黄河水体沉积物对敌百虫和甲拌磷的吸附

对敌百虫和甲拌磷在黄河水体沉积物中的吸附特性进行了研究,观察了ｐＨ值和离子强度等因素对吸附的影响．结果表明,敌百虫的吸附过程为一级动力学规律;敌百虫的吸附符合Ｌａｎｇｍｕｉｒ等温式,甲拌磷的吸附可用Ｆｒｅｕｎｄｉｃｈ等温式较好地描述．ｐｈ值降低或离子强度增加使敌百虫和甲拌磷在沉积物中的吸附程度明显减小．敌百虫在黄河水体沉积物中的吸附以表面吸附为主,而甲拌磷则表现为表面吸附和在有机碳中的分配作用两种吸附方式．     

长江口潮滩沉积物中活性重金属的空间分异及控制机制

利用盐酸羟氨-25%醋酸溶液，提取了长江口潮滩沉积物中活性重金属含量。研究发现，长江口潮滩沉积物中活性重金属占总量的百分含量依次为Cu 26%，Pb 36%，Fe 7%，Mn 49%，Zn 32%，Cr 14%和Al 16%，沉积物基本未受到Cr污染，其余重金属污染程度处于中等偏下水平。除Zn、Cr外，其余活性重金属在夏季沉积物中的含量明显低于春季，其主要原因是夏季风暴潮将大量细颗粒泥沙及其富集的重金属带离潮滩进入了河口水体中。受点源污染排放及沉积物粒度影响，活性重金属在长江口南岸的浒浦、顾路和浦东机场出现峰值含量，且高潮滩含量明显高于中、低潮滩。在垂向上，重金属一般在沉积物表层或亚表层形成富集。在口门附近的滨岸潮滩沉积物中，Cu、Pb的空间分异主要受早期成岩作用的控制，在污染较为严重、水动力作用相对较弱的潮滩沉积物中，Cu、Pb的空间分异主要受沉积物中有机质含量变化的控制.     

Genotoxicity of sediment extracts of the Berre lagoon (France)

To evaluate the genotoxic risk that contaminated sediment could constitute for benthic organisms, three contaminated (VA, VC and VN) and one uncontaminated (RN) sediment samples were collected in the Berre lagoon (France). Potentially bioavailable contaminants in sediments were obtained using sediment extraction with synthetic seawater adjusted to pH 4 or pH 6, simulating the range of pH prevailing in the digestive tract of benthic organisms. The genotoxic activities of these extracts were evaluated by three short-term bioassays: the Salmonella mutagenicity test using the Salmonella typhimurium strain TA102, the alkaline comet assay and the micronucleus assay on the Chinese Hamster Ovary cells CHO-K1. Results of the Salmonella mutagenicity assay detected a mutagenic response for RN extract at pH 6, and for VA extract at pH 4. Results of the comet and micronucleus assays detected low genotoxic/clastogenic activities for VA and VC extracts at pH 6 and higher activities for RN, VA and VC extracts at pH 4. To identify if metals (Al, Fe, Mn, As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were involved in these genotoxic activities, their concentrations were determined in the extracts, and their speciation was assessed by thermodynamic calculations. Results showed that extracts from sites VA, VC and VN generally presented the highest trace metal contents for both extractants, while the site RN presented lower trace metal contents but the highest Fe and Mn contents. Thermodynamic calculations indicated that Fe, Mn, As and in a lower extend Co, Ni and Zn were mainly present under free forms in extracts, and were consequently, more likely able to induce a genotoxic effect. Results globally showed no correspondence between free metal contents and genotoxic activities. They suggested that these positive results could be due to uncharacterized compounds, acting as direct genotoxic agents or enhancing the genotoxic properties of analyzed metals.     

