Lignin biomarkers as tracers of mercury sources in lakes water column

This study presents the role of specific terrigenous organic compounds as important vectors of mercury (Hg) transported from watersheds to lakes of the Canadian boreal forest. In order to differentiate the autochthonous from the allochthonous organic matter (OM), lignin derived biomarker signatures [Lambda, S/V, C/V, P/(V ? S), 3,5-Bd/V and (Ad/Al)v] were used. Since lignin is exclusively produced by terrigenous plants, this approach can give a non equivocal picture of the watershed inputs to the lakes. Moreover, it allows a characterization of the source of OM and its state of degradation. The water column of six lakes from the Canadian Shield was sampled monthly between June and September 2005. Lake total dissolved Hg concentrations and Lambda were positively correlated, meaning that Hg and ligneous inputs are linked (dissolved OM r2 = 0.62, p\0.0001; particulate OM r2 = 0.76, p\0.0001). Ratios of P/(V ? S) and 3,5-Bd/V from both dissolved OM and particulate OM of the water column suggest an inverse relationship between the progressive state of pedogenesis and maturation of the OM in soil before entering the lake, and the Hg concentrations in the water column. No relation was found between Hg levels in the lakes and the watershed flora composition—angiosperm versus gymnosperm or woody versus non-woody compounds. This study has significant implications for watershed management of ecosystems since limiting fresh terrestrial OM inputs should reduce Hg inputs to the aquatic systems. This is particularly the case for largescale land-use impacts, such as deforestation, agriculture and urbanization, associated to large quantities of soil OM being transferred to aquatic systems

Relationship between concentration of dissolved organic matter (DOM) and the effect of DOM on the bioconcentration of benzo[a]pyrene

Haitzer M, Hoess S, Traunspurger W, Steinberg C. Relationship between concentration of dissolved organic matter (DOM) and the effect of DOM on the bioconcentration of benzo[a]pyrene. Aquatic Toxicology. 1999;45(2-3):147-158

Refractory dissolved organic matter can influence the reproduction of Caenorhabditis elegans (Nematoda.

Hoess S, Bergtold M, Haitzer M, Steinberg CEW, Traunspurger W. Refractory dissolved organic matter can influence the reproduction of Caenorhabditis elegans (Nematoda. Freshwater Biology. 2001;46:1-10

Effects of humic substances on the bioconcentration of polycyclic aromatic hydrocarbons: Correlations with spectroscopic and chemical properties of humic substances

Haitzer M, Abbt-Braun G, Traunspurger W, Steinberg C. Effects of humic substances on the bioconcentration of polycyclic aromatic hydrocarbons: Correlations with spectroscopic and chemical properties of humic substances. Environmental Chemistry and Toxicology. 1999;18(12):2782-2788

Effects of dissolved organic matter (DOM) on the bioconcentration of organic chemicals in aquatic organisms - a review

Haitzer M, Höss S, Steinberg C, Traunspurger W. Effects of dissolved organic matter (DOM) on the bioconcentration of organic chemicals in aquatic organisms - a review. Chemosphere. 1998;37(7):1335-1362

Interactions between dissolved organic matter and mercury in the Florida Everglades

Experiments were conducted using organic matter isolated from various surface waters in the Florida Everglades to study the interactions between dissolved organic matter (DOM) and Hg (II). Conditional distribution coefficients ($K_{DOM^\prime}$), obtained using an equilibriurn dialysis ligand exchange method, were strongly affected by the Hg/DOM concentration ratio. Very strong interactions ($K_{{\rm DOM}^\prime}$ = 10$^{23.2 \pm 05}$ L kg$^{-1}$), indicative of Hg-thiol bonds, were observed at Hg/DOM ratios below approximately 1 $\mu$g Hg per mg DOM. Above approximately 10 $\mu$g Hg per mg DOM much lower $K_{{\rm DOM}^\prime}$ values ($10^{10.7\pm 05}$ L kg$^{-1}$) were obtained. DOM-Hg interactions were also studied by HgS (log K$_{\rm sp}=-52.4$) dissolution and precipitation experiments. In the dissolution experiments, a significant amount of Hg was released from cinnabar in the presence of DOM, suggesting strong interactions. Conversely, precipitation of HgS was strongly inhibited in the presence of low concentrations ($\leq$3 mg C/L) of DOM. In both the dissolution and precipitation experiments, organic matter rich in aromatic moities was more reactive with HgS than less aromatic fractions and sulfur-containing model compounds. These results suggest that DOM can influence the geochemistry of inorganic complexes of Hg in the Everglades, especially HgS, by strong Hg-DOM binding and colloidal stabilization

Ecotoxicological assessment with Caenorhabditis elegans (Nematoda) - Method for testing on agar, in liquid medium and in situ sediment

Traunspurger W, Haitzer M, Höss S, Beier S, Ahlf W, Steinberg C. Ecotoxicological assessment with Caenorhabditis elegans (Nematoda) - Method for testing on agar, in liquid medium and in situ sediment. Environ. Toxicol and Chem. 1997;16(2):245-250