The distribution and composition of hydrocarbons in sediments from the Fladen Ground, North Sea, an area of oil production

The distribution and composition of hydrocarbons in sediment from the Fladen Ground oilfield in the northern North Sea have been investigated. The total PAH concentrations (2- to 6-ring parent and alkylated PAHs, including the 16 US EPA PAHs) in sediments were relatively low (<100 microg kg(-1) dry weight). The PAH, the Forties crude and diesel oil equivalent concentrations were generally higher in sediment of fine grain size and higher organic carbon concentration. PAH distributions and concentration ratios indicated a predominantly pyrolytic input, being dominated by the heavier, more persistent, 5- and 6-ring compounds, and with a high proportion of parent PAHs. The n-alkane profiles of a number of the sediments contained small, high boiling point, UCMs, indicative of weathered oil arising from a limited petrogenic input. The geochemical biomarker profiles of the sediments that contained UCMs showed a small bisnorhopane peak and a high proportion of norhopane relative to hopane, indicating that there was contamination from both Middle Eastern and North Sea oils. Therefore contamination was not directly as a result of oil exploration activity in the area. The most likely source of petrogenic contamination was from general shipping activity.     

Estimated occupational risk from bioaerosols generated during land application of class B biosolids

Some speculate that bioaerosols from land application of biosolids pose occupational risks, but few studies have assessed aerosolization of microorganisms from biosolids or estimated occupational risks of infection. This study investigated levels of microorganisms in air immediately downwind of land application operations and estimated occupational risks from aerosolized microorganisms. In all, more than 300 air samples were collected downwind of biosolids application sites at various locations within the United States. Coliform bacteria, coliphages, and heterotrophic plate count (HPC) bacteria were enumerated from air and biosolids at each site. Concentrations of coliforms relative to Salmonella and concentrations of coliphage relative to enteroviruses in biosolids were used, in conjunction with levels of coliforms and coliphages measured in air during this study, to estimate exposure to Salmonella and enteroviruses in air. The HPC bacteria were ubiquitous in air near land application sites whether or not biosolids were being applied, and concentrations were positively correlated to windspeed. Coliform bacteria were detected only when biosolids were being applied to land or loaded into land applicators. Coliphages were detected in few air samples, and only when biosolids were being loaded into land applicators. In general, environmental parameters had little impact on concentrations of microorganisms in air immediately downwind of land application. The method of land application was most correlated to aerosolization. From this large body of data, the occupational risk of infection from bioaerosols was estimated to be 0.78 to 2.1%/yr. Extraordinary exposure scenarios carried an estimated annual risk of infection of up to 34%, with viruses posing the greatest threat. Risks from aerosolized microorganisms at biosolids land application sites appear to be lower than those at wastewater treatment plants, based on previously reported literature.     

历史时期长江中游水灾与厄尔尼诺事件的遥相关

长江中游历来是长江流域水灾最严重的地区，研究历史时期这一地区水灾发生的变化波动并找出其与厄尔尼诺事件的遥相关，将有助于对长江中游水灾发生的预测。对这二个时间序列自1525年以来的数据进行了统计学分析。结果表明，水灾发生的主要周期比厄尔尼诺事件发生的周期要长：后者主要表现为2年和3~4年的振动，而前者的主要周期为2年、8年和40年，其显著性也没有后者明显（但都超过了0.03的置信度）。通过进一步分析历史时期长江中游水灾与厄尔尼诺事件的耦合振动，发现它们之间存在显著的遥相关。结果表明，长江中游水灾对厄尔尼诺现象的响应不仅存在着如许多中国学者相信的短期滞后（如：1年），而且还存在着比较长时间的滞后（最长可达8年）。研究结果同时表明，如果厄尔尼诺事件发生的相距时间愈短，这一时期长江中游水灾响应的滞后时间也愈短，反之亦然。     

Household Willingness to Pay and Farmers' Willingness to Accept Compensation for Establishing a Recreational Woodland

The UK Forestry Commission's recently implemented Community Woodland scheme sets out to provide new recreational woodland facilities near to towns and cities where such resources are in short supply. This study examines household willingness to pay (WTP) for such a proposed woodland by means of the contingent valuation (CV) method. A stratified sample of 325 households in Wantage, Oxfordshire, was interviewed and asked to state both their annual and per-visit WTP. Analysis of a number of recognized potential biases suggested that the results obtained must be treated with caution although we argue that the CV provides a useful ballpark indication of preferences. A simultaneous CV survey of farmers' willingness to accept compensation for converting agricultural land into woodland proved to be far more robust, despite a small sample size. We conclude that farmers are more familiar with the concept of assessing potential compensation than are households with estimating hypothetical payments for increased provision of public goods.     