Historical change of mercury pollution in remote Yongle archipelago, South China Sea

We collected three ornithogenic coral sand sedimentary profiles from Jinyin Island, Jinqing Island and Guangjin Island of Yongle archipelago, South China Sea and reconstructed the deposition flux of anthropogenic Hg over the past 700 years in the study area. On the whole, the anthropogenic Hg flux is relatively low; it remained at a low level before the Industrial Revolution with a small peak at about 1450-1550 AD, which may record the enhanced metallurgy activity in Ming Dynasty of China. During the 20th century, the deposition flux of anthropogenic Hg increased rapidly, but two troughs occurred during the periods around 1940s and 1970s, corresponding to the economic depression caused by World War II, Civil War in China (1945-1949), and the Culture Revolution (1966-1976) in China. Since the 1970s the deposition flux of anthropogenic Hg has been persistently increasing, apparently the result of fast economic development in East and Southeast Asia countries around South China Sea.     

DISTRIBUTION AND GRAIN-SIZE PARTITIONING OF METALS IN BOVFOM SEDIMENTS OF AN EXPERIMENTALLY ACIDIFIED WISCONSIN LAKE1

ABSTRACT: A study of concentrations and distribution of major and trace elements in surficial bottom sediments of Little Rock Lake in northern Wisconsin included examination of spatial variation and grain-size effects. No significant differences with respect to metal distribution in sediments were observed between the two basins of the lake, despite the experimental acidification of one of the basins from pH 6.1 to 4.6. The concentrations of most elements in the lake sediments were generally similar to soil concentrations in the area and were well below sediment quality criteria. Two exceptions were lead and zinc, whose concentrations in July 1990 exceeded the criteria of 50 μg/g and 100 μg/g, respectively, in both littoral and pelagic sediments. Concentrations of some elements, particularly Cu, Pb, and Zn, increased along transects from nearshore to midlake, following a similar gradient of sedimentary organic carbon. In contrast, Mn, Fe, and alkali/alkaline-earth elements were at maximum concentrations in nearshore sediments. These elements are less likely to partition to organic particles, and their distribution is more dependent on mineralogical composition, grain size, and other factors. Element concentrations varied among different sediment grain-size fractions, although a simple inverse relation to grain size was not observed. Fe, Mn, Pb, and Zn were more concentrated in a grain-size range 20–60 tm than in either the very fine or the coarse fractions, possibly because of the aggregation of smaller particles cemented together by organic and Fe/Mn hydrous-oxide coatings.     

LONG-TERM PATTERNS OF WATER QUALITY IN A MANAGED WATERSHED IN OREGON: 1. SUSPENDED SEDIMENT1

The cumulative effects of forest management activities on water quality at a downstream point were monitored from 1972-1980 during development of a watershed for timber resources. Suspended sediment concentration and turbidity were measured at two hydrologic stations which bracketed a 10-km reach of the Middle Santiam River in the Western Cascades of Oregon as it flowed through an 8000-ha block of intensively managed forest land. Slope failures often accompany road building and harvesting in steep forested watersheds and pose the most serious threat to water quality. Although 180 km of road were constructed and 3400 ha of old-growth forests were harvested from slopes averaging over 60 percent, long-term changes in sediment yields remained undetectable during the period of measurement. The geologic characteristics of the basin and the road construction and maintenance techniques as prescribed by Oregon's forest practice regulations helped to minimize the occurrence of slope failures so that long-term changes in suspended sediment export rates did not occur. Throughout the nine-year measurement period, seven slope failures which added sediment directly to streams produced measurable short-term responses at the downstream sampling location, but these erosion events were too small and too infrequent to produce long-term changes in sediment yield from the watershed.     

FACTORS INFLUENCING ACUTE TOXICfrY OF COAL ASH TO RAINBOW TROUT (SALMO GAIRDNERI) AND BLUEGILL SUNFISH (LEPOMIS MACROCHIRUS)1

