Sulfur constituents of sediments and their relationship to lake acidification

Sulfate is a major component of acid precipitation in the Northeastern United States. Transformations and fluxes of S may be important indices of the effect of acidification on limnetic systems. Sulfur constiuents and respiration rates were compared in sediments among Oneida, Deer and South Lakes in New York which exhibit a range of buffering capacity and pH from high to low, respectively. Total S in Deer and South was higher near their major inlets. Sulfide was highest in Oneida sediment, which had a lower redox potential (Eh). Ester sulfate was a major portion of the S in the three lakes. Oxygen consumption was highest in Oneida and lowest in South sediments. The low ester sulfate and an elevated C/N ratio of South sediment may indicate that acidification inhibits decomposition     

Assessing the impacts of the main river and anthropogenic use on the degree of metal contamination of oxbow lake sediments (Tisza River Valley,Hungary)

Journal of Soils and Sediments - Oxbow lakes, reaches that were cut off from a river during river straightening works, can accumulate during flooding metal-rich suspended sediments transported by a...     

海南省南渡江新坡河塘底泥养分状况及重金属污染评价

南渡江流域新坡河塘疏浚底泥的利用方向规划为农田土地整治工程中耕作层的替代土,用来发展蔬菜种植业。为了探清该流域河塘疏浚底泥的养分水平及重金属污染状况,综合考虑河塘的形态、水域面积、断面特征、流速、底泥沉积量采取典型断面布设和网格法布点,将所调查的河塘分为上游和下游,共采集0～40cm深的底泥样品78个。通过室内底泥样品成分检测、养分灰色关联度评价、内梅罗综合污染评价、GIS空间分析等方法,分析和评价了河塘底泥的养分特征、肥力水平、重金属的含量、污染程度及空间格局分布特征,掌握了该流域底泥的养分条件、底泥重金属污染状况及底泥农业利用的风险。结果表明:1)底泥的全氮、全磷、全钾及有机质含量呈现空间异质性,下游的全氮、全磷均值含量较上游分别高出32.45%、11.88%,而下游的全钾、有机质均值含量较上游分别低14.64%、14.62%,上游段底泥养分数据的变异系数普遍高于下游段,底泥养分异质性是由河流流速、周边的自然环境及人为耕作活动造成。底泥中的全氮、全磷、有机质等养分指标达到1级(丰)水平,统计分析全钾含量为5级(缺)水平;整个河塘底泥养分要高于对照点,为底泥的农业土地利用提供了有利条件。2)底泥重金属污染物主要为Cd和Cu,其次为和Cr和Ni,Cd、Cu、Cr、Ni样品单因素污染超标率分别为76.92%、47.44%、56.41%、23.07%,且超标幅度分别为58.45%、104.58%、6.06%、68.48%;底泥重金属污染是因基性火山岩为成土母质,背景值偏高,土壤重金属被酸雨淋溶出,并随地表径流汇集在河塘中,造成了底泥的重金属超标。内梅罗综合污染指数评价可知河塘底泥是以轻微污染和中度污染为主,分别占样品数的46.15%、28.21%;底泥污染状况具有明显的空间异质性,轻微污染水平(3级)和中度污染水平(4级)的区域面积分别为62.05%、25.80%,以中、轻微污染水平的区域为主。河塘下游水面宽阔,流速减慢,造成底泥沉积量增加,污染加重及污染空间分布异质性强。应该根据底泥的污染等级及养分条件综合决定其农业土地利用。     

Characteristic of nutrients and evaluation of heavy metal contamination on sediments among Xinpo pond,Nandu river in Hainan province

