排序方式： 共有59条查询结果，搜索用时 15 毫秒
11.
Snezana Maletic Jelena Beljin Dragana Tamindzija Marko Grgic Jelena Molnar Jazic Marijana Kragulj Isakovski Srdan Roncevic 《国际泥沙研究》2021,36(4):479-488
The purpose of the current study is to compare the influence of different aerobic conditions(biostimulation(BS),bioaugmentation(BA),and a combination of biostimulation and bioaugmentation(BB))on polycyclic aromatic hydrocarbons(PAH)degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia(S1,S2,and S3).A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published,but to the authors’knowledge,a limited number of papers studied aged,historically polluted sediment and a sum of chosen U.S.Environmental Protection Agency(USEPA)PAHs.A significant reduction(up to67%)in PAH concentration was observed,while the percentage of reduction varied depending on the sediment sample and treatment used.BS treatment successfully stimulated growth of indigenous bacteria.Further,PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes.Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction.Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified,easier,and lower cost method for bioavailability assessment. 相似文献
12.
干旱区绿洲土壤共存重金属元素形态变化及生物有效性实验分析——以Cd、Zn、Ni元素为例 总被引：3，自引：0，他引：3
采用盆栽试验,初步研究了干旱区绿洲土壤—胡萝卜系统中镉、锌、镍3种重金属的形态变化特征及其生物有效性问题。结果表明:供试绿洲土壤原状土中,Cd、Zn、Ni均以稳定的残渣态形式存在,而处理土壤中重金属被钝化的量有限,Cd的存在形式主要以碳酸盐态为主,Zn、Ni则主要以铁锰氧化态为主;3种元素的活性大小依次为Cd>Ni>Zn。根据回归分析,元素Zn对胡萝卜块茎和茎叶吸收Zn量贡献最大的分别是Zn的碳酸盐结合态和铁锰氧化态;元素Ni对胡萝卜各部位吸收贡献最大的均为Ni的铁锰氧化态。 相似文献
13.
Chromium (Cr) is a heavy metal that exists in soils in two stable oxidation states, +III and +VI. The trivalent species is an essential nutrient, whereas the hexavalent species is highly toxic. This study investigated the environmental impact of CrIII potentially released into soil from wastes and various materials by determining the risk of oxidation of initially soluble inorganic CrIII into hazardous CrVI. The principal aim was to describe the pH-dependent mechanisms that regulate 1) the formation of CrVI from the easily soluble CrIII and 2) the potential bioavailability of CrIII and that of CrVI species produced in the oxidation of CrIII in agricultural soil (fine sand, organic carbon 3.2%). The amount of CrVI formed in oxic soil conditions was regulated by two counteracting reactions: 1) oxidation of CrIII into CrVI by manganese oxide (MnIVO2) and 2) the subsequent reduction of CrVI by organic matter back to CrIII. The effect of pH on this net-oxidation of CrIII and on the chemical availability of both CrIII and CrVI species was investigated in soil samples incubated with or without excessive amounts of synthetic MnO2, over the chemically adjusted pH range of 3.9–6.3 (+22 °C, 47 d). In soil subsamples without added MnO2, the net-oxidation of CrIII into CrVI (1 mM CrCl3 in soil suspensions, 1:10 w/V) was negligible. As for the MnO2-treated soils, at maximum only 4.7% of added CrIII was oxidized – regardless of the high oxidation potential of these subsamples. The lowest production of CrVI was observed under acidic soil conditions at pH ∼4. At low pH, the net-oxidation diminished as result of enhanced reduction of CrVI back to CrIII. At higher pHs, the oxidation was limited by enhanced precipitation (or adsorption) of CrIII, which lowered the overall amount of CrIII susceptible for oxidation. Moreover, the oxidation reactions by MnO2 were inhibited by formation of Cr(OH)3 coverage on its surface. The pH-dependent chemical bioavailability of added CrIII differed from that of the CrVI formed. At elevated pHs the chemical availability of CrIII decreased, whereas that of CrVI produced increased. However, the risk of CrVI formation through oxidation of the easily soluble inorganic CrIII was considered to be low in agricultural soils high in organic matter and low in innate MnO2. 相似文献
14.
