Native macrophytes as metal biomonitors in peri-urban wetlands

HADAD, H.R.; MUFARREGE, M.M.; DI LUCA, G.A.; NOCETTI, E.; DENARO, A.C.; CAMPAGNOLI, M.A.; MAINE, M.A.

Viena

Simposio; 9th International Symposium on Wetland Pollutant Dynamics and Control, WETPOL 2021; 2021

University of Natural Resources and Life Sciences (BOKU)

The aim of this work was to evaluate the use of different native macrophytes as metal biomonitors in peri-urban wetlands (Santa Fe city, Argentina). Plants, water, and sediment were collected in sampling points located near of urban centers and roads during year 2018. The study sites were chosen according to signs of environmental degradation, e.g., closeness to urban areas and roads, and pipe dump of unknown origin. They study sites were: Rincon city, an industrial park, an urban ecological reserve (UER), a university campus, and Leyes village. The following dominant macrophytes were studied in each site: 1) Rincon: Typha domingensis, 2) industrial park: Typha domingensis, 3) UER: Typha domingensis-Panicum elephantipes, 4) university campus: Canna glauca, 5) Leyes: Pontederia rotundifolia Plants were sampled by hand and metal measurements were carried out in aerial and submerged parts of leaves, roots and rhizomes. Water samples were collected in triplicate using plastic bottles. A 3-cm diameter PVC corer was used for the sampling of surface sediment at a depth of approximately 10 cm. A preliminary multi-elemental screening was carried out in the samples of water, plant tissues, and sediment by inductively coupled plasma emission spectroscopy (ICP). According to these results, the main metals found Cr, Ni, Zn, and Pb were studied. During the study, for the determination of metals in water, plant tissues and sediment, samples were treated according to EPA method 200.2 and analyzed by atomic absorption spectrometry. In water, the industrial park showed the highest values of Cr and Pb, while Cr also was detected in UER. Although the UER is a protected site, it was observed that receives run-off from a near sports park. In sediment, the industrial park and Leyes showed the highest Cr and Zn concentrations. However, all metal concentrations in plant tissues from the industrial park were the highest, and P. rotundifolia plants from Leyes showed the highest Pb root tissue concentrations. These results indicates that the studied metal concentrations are not correlated between water, sediment, and plant tissues, demonstrating that macrophytes are better indicators of metal presence than environmental compartments. The plant morphology and the different propagation ways are important characteristics in the acquisition and accumulation of metals. The species that present a high biomass, such as T. domingensis, are efficient contaminant bioaccumulators. The submerged parts of leaves accumulate a remarkable amount of contaminants followed by roots. Due to these tissues are in direct contact with water, metals are accumulated mainly by adsorption on the epidermis. Native macrophytes are efficient bioaccumulators and biomonitors for metals. Therefore, designing successful biomonitoring and bioassessment programs are an important basis for the rehabilitation and restoration of aquatic ecosystems. It is necessary to carry out further studies focused in different plant species and contaminants. These studies could contribute to the knowledge of plant mechanisms of contaminant accumulation in treatment wetlands.