (2019) [37
] sampled sites in West Atlanta to measure baseline HMM soil contamination in the area. Of these sites, several were found to have lead contamination that exceeded the Environmental Protection Agency (EPA) residential screening limits. Slag, a metal waste scrap created during the smelting or refining of metal ore, was also discovered in August of 2018 in West Atlanta. Slag can leach HMM contaminants into soil and plants, which can then be transferred to animals and humans who consume these plants [38
]. Large quantities of slag are especially likely to be dumped in areas of the U.S. where iron and steel mills have historically been located [39
Given the detection of slag dumpsites in the neighborhood, this study sought to understand the knowledge of potentially vulnerable residents better. Additional research in this area could help determine whether different levels of knowledge are associated with different levels of exposure. Through surveys and follow-up interviews, our study was conducted to explore whether Atlanta community and home gardeners were aware of soil contaminant sources and potential remediation options. Special consideration was given to using the research as an outlet for educating community members on HMM exposure, dietary-related personal health, and soil health (the capacity of soil to sustain plants, animals, and other components of the ecosystem). In the past, many researchers have not reported information or educational materials to study participants to promote environmental health literacy [40
]. However, such studies provide an opportunity for researchers to educate community members about environmental health risks and potential opportunities for improvement. This study sought to integrate educational opportunities to provide community members and urban gardeners with these benefits.
2. Materials and Methods
Surveys were collected from January 2019 to March 2019 throughout the Atlanta area, with a focus on gardeners associated with Historic Westside Gardens Atlanta, Inc. (HWG). HWG is an organization dedicated to providing individuals in West Atlanta with resources and education necessary to develop and maintain community and home gardens. The anonymous survey had 37 questions and asked a combination of general demographic and personal knowledge/awareness questions. The survey took 10–20 minutes for each study participant to complete. There was a combination of multiple-choice and open-ended/short answer questions. Demographic questions asked about age, race, number of children in the household, and average annual household income. At the end of the survey, participants were given the option to provide their contact information for follow-up, individual interviews. Each interview was recorded with the permission of the interviewees, and all interviews were transcribed for analytical purposes. Interviews were conducted either in person or by phone, and nine interviews were conducted in total. Quotes from interviews were used as supplements to surveys to support and/or refute findings from survey data.
Both paper surveys and online surveys were offered to gardeners to increase the response rate for potential participants who did not have access to a computer and/or internet. Study participants and gardening organizations were contacted through a variety of methods to increase the diversity of potential participants. The American Community Gardening Association’s database of community gardens in Atlanta was used to recruit many of the community gardeners who participated in the study. We contacted 48 community gardening organizations to reach a variety of gardeners and obtain an adequate number of responses. Surveys were also administered at weekly HWG meetings and during an Atlanta Science Festival (ASF) event at an HWG growing site. To increase survey response rates, we sent gardeners and gardening organizations follow-up reminders requesting participation and informed them of how their feedback would be used.
Inclusion criteria for participants were to be at least 18 years old, residents of Atlanta, and actively engaged in either a community garden and/or a home garden. Each participant signed written consent forms before the study was administered. Participants were informed that their names would not be directly associated with any quotes included in the study. Community researchers and representatives from HWG who help lead community and residential gardening efforts were included in the development of research questions.
Participants were asked to describe prior knowledge of HMM soil contaminants and their health effects, as well as whether they felt that they had adequate resources to learn more about the contaminants. When developing outline questions for the interviews, special consideration was given to previous research and best practices regarding the use of social science methods for environmental health studies [41
]. A full list of the survey questions can be found in Appendix A
Participants were not offered direct compensation for engaging in the study. However, they were encouraged to collect soil from their yards and gardens to bring to the ASF event for free HMM contamination testing. Participants were also offered help with collecting these soil samples and transporting them to the ASF event for testing to make the process and survey more accessible to as many participants as possible.
Based on past studies and knowledge of common gardening practices in Atlanta, we hypothesized that individuals participating in community gardens would be more aware of the health effects of heavy metal soil contaminants and possible remediation strategies than individuals participating only in private home gardens. This hypothesis was made under the assumption that community gardens may provide more opportunities for education regarding gardening and urban agriculture.
2.1. Social Science, Community Education, and Outreach
Social science methods, such as surveys and interviews, provide forums for researchers to gather a variety of thoughts and opinions to understand how a community feels and behaves as a whole. For instance, individual interviews are beneficial because researchers can ask more specific questions about personal matters, such as health or income [41
]. Lobdell et al. (2005) [43
] suggests that social science can play a key role in environmental health studies, especially studies that seek to identify risk perceptions of environmental exposures and develop awareness for limiting exposure to harmful environmental contaminants.
