Spatial analysis of a large magnitude erosion event following a Sierran wildfire

High intensity wildfire due to long-term fire suppression and heavy fuels buildup can render watersheds highly susceptible to wind and water erosion. The 2002 "Gondola" wildfire, located just southeast of Lake Tahoe, NV-CA, was followed 2 wk later by a severe hail and rainfall event that deposited 7.6 to 15.2 mm of precipitation over a 3 to 5 h time period. This resulted in a substantive upland ash and sediment flow with subsequent down-gradient riparian zone deposition. Point measurements and ESRI ArcView were applied to spatially assess source area contributions and the extent of ash and sediment flow deposition in the riparian zone. A deposition mass of 380 Mg of ash and sediment over 0.82 ha and pre-wildfire surface bulk density measurements were used in conjunction with two source area assessments to generate an estimation of 10.1 mm as the average depth of surface material eroded from the upland source area. Compared to previous measurements of erosion during rainfall simulation studies, the erosion of 1800 to 6700 g m(-2) mm(-1) determined from this study was as much as four orders of magnitude larger. Wildfire, followed by the single event documented in this investigation, enhanced soil water repellency and contributed 17 to 67% of the reported 15 to 60 mm ky(-1) of non-glacial, baseline erosion rates occurring in mountainous, granitic terrain sites in the Sierra Nevada. High fuel loads now common to the Lake Tahoe Basin increase the risk that similar erosion events will become more commonplace, potentially contributing to the accelerated degradation of Lake Tahoe's water clarity.     

Systematic analysis and overall toxicity evaluation of dioxins and hexachlorobenzene in human milk

A systematic method for analyzing dioxins (PCDDs, PCDFs and dioxin-like PCBs), hexachlorobenzene (HCB), heptachlor epoxide and beta-hexachlorocyclohexane (HCH) in human milk was developed to determine the residual amount of HCB in human milk and to evaluate the overall toxicity of both dioxins and HCB in human milk. The fractionation behavior of HCB on chromatography with silica gel, alumina, and activated carbon/silica gel, and the concentrated sulfuric acid decomposition method, which is widely used as a dioxin cleanup method, were studied in order to make the preprocessing operation for HCB measurement compatible with that for conventional dioxin measurement. HCB was found to be eluted in the 2% dichloromethane (DCM)/hexane 60 ml fraction from an alumina column. Heptachlor epoxide and a part of beta-HCH were eluted in the 10% DCM/hexane 50 ml fraction from a silica gel column, while the remaining beta-HCH was eluted in the 25% DCM/hexane 60 ml fraction from an activated carbon/silica gel column. Moreover, HCB showed significant correlation with dioxin congeners having high toxicity equivalence factors (TEFs). The results suggest that the exposure route to HCB and its accumulation behavior in the human body are similar to those of the dioxins.     

Distribution of poly(β-hydroxybutyrate) and poly(ε-caprolactone)aerobic degrading microorganisms in different environments

To assess the capacity of the natural environment for degrading plastics, the populations of poly(-hydroxybutyrate)(PHB)-and poly(-caprolactone)(PCL)-degrading aerobic microorganisms and their ratios to the total number of microorganisms in soil samples were estimated by the plate count method with agar medium containing emulsified PHB or PCL. The numbers of the degrading microorganisms were determined by counting colonies that formed clear zones on the plate. It was found that PHB- and PCL-degrading (depolymerizing) microorganisms are distributed over many kinds of material, including landfill leachate, compost, sewage sludge, forest soil, farm soil, paddy soil, weed field soil, roadside sand, and pond sediment. Of total colony counts, the percentages of PHB and PCL degrading microorganisms were 0.2–11.4 and 0.8–11.0%, respectively. The results suggest that many kinds of degrading microorganisms are present in each environment and that specific consortia differing in biodegradation capacity are constructed.     

Sources of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (Co-PCBs), and their bioaccumulation through the marine food web in Sendai Bay,Japan

The concentrations of PCDD/F and Co-PCB congeners in seawater, sediment, Pacific oyster, Japanese anchovy, marbled sole, and Japanese flounder samples from Sendai Bay, Japan, were analyzed. The compositions of total PCDD/F and total Co-PCB concentrations in sediment and Pacific oyster reflected that in seawater--the compositions of total PCDD, PCDF, and Co-PCB concentrations were approximately 60, 10, and 30%, respectively. The compositions in Japanese anchovy, marbled sole, and Japanese flounder were different from those in seawater and sediment-the ratio of total Co-PCB concentration to total PCDD/F plus Co-PCB concentrations in Japanese anchovy, marbled sole, and Japanese flounder was above 90%. Tetrachlorinated PCDDs (T4CDDs), such as 1,3,6,8- and 1,3,7,9-T4CDD, were the predominant congeners in seawater and sediment; the total T4CDD concentrations in seawater and sediment were approximately 46 and 48% of the total PCDD concentration. Furthermore, shipments of the herbicide 1,3,5-trichloro-2-(4-nitrophenoxy)benzene to Miyagi Prefecture, the so-called granary of Japan, were the highest in Japan over the last 12 years. The major sources of PCDD/Fs and Co-PCBs in Sendai Bay, which is in Miyagi Prefecture, are impurities in chlorinated herbicides. The order of concentration of PCDD/Fs was Pacific oyster > Japanese anchovy = marbled sole > Japanese flounder; the concentration in Japanese flounder, which is a higher-trophic-level consumer in the marine food web, was lower than that in shellfish (Pacific oyster) and Japanese anchovy, which are lower-trophic-level consumers. The order of concentration of Co-PCBs was Pacific oyster < Japanese anchovy = marbled sole < Japanese flounder; the concentrations in the higher-trophic-level consumers were higher than the concentrations in the lower-trophic-level consumers. Different PCDD/F congeners tended to bioaccumulate in different organisms. On the other hand, all species of Co-PCB congener tended to bioaccumulate in all organisms.     

