Different Nanomaterials for Soil Remediation Affect Avoidance Response and Toxicity Response in Earthworm (Eisenia fetida)

Bulletin of Environmental Contamination and Toxicology - The application of nano-level passivating agents in the remediation of soil heavy metal pollution has received widespread attention, but its...     

Biochemical Responses of Earthworm Eisenia fetida Exposed to Cadmium-Contaminated Soil with Long Duration

The biochemical responses of the earthworms, Eisenia fetida, exposed to a series of Cd concentrations (0.00, 1.25, 2.50, 5.00 and 10.00?mg Cd²⁺?kg^?1 soil) for up to 8?weeks were investigated, aiming to evaluate the sublethal effects of Cd with long exposure and to explore the potential for applying these responses as biomarkers to indicate the Cd-contaminated soil. The following biochemical parameters were determined: cytochrome P450 (CYP) contents and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione-s-transferase (GST). Cadmium concentrations in all earthworms were apparently accumulated in 4?weeks, and showed minor changes in weeks 6–8 compared to the first 4?weeks. CYP presented a significant elevation in 2–4?weeks and a decline in 6–8?weeks in each treated group. The activities of SOD and CAT showed an obvious increase with exposure of 6–8?weeks while their levels were not affected in 4?weeks in each treated group. GST activity revealed significant activation starting from week 4. This study confirmed the significance of applying a suite of biomarkers rather than a selective choice to assess the impact of pollutants on organisms. It also indicated that the observed effects were more dependent upon exposure duration than dose.     

Toxicological Responses of the Earthworm Eisenia fetida to 18-Crown-6 Under Laboratory Conditions

The earthworm Eisenia fetida was exposed to artificial soil supplemented with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) to investigate its effects on earthworm mortality, growth, avoidance, burrowing behavior and respiration. The results revealed that 18-crown-6 had the potential to negatively affect the behavior of earthworms. The 7-d LC₅₀ was 585 mg kg^?1 soil. Avoidance behavior was the most sensitive endpoint, with a 48-h EC₅₀ of 120 mg kg^?1 soil. Growth, burrow length and respiration showed general decreases with increasing 18-crown-6 concentrations. Behavioral endpoints and respiration may be regarded as sensitive parameters in evaluating the toxicity of this chemical to earthworms.     

Effect of Nano-Carbon Black Surface Modification on Toxicity to Earthworm (Eisenia fetida) Using Filter Paper Contact and Avoidance Test

Bulletin of Environmental Contamination and Toxicology - Engineered nanomaterials (NMs) may enter the soil through various channels and pose potential harm to soil animals, especially those...     

Inhibitory Effect of a Herbicide Formulation on Toxicity of Malathion to the Worm Eisenia fetida

No abstract available.     

Toxicity of chromium(III) and chromium(VI) to the earthworm Eisenia fetida

The effects of Cr(III) and Cr(VI) on the survival, behavior, and morphology of the earthworm, Eisenia fetida, in water at pH 6, 7, and 8 and their toxicity in 10 different soils and an organic substrate have been assessed. A decrease in the pH of water resulted in increased toxicity of Cr to the earthworm. In water, both Cr species produced behavioral changes and morphological symptoms. The 48-h LC(50) values of Cr(III) at pH 6, 7, and 8 were 1.93, 2.55, and 2.78 mg/L, and those of Cr(VI) were 0.47, 0.61, and 0.63 mg/L, respectively. The 14-day median lethal concentrations (LC(50)) of Cr(III) and Cr(VI) for earthworm range from 1656 to 1902 mg/kg for Cr(III) and from 222 to 257 mg/kg for Cr(VI) in soil. In the organic substrate, the LC(50) values of Cr(III) and Cr(VI) were 1635 and 219 mg/kg, respectively. Stepwise multiple regression analysis predicted that clay content of soils accounted for 92% and 88% of the variation in the LC(50) values of Cr(III) and Cr(VI), respectively.     

Toxicity Assessment of Contaminated Sediments after Dredging

No abstract available.     

Potentiation Effect of Metolachlor on Toxicity of Organochlorine and Organophosphate Insecticides in Earthworm Eisenia andrei

Acetylcholinesterase, glutathione-S-transferase and catalase activities were determined in earthworms Eisenia andrei exposed to insecticides (endosulfan, temephos, malathion, pirimiphos-methyl) alone and in a binary combination with the herbicide metolachlor. Metolachlor individually was not acutely toxic, even at high concentrations applied; however, in the treated earthworms metolachlor enhanced the toxicity of endosulfan and temephos by significantly reducing the acetylcholinesterase activity. In binary combination with malathion and pirimiphos-methyl, metolachlor did not increase toxicity. The potentiation character of metolachlor is specific rather than general, and probably depends on the chemical structure of pesticides in the mixture.     

