The Optimization Strategy of the Existing Urban Green Space Soil Monitoring System in Shanghai, China

Weiwei Zhang,Yin Ren,Jigang Han,Abiot Molla,Shudi Zuo

doi:10.3390/ijerph18094820

Abstract

High concentrations of potentially toxic elements (PTE) create global environmental stress due to the crucial threat of their impacts on the environment and human health. Therefore, determining the concentration levels of PTE and improving their prediction accuracy by sampling optimization strategy is necessary for making sustainable environmental decisions. The concentrations of five PTEs (Pb, Cd, Cr, Cu, and Zn) were compared with reference values for Shanghai and China. The prediction of PTE in soil was undertaken using a geostatistical and spatial simulated annealing algorithm. Compared to Shanghai’s background values, the five PTE mean concentrations are much higher, except for Cd and Cr. However, all measured values exceeded the reference values for China. Pb, Cu, and Zn levels were 1.45, 1.20, and 1.56 times the background value of Shanghai, respectively, and 1.57, 1.66, 1.91 times the background values in China, respectively. The optimization approach resulted in an increased prediction accuracy (22.4% higher) for non-sampled locations compared to the initial sampling design. The higher concentration of PTE compared to background values indicates a soil pollution issue in the study area. The optimization approach allows a soil pollution map to be generated without deleting or adding additional monitoring points. This approach is also crucial for filling the sampling strategy gap.

Highlights

The quality of the urban ecosystem depends on the green space soil quality
Urban areas become the sources of various pollutant elements that can be accumulated for an extended period of time in the soil [4,5,6]
The main objectives of this work were as follows: (i) Evaluate the concentration levels of five potentially toxic elements (PTE) (copper (Cu), zinc (Zn), cadmium (Cd), chromium (Cr), and lead (Pb)) in green space soil; (ii) improve the prediction accuracy of the initial sampling design using an optimization strategy, and showing methodological approaches how to generate of soil pollution map without the extra expense

Summary

Introduction

The quality of the urban ecosystem depends on the green space soil quality. Urban areas become the sources of various pollutant elements that can be accumulated for an extended period of time in the soil [4,5,6]. Studies on the concentrations of potentially toxic elements (PTE) in urban soils, previously known as heavy metals, started in the 1960s and identified massive heavy metals sources of urban soil pollution [4,5]. The origins of PTE in urban soils are natural and anthropogenic. The coefficients of variation (CV, %) for Pb, Cu, Zn, and Cd were higher, meaning more significant variations among the urban green spaces soils (Table 1). The high CV of Pb, Cu, Zn, and Cd suggests soil pollution sources in urban green spaces are from anthropogenic sources [65].

Objectives

Methods

Results

Conclusion