Bioaccumulation

About: Bioaccumulation is a research topic. Over the lifetime, 7112 publications have been published within this topic receiving 208953 citations. The topic is also known as: bioakumulace.

Bioaccumulation of chromium, copper and iron in the organs and tissues of Clarias gariepinus in the Olifants River, Kruger National Park

Abstract: An investigation was undertaken into the hioaccumulation of Cr, Cu and Fe in the gills, liver, muscle and skin of the fish Clarias gariepinus from two sites on the Olifants River in the Kruger National Park. During 1994, four surveys (February, May, July and November) were undertaken. Metal bioaccumulation was analysed using atomic absorption spectrophotometry and was then applied to differentiate between the concentrations found at the two locations, and between all of the surveys, The greatest concentration of Cr was detected in the gills, suggesting that this was the prime site of absorption and loss of Cr to and from the aquatic environment. The concentrations of Cu and Fe were highest in the liver, which is a storage and detoxification organ for metal, followed by the gills. Mamba and Balule generally showed very little difference in the concentration of bioaccumulated metal. However, the gills as in the case of Cr generally showed high concentrations at Mamba, while the liver as in the case of Fe, showed consistently higher concentrations at Balule. The possible effects that temperature, pH, hardness and salinity have on the individual metals, as well as bioaccumulation of these metals, are discussed in detail. The continuous monitoring of the quality of water in the Olifants River is imperative for the future sustainability of the Kruger National Park.

Effect of bioturbation on metal-sulfide oxidation in surficial freshwater sediments

Abstract: Recent studies have demonstrated the role of acid-volatile sulfide (AVS) in controlling the bioavailability of several cationic metals in anoxic sediments. However, metal-sulfide complexes can be relatively labile with respect to oxidation associated with factors such as seasonal changes in rates of oxidation/production of AVS. Another potentially important mechanism of AVS oxidation in surficial sediments is bioturbation. We used different densities of the burrowing oligochaete Lumbriculus variegatus in a series of laboratory experiments to evaluate the effect of bioturbation on oxidation of AVS and subsequent bioavailability of cadmium and zinc spiked into freshwater sediments. Metal bioavailability was determined directly by bioaccumulation in the test organisms and indirectly through analysis of interstitial (pore) water metal concentrations. In our studies, horizon-specific sediment analyses were conducted to assess spatial differences in AVS and pore-water metal concentrations specifically related to organism activity. Burrowing activity of the oligochaete significantly reduced AVS concentrations in surficial sediments in a density-dependent manner and resulted in elevated interstitial water concentrations of cadmium but not zinc. Concentrations of cadmium in pore water from deeper horizons (below the zone of active burrowing) were consistently lower than those in the surficial sediments. The bioaccumulation of cadmium and zinc by L. variegatus was reflective of pore-water concentrations of the two metals, i.e., there was significant accumulation of cadmium, but not zinc, by the oligochaetes. Overall, our results indicate that bioturbation can enhance the bioavailability of some cationic metals in surficial sediments, via oxidation of AVS, and demonstrate the importance of analyzing surficial sediments when assessing bioavailability of metals in sediments.

Predicting PAH bioaccumulation and toxicity in earthworms exposed to manufactured gas plant soils with solid-phase microextraction

Abstract: Soils from former manufactured gas plant (MGP) sites are often heavily contaminated with polycyclic aromatic hydrocarbons (PAHs). Current risk assessment methods that rely on total PAH concentrations likely overstate adverse effects of such soils since bioavailability is ignored. In this study, solid-phase microextraction (SPME) was applied to estimate bioavailable PAH concentrations and toxicity in earthworms exposed to 15 MGP soils. In addition, PAH sorption to all soils (Koc values) was determined. The results showed a several orders of magnitude variation in Koc values, demonstrating that generic organic carbon-normalized sorption coefficients will typically be overconservative at MGP sites. SPME-predicted bioaccumulation generally was within a factor of 10 of measured bioac cumulation (in earthworm bioassays), in contrast to current risk assessment model estimates that overpredicted bioaccumulation 10−10 000 times. Furthermore, on the basis of estimated total body residues of narcotic PAHs, SPME corr...