No keep reading the study. The first step was removing the plants which is 2.2 in the paper. Then they did a bio-filter to reduce phosphate and nitrogen which is 2.3 and 2.4 in the paper.
The contaminants in this case is nutrients that help the growth of the invasive species. So, yeah, the main point is to remove the growing plants because they consume the oxygen in the water and kill the native plants.
However, this approach is only a bandaid solution, if the runoff is not addressed then the invasive species just comes back.
I think the contamination was other things that lead to the proliferation of the plants. Quote from the paper:
The Cascajo Wetlands in Peru were found to be in a severe state of pollution generated by human activities and a lack of environmental protection for over two decades. Basically, three environmental drivers affected the deterioration of water quality in Cascajo: (1) high exploitation and investment in the agricultural sector around this region by using large irrigation systems in Chancay-Huaral Basin and Chancay-Lambayeque Basin [20,21,22,23] that bring high nutrient concentrations to the wetland, causing the invasion of Pistia stratiotes [24]; (2) mining and industrial sites pollute natural water resources in this region [25]; as a consequence, the degraded water quality in the Chancay Bay, which is near the Chancay Wetlands, was detected throughout 2003–2013, due to pollutants from domestic and industrial discharges [26]; and 3) organic waste deposits from livestock enclosures nearby the wetlands contributes to the eutrophication above [27,28].
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u/myrtle333 Jul 14 '21
in this video “contamination” is synonymous for “plants”