ABSTRACT: The potentially toxic components in coal ash (ash particles, heavy metals) were evaluated in laboratory static, acute (96 hr) bioassays, both separately and in various combinations with extreme pH (5.0 and 8.5), using rainbow trout (Salmo gairdneri) and bluegifi sunfish (Lepomis macrochirus). Ash particle morphology and metal distribution anlaysis, using electron microscopy and surface-subsurface analysis by ion microscopy, showed that metals could be either clumped or evenly distributed on the surface of fly ash. Surface enrichment on fly ash particles from electrostatic precipitators, as measured by ion microscopy, was found for cadmium, copper, chromium, nickel, lead, mercury, titanium, arsenic, and selenium. Bottom (heavy) ash was not acutely toxic to either fish species at concentrations of up to 1500 mg/l total suspended solids (TSS) at pH 5.0, 7.5, or 8.5. Fly ash particles were not acutely toxic to blue-gill at levels up to 1360 mg/l TSS. Rainbow trout were highly sensitive to fly ash (25 to 60 percent mortality) at concentrations of 4.3 to 20.5 mg/I TSS when dissolved metal availability was high but were not sensitive at higher particulate concentrations (58 to 638 mg/I TSS) when dissolved metals were low. When metals were acid-leached from fly ash prior to testing, no rainbow trout mortality occurred at TSS concentrations of up to 2,350 mg/l TSS. When the percent of dissolved metal was high (e.g., 50–90 percent of the total), fish mortality was increased. Rainbow trout were nearly two orders of magnitude more sensitive than bluegill when subjected to a blend of cadmium, chromium, copper, nickel, lead, and zinc. The two species were similar in their acute sensitivity to acidic pH at levels at or below 4.0 and alkaline pH of 9.1. If the pH of coal ash effluent is contained within the range 6.0 to 9.0, acute toxicity to fish can be attributed to trace element availability from fly ash but not heavy ash. Control of holding pond and effluent pH and maximizing pond residence time are important strategies for minimizing effects of ash pond discharges on fish.     

Industrial Tailings in Traunsee (Austria) Revisited: The Status of 1999

Alkaline tailings from a salt work and a soda plant have been pumped into the southernmost part of Traunsee at Ebensee for many decades. A survey in 1981 showed an accumulation of more than 3 × 10⁶ m³ alkaline mud in the Bay of Ebensee and the existence of slumping structures and turbidites in the profundal zone of the lake. A new survey of the industrial tailings has been performed in 1999. Compared to the earlier survey, the accumulation in the Bay of Ebensee has grown to >4 × 10⁶ m³, which suggests an average yearly input of 90 000 m³. Slumping structures and turbidites document the unstable situation of the tailings near the waste inlet. The lake area occasionally affected by the turbidity currents in the profundal zone has increased to 19%. Within the central profundal area these tailings reach <1 m in thickness.     

Use of toxicity identification evaluation techniques to identify dredged material disposal options: A proposed approach

It is common to use the results of various solid-phase and aqueous-fraction toxicity tests as part of the decision-making process for selecting disposal options for dredged sediments. The mere presence of toxicity, however, does not provide a logical basis for selecting economical, environmentally protective disposal techniques. To achieve this, it is necessary to be able to identify specific compounds responsible for sediment toxicity. Toxicity identification evaluation (TIE) procedures, originally developed for complex effluents, represent a useful approach for identifying acutely toxic compounds in dredged materials. Herein we present a conceptual overview for TIE use in part of the decision-making framework for selecting dredged material disposal options; included are discussions concerning appropriate test fractions and species for TIE analyses, and specific TIE manipulations useful for ascertaining whether toxicity is due to any of a number of common sediment contaminants including ammonia, hydrogen sulfide, metals, or nonpolar organics.     

Distribution of Trace Metals in the Surface Sediments of Two Pristine Subalpine Lakes in Taiwan

Sediment cores were collected from two remote subalpine lakes: the rather shallow (1.5 m) Little Ghost Lake at 2040 m elevation and the deeper, Great Ghost Lake (40 m) at 2150 m elevation. Different early diagenesis of metals were observed. the seasonally anoxic hypolimnion drives the annual iron redox cycle and causes the remobilization of metals in the mobile fractions of sediments in the Great Ghost Lake. These result in the redistribution of metals in the mobile fractions of sediment and poor correlation between metal concentrations. in the Little Ghost Lake, the shallow water column is always oxic with less change of metals in the mobile fractions of sediments. As a result, most metals have strong positive correlations with each other.

The distributions of metal/Al ratios, total metal contents and acid-leached metal concentrations in the near-surface sediments of these two lakes suggest that the anthropogenic inputs from the atmospheric fallouts in recent decades are one of the major factors affecting the distributions of metals such as cadmium, lead and, to a lessor extent, zinc. the Pb-206/Pb-207 ratios confirm the anthropogenic lead input in these surface sediments.