Accumulation of toxic metals in sediment and biota of the Lužické mountains springs

Abstract

La acumulación de Cd, Cu, Zn y Pb en agua, sedimentos y biota recogidos a lo largo de los manantiales de las montañas de Lužické se determinó utilizando un espectrómetro de absorción atómica de llama (F55AAS) y un atomizador de tubo de grafito AA (GTA 120) (tecnología Agilent). Los sedimentos se sometieron a procedimientos de extracción secuencial y digestión pseudototal. El PH, conductividad eléctrica, OD y temperatura fueron más bajos en otoño que en primavera. Según el coeficiente de distribución logarítmica - log Kd, el metal más fácilmente liberado del sedimento es Cu (2,8) en BS1017. Según el cociente de riesgo - HQ, los sedimentos de los manantiales no parecen tener altas concentraciones de metales tóxicos, excepto Pb. El factor de movilidad - MF es significativamente alto para Cd (91 %), Cu (73,60 %) , Zn (36,85 %) y Cd (4,05 %). El factor de acumulación de sedimentos de Biota (BSAF) registró los valores más altos en la acumulación de Cd. EN1022 fue considerado el manantial más contaminado con metales tóxicos, especialmente Cu, 13 veces más que los estándares. El siguiente orden de biodisponibilidad de los metales tóxicos fue encontrado Cd> Zn > Cu> Pb.

The accumulation of Cd, Cu, Zn and Pb in water, sediment and biota collected along Lužické mountains springs were determined using flame 55 Atomic Absorption Spectrometer (F55AAS) and graphite tube atomizer AA (GTA 120) (Agilent technologies). Sediments were subjected to both sequential extraction and pseudototal digestion procedures. Low pH, electrical conductivity, OD, and temperature were found in the autumn season than spring season. Near neutral pH (5.49 - 8.02) was found in 11 from 20 springs during spring season; while in the autumn season, acid pH (4.62 - 6.80) was observed in 15 from 18 springs. During spring season conductivity ranged from 78.7 - 762 μS/cm, the temperature ranged from 7.3 - 14.1ºC and OD ranged from 4.11 - 10.83 mg.l-1. During autumn season conductivity ranged from 93 - 907 μS/cm, the temperature ranged from 6.6 - 11.6ºC and OD ranged from 3.19 - 11.28 mg.l-1. The toxic metal concentrations in water ranged from 0.0001 - 0.0015 mg/l Cu, 0.0002 - 0.0116 mg/l Zn, 0.0000 - 0.0002 mg/l Pb and 0.0000 - 0.0004 mg/l Cd; in sediment 0.00 - 91.70 mg/kg Cu, 9.15 - 134.71 mg/kg Zn, 0.00 - 83.67 mg/kg Pb and 0.01 - 3.56 mg/kg Cd and in biota 4.86 - 53.52 mg/kg Cu, 46.82 - 191.44 mg/kg Zn, 0.00 - 6.93 mg/kg Pb and 0.01 - 5.99 mg/kg Cd. According to the logarithmic distribution coefficient – log Kd, the metal most easily released from the sediment is Cu (2.8) in BS1017, log Kd ranged from 2.80 - 5.58 Cu, 3.53 - 5.53 Zn, 3.39 - 4.88 Cd and 5.01 - 6.62 Pb, log Kd values >4 reflect lower availability, which means lower migration potential into liquid phase. According to HQ, sediments of springs do not seem to be significantly loaded by toxic metals, with the exception of Pb, HQ-TEC > 1 were found in ES1014, ES1009, EN1021, EN1011, EN1004, DN1012 and DN1010, and HQ-PEC > 0.5 was found in EN1021. EN1022 was considered the most contaminated spring with toxic metals Cd (3.56 mg.kg-1), Zn (134.71 mg.kg-1), Cu (43.48 mg.kg-1) and Pb (62.37 mg.kg-1), specially Cu, 13 times more than the background values; however, mobility factor – MF is significantly very high for Cd - 91%, Cu - 73.60%, Zn - 36.85% and Cd - 4.05%. Biota sediment accumulation factor – BSAF ranged from 0.96 - 16.44 Cu, 1.11 - 16.89 Zn, 0.87 - 81.89 Cd and 0.02 - 0.37 Pb, BSAF recorded the highest values Cd accumulation. The following order of bioavailability was found with the toxic metals Cd > Zn > Cu > Pb.