Natural processes and anthropogenic activities may result in the formation and/or introduction of perchlorate (ClO4−) at elevated levels into the environment. Perchlorate in soil environments on Earth and potentially in Mars may modify the dynamics of metal release and their mobilization. Serpentine soils, known for their elevated metal concentrations, provide an opportunity to assess the extent that perchlorate may enhance metal release and availability in natural soil and regolith systems. Here, we assess the release rates and extractability of Ni, Mn, Co and Cr in processed Sri Lankan serpentine soils using a range of perchlorate concentrations (0.10–2.50 w/v ClO4−) via kinetic and incubation experiments. Kinetic experiments revealed an increase of Ni, Mn, Co and Cr dissolution rates (1.33 × 10−11, 2.74 × 10−11, 3.05 × 10−12 and 5.35 × 10−13 mol m−2 s−1, respectively) with increasing perchlorate concentrations. Similarly, sequential and single extractions demonstrated that Ni, Mn, Co and Cr increased with increasing perchlorate concentrations compared to the control soil (i.e., considering all extractions: 1.3–6.2 (Ni), 1.2–126 (Mn), 1.4–34.6 (Co) and 1.2–6.4 (Cr) times greater than the control in all soils). Despite the oxidizing capability of perchlorate and the accelerated release of Cr, the dominant oxidation state of Cr in solution was Cr(III), potentially due to low pH (<2) and Cr(VI) instability. This implies that environmental remediation of perchlorate enriched sites must not only treat the direct hazard of perchlorate, but also the potential indirect hazard of related metal contamination. 相似文献
15.
Michael P. Labare Michael A. Butkus Dawn Riegner Nick Schommer Jason Atkinson 《Environmental Geology》2004,46(6-7):750-754
An investigation to characterize the extent and speciation of lead contamination in water, soil, and surrounding biota was conducted at a small-arms firing and skeet range in West Point, New York. Specifically, lead concentrations were examined in sediment, soil, water, plants, fish and invertebrates. There is an elevated concentration of lead in the soil and sediment up to 11,000 g/g and 340 g/g and also evidence of bioconcentration of the lead by the surrounding biota. Earthworms had up to 90% higher concentrations of lead while tadpoles showed 20% higher concentrations compared with their controls. Lead uptake by indigenous plants gave varying results. Two species bioconcentrated lead 20 and 55 times greater than the control plants. These differences were significant (P <0.05 level) when tested by the students t test. Further studies show that the total leachable lead was highest in the invertebrates and vertebrates but not in the plants. 相似文献
16.
采用盆栽试验,初步研究了干旱区绿洲土壤—胡萝卜系统中镉、锌、镍3种重金属的形态变化特征及其生物有效性问题。结果表明：供试绿洲土壤原状土中,Cd、Zn、Ni均以稳定的残渣态形式存在,而处理土壤中重金属被钝化的量有限,Cd的存在形式主要以碳酸盐态为主,Zn、Ni则主要以铁锰氧化态为主;3种元素的活性大小依次为Cd＞Ni＞Zn。根据回归分析,元素Zn对胡萝卜块茎和茎叶吸收Zn量贡献最大的分别是Zn的碳酸盐结合态和铁锰氧化态;元素Ni对胡萝卜各部位吸收贡献最大的均为Ni的铁锰氧化态。 相似文献
17.
This study reports on trace metal uptake by the grass species Melinis repens, growing in roadside soils and sediments in tropical northeastern Australia. Median total Cu, Pb, Ni and Zn concentrations
were significantly (P < 0.05) higher in road edge soils (Cu = 61.1 mg/kg, Pb = 97.3 mg/kg, Ni = 28.6 mg/kg, Zn = 729 mg/kg) than in background
soils collected away from roads (Cu = 5.8 mg/kg, Pb = 11.2 mg/kg, Ni = 3.7 mg/kg, Zn = 21 mg/kg). Significantly (P < 0.05) elevated Zn values were recorded in the stems of the M. repens specimens growing on roadside soils (231.6 mg/kg dry weight of tissue) compared with those of grasses growing on background
soils (40.8 mg/kg dry weight of tissue). Moreover, median Cu, Ni and Zn values in the roots of roadside grasses (Cu = 29.1 mg/kg,
Ni = 2.73 mg/kg, Zn = 169 mg/kg) were significantly (P < 0.05) higher than their respective levels in the roots of background M. repens samples (Cu = 5.98 mg/kg, Ni = 0.70 mg/kg, Zn = 22 mg/kg). A greenhouse experiment showed that Cu and Zn in road sediments
are labile and are available for uptake by M. repens. The studied roadside soils and sediments were leached with a diethylenetriaminepentaacetic acid–CaCl2–triethanolamine–HCl extraction solution, which proved to be a rudimentary indicator of Zn availability and uptake to the
root tissue of M. repens. The results demonstrate that trace metals in roadside grasses have the potential to be directed up the food-chain as grasses
are consumed by herbivores. In addition, bioavailable metal contaminants hosted by road sediments have the capacity to impact
on ecosystems downstream of roads because these sediments are mobilised by road runoff waters from road surfaces into adjoining
catchments. 相似文献
18.