Given the outreach-based objectives of this study, each survey concluded with details on attending the ASF event. Participants recruited at the ASF event were provided with additional information about the opportunities at ASF for education and outreach related to HMM contamination. Each participant was given a flyer for soil testing at ASF, and each participant was offered educational handouts provided by the Centers for Disease Control and Prevention, the Agency for Toxic Substances and Disease Registry, and the EPA. Handouts provided information on safe practices for gardening in HMM contaminated soils, effective methods to protect oneself and one’s children from lead poisoning, and ways to recognize lead poisoning. All participants were provided with contact information for researchers so they could ask follow-up questions. Various resources were also posted on the project website at https://atlsoilsafety.com
The study concluded with an outreach event at a final ASF event, entitled “Getting Dirty: Exploring Soil on Atlanta Farms” on May 9th, 2019. The event included an urban farm tour focused on soil contamination and remediation education, as well as a booth where community soil samples were analyzed with x-ray fluorescence. All participants received seeds and a garden startup kit for attending the event.
2.2. Coding and Statistics
A codebook was developed in the programming language R (Version 3.5.1, R Foundation for Statistical Computing, Vienna, Austria) based on the survey questions and patterns from the initial responses [45
]. Questions with multiple-choice answers were combined into one categorical variable for analysis rather than multiple binary variables. Results were compiled to a complete data set including questions, question numbers, and all responses in a readable format. Upon review of final survey responses, the coding schema was adjusted accordingly.
Survey responses for categorical questions were sorted into categories by two researchers. The two researchers compared their groupings and ensured that groupings matched before finalizing them. For questions asking whether participants were or were not aware of health effects/sources of exposure to HMM soil contaminants, follow-up questions were included to ensure that participants who answered “yes” were correct in their knowledge (Q22/Q23, Q24/Q25, and Q27/28 in Appendix A
). Researchers checked these follow-up answers to ensure that participants who indicated “yes” but incorrectly described health effects/sources of exposure were not counted as aware and were grouped with those who originally answered “no” instead. Fisher’s exact test was used to analyze qualitative/categorical data statistically.
Follow-up interview quotes best-representing themes from the survey results are also included in the results section. These quotes exemplify the main patterns detected through coding the survey responses.
2.3. Ethical Considerations
All study protocol, interview/focus group questions, and flyers were reviewed and subsequently approved by Emory University’s Institutional Review Board (IRB). All participants were informed that they were not required to answer any survey questions that they did not wish to answer and had the right to withdraw at any time. Participants were also informed that their names would not appear in any report or publication from this project.
4.1. Main Findings
Many participants seemed to express some concerns with the possibility of HMM contaminants, especially when describing the adverse health effects. Despite this, nearly 80% of participants were unconcerned with eating and buying produce grown in urban gardens. Interviews revealed that many respondents had never had their soil tested, even those who lived in former industrial sites. For some, this was a result of never thinking that soil testing was necessary, and for others, this was a matter of convenience. Given these findings, it is possible that while participants are aware of the health effects of HMM, they do not think that the amount of contamination is high enough to pose a significant risk to their health. Even though they have not had their soil samples tested to prove that it is safe, they did not believe the level of contamination would have a significant impact on them. Improved access to soil testing through cheaper and closer facilities and/or programs may help to better connect gardeners to the quality and safety levels of their soil on a more individualized level.
It is also worthwhile to recognize that the majority of participants were unaware of possible sources of exposure to soil contaminants. For example, participants indicated varied knowledge of slag as a potential source of soil contamination. Local extension offices and community organizations should consider educating gardeners about possible sources of exposure. It would also be beneficial to inform gardeners of personal actions that they can take to reduce exposure, such as thoroughly washing produce, keeping garden plots far away from industrial sites and busy roads, and leaving garden tools outside of the home. Such actions can reduce harmful exposures, regardless of the awareness of whether contaminants exist in high concentrations.
