Evaluation of the distribution and effect of potentially toxic elements in the sediments, surface water, and plants system with touristic activities in Xochimilco channels, Mexico

Xochimilco is located in the southeastern part of the Mexico City basin; it is influenced by a floating agricultural system called chinampa. In this system, aquatic plants play an essential role in the environment and are impacted by various anthropogenic activities. This study aimed to determine the concentrations, distributions, and sources of potentially toxic elements (PTE) in water, sediments, and plants and evaluate the water quality of seven chinampa sites. The plants collected were Typha latifolia L. and Eichhornia crassipes (Mart.) Solms. T. latifolia is an emergent plant, whereas E. crassipes is a floating one. The results showed that most of the water's physicochemical parameters were within acceptable ranges, except for total dissolved solids, which exceeded the federal law on water rights (FLWR). The PTE did not exceed the limits proposed by SQuiRTs; however, Mn and Zn exceeded FLWR at all sites. PTE concentrations in the channel sediments were within normal ranges. PTE concentrations in the plants were within normal ranges, except for Zn in T. latifolia at sampling site 2. Pb was not bioaccumulated, indicating that these plants are Pb excluders or that Pb is not bioavailable. The bioconcentration and bioaccumulation factor showed a high accumulation of Zn in most chinampa sampling sites, indicating its bioavailability. Hazard Quotient and Hazard index showed a risk of ingestion and inhalation of Pb for people through sediments. However, contact with water does not pose a risk of oral ingestion, inhalation, or dermal contact.