Paraskevi N. Polymenakou Glykeria Fragkioudaki Anastasios Tselepides 《Continental Shelf Research》2007
Recently, black carbon has been introduced as the form of carbon that may be separated from the biologically mediated carbon cycle thereby representing the non-bioavailable fraction of the estimated organic carbon. It has been speculated that the bioavailability of organic matter may be a limiting factor for the presence of active bacteria within the sediments. In order to address this question, marine sediments were collected from the Thracian Sea (Eastern Mediterranean), a complex system impacted by riverine inputs and Black Sea water masses. In addition to counts of total bacteria, we estimated the fraction of active bacteria by using a destaining step to the DAPI staining method. Black carbon was also estimated following the thermal oxidation method in order to determine the fraction of the refractory organic matter. The fraction of black carbon to total organic carbon varied from 16% to 53% indicating that black carbon constitutes a significant pool of sedimentary organic carbon in the Thracian sea. A fraction ranging from 18% to 97% was scored as nucleoid containing cells. We did not record any significant differences in the fraction of nucleoid-containing bacteria among sediment depths (P<0.05) indicating that there was no accumulation of dead bacterial cells with depth. The same was observed for the fraction of black carbon and bioavailable organic carbon with sediment depth (P<0.05) indicating that benthic consumers are not the key regulators of the organic matter pool in these sediments but have a minor effect. A possible reason for these observations and for the uncoupling between the active bacterial fraction and the bioavailability of organic matter could be (i) the presence of refractory components in the estimated bioavailable organic matter and (ii) the hydrological and geological complexity of the study area. The North Aegean marginal slopes are highly unstable experiencing frequent seismic events. These events are capable of inducing sediment transport from the upper slopes thus altering the entire sediment profile. On the other hand, the significant correlations that were recorded between nucleoid-containing cells and phytopigments (chlorophyll a, phaeopigments, chloroplastic pigment equivalents) at all sediment depths indicate that bacterial communities respond immediately to the deposited phytodetritus, using it as a primary source of carbon and energy. Our data suggests that the Thracian Sea sediments are by no means homogeneous and can best be described as a mosaic controlled by numerous local and regional environmental factors. 相似文献
19.
Yunker MB Lachmuth CL Cretney WJ Fowler BR Dangerfield N White L Ross PS 《Marine environmental research》2011,72(3):105-126
The question of polycyclic aromatic hydrocarbon (PAH) bioavailability and its relationship to specific PAH sources with different PAH binding characteristics is an important one, because bioavailability drives PAH accumulation in biota and ultimately the biochemical responses to the PAH contaminants. The industrial harbour at Kitimat (British Columbia, Canada) provides an ideal location to study the bioavailability and bioaccumulation of sediment hydrocarbons to low trophic level biota. Samples of soft shell clams (Mya arenaria) and intertidal sediment collected from multiple sites over six years at various distances from an aluminium smelter and a pulp and paper mill were analysed for 106 PAHs, plant diterpenes and other aromatic fraction hydrocarbons. Interpretation using PAH source ratios and multivariate data analysis reveals six principal hydrocarbon sources: PAHs in coke, pitch and emissions from anode combustion from the aluminium smelter, vascular plant terpenes and aromatised terpenes from the pulp and paper mill, petroleum PAHs from shipping and other anthropogenic activities and PAHs from natural plant detritus. Harbour sediments predominantly contain either pitch or pyrogenic PAHs from the smelter, while clams predominantly contain plant derived PAHs and diterpenes from the adjacent pulp mill. PAHs from the smelter have low bioavailability to clams (Biota-Sediment Accumulation Factors; BSAFs <1 for pitch and coke; <10 for anode combustion, decreasing to ∼0.1 for the mass 300 and 302 PAHs), possibly due to binding to pitch or soot carbon matrices. Decreases in PAH isomer ratios between sediments and clams likely reflect a combination of variation in uptake kinetics of petroleum PAHs and compound specific metabolism, with the importance of petroleum PAHs decreasing with increasing molecular weight. Plant derived compounds exhibit little natural bioaccumulation at reference sites, but unsaturated and aromatised diterpenes released from resins by industrial pulping processes are readily accumulated by the clams (BSAFs >500). Thus while most of the smelter associated PAHs in sediments may not be bioavailable to benthic organisms, the plant terpenes (including retene, totarol, ferruginol, manool, dehydroabietane and other plant terpenes that form the chemical defence mechanism of conifers) released by pulp mills are bioavailable and possess demonstrated toxic properties. The large scale release of plant terpenes by some of the many pulp mills located in British Columbia and elsewhere represents a largely undocumented risk to aquatic biota. 相似文献
20.
Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0.46 and 6.40 μg g−1 with significant decrease in surficial sediment as a result of closing of two Hg-cell based chlor-alkali plants. Results of sequential extraction showed that >65% Hg was strongly bound to organo-sulphur and inorganic sulphide species that are not bioavailable. Flux of only 18.8% of Hg was found compared to its value deposited on sediment–water interface. Hence, it is concluded that there is no significant diagenetic remobilization of Hg in Ulhas Estuary. This core also has been analyzed for 210Pb geochronology. The estimated sedimentation rate is 0.31 cm y−1 in the present sampling region. 相似文献