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Soil Pollution in Local Brownfields of Suzhou
Abstract:
Worldwide industrialization has led to soil health impairment in urban and peri-urbanenvironments mainly via contamination with heavy metals. In this study, levels of soil contaminationand other soil health properties were investigated in soils from three brownfield sites located in Xiangcheng District, Suzhou, China were investigated in comparison with soil from a nearby RicePaddy Field uninfluenced by industrial activities. A combination of field-based qualitative methods(Tea Bag Decomposition Test, Rice Trap Test, Sesame Root Measurement) and lab-based uantitativeanalysis (Soil Texture Analysis, Soil pH Test, H2O2 Effervescence Test, ICP Heavy MetalAnalysis) methods were employed to evaluate the influence of soil capping on contamninated soils atthe three industrial sites. activities and soil capping policy in these areas. Compared to the Rice PaddyField, soils from all three brownfield sites display compromised physical, chemical, and biologicalproperties. Extremely high Ca content was found in two of the brownfield sites, potentially resultingfrom the accumulation of construction and demolition waste. Although ICP Elemental Analysis resultssuggest that soil capping practices were shown to effectively mitigate heavy metal exposure, severalhigher-than-normal concentrations of Cr, Cu, Cd, As were still present. It is proposed toimplement agricultural activities and revegetation to help enhance soil quality at brownfield sites. Thisresearch suggests that nature-based solutions, consistent monitoring, and agricultural developmentcould be conducted in the study sites to mitigate industrial-driven soil degradation in Xiangchengbrownfield sites.
Keywords:
Soil Degradation, Heavy Metal Pollution, Soil Capping, Industrialization, Brownfield, Phytoremediation.
Research Details:
I conducted this research from June, 2025 to September, 2025. At that time, I was motivated to spend the summer studying wider soil pollution issue in my hometown, inspired by soil pollution issue observed in the School Garden's wasteland.
Before starting, I self-led field trips to local brownfield sites in the peri-urban industrial zone of Suzhou. I asked my parents for their insights towards soil pollution in Suzhou, and read governmental report. I gained a brief understanding of the soil pollution situation, and took a lot of pictures there.
In my research, I select three local brownfield sites and one local Rice Paddy Field sites (as a control group) to collect composite soil samples from. I designed 7 experiments to analyze and compare the soil quality in these four sites.
Working in lab, I used ICP-OES analysis to analyze their heavy metal concentrations.
(I worked on lab conducting soil experiments.)
Working at field, I collected composite soil sample, installed self-made tea bags to assess the soil microbial activity, and installed pitfall traps to assess vertebrate diversity.
(I worked on local field sites collecting soil samples and installing tea bags.)
After the research, I wrote a brownfield remediation proposal for local government. In the government's response, they wrote:
"The proposed solutions demonstrate strong feasibility and align well wth actual policy-making needs. The study has been conducted in-depth, and the research paper is of high quality, making the proposal instructive for operational context"
When finishing the research, I understood that "soil capping" actually can effectively control the exposure of pollutants in soil - a counterintuitive result from my initial perception. However, industrial activities do degrade soil health from multiple aspects.