Bioavailability of Lead and Cadmium in Soils Artificially Contaminated with Smelter Fly Ash

This study evaluated lead and cadmium uptake by maize grown on soils artificially spiked with smelter fly ash and possible changes in chemical fractionation of these metals in the soil. Maize grown on the less contaminated soil (1,466 mg Pb kg⁻¹; 19 mg Cd kg⁻¹) did not exhibit any chlorosis/necrosis symptoms or lower biomass yields compared to the control. The addition of the chelating agent ethylenediaminetetraacetic acid increased lead uptake by maize, as expected. Neither maize cultivation nor the addition of the chelant influenced significantly the chemical fractionation of lead and cadmium in the soil during the experiment.     

广州市不同功能区土壤铅的健康风险评估

[目的]了解广州市不同功能区土壤铅（Pb）污染状况及其生物可给性,初步探讨pb生物可给量的影响因素,评估不同功能区土壤Pb经口无意摄入途径的人体健康风险。[方法]选择广州居民区、商业区、汽车站、文教区、医疗区和公园土壤为研究对象,采用体外实验法模拟人体消化系统进行消化,运用原子吸收分光光谱法测定胃、小肠消化阶段反应液中可溶态Pb和土壤Pb含量并计算其生物可给性,根据Pb生物可给量进行健康风险评价。[结果]广州市中小城区土壤Pb平均含量（90．34mg／kg）高于广州市、广东省和中国土壤背景值（P〈0．05）。土壤在模拟胃、小肠阶段中Pb平均生物可给性分别为36．55％、9．03％,其中以公园最高（41．98％,14.17％）。儿童和成人经口无意摄入途径的Pb平均摄入量分别为18．32、4．58μg／d,其中商业区最高（28．14、7．03μg／d）。儿童在模拟胃阶段和小肠阶段中的Pb平均生物可给量分别为6．86、1．46μg／d,其中以商业区最高（13．03、2．03μg/d）;成人在模拟胃阶段和小肠阶段中的Pb平均生物可给量则分别为1．72、0．36μg／d,其中商业区最高（3．26、0．51μg/d）。儿童和成人在胃肠消化阶段中Pb生物可给量与土壤Pb总量有直线关系（P〈0．05）。不同功能区土壤Pb对儿童和成人的健康绝对风险系数（丘）以及模拟胃、小肠阶段的健康相对风险系数（Kr1、Kr2）,均未超过世界卫生组织（WHO）人体健康风险警戒线。[结论]广州市不同功能区土壤Pb污染程度不同,但不同功能区土壤Pb尚未超过WHO人体健康风险警戒线。     

Acute Toxicity, Toxicokinetics, and Tissue Target of Lead and Uranium in the Clam Corbicula fluminea and the Worm Eisenia fetida: Comparison with the Fish Brachydanio rerio

The general objective of our work was to propose new reference material for chemical toxicity testing and new sentinel organisms for environmental quality survey programs (freshwater or soils). We also wanted to provide basic toxicological data on the environmental effects of uranium. Thus, we conducted a comparative study to establish the acute toxicity and toxicokinetics of lead (Pb) and uranium (U) to the bivalve mollusc Corbicula fluminea and the terrestrial annelid Eisenia fetida andrei and to compare these findings with those of the well-known teleost fish Brachydanio rerio. We then measured the concentration of these metals in various tissues of the clam and the worm after two periods of exposure (4 and 11 days) to identify the affinities of these tissues for Pb and U. Our results have shown that Pb and U are very toxic to Eisenia and relatively nontoxic to Corbicula. By comparison, Pb was relatively nontoxic and U appeared to be very toxic to the fish. The toxicokinetic studies indicated that the three species are able to accumulate Pb and U, the rate and level of accumulation depending both on the species and the metal. We also found that fish and clams depurate the two metals. Data collected for the worm were conflicting: Pb was not depurated whereas tissue concentrations of U declined after the eighth day of exposure. Our study has also shown that the tissue distribution of Pb in the mollusc and in the earthworm differs significantly from that of U, both after 4 and 11 days exposure. In conclusion, these three species showed potential as bioindicators of environmental contamination by metals. Indeed, they could be used in conjunction to test different compartments of an ecosystem: worms for soils, fish for the water column, and clams for the water/sediment interface. Received: 30 October 1996/Accepted: 1 September 1998     

Acute ecotoxicity of creosote-contaminated soils to Eisenia fetida: a survival-based approach

