Green stormwater infrastructure (GSI) is adopted to reduce the impact of stormwater on urban flooding and water quality issues. Traditional methods use inflow versus outflow metal and base cation concentrations from water samples at inlet and outlet to determine accumulation in GSI basins which can be expensive sometimes. Soil sampling could be a more cost-effective and time-averaged approach in evaluating the accumulation of metals and base cations in GSI compared to the traditional methods. This dataset presents data from twenty-one GSI basins soils located in New York and Pennsylvania, USA. The dataset contains a description of GSI basins considered in the study and the concentration of metals and base cations in those basins. The dataset includes concentrations of 3 base cations (Ca, Mg, Na) and 6 metals (Cd, Cr, Cu, Ni, Pb, and Zn). Various GSI basin characteristics are included in the dataset which includes information such as age of the basins, sources of runoff draining into the GSI basins, and drainage area ratio (ratio of the area draining into a GSI basin to the area of the GSI basin itself).

Twenty-one GSI basins were considered which were concentrated around two locations – The Pennsylvania State University (Penn State) and Cornell University. Twelve GSI basins around Penn State University and nine GSI basins around Cornell University were sampled in this study.

(a) Soil samples collection:

Three locations at each site were chosen for the collection of soil samples: (i) reference, a location that does not receive the stormwater runoff from any impervious areas, (ii) inlet of the basin, through which the stormwater runoff enters, and (iii) pool of the basin, where runoff is detained and/or infiltrated. The soil samples were collected using a hand-held 1.9 cm diameter tubular steel soil core sampler. Five-cm deep soil core samples were collected at random from all locations since the metals are likely to be accumulated in the topsoil and their median concentration is likely higher in the surface. At Penn State sites, five samples from each location (reference, inlet and pool) in the GSI basin were collected for, which occurred in 2019. At Cornell sites, five samples were collected from reference, four samples from pool, and three samples from inlet locations of each basin during 2009.

(b) Metals and base cations concentration:

The soil samples were first oven dried at 105°C and then ground with mortar and pestle, and sieved to remove particles larger than 2 mm. 0.5g of each dry soil sample was collected in test tubes and mixed well for homogeneity. The acid digestion of soil samples from Penn State for metals extraction by inductively coupled plasma atomic emission spectrometry (ICP-AES) was carried out according to EPA method 3050B. This digestion is intended to represent environmentally available metals that could become available/soluble under various environmental conditions, but does not represent a complete digestion of all metals contained in the soil matrix. The reported detection limit for the ICP-AES analysis at the Penn State Laboratory of Isotopes and Metals in the Environment was 0.01ppm for all base cations and 0.005 ppm for all metals. The method for acid digestion of soil samples at Cornell sites was a modification of EPA method 3050A and was thus slightly different from the one used for Penn State samples, given that the samples were originally collected for different projects at the two institutions. The dry mass of each soil sample used for the digestion at Cornell was 0.25g. These soil samples were mixed with 5ml of 1.0M nitric acid and incubated overnight at room temperature. They were then digested on a hotplate for one hour at 100°C. The digestate was diluted with 15 mL de-ionized water and centrifuged. The supernatant was analyzed via ICP-AES analysis in the Cornell Soil and Water Lab. The method detection limit established in the Cornell lab was reported as 0.05 ppm. The concentration of nine metals and base cations in the original soil sample – cadmium (Cd), calcium (Ca), chromium (Cr), copper (Cu), lead (Pb), magnesium (Mg), nickel (Ni), sodium (Na), and zinc (Zn) were obtained.

Two CSV files are attached: (i) Metals and base cations concentrations, which include concentrations at inlet, pool and reference locations at all sites, and (ii) General site characteristics which include information such as GSI basin area, Impervious drainage area draining into the GSI basin, age during the sampling, main water source, types of GSI basin, and more. One README file is also provided where description of various abbreviations in the dataset along with any other relevant information is provided.