Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306 mg kg⁻¹) and bioavailable (cyclodextrin extractable) (276 to 182 mg kg⁻¹) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2 mg kg⁻¹), Cu (60.0 to 120.1 mg kg⁻¹) and Ni (31.7 to 83.0 mg kg⁻¹) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37 mg kg⁻¹). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed.     

Emission reductions from woody biomass waste for energy as an alternative to open burning

Woody biomass waste is generated throughout California from forest management, hazardous fuel reduction, and agricultural operations. Open pile burning in the vicinity of generation is frequently the only economic disposal option. A framework is developed to quantify air emissions reductions for projects that alternatively utilize biomass waste as fuel for energy production. A demonstration project was conducted involving the grinding and 97-km one-way transport of 6096 bone-dry metric tons (BDT) of mixed conifer forest slash in the Sierra Nevada foothills for use as fuel in a biomass power cogeneration facility. Compared with the traditional open pile burning method of disposal for the forest harvest slash, utilization of the slash for fuel reduced particulate matter (PM) emissions by 98% (6 kg PM/BDT biomass), nitrogen oxides (NOx) by 54% (1.6 kg NOx/BDT), nonmethane volatile organics (NMOCs) by 99% (4.7 kg NMOCs/BDT), carbon monoxide (CO) by 97% (58 kg CO/BDT), and carbon dioxide equivalents (CO2e) by 17% (0.38 t CO2e/BDT). Emission contributions from biomass processing and transport operations are negligible. CO2e benefits are dependent on the emission characteristics of the displaced marginal electricity supply. Monetization of emissions reductions will assist with fuel sourcing activities and the conduct of biomass energy projects.     

Bacteria associated with oak and ash on a TCE-contaminated site: characterization of isolates with potential to avoid evapotranspiration of TCE

Background, aim, and scope  

Along transects under a mixed woodland of English Oak (Quercus robur) and Common Ash (Fraxinus excelsior) growing on a trichloroethylene (TCE)-contaminated groundwater plume, sharp decreases in TCE concentrations were observed, while transects outside the planted area did not show this remarkable decrease. This suggested a possibly active role of the trees and their associated bacteria in the remediation process. Therefore, the cultivable bacterial communities associated with both tree species growing on this TCE-contaminated groundwater plume were investigated in order to assess the possibilities and practical aspects of using these common native tree species and their associated bacteria for phytoremediation. In this study, only the cultivable bacteria were characterized because the final aim was to isolate TCE-degrading, heavy metal resistant bacteria that might be used as traceable inocula to enhance bioremediation.     

Modeling the photo-oxidation of dissolved organic matter by ultraviolet radiation in freshwater lakes: implications for mercury bioavailability

Uncertainties in projected ultraviolet (UV) radiation may lead to future increases in UV irradiation of freshwater lakes. Because dissolved organic carbon (DOC) is the main binding phase for mercury (Hg) in freshwater lakes, an increase in DOC photo-oxidation may affect Hg speciation and bioavailability. We quantified the effect of DOC concentration on the rate of abiotic DOC photo-oxidation for five lakes (DOC=3.27-12.3 mg L(-1)) in Kejimkujik National Park, Canada. Samples were irradiated with UV-A or UV-B radiation over a 72-h period. UV-B radiation was found to be 2.36 times more efficient at photo-oxidizing DOC than UV-A, with energy-normalized rates of dissolved inorganic carbon (DIC) production ranging from 3.8×10(-5) to 1.1×10(-4) mg L(-1)J(-1) for UV-A, and from 6.0×10(-5) to 3.1×10(-4) mg L(-1)J(-1) for UV-B. Energy normalized rates of DIC production were positively correlated with DOC concentrations. Diffuse integrated attenuation coefficients were quantified in situ (UV-A K(d)=0.056-0.180 J cm(-1); UV-B K(d)=0.015-0.165 J cm(-1)) and a quantitative depth-integrated model for yearly DIC photo-production in each lake was developed. The model predicts that, UV-A produces between 3.2 and 100 times more DIC (1521-2851 mg m(-2) year(-1)) than UV-B radiation (29.17-746.7 mg m(-2) year(-1)). Future increases in UV radiation may increase DIC production and increase Hg bioavailability in low DOC lakes to a greater extent than in high DOC lakes.     

Evaluation of bendiocarb cytotoxicity in mammalian and insect cell cultures

There is an increasing need for rapid and easily interpreted in vitro assays to screen for possible cytotoxicity of pesticides. The objective of this study was to investigate the effect of the carbamate insecticide bendiocarb on mammalian and insect cell cultures. The cytotoxicity of this insecticide was evaluated by cell proliferation and cellular damage was assessed by evaluation of the cytopathic effect and lactate dehydrogenase (LDH) leakage. Cells of insect origin (Sf21) were the most sensitive to bendiocarb with significant (P < 0.01) suppression of their proliferative activity ranging from 10(-1)-10(-5) M. However, significant suppression of proliferative activity was also recorded in rat liver cells (WBF344; 10(-1)-10(-3) M; P < 0.01-0.05) and rabbit kidney cells (RK13; 10(-1) M; P < 0.01). In contrast with the proliferation activity of cells, a cytopathic effect based on cellular damage and LDH leakage into the medium was observed only at the highest concentration (10(-1) M) in RK 13 and WBF344 cells, but not in the Sf21 insect cell line. Our results indicate that bendiocarb exposure caused a cell-type dependent decrease in cell proliferation; however, cell damage and LDH leakage into the medium were not present or were strongly limited, dependent on the cell phenotype. Cell proliferation was shown as a sensitive indicator for evaluation of the cytotoxic effect of bendiocarb in vitro; on the other hand, microscopic signs of cellular damage and LDH leakage were insufficient in vitro markers.     