Physical properties and biodegradability of blends containing poly(ε-caprolactone) and tropical starches

In order to assess feasibility of tropical starches (sago and cassava starches) as biodegradable plastic materials, blending with poly(-caprolactone) (PCL), a biodegradable polymer, was carried out. It was confirmed that the physical properties (tensile strength and elongation) of PCL/sago and PCL/cassava blends were similar to those of PCL/corn blend, suggesting that sago and cassava starches can also be blended with PCL for production of biodegradable plastic. However, the properties of all PCL/starch blends were still low compared with those of polyethylene. Enzymatic degradability evaluation showed that lipase degradation of PCL and-amylase degradation of starch increased as the starch content in the blend increased. Burial test of the blends for 1, 3, and 5 months was carried out and the rate of degradation of the PCL/sago blend was confirmed to be slower than those of PCL/corn and PCL/cassava blends. Observation of the film blends structure by scanning electron microscope revealed that the starch was dispersed in a PCL continuous phase. Furthermore, changes in the film surface before and after enyzme treatments were observed.     

Adsorption of surfactants on microbiologies

Adsorption isotherms of 5 priority surfactants on microbiologies were obtained. The sources and the conditions of microbiologies were little influenced on the adsorption, except in endogenous state. The employed surfactants were ready to adsorb in the order of AE>APE>LAS>AES>AOS.     

Regulatory off-gas analysis from the evaporation of Hanford simulated waste spiked with organic compounds

After strontium/transuranics removal by precipitation followed by cesium/technetium removal by ion exchange, the remaining low-activity waste in the Hanford River Protection Project Waste Treatment Plant is to be concentrated by evaporation before being mixed with glass formers and vitrified. To provide a technical basis to permit the waste treatment facility, a relatively organic-rich Hanford Tank 241-AN-107 waste simulant was spiked with 14 target volatile, semi-volatile, and pesticide compounds and evaporated under vacuum in a bench-scale natural circulation evaporator fitted with an industrial stack off-gas sampler at the Savannah River National Laboratory. An evaporator material balance for the target organics was calculated by combining liquid stream mass and analytical data with off-gas emissions estimates obtained using U.S. Environmental Protection Agency (EPA) SW-846 Methods. Volatile and light semi-volatile organic compounds (<220 degrees C BP, >1 mm Hg vapor pressure) in the waste simulant were found to largely exit through the condenser vent, while heavier semi-volatiles and pesticides generally remain in the evaporator concentrate. An OLI Environmental Simulation Program (licensed by OLI Systems, Inc.) evaporator model successfully predicted operating conditions and the experimental distribution of the fed target organics exiting in the concentrate, condensate, and off-gas streams, with the exception of a few semi-volatile and pesticide compounds. Comparison with Henry's Law predictions suggests the OLI Environmental Simulation Program model is constrained by available literature data.     

17α-Ethinylestradiol in Lakes of Hanoi and its effect on seed germination

Abstract

The lakes of Hanoi are important water resources for urban agriculture. The concentrations of 17α-ethinylestradiol in the water of three major lakes were found to range from 0.1 to 9.1?ng/L, peaking during the rainy season. Effects at levels from 1?ng/L to 1?µg/L on the germination of mung bean (Vigna radiata) and bok choy (Brassica rapa) were studied. Soaking the seeds in solutions containing 17α-ethinylestradiol at 10?ng/L and higher increased the germination rate of mung bean but not of bok choy. For the latter, irrigation after sowing with solutions containing 17α-ethinylestradiol at 10?ng/L and higher accelerated germination.

Abbreviations: MNRE: Ministry of Natural Resources and Environment; PE₆₀: Population equivalent; USGS: U.S. Geological Survey; SPE: Solid phase extraction; EDTA: Disodium ethylenediaminetetraacetate; HPLC: High performance liquid chromatography; ELISA: Enzyme-linked immunosorbent assay; DOM: Dissolved organic matter; EEQ: Estradiol equivalent     

Phosphate recovery from phosphorus-rich solution obtained from chicken manure incineration ash

The recovery of phosphorus from waste is very important for Japan because Japan has no natural phosphorus resources. In order to recover phosphorus from incineration ash of chicken manure, an acid dissolution–alkali precipitation method was investigated. Phosphorus content in the ash was 8%. The ash was treated with hydrochloric acid to obtain phosphorus-rich solution. Phosphorus could then be recovered as a precipitant by adding sodium hydroxide solution into the phosphorus-rich solution and gradually changing the pH in the solution to 3, 4, and 8. At pH 3, a small amount of phosphorus was precipitated to remove iron, which would cause coloring of subsequent precipitants. At pH 4, 84% of the phosphorus in the original solution could be recovered as CaHPO₄ · 2H₂O with a purity of 92%. At pH 8, 8% of the phosphorus in the phosphorus-rich solution could be recovered as identified hydroxyapatite. A recovery rate of 92% phosphorus as CaHPO₄ · 2H₂O and identified as hydroxyapatite was achieved.