Northern Idaho House Dust and Soil Lead Levels Compared to the Bunker Hill Superfund Site

House dust has been identified as a major exposure medium for lead (Pb) in children. High levels of Pb in soil and house dust have been recorded at the Bunker Hill Superfund Site (BHSS) in northern Idaho, an historic mining and smelting district. Soil and dust remediation at the site was required; however, regional background soil and dust Pb levels had not been well characterized. The objective of this survey was to determine background house dust Pb levels and to compare those levels with concentrations, and dust and Pb loading rates measured at the BHSS. Soil and house dust samples were collected in five towns demographically similar to the BHSS but unaffected by the mining industry. The background concentrations and loading rates were significantly lower than those observed at the site. House age was a significant factor affecting background soil and house dust Pb concentrations and loading rates.     

Dissolved antimony concentrations in contrasted watersheds: the importance of lithogenic origin

A large series of data on dissolved antimony concentrations (900 values) from the hydrological network of Canton Geneva, Switzerland, has been statistically analysed. Data were collected from 90 sampling sites over 12 years. The watercourses surveyed (178 km) accounted for 73% of the total network. Previous studies have classified these rivers as belonging to three clearly-differentiated lithogenic zones: Alps (rivers draining crystalline regions), Jura (rivers draining carbonate-rich zones) and Plain (rivers draining molasses derived from the Alps). Antimony concentrations in the different river waters have been found to be significantly dependent on the geological characteristics of the drainage basins (median values: 0.13, 0.08 and 0.16 microg L(-1) for Alps, Jura and Plain, respectively). For antimony, it is thus possible to define background levels of the element adapted to the lithogenic characteristics for a system of interest. Since establishing background levels is an unavoidable preliminary step in any study aiming to identify and evaluate the various sources of pollution, the behaviour described here has undeniable implications for environmental surveys.     

New Approaches Toward a Better Understanding of the Decline of Takahe (Porphyrio mantelli) in New Zealand

Island populations of endemic birds are known to be particularly susceptible to extinction. This paper focuses on factors behind past and present declines of the highly endangered Takahe ( Porphyrio mantelli ), a flightless rail endemic to New Zealand. Subfossil evidence indicates that Takahe were once found throughout this island nation, being most abundant along forest margins and streams in lowland regions. Their numbers have declined dramatically since human colonization about 800–1000 years ago, probably due to a combination of habitat destruction and hunting by early Polynesian settlers. Today, the wild Takahe population consists of about 100 adult birds in an isolated alpine habitat and approximately 30 individuals recently released on several small offshore islands. Despite protection and intensive management, including removal of an introduced competitor (red deer, Cervus elaphus ), the alpine population has continued to decline. In contrast, the Takahe's nearest relative, the Pukeko ( Porphyrio porphyrio ) has expanded its range across New Zealand despite heavy hunting pressure since its colonization from Australia less than 1000 years ago. We suggest that, unlike Pukeko, Takahe lack appropriate behavioral responses to cope with mammalian predators such as stoats ( Mustela erminea ), which have been introduced relatively recently by European colonists. A study comparing predator defense behavior between these two closely related species is currently underway.     

Geochemical partitioning of copper, lead, and zinc in benthic, estuarine sediment profiles

The geochemical partitioning of copper (Cu), lead (Pb), and zinc (Zn) was examined in benthic sediment profiles (0- to 20-cm depth interval) composed of relatively coarse (65-90% sand-sized particles), noncohesive, suboxic material (Eh +120 to +260 mV). Total Cu, Pb, and Zn concentrations ranged from 8.3 to 194, 16.3 to 74.8, and 30.1 to 220 mg/kg, respectively, and were related to vertical trends in sediment texture. The observed distribution coefficients describing solid-solution partitioning were in the range of 100 to 1000 L/kg. The geochemical partitioning of solid-phase Cu, Pb, and Zn between six operationally defined fractions was examined with a sequential extraction scheme. The association of Cu, Pb, and Zn with amorphous oxides, crystalline oxides, and organic matter was linearly dependent on the abundance of each respective phase. For retention by amorphous oxide minerals, the observed stoichiometry ranged from 5.2 to 23.7 mg/g for Cu, 12.8 to 21.5 mg/g for Pb, and 23.1 to 85.7 mg/g for Zn. Corresponding values for association with crystalline oxides were an order of magnitude less than those for amorphous oxides, indicating a lesser affinity of trace metals for crystalline oxides. The stoichiometric relationships describing association with organic matter ranged from 17.6 to 54.0 mg/g for Cu, 6.1 to 9.6 mg/g for Pb, and 6.4 to 16.4 mg/g for Zn. The results from this study provide an insight into processes controlling trace metal partitioning in coarse-textured, suboxic, estuarine sediments.