Effects of Land Use and Pollution Loadings on Ecotoxicological Assays and Bacterial Taxonomical Diversity in Constructed Wetlands

Subhomita Ghosh Roy,Charles F Wimpee,Stephen A Mcguire,Timothy J Ehlinger

doi:10.3390/d13040149

Subhomita Ghosh Roy, Charles F Wimpee + Show 2 more

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https://doi.org/10.3390/d13040149

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Journal: Diversity	Publication Date: Mar 30, 2021
Citations: 3	License type: CC BY 4.0

Affiliation: University of Wisconsin–Milwaukee

Abstract

Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensively studied the concentrations of metals, nutrients, and water quality as measurements of pollution in freshwater ecosystems. However, few studies have been able to link these pollutants to bioindicators as a risk assessment tool. This study aimed to examine the potential of two bioindicators, plant ecotoxicological assays and sediment bacterial taxonomic diversity, in ecological risk assessment for six freshwater constructed wetlands in a rapidly urbanizing watershed with diverse land uses. Sediment samples were collected summer, 2015 and 2017, and late summer and early fall in 2016 to conduct plant ecotoxicological assays based on plant (Lepidium, Sinapis and Sorghum) growth inhibition and identify bacterial taxonomical diversity by the 16S rRNA gene sequences. Concentrations of metals such as lead (Pb) and mercury (Hg) (using XRF), and nutrients such as nitrate and phosphate (using HACH DR 2800TM spectrophotometer) were measured in sediment and water samples respectively. Analyses of response patterns revealed that plant and bacterial bioindicators were highly responsive to variation in the concentrations of these pollutants. Hence, this opens up the scope of using these bioindicators for ecological risk assessment in constructed freshwater wetland ecosystems within urbanizing watersheds.

Highlights

Decades of industrialization, agriculture, and urbanization have resulted in toxic discharges such as metals, petroleum products, domestic wastes, nutrients, and other pollutants finding their way into freshwater ecosystems [1,2]
What is lacking in the management of freshwater ecosystems is the extensive use of diverse bioindicators and linking them to pollutants as ecological risk assessment tools
The regression analysis suggested a negative estimated relationship between Hg, a chemical of concern often released into the environment through industrial pollution, mining, and the burning of fossil fuels [53,54], and the root growth inhibition of two of the three plant bioindicator species (Table 2 and Figure 4)

Summary

Introduction

Agriculture, and urbanization have resulted in toxic discharges such as metals, petroleum products, domestic wastes, nutrients, and other pollutants finding their way into freshwater ecosystems [1,2]. What is lacking in the management of freshwater ecosystems is the extensive use of diverse bioindicators and linking them to pollutants as ecological risk assessment tools. To explore this possibility, our study examined six freshwater constructed wetlands along the Pike River, Racine, WI, USA, in the southwestern portion of the Lake Michigan watershed (Figure 1). In the context of this study, the six constructed wetlands play an important role in ameliorating water quality before being discharged to the Pike River, impacting ecological health This warrants an investigation into their function and contribution to the mitigation of stormwater pollution (Figure 1) [5,6,7]. A careful process needs to be developed that looks into the status of the input pollutants (such as metals and nutrients) from the surrounding watershed into the freshwater constructed wetlands, as well as the possible response from the series of bioindicators in relation to the pollutants, to understand the effect on the biota

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