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Jason?M.?ConderEmail author Roman?P.?LannoEmail author 《Journal of Soils and Sediments》2003,3(1):13-20
Background. Earthworm heavy metal concentrations (critical body residues, CBRs) may be the most relevant measures of heavy
metal bioavailability in soils and may be linkable to toxic effects in order to better assess soil ecotoxicity. However, as
earthworms possess physiological mechanisms to secrete and/or sequester absorbed metals as toxicologically inactive forms,
total earthworm metal concentrations may not relate well with toxicity.
Objective The objectives of this research were to: i) develop LD50s (total earthworm metal concentration associated with 50% mortality) for Cd, Pb, and Zn; ii) evaluate the LD50 for Zn in a lethal Zn-smelter soil; iii) evaluate the lethal mixture toxicity of Cd, Pb, and Zn using earthworm metal concentrations
and the toxic unit (TU) approach; and iv) evaluate total and fractionated earthworm concentrations as indicators of sublethal
exposure.
Methods Earthworms (Eisenia fetida (Savigny)) were exposed to artificial soils spiked with Cd, Pb, Zn, and a Cd-Pb-Zn equitoxic mixture to estimate lethal CBRs
and mixture toxicity. To evaluate the CBR developed for Zn, earthworms were also exposed to Zn-contaminated field soils receiving
three different remediation treatments. Earthworm metal concentrations were measured using a procedure devised to isolate
toxicologically active metal burdens via separation into cytosolic and pellet fractions.
Results and Discussion Lethal CBRs inducing 50% mortality (LD50, 95% CI) were calculated to be 5.72 (3.54-7.31), 3.33 (2.97-3.69), and 8.19 (4.78-11.6) mmol/kg for Cd, Pb, and Zn, respectively.
Zn concentrations of dead earthworms exposed to a lethal remediated Zn-smelter soil were 3-fold above the LD50 for Zn and comparable to earthworm concentrations in lethal Zn-spiked artificial soils, despite a 14-fold difference in total
soil Zn concentration between lethal field and artificial soils. An evaluation of the acute mixture toxicity of Cd, Pb, and
Zn in artificial soils using the Toxic Unit (TU) approach revealed an LD50 (95% CI) of 0.99 (0.57-1.41) TU, indicating additive toxicity.
Conclusions Total Cd, Pb, and Zn concentrations in earthworms were good indicators of lethal metal exposure, and enabled the calculation
at LD50s for lethality. The Zn-LD50 developed in artificial soil was applicable to earthworms exposed to remediated Zn-smelter soil, despite a 14-fold difference
in total soil Zn concentrations. Mixture toxicity evaluated using LD50s from each single metal test indicated additive mixture toxicity among Cd, Pb, and Zn. Fractionation of earth worm tissues
into cytosolic and pellet digests yielded mixed results for detecting differences in exposure at the sublethal level
Recommendation and Outlook CBRs are useful in describing acute Cd, Pb, and Zn toxicity in earthworms, but linking sublethal exposure to total and/or
fractionated residues may be more difficult. More research on detoxification, regulation, and tissue and subcellular partitioning
of heavy metals in earthworms and other invertebrates is needed to establish the link between body residue and sublethal exposure
and toxicity. Keywords: Bioavailability; Cd; critical body residues; earthworms; metals; Pb; soil; Zn
An erratum to this article is available at . 相似文献
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Körner C Asshoff R Bignucolo O Hättenschwiler S Keel SG Peláez-Riedl S Pepin S Siegwolf RT Zotz G 《Science (New York, N.Y.)》2005,309(5739):1360-1362
Whether rising atmospheric carbon dioxide (CO2) concentrations will cause forests to grow faster and store more carbon is an open question. Using free air CO2 release in combination with a canopy crane, we found an immediate and sustained enhancement of carbon flux through 35-meter-tall temperate forest trees when exposed to elevated CO2. However, there was no overall stimulation in stem growth and leaf litter production after 4 years. Photosynthetic capacity was not reduced, leaf chemistry changes were minor, and tree species differed in their responses. Although growing vigorously, these trees did not accrete more biomass carbon in stems in response to elevated CO2, thus challenging projections of growth responses derived from tests with smaller trees. 相似文献
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Elena V. Girich Anton N. Yurchenko Olga F. Smetanina Phan Thi Hoai Trinh Ngo Thi Duy Ngoc Mikhail V. Pivkin Roman S. Popov Evgeny A. Pislyagin Ekaterina S. Menchinskaya Ekaterina A. Chingizova Shamil S. Afiyatullov Ekaterina A. Yurchenko 《Marine drugs》2020,18(12)