These findings closely support previous studies conducted. For instance, Kim et al. (2014) [12
] identified low levels of concern and knowledge about HMM contaminants and a lack of confidence in the ability to reduce exposure and remediate soil. Both this study and Kim et al. (2014) [12
] found that lead was the most frequently described contaminant because respondents infrequently mentioned other trace metals, such as arsenic. In both studies, the lack of confidence in listing potential soil remediation practices was particularly noticeable. Some interviewees in this study mentioned that they refrain from growing produce in a certain area if they find out the area is contaminated, and Kim et al. (2014) [12
] likewise found that 50% of respondents view this as an adequate form of remediation. Both studies found that urban gardeners generally lacked knowledge regarding other remedial practices, such as phytoremediation. Unlike Kim et al. (2014) [12
], however, this study found that respondents generally preferred indirect education tools, such as handouts and online information hubs, rather than interactive, in-person outreach. Additionally, the findings of this study closely resemble those of Harms et al. (2013) [28
], who found that urban gardeners had minimal confidence in their knowledge of remedial resources.
Particular attention should be paid to differences in findings between racial groups throughout this study. Some risk assessments of different racial groups were negligible. For instance, black/African American respondents were only minimally more concerned about the health effects of HMM in soil. The difference in responses between black/African American respondents and white/Caucasian respondents in this area was not large enough to draw a valid conclusion. This finding contrasts Wong et al. (2018) [46
], suggesting that black/African American individuals are significantly more concerned with soil contamination. This contrast may be due to the location of the study or the level of education and knowledge among participants.
However, in some cases, differences in survey results from various ethnic groups were more noticeable. White/Caucasian participants were much more likely to answer that they were aware of the health effects of HMM. This information is important to determine which racial groups and communities in metro-Atlanta should be targeted more for intervention strategies. Based on these results, black/African American communities may be more likely to benefit significantly from additional outreach efforts, such as classes, events, and educational materials regarding the health effects of soil contaminants and remediation efforts.
This study also found that home gardeners tended to be much more aware of the potential health hazards of HMM in soil, compared to community gardeners. This finding is supported by the fact that home gardeners were much more likely to cite health as a significant benefit of engaging in gardening than community gardeners were. Since home gardeners were more likely to view improved health as a benefit, they may have been more likely to educate themselves on the health outcomes related to gardening. Future studies should seek to understand better why home gardeners are more likely than community gardeners to view health as a benefit.
Community gardeners, more so than home gardeners, therefore, may also greatly benefit from additional outreach and education efforts. Differences in awareness between the community and home gardeners regarding sources of exposure and remediation methods were minimal. However, home gardeners appeared to have a significantly greater understanding of the adverse health effects of HMM. This outcome was surprising, especially because community gardeners frequently cited education and the sharing of knowledge and information as perceived benefits of working and/or volunteering in community gardens. This difference in knowledge could potentially be attributed to home gardeners engaging in more independent research on the subject rather than relying on the knowledge of their neighbors and community members. For home gardeners working with HWG, this may be due to their close interaction with community garden leaders who provide information about health, the environment, and gardening. Future studies could determine whether this is true through surveys and focus groups with community members. High-income participants were less likely to believe that HMM was a very high risk to their health. This result may be because high-income participants did not live in areas with high pollution, but further research is also needed to determine whether this is true.
During interviews, participants brought up factors that may be important to address to improve awareness of this topic. For example, one participant addressed the fact that many gardeners in her community were reluctant to seek soil testing because they would not be able to remediate their soil or find other, uncontaminated plots of land to garden. This suggested that more focus should be placed on educating individuals about how they can easily access low-cost remediation resources. If individuals understand that remediation efforts are feasible options for them, they may be more inclined to test their soil for contaminants. Findings from Hunter (2019) [47
] suggest that resources and training are important factors that influence the likelihood of community gardeners shifting their behavior to create healthier soil. Hunter et al. (2019) [48
] also found that individuals would like to have more access to HMM soil testing, but were unable to due to lack of time and ease in doing so.
The results from this study suggest a potential need to communicate and educate health exposures, soil testing, and remediation methods related to HMM better. Citizen science programs such as VegeSafe have provided free soil metal screening to communities, allowing researchers to gather data on HMM soil exposures, which they then report to community members. The program also advises community members on solutions if soils contain high levels of HMM [49
]. Tools such as this one may benefit urban gardeners.
The event “Getting Dirty: Exploring Soil on Atlanta Farms” at the ASF proved to be a successful outreach event that attracted 250 residents of metro-Atlanta, as well as individuals interested in beginning gardening. This outreach event, which provided a combination of both hands-on activities such as soil testing, as well as more informal opportunities to hand out educational flyers, allowed over 50 Atlanta residents to have their soil tested. Results from soil testing led to an Environmental Protection Agency (EPA) investigation and later excavation of HMM contaminated soil. This study provides information that supports the need for further outreach efforts. It also suggests black/African American communities should be targeted, as well as identifying which outreach methods should be used to most effectively improve awareness of HMM. The study also indicates that resources for soil testing and remediation should be more widely publicized and more accessible to urban gardeners.
