More realistic soil cleanup standards with dual-equilibrium desorption

The desorption of contaminants from soils/sediments is one of the most important processes controlling contaminant transport and environmental risks. None of the currently adopted desorption models can accurately quantify desorption at relatively low concentrations; these models often overestimate the desorption and thus the risks of hydrophobic organic chemicals, such as benzene and chlorinated solvents. In reality, desorption is generally found to be biphasic, with two soil-phase compartments. A new dual-equilibrium desorption (DED) model has been developed to account for the biphasic desorption. This model has been tested using a wide range of laboratory and field data and has been used to explain key observations related to underground storage tank plumes. The DED model relates the amount of a chemical sorbed to the aqueous concentration, with simple parameters including octanol-water partition coefficient, solubility, and fractional organic carbon; thus, it is the only biphasic model, to date, that is based on readily available parameters. The DED model can be easily incorporated into standard risk and transport models. According to this model, many regulatory standards of soils and sediments could be increased without increasing the risks.     

日本本州岛地区地震活动频繁

据塔斯社1988年6月27日至8月6日发自东京的电讯报道:日本的本州岛地区地震活动频繁,强度为日本气象厅7度烈度标度的1至     

苏联地质部长谈苏联的地质勘探工作

根据对地壳和地幔所有构造层进行的综合观测,苏联已经完成了对地球深部的新研究。苏联地质部长科兹洛夫斯基在会见塔斯社记者时说,这些研究工作对许多国家的专家也具有重大的科学和实际意义。这位部长还说,新型的地球物理仪器,技术手段和先进的钻探工序为研究工作的成功提供了主要保证。部长首先介绍了科拉半岛(苏联国土欧洲部分的北部)和萨阿特雷(外高加索)超深井的试钻情况,这些超深井已提供了关于地球深部的构造和所发生过程的丰富资料;然后他又介绍了苏联2000年以前在辽阔国土上进行深部     

观察自然的地震窗——古宾谈地震构造规律

苏联科学院通讯院士、地质矿物学博士古宾对不同地区(其中也包括塔吉克斯坦)的地质构造及其沿断层发生的孕震运动进行了半个多世纪的研究,确定了人们过去还不知道的地震能量与地震构造(地壳块体)尺度和类型之间有规律性的数值关系。这种综合性关系被称为古宾地震构造规律。这个规律不仅能导致建立预报地震各种不同要素的新(原则上)方法,而且还能导致绘制出完全新的、反映许多要素的地震区划图(标出可能     

Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American Test Flight of Boomerang

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 μK(CMB).     

Assessment of carbon in woody plants and soil across a vineyard-woodland landscape

Background

Quantification of ecosystem services, such as carbon (C) storage, can demonstrate the benefits of managing for both production and habitat conservation in agricultural landscapes. In this study, we evaluated C stocks and woody plant diversity across vineyard blocks and adjoining woodland ecosystems (wildlands) for an organic vineyard in northern California. Carbon was measured in soil from 44 one m deep pits, and in aboveground woody biomass from 93 vegetation plots. These data were combined with physical landscape variables to model C stocks using a geographic information system and multivariate linear regression.

Results

Field data showed wildlands to be heterogeneous in both C stocks and woody tree diversity, reflecting the mosaic of several different vegetation types, and storing on average 36.8 Mg C/ha in aboveground woody biomass and 89.3 Mg C/ha in soil. Not surprisingly, vineyard blocks showed less variation in above- and belowground C, with an average of 3.0 and 84.1 Mg C/ha, respectively.

Conclusions

This research demonstrates that vineyards managed with practices that conserve some fraction of adjoining wildlands yield benefits for increasing overall C stocks and species and habitat diversity in integrated agricultural landscapes. For such complex landscapes, high resolution spatial modeling is challenging and requires accurate characterization of the landscape by vegetation type, physical structure, sufficient sampling, and allometric equations that relate tree species to each landscape. Geographic information systems and remote sensing techniques are useful for integrating the above variables into an analysis platform to estimate C stocks in these working landscapes, thereby helping land managers qualify for greenhouse gas mitigation credits. Carbon policy in California, however, shows a lack of focus on C stocks compared to emissions, and on agriculture compared to other sectors. Correcting these policy shortcomings could create incentives for ecosystem service provision, including C storage, as well as encourage better farm stewardship and habitat conservation.

     

Survey of PAH in low density residential stormwater ponds in coastal South Carolina: false dark mussels (Mytilopsis leucophaeata) as potential biomonitors

The distribution of PAHs was studied in sediment and false dark mussels, Mytilopsis leucophaeata, of three brackish stormwater retention ponds on Kiawah Island, a gated residential community and golf resort. Impervious surface in pond watersheds ranged from 5 to 30%. Sediment concentrations were lower than those found in other studies of suburban residential areas, and there were no significant differences among ponds or seasons. Mean summation operatorPAH(16) values for sediments in Ponds 67, 100, and 37 were 184.7+/-101.3ng g(-1), 67.5+/-26.0ng g(-1), and 84.3+/-75.5ng g(-1), respectively. Mussel summation operatorPAH(16) concentrations from Pond 67 in August (mean 734.5+/-148.1ng g(-1)), and from Pond 37 in December (mean 1115.1+/-87.7ng g(-1)), were significantly higher than other ponds. Mean summation operatorPAH(16) values for mussels in Ponds 67, 100, and, 37 were 555.9+/-219.7ng g(-1), 312.5+/-99.1ng g(-1) and 737.8+/-419.8ng g(-1), respectively. The mean biota-to-sediment ratio was 7.6+/-8.1. Isomer ratios generally suggested pyrogenic sources. False dark mussels are a promising indicator species for PAH contamination because they are abundant, easy to sample, bioaccumulate PAH profiles representative of the time-integrated sediment profiles, and their PAH levels are less variable than either stormwater or sediment samples.