南渡江流域新坡河塘疏浚底泥的利用方向规划为农田土地整治工程中耕作层的替代土,用来发展蔬菜种植业。为了探清该流域河塘疏浚底泥的养分水平及重金属污染状况,综合考虑河塘的形态、水域面积、断面特征、流速、底泥沉积量采取典型断面布设和网格法布点,将所调查的河塘分为上游和下游,共采集0～40 cm深的底泥样品78个。通过室内底泥样品成分检测、养分灰色关联度评价、内梅罗综合污染评价、GIS空间分析等方法,分析和评价了河塘底泥的养分特征、肥力水平、重金属的含量、污染程度及空间格局分布特征,掌握了该流域底泥的养分条件、底泥重金属污染状况及底泥农业利用的风险。结果表明：1）底泥的全氮、全磷、全钾及有机质含量呈现空间异质性,下游的全氮、全磷均值含量较上游分别高出32.45%、11.88%,而下游的全钾、有机质均值含量较上游分别低14.64%、14.62%,上游段底泥养分数据的变异系数普遍高于下游段,底泥养分异质性是由河流流速、周边的自然环境及人为耕作活动造成。底泥中的全氮、全磷、有机质等养分指标达到1级（丰）水平,统计分析全钾含量为5级（缺）水平;整个河塘底泥养分要高于对照点,为底泥的农业土地利用提供了有利条件。2）底泥重金属污染物主要为Cd和Cu,其次为和Cr和Ni,Cd、Cu、Cr、Ni样品单因素污染超标率分别为76.92%、47.44%、56.41%、23.07%,且超标幅度分别为58.45%、104.58%、6.06%、68.48%;底泥重金属污染是因基性火山岩为成土母质,背景值偏高,土壤重金属被酸雨淋溶出,并随地表径流汇集在河塘中,造成了底泥的重金属超标。内梅罗综合污染指数评价可知河塘底泥是以轻微污染和中度污染为主,分别占样品数的46.15%、28.21%;底泥污染状况具有明显的空间异质性,轻微污染水平（3级）和中度污染水平（4级）的区域面积分别为62.05%、25.80%,以中、轻微污染水平的区域为主。河塘下游水面宽阔,流速减慢,造成底泥沉积量增加,污染加重及污染空间分布异质性强。应该根据底泥的污染等级及养分条件综合决定其农业土地利用。     

Using isotopic tracers in lake sediments to assess atmospheric transport of lead in Eastern Canada

The isotopic composition of lead pollution in the environment provides information as to the source of emission. The ²⁰⁶Pb/²⁰⁷Pb ratio for Canadian industrial emissions (1.153±0.005) is significantly less than U.S. industrial emissions (1.213±0.008) making it possible to determine the relative contributions of emissions from both countries within Eastern North America by means of a simple isotopic mixing model. Profundal sediments in lakes chronicle contaminant inputs and are therefore useful monitors of environmental pollution. Surface sediment from 32 sediment cores across Quebec and Ontario, Canada were analyzed for ²⁰⁶Pb^/207Pb to ascertain the relative proportions of Pb emission from Canada and the U.S.A. Data show that U.S. contributions to the total lead burden in surficial sediments across much of southern Quebec and Ontario are often in excess of 50%. Local sources were particularly important in the Eastern Township region of Quebec which lies 200 km south east of the city of Montreal. The results are discussed in relation to the major sources of industrial lead emissions in North America.     

Influence of pollution and acidification on metal concentrations in Finnish Lapland lake sediments

Fifteen Finnish Lapland lakes have been investigated to study pollution levels and possible acidification effects on nickel (Ni), copper (Cu), cobalt (Co), zinc (Zn), cadmium (Cd), lead (Pb), manganese (Mn), iron (Fe), potassium (K), sodium (Na), calcium (Ca), magnesium (Mg) and aluminium (Al) concentrations in sediments. Four lakes have average water pH lower than 6.0 and alkalinity lower than 0.050 meq/1. Contamination factor (C_f, ratio of metal concentrations in the uppermost to the deepest layers for a given lake sediment core) of Pb is high, particularly for acidic and acidifying lakes (C_f=5.2–10.4). Ni, Cu, Co, Zn and Cd concentrations increase insignificantly towards sediment surface of some lakes (with a neutral pH) with the rare exception. The influence of passible lake acidification consists of decreasing Cu, Cd, Al, Zn concentrations and organic material contents (loss on ignition) towards the sediment surface. The buffer capacity index (BCI), determined as the ratio of the sum of alkaline and alkaline-earth metals (K, Na, Ca, Mg) to Al, is lower for acidic lakes (from 0.12 to 0.36), whereas for the other lakes the BCI values are higher (from 0.42 to 1.34). Thus, BCI-values, decreased contents of Al, Cd, Zn and Cu, as well as organic matter contents (OMC in the upper lake sediment suggest acidification of freshwater environments.     

