A methodological approach for ecotoxicological characterization of non-hazardous sediments for their beneficial reuse

Purpose

In France, the beneficial reuse of sediments is conditioned upon a demonstration of environmental acceptability for each scenario. Such evidence has to be provided in application of the NF EN 12920 +A1 standard methodologies. Before the application of risk assessment methodology, the HP14 hazard property must be measured using specific bioassays. However, sediments may have ecotoxicological impacts despite a non-hazardous classification. The application of a battery of bioassays sensitive to non-hazardous sediments could allow to select sediments before choosing the beneficial reuse option.

Materials and methods

First, HP14 methodologies were applied on the studied sediments. These sediments had to be managed on shore according to French legislation. Then, following recommendations from a previous study, other ecotoxicological tests and modified ecotoxicological tests from HP14 methodology were selected. Ostracods mortality and growth tests were selected as a complement because its sensitivity to sediment ecotoxicity is known. To take into account the effects of extraction method and liquid/solid ratio on ecotoxicological impact of sediments, ecotoxicological tests have been applied to percolates. They have been obtained from up-flow percolation tests following the standard NF EN 14405. For each percolate, the rotifer clones reproduction test and the ostracod mortality and growth tests were performed.

Results and discussion

Contaminant analyses of sediments studied reveal differences in contamination between non-hazardous sediments. The majority of ecotoxicological tests carried out in the HP14 test batteries do not differentiate between non-hazardous sediments with low ecotoxicity. However, inhibition of rotifer reproduction and inhibition of plant germination and growth tests can be used. Among the complementary bioassays performed, the ostracods growth inhibition and multigenerational Daphnia reproduction inhibition tests are especially sensitive. Bioassays performed on percolates reveal low ecotoxicities that were not detected with conventional bioassays. For these tests, maximum ecotoxicities are observed on the first percolates for most of the tested sediments, and ecotoxicity effects decrease with the increase in the liquid/solid ratio.

Conclusions

The results enable us to propose a bioassay battery able to highlight the intrinsic toxicity of non-hazardous sediments. This is achieved through bioassays and using up-flow percolation columns to detect low ecotoxicity. This battery can be integrated into the SEDIMATERIAUX approach to ensure the choice of the beneficial reuse option for such sediment. As some of the proposed bioassays remain unsuitable for marine sediments, future studies will adapt the methodology to the presence of marine salts.

     

乡镇企业废水的综合再利用计划和湿地战略: 实例研究

A waste water reuse engineering was designed and then operated in Hongshan,a small town in Zhejiang Province,China,in order to solve pollution and shortage of water resources due to the development of rural enterprises.The results showed that series-structure design and cycling model were two effective modes of saving water and decreasing pollutants into environment,and wetland strategy should be a component part of the integrated planning for waste water reuse of rural enterprises.This case study could provide a basis for the optimum utilization and pollution avoidance of water resources.     

chemometric analysis of hydro-chemical data of an alluvial river – a case study

Hydrochemistry of an alluvial river was investigated employing the chemometric techniques such as cluster analysis (CA), principal component analysis (PCA), discriminant analysis (DA) and partial least square (PLS) with a view to extract information about the variables responsible for spatial and temporal variations in river hydrochemistry and water quality, the hidden factors explaining the structure of the hydro-chemical database of the river, factors/processes influencing the river hydro-chemistry. Analysis of spearman's correlation coefficient revealed non-significant correlation of the pollution indicator (BOD, COD, SO₄, F, NH₄-N, NO₃-N) variables with season and significant correlation with site, indicating contribution of the site-specific anthropogenic sources in the catchments. Spatial CA clustered the monitoring sites (10nos.) into three groups of relatively non-polluted sites, moderately polluted sites, and highly polluted sites. Temporal CA differentiated among the samples of monsoon and non-monsoon months. PCA rendered considerable data reduction, in terms of eight parameters explaining about 71% of the total variance and evolved six PCs. PCA grouped samples belonging to different seasons and sites distinctly correlating them with natural and anthropogenic variables. Temporal and spatial DA rendered 97 and 92% correct assignations of the samples, respectively, and revealed that temperature, pH, BOD, DO, alkalinity and Ca are the most significant variables to discriminate between the different seasons and account for most of the expected temporal variations in hydrochemistry of the river, whereas, hardness, DO, BOD, COD, Ca and Mg were the most significant discriminating variables in space. Spatial and temporal groupings of the samples were successfully achieved through PLS modeling. PLS showed that the summer season samples are dominated by PO₄, TDS, F, K, COD, BOD, Na, Cl, hardness and alkalinity, whereas, samples of winter season by DO, pH, NH₄-N and coliforms. Furthermore, PLS indicated site-specific dominance of anthropogenic contaminants suggesting for their pollution sources in the corresponding catchments of these sites.     