Low molecular weight secondary metabolites of marine fungi Aspergillus flocculosus, Aspergillus terreus and Penicillium sp. from Van Phong and Nha Trang Bays (Vietnam) were studied and a number of polyketides, bis-indole quinones and terpenoids were isolated. The structures of the isolated compounds were determined by 1D and 2D NMR and HR-ESI-MS techniques. Stereochemistry of some compounds was established based on ECD data. A chemical structure of asterriquinone F (6) was thoroughly described for the first time. Anthraquinone (13) was firstly obtained from a natural source. Neuroprotective influences of the isolated compounds against 6-OHDA, paraquat and rotenone toxicity were investigated. 4-Hydroxyscytalone (1), 4-hydroxy-6-dehydroxyscytalone (2) and demethylcitreoviranol (3) have shown significant increasing of paraquat- and rotenone-treated Neuro-2a cell viability and anti-ROS activity. 相似文献
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AG Loeser Z Shen DS Dessau DS Marshall CH Park P Fournier A Kapitulnik 《Science (New York, N.Y.)》1996,273(5273):325-329
Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+delta. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2-y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed. 相似文献
7.
Mark P. Richards Roman Aranda IV Cai He George N. Phillips Jr. 《Journal Of Aquatic Food Product Technology》2013,22(4):416-423
pH can be manipulated to alter the oxidative stability of fish-based foods during storage. X-ray diffraction was used to investigate the ability of reduced pH to cause structural changes in fish hemoglobins that lead to enhanced oxidative degradation. Decreasing pH from 8.0 to 6.3 and 5.7 created a large channel for solvent entry into the heme crevice of perch hemoglobin beta chains. The proton-induced opening of this channel occurred between site CD3 and the heme-6-propionate. Solvent entry into the heme crevice can enhance metHb formation and hemin loss, processes that accelerate lipid oxidation. Reduced pH also decreased the distance between Ile at E11 in one of the alpha chains and the ligand above the heme iron atom. This sterically displaces O2 and protonated O2 which increases metHb formation. These studies demonstrate that pH reduction causes structural changes in perch hemoglobin which increase oxidative degradation of the heme pigment. 相似文献
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Shah Mujahid Ali Saito Taiju Šindelka Radek Iegorova Viktoriia Rodina Marek Baloch Abdul Rasheed Franěk Roman Tichopád Tomáš Pšenička Martin 《Fisheries Science》2021,87(1):71-83
Fisheries Science - The cleavage pattern of a vertebrate’s embryo is either holoblastic (complete) or meroblastic (partial). Sturgeon and other basal bony fishes represent a transition of the... 相似文献
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Reducing greenhouse gas emissions from arable soil while maintaining productivity is a major challenge for agriculture. Biochar is known to reduce N2O emissions from soil, but the underlying mechanisms are unclear. This study examined the impact of green waste biochar (20 Mg ha?1) and lime (CaCO3; 2 Mg ha?1) application on soil gas transport properties and related changes in these to soil N2O and CO2 emissions measured using automated chambers in a field experiment cropped with maize. In situ soil water content monitoring was combined with laboratory measurements of relative soil gas diffusion coefficient (Dp/D0) at different matric potentials, to determine changes in Dp/D0 over time. Cumulative N2O emissions were similar in the control and lime treatment, but much lower in the biochar treatment. Cumulative CO2 emissions decreased in the order: lime treatment > biochar treatment > control soil. When N2O emissions were not driven by excess N supply shortly after fertilisation, they were associated with Dp/D0 changes, whereby decreases in Dp/D0 corresponded to N2O emissions peaks. No distinct pattern was observed between CO2 emissions and Dp/D0. Cumulative N2O emissions were positively related to number of days with Dp/D0 < 0.02, a critical limit for soil aeration. These results indicate that improved soil gas diffusivity, and hence improved soil aeration, may explain the effect of biochar in reducing N2O emissions. They also suggest that knowledge of Dp/D0 changes may be key to explaining N2O emissions. 相似文献
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