Observations Of The Seasonal Buildup And Washout Of Salts In Urban Bioswale Soil

Details

• Journal Title:
  Science of the Total Environment
• Personal Author:
  Shetty, Nandan H. ; Mailloux, Brian J. ; Mcgillis, Wade R. ; Culligan, Patricia J.
• NOAA Program & Office:
  Sea Grant ; OAR (Oceanic and Atmospheric Research)
• Sea Grant Program:
  SCSGC (South Carolina Sea Grant)
• Description:
  The objective of this study was to quantify the seasonal risk of salt damage to bioswale plants, soil, microbes, and downstream waterbodies. To do so, we measured sodium, chloride, and electrical conductivity levels at seven bioswales located in the Bronx, New York City, over 42 storm events during a three-year monitoring period. The bioswale with the greatest salt contamination (median 206 mg/L chloride) had a unique inlet design without any possibility of inlet bypass. The most severe effects at all sites were found during the winter season, as infiltrate concentrations frequently (40% of winter samples) exceeded 1000 mg/L chloride, a level lethal to aquatic plants and invertebrates, and electrical conductivity exceeded 1500 μS cm−1 (50% of winter samples), a level that may displace bound metals from bioswale soils and into the subsurface. However, low levels of permanent salt contamination may be expected all year, as concentrations frequently (87% of all samples) exceeded the United States Environmental Protection Agency drinking water standard of 20 mg/L sodium. A regression of chloride washout over the year yielded concentrations greater than those damaging to soil structure and soil microbes (90 mg/L) until August 20th, and above those damaging to roadside vegetation (30 mg/L) for the entire year. Today, the vast majority of bioswales in cold climates are built with salt-tolerant vegetation, but prior to this study, it was unclear to what degree this was, in fact, necessary. Our findings confirm salt-tolerant vegetation to be optimal, as winter de-icing salts are not sufficiently flushed from soils by the spring growing season. Our findings also demonstrate how bioswale inlet design and site location can influence soil contamination.
• Keywords:
  Bioswales Chloride Water Quality Water Quality
• Source:
  Science of the Total Environment, 772: 137834
• DOI:
  https://doi.org/10.1016/j.scitotenv.2020.137834
• Document Type:
  Journal Article
• Rights Information:
  Accepted Manuscript
• Rights Statement:
  The NOAA IR provides access to this content under the authority of the government's retained license to distribute publications and data resulting from federal funding. While users may legally access this content, the copyright owners retain rights that govern the reproduction, redistribution, and re-use of this work. The user is solely responsible for complying with applicable copyright law.
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha-512:e942ad5ab83a8ba47efd8112bc529ee751c1a498e924dc30d9d2ce337cdf403597a71ef31413bc886df9cc55e921a30718620cf7b3dc82dc14a3110c23a5a035
• Download URL:
  https://repository.library.noaa.gov/view/noaa/36928/noaa_36928_DS1.pdf
• File Type:
  [PDF - 2.41 MB ]