A framework for the integrated assessment and management of dredged materials in Italy: a case study based on the application of Local Sediment Quality Guidelines

Purpose

In order to assess sediment quality and to account for the great geochemical heterogeneity of Italian coasts, Local Sediment Quality Guidelines (LSQGs) have to be defined for specific portions of the coastline based on the approach developed by ICRAM–APAT (2007). This paper describes the application of LSQGs to the harbour of Fiumicino (Rome, Italy). The aims were to evaluate the quality of dredging sediments through an integrated chemical–ecotoxicological approach and to define suitable management options.

Materials and methods

Thirty-eight sediment cores, covering the planned dredging depth, were collected in the study area and sliced into 92 sediment samples. Chemical analyses, including inorganic and organic contaminants as well as microbiological parameters, were carried out for all the samples. A bioassay battery composed by the bacterium Vibrio fischeri, the sea urchin Paracentrotus lividus and the alga Dunaliella tertiolecta was applied on one third of the samples. LSQGs were derived from chemical and ecotoxicological data of the harbour area, and were integrated with those from the identified dumping site. The Baseline Chemical Level, corresponding to an absent or unlikely ecotoxicological hazard, and the Limit Chemical Level, corresponding to a probable ecotoxicological hazard, were the LSQGs derived for each chemical.

Results and discussion

A gradient of increasing contamination, moving inland due to urban and agricultural effluents, was observed. Ecotoxicological analyses, similar to microbiological ones, confirmed the poor sediment quality, with the exception of a sample located at the port entrance, where hydrodynamics flush sediment away from the site. Principal component analysis allowed a clear discrimination of three areas, each affected by a different contamination degree and influenced by many sources related to industrial, commercial and/or urban activities. Using LSQGs and the results of bioassays, it was possible to classify the sediment quality of the whole harbour area and to define the most suitable management options. It was found that Fiumicino harbour sediment was not suitable for either beach nourishment or for offshore dumping, with the exception of a negligible amount located at the port entrance. In turn, most sediment seemed to be suitable for disposal in a properly sealed confined disposal facility or for mechanical/chemical treatment.

Conclusions

This case study provided useful insights for implementing the development of LSQGs for more realistic sediment management and will assist in promoting its application to harbour dredging at the local level.     

Acid sulphate soil characterization in Negara Brunei Darussalam: a case study to inform management decisions

A diverse range of acid sulphate soils occur in Negara Brunei Darussalam on the inland flat areas that are important agricultural lands. Prior to this study, there was no information on their occurrence. Information about these soils is critical because they present significant management challenges for both agriculture and protection of the environment. Field surveys and laboratory analysis conducted in eight areas of the Brunei‐Muara district and four areas of the Belait district identified, characterized and classified using Soil Taxonomy, a wide range of 10 acid sulphate soil types in four soil orders: Histosols, Vertisols, Inceptisols and Entisols. A user‐friendly soil identification key using easily observed soil characteristics was developed to assist users with the recognition of the range of acid sulphate soils. Conceptual soil hydro‐toposequence models in the form of cross‐sections were constructed to explain the spatial heterogeneity of (i) acid sulphate soil properties comprising a range of features (e.g. organic‐rich materials/peats, clays, sands, cracks and jarosite‐rich mottles), sulphidic material and sulphuric horizons, (ii) pyrite shale outcrops and (iii) soil types using both the soil identification key and Soil Taxonomy. The soil hydro‐toposequence models together with the soil identification key helped to easily visualize and illustrate the complexities and importance of understanding specific sites to assess the detailed behaviour and implications of various soil, regolith and topographic features.     

Combinatorial approach to flavor analysis. 1. Preparation and characterization of a S-methyl thioester library.

A new method for the "one-pot" synthesis of S-methyl thioesters has been developed by reacting methyl chlorothiolformate with carboxylic acids. The resulting "flavor library" contained all the intended thioesters and a single major impurity, identified by GC-MS as S, S-dimethyldithiocarbonate. Quantification of individual compounds present in the library was performed by GC analysis using two independent methods of detection, SCD and FID. It was shown that apart from S-methyl thioacetate (0.8 mol %), molar concentrations of other thioesters varied in a relatively narrow range from 4.2 mol % for S-methyl thiopropionate to 14.1 mol % for S-methyl thiohexanoate. In general, medium chain S-methyl thioesters were present in slightly higher molar concentrations than those prepared from short or long chain carboxylic acids. This variation was attributed to partial loss of the most volatile components during extraction and the lower reactivity of higher homologues. The library was used for the characterization of some physicochemical parameters of thioesters. In particular, lipophilicity coefficients (log k(w)) and thioester retention in 10, 20, and 33% triolein (used as a model lipid phase) were determined directly by reverse-phase HPLC and extrapolated from the respective data. This analysis illustrates that substantial information can be generated using a library containing a relatively large number of compounds in effectively the same way as is necessary for the analysis of a single sample.     