Controlled experimental acidification of lake sediments and resulting trace metal behavior

Severe stream water acidification occurs at higher altitudes (> 600 m a.s.l.) in the Western Harz mountains in Northern Germany. Since 1986 an interdisciplinary research team has followed the fate of pollutants in the 50 km² catchment of an important drinking water reservoir (Lake Söse). An acidification experiment has estimated the role of the remobilization of selected elements from the lake sediments via acidification. Aquaria were used to monitor the effects of a stepwise acidification (from the natural pH of 6.5 to 5.0, 4.0 and 3.0) of the water column over a reconstituted sediment layer. The sediment chemistry has been analyzed before and after the acidification by XRF. The water chemistry was sampled at time intervals and analyzed by ICP-MS. With a pH drop from 6.5 to 3.0, many elements increase in concentration in the water of the acidified basins. Enrichment factors were: Al (5000), Ba (10), Cd (220), Co (800), Cu (170), Ni (90), Pb (5000), and Zn (400). This corresponds fairly well with the field data. Al, Cd, Fe, Mn, and Pb exceed German drinking water limits at pH 4.0. The combined high concentrations (μg L^?1) of Al (1000–2600), Cd (2–4), Cu (4–7), Pb (30–60), and Zn (100–300) in the water column of the acidified streams are not only toxic for fish but also for many other aquatic organisms. Chemical changes in the sediment are not significant within the experimental setup.     

Metal mobility and mineral transformations driven by bacterial activity in acidic pit lake sediments: evidence from column experiments and sequential extraction

Journal of Soils and Sediments - Biogeochemical processes occurring in lake sediments are crucial for element cycling. In acidic pit lakes, they play a major role in acidity neutralization and...     

Phosphorus fractionation and adsorption characteristics in drinking water reservoir inlet river sediments under human disturbance

Journal of Soils and Sediments - Sediment phosphorus fractionation, adsorption kinetics, and adsorption isotherm characteristics were studied in two rivers, Muyang River and Lengshui River in...     

Heavy metal and chlorinated hydrocarbon contamination of selected aquatic sediments from the Berlin area

Sediments from the Berlin area were analysed for heavy metals and chlorinated hydrocarbons. the sedimentological and hydrogeological aspects of the Holocene sediments are discussed and an adapted sampling device for muds with a high water content is described. the contamination of surface sediments and dated cores is shown back in the 19th century; the hydrological influences on the degree of contamination and potential threats to groundwater and, via remobilisation, to surface waters are considered. It is concluded that the sediments of the Berlin area are highly contaminated.     

Fractionation of copper and uranium in organic and conventional vineyard soils and adjacent stream sediments studied by sequential extraction

Purpose

Particularly in organic viticulture, copper compounds are intentionally released into the environment as fungicide, whereas uranium originates from conventional phosphate fertilization. Both activities contribute to the metal contamination in wine-growing areas. This pilot study aimed to better understand how soil properties influence the presence and environmental fate of copper and uranium with respect to viticultural management.

Materials and methods

We characterized metal binding forms, i.e., their association with different soil constituents, in organically and conventionally cultivated vineyard soils and adjacent upstream and downstream sediments. The available metal fraction and the fractions associated with manganese oxides, organic matter, iron oxides, and total contents were extracted sequentially.

Results and discussion

Total soil copper ranged from 200 to 1600 mg kg^?1 with higher contents in topsoil than subsoil. The majority of copper (42–82%) was bound to soil organic matter. In all fractions, copper contents were up to 2-fold higher in organic than in conventional vineyards, whereas the sediment concentrations were independent of the adjacent viticultural management. A net increase of copper in downstream sediments was found only when water-extractable organic carbon (WEOC) in an adjacent vineyard was elevated. With 11 ± 1 mg kg^?1, total uranium was 25% higher in conventional than in organic vineyard soils. Its affinity to iron or WEOC potentially rendered uranium mobile leading to a substantial discharge to downstream sediments.

