Exploring the Use of E. scirpoides in a Constructed Wetland for Remediation of Aqueous Heavy Metal Pollution

This study measured the efficiency of Equisetum scirpoides in a Horizontal Flow Constructed Wetland and its remediation of aqueous heavy metal pollution, copper, and zinc. E. scirpoides is native to New York state and grows well in environments impacted by anthropogenic structures and general disturbances that may upturn the soil. This study was particularly motivated by high levels of copper found in the drinking water of Niskayuna and Schenectady, New York in 2025. Urban streams are an essential part of local ecology, especially in Schenectady. Constructed wetlands are a developing green technology that work as an integrated unit: vegetation, soil, microbacteria, to remediate surrounding water and soils from pollutants. A 24" x 12" x 4" Horizontal Flow Constructed Wetland (CW) was designed and built, where E. scirpoides was planted, and fed several rounds of Copper Sulfate and water to measure its phytoremedial ability. A 20L carboy drip system was set up to mimic a slow stream flow into the inlet of the CW, and a 1" hole was drilled at the outlet for water to exit the wetland into a collection jug. The system underwent a control and three trials at increasing copper concentrations of 4.98 ppm, 9.95 ppm and 19.91 ppm. Additionally, a separate analysis (smaller scale Zinc Pond Study) was conducted for three weeks in hopes to gain insight on a stagnant flow CW and zinc accumulation within plant tissue in a non stream environment. Samples of plant tissue, soil and water were taken between each trial and analyzed using Inductively Coupled Plasma Mass Spectrometry (ICP - MS). Overall, the CW demonstrated high efficiency in removing copper from the water, with a peak removal rate of the vegetation in Trial 2 of about 95.29%. The copper concentrations in the outlet were much lower compared to the inlet, leading us to infer that the CW was successful in accumulating copper over time. The Zinc Pond Study allowed for further analysis on E. scirpoides as a potential hyperaccumulator, and plant tissue samples measured 2658.50 ppm Zn after three weeks of zinc doses. Our results suggest that E. scirpoides is a resilient species, with great potential to accumulate copper and hyperaccumulate zinc. This horsetail may have a significant role in the future of green technology, particularly at sustainable solutions in effort to mitigate heavy metal pollution and impaired water bodies, especially urban streams.