A general approach to modeling and analysis of species abundance data with extra zeros

A general method for the analysis of ecological count data with extra zeros is presented using a Markov birth process representation of discrete distributions. The method uses a non parametric formulation of the birth process to model the residual variation and therefore allows the data to play a greater role in determining an appropriate distribution. This enables a more critical assessment of covariate effects and more accurate predictions to be made. The approach is also presented as a useful diagnostic tool for suggesting appropriate parametric models or verifying standard models. As an ill ustrative example, data describing a bundance of a species of possum from the montane ash forests of the central highlands of Victoria, southeast Australia, is considered.     

Correction to: Interaction dynamics between a contaminated dredged sediment and extracting solutions of different nature

Journal of Soils and Sediments - Figure 4 is not correct in the PDF format of the originally published article. Please note that in the HTML or online format, the image is correct.     

A multi-scale approach of runoff generation in a Sahelian gully catchment: a case study in Niger

Runoff production conditions in a small gully catchment are studied at four different scales: the point scale (0.001 m²), the local scale (1 m²), the field scale (of the order of 100 m²) and the catchment scale (0.2 km²). At the point scale, infiltration measurements were conducted using a tension infiltrometer. At the local and the field scale, runoff plots were setup on typical soil surface conditions of the catchment (plateau bare soil, hillslope bare soil and fallow grassland). At the catchment scale, stream discharges were measured at two gauging stations.The overland flow yield is significantly nonuniform in space, due to the high spatial variability of infiltration capacities and the depressional storage of the soil surface. The runoff and the infiltration data collected confirmed the major role played by soil crusting on runoff generation in that part of Sahel. At the point scale, hydraulic conductivity measurements have shown that infiltration and runoff were driven by the hydraulic properties of the crust. At the field scale, microtopography and heterogeneity in the soil surface crusting decreased discharge volumes. The influence of vegetation growth on runoff yield was evident in the case of the fallow sites. Analysis of discharge data at the catchment scale highlights that infiltration through the bottom of the gully between two gauging stations leads to considerable runoff water transmission losses.     

Integrating occupancy modeling and interview data for corridor identification: A case study for jaguars in Nicaragua

Corridors are critical elements in the long-term conservation of wide-ranging species like the jaguar (Panthera onca). Jaguar corridors across the range of the species were initially identified using a GIS-based least-cost corridor model. However, due to inherent errors in remotely sensed data and model uncertainties, these corridors warrant field verification before conservation efforts can begin. We developed a novel corridor assessment protocol based on interview data and site occupancy modeling. We divided our pilot study area, in southeastern Nicaragua, into 71, 6 × 6 km sampling units and conducted 160 structured interviews with local residents. Interviews were designed to collect data on jaguar and seven prey species so that detection/non-detection matrices could be constructed for each sampling unit. Jaguars were reportedly detected in 57% of the sampling units and had a detection probability of 28%. With the exception of white-lipped peccary, prey species were reportedly detected in 82–100% of the sampling units. Though the use of interview data may violate some assumptions of the occupancy modeling approach for determining ‘proportion of area occupied’, we countered these shortcomings through study design and interpreting the occupancy parameter, psi, as ‘probability of habitat used’. Probability of habitat use was modeled for each target species using single state or multistate models. A combination of the estimated probabilities of habitat use for jaguar and prey was selected to identify the final jaguar corridor. This protocol provides an efficient field methodology for identifying corridors for easily-identifiable species, across large study areas comprised of unprotected, private lands.     

A fuzzy logic approach for assessment and mapping of groundwater irrigation quality: a case study of Marvdasht aquifer,Iran

Two shortcomings of the non-numeric United States Soil Laboratory (USSL) water quality designation process are, first, the uncertainty involved with assigning samples to the bordering discrete classes is not considered and, secondly, it is difficult to map. One solution to these may lie in the use of a Mamdani fuzzy inference system (MFIS). The main aims of this study were (1) to compare the MFIS and USSL approach to classifying groundwater quality for irrigation and (2) to explore the spatial variability of groundwater quality for irrigation in the Marvdasht aquifer using the MFIS output. For this purpose, 49 agricultural wells were sampled and their sodium adsorption ratio and electrical conductivity were determined. In 81% of cases, the MFIS led to the same class as USSL and in 92.8% of cases agreed with USSL classification. In only 2 out of 49 samples did the MFIS and USSL strongly disagree. The comparison showed that the MFIS method is more acceptable, reliable, and logical in the classification of water quality for irrigation purposes than other methods. The output map of the MFIS scores indicates that the upper part of Marvdasht aquifer has better quality water for irrigation.     