Conclusions

Translocation of copper and uranium from vineyards into adjacent stream sediments may rather be attributed to WEOC and iron contents than the viticultural management. Follow-up studies should scrutinize the processes driving metal availability and transport as well as their interaction at the aquatic–terrestrial interface.

     

An appraisal of microwave-assisted Tessier and BCR sequential extraction methods for the analysis of metals in sediments and soils

Purpose  

The purpose of this research was to assess the precision and accuracy of a BCR and Tessier microwave-assisted sequential extraction procedure, in comparison to the conventional versions for a range of metals using a soil, lake and estuarine certified reference material (CRM).     

基于同位素标记和连续提取法研究磷基材料对土壤铅的钝化行为

通过同位素标记手段,并结合Tessier连续提取法,研究贝壳粉、磷酸氢二铵、羟基磷灰石以及这3种磷基材料的复合钝化剂对土壤Pb的钝化行为及其作用机理.结果发现,土壤中所有Pb形态都可被外加的富集206Pb同位素标记,但其中残渣态Pb较难与富集同位素交换,表明残渣态Pb在土壤中稳定性较强.添加磷基钝化剂(除羟基磷灰石外)...     

The efficiency of sequential extraction of phosphorus in soil and sediment: insights from the oxygen isotope ratio of phosphate

Journal of Soils and Sediments - Phosphorus (P) occurs in different chemical forms in soil and sediment, and they play different ecological and environmental roles. Thus, separation and...     

Spatial patterns and temporal changes of heavy metal distributions in river sediments in a region with multiple pollution sources

Purpose

The main purpose of this study was to evaluate temporal and regional variability of contamination by heavy metals (HMs) in river sediments using their enrichment factors (EFs) and benchmarking according to sediment quality guidelines (SQGs). The Zlin region in the Czech Republic (Morava and Drevnice River basins) represents a model area where several regionally specific ecological risk assessment studies have recently been conducted with a focus on organic pollution, eco-toxicity, geological, and geochemical characteristics.

Materials and methods

Four consecutive sediment sampling campaigns were undertaken in spring and autumn 2005–2006. Aqua-regia leachable content of Cd, Co, Cr, Cu, Ni, Pb, Sb, V, and Zn in surface sediments from 14 sites was analyzed using ICP-MS, and Hg content was analyzed using AMA-254 analyzer. EFs were calculated to identify the human impact on pollution in the area. Comparisons to SGQs were conducted to identify the areas and HMs of greatest risk.

Results and discussion

Calculation of EFs contributed to the effective clustering of HMs. Median EFs of Co, Ni, and V ranged from 0.9 to 1.4 at all sites indicating concentrations very close to natural geological background levels. There was greater enrichment at locally polluted sites, the highest in the cases of Cd, Sb, Hg, and Cr. Widespread influence of diffuse HM sources (traffic, agriculture, and urban wastes) was apparent from elevated concentrations of Pb, Cu, and Zn at all sites. EF values also helped to identify the greatest temporal changes and shifts in HMs contamination between adjacent sites caused by 50-year recurrence interval floods in early spring 2006. The impact was most apparent in downstream sites; namely directly below the confluence of the two major rivers.

Conclusions

The overall contamination of HMs in the region was classified as low-to-moderate with significantly contaminated sub-areas. The study showed relatively stable spatial distributions of HMs, indicating potential sources of pollution. Cu was identified as the HM of greatest risk. The study emphasizes the necessity of considering both environmental circumstances and background HM occurrence to prevent misinterpretation of the pollution situation. The use of EFs which include grain size proxy normalization and HM background levels, along with the comparison of the detected concentrations to SQGs, proved an efficient way to identify hazardous contamination from anthropogenic sources.     

Comparison of different exhaustive and biomimetic extraction techniques for chemical and biological analysis of polycyclic aromatic compounds in river sediments

Purpose

The importance of the bioaccessible fractions of particle-bound contaminants is a key feature for the assessment of their likely risks to the aquatic environment. The present study investigated the extractability and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in river sediments. This study combined chemical with bioanalytical tools to establish a more in-depth insight into the relationship between the extractability of sediment contaminants, the chemodynamic properties of each extraction approach, and resulting toxicity.

