Pollutant accumulation and microbial community evolution in rain gardens with different drainage types at field scale

Abstract

Rain gardens play a key role in urban non-point source pollution control. The drainage type affects the infiltration processes of runoff pollutants. The soil properties and microbial community structures were studied to reveal the stability of the ecosystem in rain gardens with different drainage types under long-term operation. The results showed that the soil water content and total organic carbon in the drained rain gardens were always higher than that of the infiltrated ones. With the increase in running time, the contents of heavy metals in rain gardens showed significant accumulation phenomena, especially the contents of Zn and Pb in drained rain gardens were higher than that in infiltrated ones. The accumulation of pollutants resulted in lower microbial diversity in drained rain gardens than in infiltrated rain gardens, but the microbial community structures were the same in all rain gardens. The effects of drainage type on microbial community evolution were not significant, only the accumulation of heavy metals led to changes in the abundance of dominant microorganisms. There were differences in the soil environment of rain gardens with different drainage types. The long-term operation of rain gardens led to fluctuations in the soil ecosystem, while the internal micro-ecosystems of the drained rain gardens were in unstable states.

A Study on Plant Selection for Low-Carbon Rain Gardens Based on an AHP-TOPSIS Model

“…Rain gardens are one of the LID measures that are designed and constructed through the design and construction of artificial gardens or landscapes, usually consisting of vegetation, permeable soils, and drainage facilities, with the aim of reducing stormwater runoff, improving water quality, increasing urban green space, and enhancing the resilience of urban ecosystems [9]. Current research on rain gardens focuses on hydrologic simulation studies [10], soil infiltration studies [11], pollutant retention capacity studies [12], hydrologic effects of different plant applications [13], and studies on low-carbon construction and application of rain gardens [14]. Due to the strong territoriality of rain garden plants, the current research on plant selection and design of rain gardens is weak, and there are few quantitative studies under multi-objective requirements.…”