Bioaccumulation of Heavy Metals by Aquatic Macroinvertebrates Along the Basento River in the South of Italy

Abstract

In this study, the occurrence of toxic heavy metals (As, Cd, Cr, Cu, Pb, and Zn) and relative bioaccumulation in biota samples were investigated in a freshwater ecosystem, the Basento river, one of the main aquatic systems in the south of Italy, which over the last years has been transformed into a sink of urban and industrial wastes. Therefore, the levels of arsenic, cadmium, chromium, copper, lead, and zinc were determined in water, sediments, and tissues of some macroinvertebrate-which are natural assessment endpoints for the evaluation of ecological risk in aquatic systems. Accumulation factors, as a ratio between the concentration of a given contaminant in biota and the one in an abiotic medium, were considered in order to estimate heavy metal contamination loads in biota. Statistical analysis was performed for a comparative evaluation of bioaccumulation among various macroinvertebrates, according to different feeding guilds. The Tukey honestly significantly different test showed significant differences in the bioaccumulation of As, Cd, and Cr among the considered biological receptors (collector-gatherer, predator, and filterer), suggesting that the biological uptake from immediate contact with the sediment or solid substratum (collector-gatherer), instead of the bioconcentration from water (filterer) or biomagnification along the biotic food webs (predators), is the more effective biological sequestering pathway for these metals. Biota-sediment accumulation factors, commonly used for the evaluation of sediment's role in aquatic systems contamination, were determined for the considered metals. A linear correlation between the concentrations of As, Cd, Cr, and Zn in macroinvertebrates and those in the sediments suggested that the metal uptake data in macroinvertebrates can provide useful information for the estimation of heavy metal exposure risk or bioavailability when making assessments of sediment toxicity in freshwater ecosystems.

Comparison between active and passive biomonitoring strategies for the assessment of genotoxicity and metal bioaccumulation in Echinogammarus veneris (Crustacea: Amphipoda)

“…The lowest values of DNA damage, observed in CDA and ONI, were due to a substantial absence of anthropogenic impacts in the two areas (Regione Lazio 2004a, 2004b. Regarding the bioaccumulation data obtained from exposure in situ (Figure 4), they show a flat trend and a very wide variability due to the different speed of uptake of the different metals and the exposure time (Mouneyrac et al 2002;Santoro et al 2009;Chojnacka 2010).…”

Invertebrates Minimize Accumulation of Metals and Metalloids in Contaminated Environments

“…For a pronounced understanding of toxicity effects, uptake and avoidance mechanisms of invertebrates have to be elucidated. In other publications, the uptake of metals by invertebrates is attributed to total metal concentration on and in the invertebrates, not differentiating between adsorbed (surface) and incorporated metals (Santoro et al 2009;Woelfl et al 2006). Considering a much higher toxicity effect the incorporated fraction is first of all of importance.…”

Tracing metals through urban wetland food webs

“…These are engineered systems designed to mimic the processes which occur in natural wetlands, with the aim of removing contaminants and pollutants from stormwater through physical, chemical and biological processes (Nuttall et al, 1997;Chavan et al, 2007). However, as constructed wetlands are designed to act as a sink for metals, they are a potential source of uptake by aquatic organisms (Rainbow, 2007;Santoro et al, 2009). Where rates of intake exceed excretion, metals bioaccumulate in an organism.…”

“…There has been a major focus on heavy metals in rivers and lakes (Watanabe and Omura, 2008;Santoro et al, 2009;Ekeanyanwu et al, 2010), with less attention on the passage of metals through food webs in constructed wetlands. Those studies that have been published have shown that contaminated sediments can act as a significant source of metals to the aquatic environment as metals which are dissolved in the sediment solution or weakly adsorbed to sediment particles can become released into the water column (Dunbabin and Bowmer, 1992;Allinson et al, 2015).…”