Quantification of risks to the ecosystem is necessary for cost-effective remediation strategies. Contaminant endpoints need to be established that consider the bioavailability of toxicants in soil. The challenge is to develop methods that assign risk to the bioavailable toxic contaminants, thereby protecting ecosystems, while balancing remediation costs. Our objective was to evaluate changes in bioavailability of creosote constituents in soils to earthworms. An acute ecotoxicological investigation of three weathered creosote-contaminated and two slurry-phase-biotreated soils was conducted using a 14-d earthworm (Eisenia fetida) survival bioassay. Soil characterization (physical and chemical) and contaminant concentration data (polycyclic aromatic hydrocarbons [PAH] and total dichloromethane extractable organics [DEO]) were also determined. The toxicity of the soils could not always be predicted based on chemical concentrations alone. Soils having a low PAH:DEO ratio had higher cumulative earthworm survival times as measured by earthworm-days. We propose that the DEO fraction may regulate toxicity by altering bioavailability of toxicants.     

Bioaccumulation of metals in Eisenia fetida after exposure to a metal-loaded bauxsol reagent

The present study investigated the acute toxic effects of a metal-loaded Bauxsol reagent (MLBR), containing more than 6,450 mg kg(-1) of bound metal, on the earthworm Eisenia fetida. Bauxsol is manufactured by Virotec Global Solutions of Gold Coast, Queensland, Australia. The E. fetida were exposed to 0, 10, 20, 40, 60, and 80% treatments of MLBR plus cow manure for 28 d. Good motility and no mortality of E. fetida were found in all treatments after 28 d of exposure. The greatest bioaccumulation of metals by E. fetida occurred in the 20 and 40% MLBR treatments. The bioaccumulation of metals in the worms and bioaccumulation factors (BAFs) were less than the reported toxicity thresholds to cause mortality and less than the reported BAF for moderately contaminated soils, indicating that metals bound to Bauxsol reagents are mostly nonbioavailable. Analyses of the 20% MLBR treatment at 28 d using a sequential extraction procedure showed that more than 95% of the metals are bound within the Fe/Mn oxide fractions. However, changes occurred in metal fractionation after exposure to E. fetida for Cd/Cr, and Fe/Mn. The data also showed that the exchangeable (1 M MgCl2) and the toxicity characteristic leaching procedure extractant are useful as indicators of metal bioavailability from MLBR to E. fetida.     

Bioavailability of phthalate congeners to earthworms (Eisenia fetida) in artificially contaminated soils

Bioavailability of phthalate congeners, dimethyl phthalate, diethyl phthalate, di-n-butyl phthalate (DBP), di-(2-ethylhexyl) phthalate (DEHP), and dioctyl phthalate, to earthworms (Eisenia fetida) were studied when earthworms were exposed to two artificially contaminated agricultural and forest soils. Only DBP and DEHP were detected in earthworms. The uptake kinetics of DBP and DEHP in earthworms was fast within the initial 10 days followed by a nearly steady state for the subsequent 20 days. An equilibrium partitioning model could be used to describe the uptake kinetics of DBP and DEHP by earthworm in two types of soils (r = 0.709-0.864). The average biota-to-soil accumulation factors (BSAFs) of DBP and DEHP at 5 mg kg(-1) in soil were 0.27 +/- 0.07 and 0.17 +/- 0.03, respectively, in agricultural soil, while the BSAFs were 0.21 +/- 0.06 and 0.07 +/- 0.02, respectively, in forest soil. The concentrations of phthalates in earthworms increased with increasing concentrations of phthalates in soil. There was a significant correlation between logC(soil) and logC(worm), with r = 0.999-0.993, demonstrating a single linear partitioning of phthalates between soil and earthworms. The bioavailability of DBP and DEHP was assessed by Soxhlet, methanol, and methanol-water (1:1) extraction methods. Our results indicated that the extractable amounts of freshly added DBP and DEHP in soils by these extraction methods were significantly correlated with those in earthworms. It was observed that the extractable DBP and DEHP by the methanol and methanol-water (1:1) extraction methods decreased with their increasing residence time in soil. In contrast, the amount extracted by the Soxhlet extraction method did not show a similar decline. Therefore, Soxhlet extraction was a poor indicator of the bioavailability of DBP and DEHP to earthworms in soil, which could lead to overestimation of the risk of soil-associated DBP and DEHP. The extractable DBP and DEHP by methanol and methanol-water (1:1) significantly decreased over 440 days. Compared with the methanol-water (1:1) extraction method, the methanol extraction method was preferred for its ability to predict the bioavailability of DBP and DEHP in aged soils.