Evaluation Criteria for Implementation of a Sustainable Sanitation and Wastewater Treatment System at Jiuzhaigou National Park, Sichuan Province, China

The administration of Jiuzhaigou National Park in Sichuan Province, China, is in the process of considering a range of upgrades to their sanitation and wastewater treatment systems. Their case history involves an ongoing series of engineering design flaws and management failures. The administration of the Park identified sustainability, environmental protection, and education goals for their sanitation and wastewater treatment system. To meet the goal of sustainability, environmental and economic concerns of the Park’s administration had to be balanced with socio-cultural needs. An advanced reconnaissance method was developed that identified reasons for previous failures, conducted stakeholder analysis and interviews, determined evaluation criteria, and introduced innovative alternatives with records of successful global implementations. This evaluation also helped the Park to better define their goals. To prevent future failures, the administration of the Park must commit to a balanced and thorough evaluation process for selection of a final alternative and institute effective long-term management and monitoring of systems. In addition, to meet goals and achieve energy efficient, cost-effective use of resources, the Park must shift their thinking from one of waste disposal to resource recovery. The method and criteria developed for this case study provides a framework to aid in the successful implementation of sanitation projects in both underdeveloped and developed areas of the world, incorporating socio-cultural values and resource recovery for a complex group of stakeholders.     

Free and conjugated estrogen exports in surface-runoff from poultry litter-amended soil

Land application of animal manures such as poultry litter is a common practice, especially in states with surplus manure. Past studies have shown that animal manure may contain estrogens, which are classified as endocrine-disrupting chemicals and may pose a threat to aquatic and wildlife species. We evaluated the concentrations of estrogens in surface runoff from experimental plots (5 x 12 m each) receiving raw and pelletized poultry litter. We evaluated the free (estrone, E1; 17beta-estradiol, E2beta; estriol, E3) and conjugate forms (glucuronides and sulfates) of estrogens, which differ in their toxicity. Sampling was performed for 10 natural storm events over a 4-mo period (April-July 2008). Estrogen concentrations were screened using enzyme-linked immunosorbent assay (ELISA), followed by quantification using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Concentrations of estrogens from ELISA were much higher than the LC/MS/MS values, indicating crossreactivity with organic compounds. Exports of estrogens were much lower from soils amended with pelletized poultry litter than the raw form of the litter. No-tillage management practice also resulted in a lower export of estrogens with surface runoff compared with reduced tillage. The concentrations and exports of conjugate forms of estrogens were much higher than the free forms for some treatments, indicating that the conjugate forms should be considered for a comprehensive assessment of the threat posed by estrogens.     

Quantifying the transport impacts of domestic waste collection strategies

This paper models the effects of three different options for domestic waste collection using data from three Hampshire authorities: (i) joint working between neighbouring waste collection authorities; (ii) basing vehicles at waste disposal sites; and (iii) alternate weekly collection of residual waste and dry recyclables. A vehicle mileage savings of 3% was modelled for joint working, where existing vehicle allocations to depots were maintained, which increased to 5.9% when vehicles were re-allocated to depots optimally. Vehicle mileage was reduced by 13.5% when the collection rounds were based out of the two waste disposal sites rather than out of the existing depots, suggesting that the former could be the most effective place to keep vehicles providing that travel arrangements for the crews could be made. Alternate weekly collection was modelled to reduce vehicle mileage by around 8% and time taken by 14%, when compared with a typical scenario of weekly collection of residual and fortnightly collection of recyclable waste. These results were based on an assumption that 20% of the residual waste would be directly diverted into the dry recyclables waste stream.     

Uptake of Cd,Pb, U,and Zn by plants in floodplain pollution hotspots contributes to secondary contamination

Environmental Science and Pollution Research - Willows, woody plants of genus Salix common in floodplains of temperate regions, act as plant pumps and translocate the Cd and Zn in the soil profiles...     

Uranium uptake by hydroponically cultivated crop plants

Hydroponicaly cultivated plants were grown on medium containing uranium. The appropriate concentrations of uranium for the experiments were selected on the basis of a standard ecotoxicity test. The most sensitive plant species was determined to be Lactuca sativa with an EC₅₀ value about 0.1 mM. Cucumis sativa represented the most resistant plant to uranium (EC₅₀ = 0.71 mM). Therefore, we used the uranium in a concentration range from 0.1 to 1 mM.Twenty different plant species were tested in hydroponic solution supplemented by 0.1 mM or 0.5 mM uranium concentration. The uranium accumulation of these plants varied from 0.16 mg/g DW to 0.011 mg/g DW. The highest uranium uptake was determined for Zea mays and the lowest for Arabidopsis thaliana. The amount of accumulated uranium was strongly influenced by uranium concentration in the cultivation medium. Autoradiography showed that uranium is mainly localized in the root system of the plants tested. Additional experiments demonstrated the possibility of influencing the uranium uptake from the cultivation medium by amendments. Tartaric acid was able to increase uranium uptake by Brassica oleracea and Sinapis alba up to 2.8 times or 1.9 times, respectively. Phosphate deficiency increased uranium uptake up to 4.5 times or 3.9 times, respectively, by Brassica oleracea and S. alba. In the case of deficiency of iron or presence of cadmium ions we did not find any increase in uranium accumulation.