Toxicity assessment using Lactuca sativa L. bioassay of the metal(loid)s As, Cu, Mn, Pb and Zn in soluble-in-water saturated soil extracts from an abandoned mining site

Abstract

SOILS, SEC 4 • ECOTOXICOLOGY • RESEARCH ARTICLEToxicity assessment using Lactuca sativa L. bioassay of the metal(loid)s As, Cu, Mn, Pb and Zn in soluble-in-water saturated soil extracts from an abandoned mining site Abstract Purpose We used the different soluble-in-water concentrations of As, Cu, Mn, Pb and Zn from contaminated soils in an abandoned mining area (anthropogenic origin) to assess the phytotoxicity of the abandoned site using the results obtained with a Lactuca sativa L. bioassay. Material and methods The study has been carried out on potentially polluted samples from the Rodalquilar mining district (southern Spain). The area was sampled according to the different metallurgical treatments for gold extraction used in each one: dynamic cyanidation and heap leaching. The saturation extracts were obtained by filtering each saturated paste with a vacuum-extraction pump, in which measurements of metal(loid) concentrations, pH and electrical conductivity were made. The variables evaluated in the bioassay, defined as toxicity indices ranging from −1 (maximum phytotoxicity) to >0 (hormesis), were seed germination (SG) and root elongation (RE) of lettuce seeds. Results and discussion In areas with a low degree of contamination, the most sensitive toxicity index is RE, whereas in highly contaminated areas, both RE and SG are good estimators of soil toxicity. According to these results, samples from the western area showed moderate to low toxicity, which was closely related to water-soluble As concentrations. Samples from the eastern area had a high degree of toxicity in 40% of the soils. Conclusions The comparison of the two indices (SG and RE) defined using the L. sativa L. bioassay indicates that, for areas with a low degree of contamination, the most sensitive toxicity index is RE, whereas in highly contaminated areas, both RE and SG are good estimators of soil phytotoxicity. Unsupervised pattern recognition methods such as HCA and PCA enabled us to conclude that the low/ moderate phytotoxicity of the soils is related to the extraction process used for the recovery of gold (mainly dynamic cyanidation in tanks located in the eastern area) and to the As and Pb contents.

Comparison in Growth Parameters of the Bacterization Effect on Axonopus affinis Seeds and EDTA against Cadmium

“…These responses were agree with the analysis done of the phytotoxic effect of Rb, Cd and EDTA, by the determination of the NRERI and NRPGI indices; where according to Bagur-González et al, (2011) (Table 3), experiments that influenced root length were characterized according to "A category" (low toxicity): Cd > Rb, "B category" (moderate toxicity): EDTA > CdRb and "C category" (high toxicity): CdEDTA > EDTARb > CdEDTARb.…”

“…The PCA as a complement of the study, showed a good separation of experiments done and their parameters evaluated; according to Bagur-González et al (2011), Fig. 3 showed that the co-treatment of Cd and these plant species treated with 0.5 mM and 1.0 mM EDTA reversed the inhibition of growth rate; Ebrahimi (2013) showed that statistically EDTA affected the growth of Echinochloa crus galii related to its germination, root length, shoot length and biomass.…”

Simple Biotoxicity Tests for Evaluation of Carbonaceous Soil Additives: Establishment and Reproducibility of Four Test Procedures

“…Furthermore, with hydrochar, the seedling fresh weight was the more sensitive parameter (see Barley Germination and Growth Test; Bagur‐González et al, 2010). Hence, although this is not part of the initial ISO–17126 guideline, seedling fresh weight (total or aboveground clipped) may serve as a sensitive parameter for the detection of biotoxic substances in char testing.…”

“…Th erefore, it is possible that the hydrochar contained osmotically active substances other than salts, such as dissolved organic carbon, which can be elevated in the process water (Libra et al, 2011). Furthermore, with hydrochar, the seedling fresh weight was the more sensitive parameter (see Barley Germination and Growth Test; Bagur-González et al, 2010). Hence, although this is not part of the initial ISO-17126 guideline, seedling fresh weight (total or aboveground clipped) may serve as a sensitive parameter for the detection of biotoxic substances in char testing.…”

Análisis del efecto de extractos de Sargassum vulgare y Ulva fasciata como bioestimulantes del crecimiento de Lens esculenta

“…Es importante destacar que, durante los primeros días de desarrollo de las plántulas, ocurren numerosos procesos fisiológicos en los que la presencia de una sustancia tóxica puede interferir en su supervivencia y su desarrollo normal (Sobrero & Ronco 2008). En este estudio; el efecto fitotóxico de los extractos acuosos de S. vulgare según la clasificación de Bagur-González et al (2011), determinó que estos se clasificaron entre una toxicidad baja (-0.18) a la concentración de S20% y de toxicidad moderada a las concentraciones de S10% (-0.28) y de U20% (-0.30). Se obtuvo un efecto hormético notable que indujo la promoción del crecimiento de las plántulas de L. esculenta expuestas a las concentraciones de S5% (0.18) y de U10% y U5% con valores de índices IER de 0.29 y 0.75, respectivamente.…”