Heavy Metals Concentration in Sediment of Lluta River Basin

Abstract

Northern Chile is characterized by water scarcity. The Lluta River, located in the XV region of Arica and Parinacota, is the one of the main rivers in northern Chile. The elevated levels of metals and metaloids in the river reduce the agricultural productivity and variety of species can be cultivated within the valley, which are of great importance for the consumption of the inhabitants of the area.Heavy metals in river bottoms may cause various effects on the water quality, as such the capacity to accumulate metals; levels of toxicity and metal stabilization in sediments have often been considered a pollution index of a territory.In this work the concentrations of Al, Cu, Fe, Mn, Mo, Pb and Zn from the pseudo-total and labile fraction of Lluta river sediments were studied. Samples from 10 sites along the river were collected. The sediments were characterized determining: pH, electrical conductivity, organic carbon (OC), organic total carbon (OTC), available phosphorus and boron. Heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS).For the metals analyzed in the pseudo-total fraction, the highest concentrations found were: Al in the site 10, (17061 mg kg -1 ) and Fe on site 6, (29898 mg kg -1 ). For the labile fraction, highest concentrations of metals were: Al in site 6 (1079 mg kg ). Using the Risk assessment code (RAC), the site 6 presents the greatest risk with high values of Cu, Mn, Pb and Zn, followed by site 1 with high values of Mn, Cu and Zn, and site 9 with high values of Mn, Cu and Pb. On the other hand, the MacDonald PEC (probable effect concentration) and TEC (threshold effect concentration) toxicity criteria, showed that the sites 4 and 6 have levels above the TEC for Cu, Fe, Pb and Zn, and levels above the PEC at six sites for Mn.

Shotgun metagenomics and microscopy indicate diverse cyanophytes, other bacteria, and microeukaryotes in the epimicrobiota of a northern Chilean wetland Nostoc (Cyanobacteria)

“…A Cyanobium relative, inferred for the Parinacota Nostoc epimicrobiota from 23S rRNA gene sequence data, has been used as a model system to assess proteomic changes associated with marine‐freshwater transition (Cabello‐Yeves and Rodriguez‐Valera, 2019). Inferred presence of Cyanobium may reflect the relatively high salinity conditions of the river system that feeds the Parinacota bofedales (Copaja and Muñoz 2018).…”

“…Like other inland wetlands of the world, bofedales are considered key to wildlife conservation, regional hydrology, and carbon storage (Rundel and Palma 2000). Throughout its extent, the river basin is characterized by high salinity (electrical conductivity > 2 mS · cm −1 ) and high concentrations of heavy metals (Copaja and Muñoz 2018).…”

The Arid Coastal Wetlands of Northern Chile: Towards an Integrated Management of Highly Threatened Systems

“…These high levels of B reduce the agricultural productivity and the variety of species that can be cultivated within the valley. In addition, Copaja and Muñoz [124] detected high levels of Cu, Fe, Mn, Zn, and Al in the sediments of the river mouth. Moreover, a coastal road gives access to the area for recreation activities with the consequent frequent transit of vehicles in the area, as well as feral dogs that disturb the fauna that live in and visit the wetland [4].…”

Adsorption-Desorption of Trace Elements in Sediments of the Maipo River Basin

“…Three independent sediment samples (1 kg) per sampling site were collected in a polyethylene bag from the top 10 cm of the surface using a plastic shovel, according to the sediment collection protocol 29 . Sediment samples were stored at 4 °C in the laboratory, and later, they were dried in polyethylene trays at room temperature and sieved to separate them into two fractions: a coarse fraction and fine fraction, with particle sizes of less than 2 mm for physical chemical characterization and 0.063 mm for metals determination.…”