Avian Conservation Areas as a Proxy for Contaminated Soil Remediation.

Wei-Chih Lin,Tsun-Su Ding,Johnathen Anthony,Yu-Pin Lin

doi:10.3390/ijerph120708312

Abstract

Remediation prioritization frequently falls short of systematically evaluating the underlying ecological value of different sites. This study presents a novel approach to delineating sites that are both contaminated by any of eight heavy metals and have high habitat value to high-priority species. The conservation priority of each planning site herein was based on the projected distributions of eight protected bird species, simulated using 900 outputs of species distribution models (SDMs) and the subsequent application of a systematic conservation tool. The distributions of heavy metal concentrations were generated using a geostatistical joint-simulation approach. The uncertainties in the heavy metal distributions were quantified in terms of variability among 1000 realization sets. Finally, a novel remediation decision-making approach was presented for delineating contaminated sites in need of remediation based on the spatial uncertainties of multiple realizations and the priorities of conservation areas. The results thus obtained demonstrate that up to 42% of areas of high conservation priority are also contaminated by one or more of the heavy metal contaminants of interest. Moreover, as the proportion of the land for proposed remediated increased, the projected area of the pollution-free habitat also increased. Overall uncertainty, in terms of the false positive contamination rate, also increased. These results indicate that the proposed decision-making approach successfully accounted for the intrinsic trade-offs among a high number of pollution-free habitats, low false positive rates and robustness of expected decision outcomes.

Highlights

Heavy metals are common by-products of, and are mobilized by, human activities and are prevalent in many natural habitats such as forests, rivers, lakes and oceans [1,2,3,4,5]
Remediation priorities were obtained from the ecological values of focal bird species, the heavy metal distribution maps, as well as the level of uncertainties in heavy metal pollution projections
Owing to the cost of remediation and difficulties in predicting the concentrations of heavy metal contaminants in soil, a robust decision-making process that considers the spatial uncertainty of the habitats of species and the distributions of multiple heavy metals is crucial in delineating high priority remediation areas

Summary

Introduction

Heavy metals are common by-products of, and are mobilized by, human activities and are prevalent in many natural habitats such as forests, rivers, lakes and oceans [1,2,3,4,5]. While the contamination of soil by heavy metals detrimentally affects most species, certain species are vulnerable to environmental contaminants; avian populations, for instance, are extremely sensitive to heavy metals, so much so that bird scarcity has often been used as a bioindicator of heavy metal pollution [9,10]. As such they could be threatened as their ranges are slowly reduced to conservation areas that are possibly contaminated, in densely populated countries where land is at a premium. Heavy metal pollution has immediate adverse health effects on birds [9,11,12,13,14], and is known to cause a severe decline in avian reproduction [15]

Methods

Results

Discussion

Conclusion