Materials and methods

Sediment samples were treated with different extraction methods, namely Soxhlet extraction with acetone (SOX), membrane dialysis extraction (MDE) with n-hexane, ultrasonic extraction with acetone (USE), and extraction with (2-hydroxpropyl)-??-cyclodextrin (HBCD). The extracts were analyzed for PAHs using gas chromatography/mass spectrometry and tested using the neutral red retention assay and the ethoxyresorufin-O-deethylase (EROD) induction assay with the permanent fish cell line RTL-W1.

Results and discussion

The SOX and MDE approaches were comparable in their extraction power regarding PAHs and their cytotoxicity. However, the EROD activity differed between SOX and MDE, possibly due to retardation effects of the polyethylene membrane used in MDE. Thus, macromolecular components of the sediment were not extracted and therefore did not contribute to toxicity. HBCD extraction provided 3.4?% of the total PAH content in the sediments and might be an appropriate approach to predict the bioaccessible fraction. USE showed an extraction power between the HBCD approach and the MDE as well as SOX and MDE method. Hence, USE is neither appropriate for exhaustive extraction nor for biomimetic extraction.

Conclusions

MDE and SOX have been approved for the exhaustive extraction of PAHs from sediments for a worst case assessment of effect potentials. The influence of the low-density polyethylene membrane and the experimental conditions on the diffusion of compounds with broad physical?Cchemical properties, and the establishment of models such as quantitative-structure relationships for the prediction of diffusion behavior of a broad range of compounds require further assessment. HBCD was confirmed as a method providing a certain, putatively bioaccessible, fraction. Mechanistic research is required regarding desorption and uptake kinetics of particularly bound compounds with different physical?Cchemical properties in the solid phase?Cwater?CHBCD system to get more insight in the underlying partitioning processes.     

Evaluation of a sequential extraction procedure for the fractionation of thallium in soils and determination of the content by flame atomic absorption spectrometry

Abstract

The release of carbonyl sulfide (COS) from 7 unamended paddy soils was estimated under aerobic and waterlogged conditions. The addition of organic materials to the soils increased the amount of COS evolved under waterlogged conditions. To assess the sources of the COS released from the soils, the soils were incubated under aerobic and waterlogged conditions after treatment with 17 inorganic or organic S-containing compounds. It was concluded that the following compounds represented sources of the COS released from the paddy soils: cystine, cysteine, thiocyanate, lanthionine and djenkolic acid.     

Effects of food quality, starvation and life stage on stable isotope fractionation in Collembola

Naturally occurring stable isotopes of carbon and nitrogen are powerful tools to investigate food webs, where the ratio of ¹⁵N/¹⁴N is used to assign trophic levels and of ¹³C/¹²C to determine the food source. A shift in δ¹⁵N value of 3‰ is generally suggested as mean difference between two trophic levels, whereas the carbon isotope composition of a consumer is assumed to reflect the signal of its diet. This study investigates the effects of food quality, starvation and life stage on the stable isotope fractionation in fungal feeding Collembola. The fractionation of nitrogen was strongly affected by food quality, i.e. the C/N ratio of the fungal diet. Collembola showed enrichment in the heavier isotope with increasing N concentration of the food source. Δ¹⁵N varied between 2.4‰, which assigns a shift in one trophic level, and 6.3‰, suggesting a shift in two trophic levels. Starvation up to 4 weeks resulted in an increase in the total δ¹⁵N value from 2.8‰ to 4.0‰. Different life stages significantly affected the isotope discrimination by Collembola with juveniles showing a stronger enrichment (Δ¹⁵N=4.9‰) compared to adults (Δ¹⁵N=3.5‰). Δ¹³C varied between −2.1‰ and −3.3‰ depending on the food quality, mainly due to compensational feeding on low quality diet. During starvation δ¹³C value decreased by 1.1‰, whereas the life stage of Collembola had no significant effect on isotopic ratios. The results indicate that the food resource and the physiological status of the consumer have important impact on stable isotope discrimination. They may cause differences in fractionation rate comparable to trophic level shifts, a fact to consider when analysing food web structure.