Extrapolation of short-term process data to long-term landform development: A case study from southwestern Australia

Short-term erosion rates by overland flow under forested conditions are considered in relation to long-term valley development. Five catenas which are representative of the range of valley forms in the study area were selected, and the nine unit landsurface model was used as a sampling framework to locate experimental plots within the catenas.Factors affecting data validity include the spatial and temporal sampling pattern, and human-induced changes to the physical environment. Over the longer time-scale of valley development, problems in extrapolating the short-term data include establishing the time period within which valley development has occurred, and identifying and estimating the effects of climatic fluctuations on process intensities.The results show that, in the long-term context, measured contemporary erosion rates are ‘reasonable’ for three of the five catenas, but that considerable additional experimental work is required to resolve the identified problems. In some instances the means by which relevant data may be obtained are not apparent.     

Limits to the bioindication potential of Collembola in environmental impact analysis: a case study of forest soil-liming and fertilization

We tested the suitability of the collembolan community as a bioindicator for assessing the effects of forest soil-liming and fertilization on the belowground decomposer community. Our investigation was based on a 5-year survey that took place in a German oak-hornbeam and spruce forest in which amelioration measures took place in 1988, 1994 and 1995, with chemical parameters and Collembola being sampled between 1993 and 1997. To address these questions, we applied new methods which have not yet, to our knowledge, been used in biomonitoring studies on forest soils. We used a time-lag analysis for the detection of directional change and a regression-tree induction to show the relationship between Collembola and soil factors. Soil parameters changed considerably after the onset of liming and fertilization. However, no change was detected in community composition over time, nor was there a relationship between Collembola and soil parameters that would make possible the development of a model with at least a moderate predictive success. Taking into account the effort invested in this study (5-year sampling period, identification of 35,000 Collembola, 99 species, 1,170 chemical analyses), we question the suitability of collembolan communities as a bioindicator for forest disturbance.     

Direct comparison of individual substrate utilization from a CLPP study: A new analysis for metabolic diversity data

For over a decade, community level physiological profile (CLPP) assays, which assess a microbial community's capacity to metabolize specific sole carbon sources under defined laboratory conditions, have been popular for study of environmental soil samples. One such assay, BiOLOG™ allows for the colorimetric measurement of metabolism through the reduction of a tetrazolium dye, which yields optical density (OD) data for each substrate. Bacterial communities are extracted from soil and 150 μL of this extract is inoculated directly into each well of the microtitre plate. The combined metabolic data obtained are most often analyzed with multivariate statistical analyses, such as principal component analysis (PCA). The objectives of this study were (1) to develop a simple, visual, statistically valid method of determining community capabilities to utilize specific substrates in CLPP studies and (2) to test the number of samples needed for such discrimination to be reliable. This was done by direct comparison of the OD values obtained for two closely related microbial communities (surface and subsurface soil), plotted against a one-to-one (y=x) line. Due to variability in the portion of the soil microbial community inoculated into the individual test wells, the accuracy of the method was dependent on the number of replicates analyzed. A variety of data set sizes were tested, from n=3 samples/soil depth to n=40 samples/depth. The method was statistically valid for all data sets tested. Those substrates that deviated from the one-to-one line consistently had F values greater than 1. Additionally, data sets of n=30,35 and 40 samples/depth consistently allowed identification of the eight substrates whose metabolism varied significantly between the two test soil communities. In conclusion, this one-to-one comparison has been shown to be a statistically valid analytical method to compare individual substrate usage between soils.     

Integration of biophysical and economic data using an expert system: results from a case study in northern Australia

Abstract. Biophysical and economic data from numerous sources are integrated using the ALES expert system. A systematic approach to data collection and evaluation procedure is presented. The collection of management data is emphasized if management and crop yield data are to be adequately correlated. Different land utilization types are evaluated for numerous land mapping units. The results show that direct comparison of land mapping units is possible both within and between different land utilization types. Use of the model enabled objective relationships to be developed between biophysical criteria, crop productivity and management, allowing economic measures of performance to be routinely determined for large databases. The study shows that land mapping units with the most favourable physical suitability class may not necessarily have the largest net return and that the best lands are determined not only by their ability to produce high yields but also their ability to achieve them at the least cost.