4.2. Concerns and Limitations
Recruiting a large group of participants for the study was a challenge, and the sample size for the study was relatively small. This limited the extent to which these results can be generalized to other urban areas and to residents of Atlanta who did not participate in the study. Given the relatively small sample size, it was difficult to infer statistical significance. While this study can help to provide a broader understanding of community gardeners’ awareness of HMM, future studies should seek to gather a larger sample size. Differences in demographic characteristics between study participants and all residents of Atlanta may limit the generalizability of these findings to the population that gardens in Atlanta. According to the U.S. Census, 40.3% of Atlanta residents were white, and 51.8% were black or African American in 2018 [50
]. These percentages are different than the demographic data found in our study population (61% white, 26% African American). This result may be because the demographic data of Atlanta gardeners is different from the demographic data of all Atlanta residents. The data from Hunter (2019) [47
], which focused on garden leaders in Atlanta, had similar racial profile as ours (69% white, 27% African American), which supports this argument.
The participants included in the study may have also skewed the data. Researchers attempted to contact a wide and diverse range of respondents through the American Community Gardening Association’s database and by collecting surveys at the ASF event, which was open and advertised to all Atlanta-area gardeners. However, many of the gardeners may still have been associated with HWG, which could have limited the ability to accurately generalize results to communities and residents outside of this organization with confidence. Additionally, participants recruited at the ASF or through HWG may have already received some information about HMM exposure from ASF events or HWG meetings.
Since most respondents were either black/African American or white/Caucasian, it was especially difficult to compare data across races. For this reason, we were unable to draw valid conclusions about American Indian/Alaskan Native, Asian/Asian American, and Hispanic, Latino participants. Instead, we compared data across demographic factors that were more varied, such as average annual household income and type of garden participated. Additionally, it was possible that the knowledge of HMM soil exposure was correlated with the decision to participate in a garden. Under these circumstances, individuals with concerns about HMM exposure may have chosen not to participate in gardening and would not have been represented in this sample.
A third possible limitation of this study is the non-response error. Given that gardeners provided with the survey were not required to complete the survey, some potential participants may have chosen not to participate in the study due to time constraints or disinterest. Some may also have been discouraged from completing the entirety of the survey due to its length. Future studies should minimize this error by attempting to recruit a larger number of respondents from the sample to obtain a normal distribution.
4.3. Opportunities for Future Studies
There are many opportunities for future studies related to measuring community awareness of HMM and determining best practices to improve awareness in communities in the future. Other social science methods, such as focus groups, can be used to continue to analyze community awareness of soil contaminants. A greater number of studies regarding this topic will help to validate the data by reaching a broader sample size and a wider variety of participants.
It is important for future research to compare the information gained through this study with the measured levels of HMM in the soil of various Atlanta communities. This study did not gather information on whether respondents had their soil tested for HMM contaminants before, and what the results of the tests were. Researchers could distribute surveys to fill this gap in information, and they could also sample soils in metro-Atlanta gardens to determine if any areas with low levels of knowledge regarding soil contaminants had high levels of contamination. This research is important to effectively target outreach efforts to vulnerable populations.
This study’s scope was limited to the metro-Atlanta area. Therefore, it is also important that follow-up studies be conducted outside of Atlanta. Other urban areas may have different levels of HMM, and thus, may have greater community awareness of these contaminants. Additionally, interventions may differ between cities. Future research should be conducted in previously unstudied areas to determine whether the results of this study were specific only to Atlanta. Additionally, it would be interesting to study related topics, such as gardeners’ cost threshold to have their soil tested or how far they would travel to do so.
Given that urban agriculture has many benefits and is growing more popular, it is important to understand better how to improve the safety of gardeners. Additional studies can help to understand which areas gardeners lack knowledge concerning HMM. This information can then be used, especially in conjunction with outreach efforts, to inform community organizations on how to better educate gardeners and policy-makers on how they can make urban agriculture sites safe and soil testing more accessible, as well as individuals on how they can continue to garden safely. Such studies are especially significant to target the most vulnerable populations and efficiently improve the safety and well-being of urban gardeners.