Showing papers in "Journal of Soils and Sediments in 2006"

Heavy Metals in Soil, Crops and Grass as a Source of Human Exposure in the Former Mining Areas (6 pp)

Abstract: In the former mining area of Northern France, the number of diseases (cancers, malformations, backwardness...) is about ten times above the national average. Environmental surveys conducted by the Ministry of Health have showed that more than 10% of children living around a lead smelter located in this area had lead levels higher than 100 µg L-1 of blood (25% in the closest city). Two main factors contribute to the population exposure: the ingestion of plants produced in the contaminated area, and also the ingestion or the inhalation of contaminated dust or soil. It is usually known that these particles are key routes of exposure to lead for younger children, in particular via hand-to-mouth transfer. For a better understanding of this problem, researchers investigated different exposure sources like soil and vegetable contamination. Materials and Methods: All these parameters that contribute to the assessment of environmental and health risks of metal contamination have been measured. About 170 composite samples of soils around the smelter or from reference areas have been analysed, mainly from fields (70), kitchen gardens (60) and lawns (38). Total contents of Cd and Pd were measured in the organo-mineral layer (0-25cm) of soils. Composite grass samples were also taken on the lawns. Crops and vegetables were sampled from fields and kitchen gardens and then, parts of the plant intended only for consumption were washed and analysed. Results: For the organo-mineral horizon of the studied sites and located in various environmental contexts (contaminated or reference), we found a very broad range of metal concentrations. Generally, the data showed a strong variability of the physicochemical parameters of the urban soils (kitchen gardens, lawns), in particular with regard to lead. This work showed that cultivated plants (agricultural or kitchen garden) or lawn grass are also significantly contaminated by heavy metals, especially lawn grasses, cereal grains (wheat, barley) and lettuces sampled around the smelter. Moreover, the proportion of lead present on lawn grasses could reach 50% of the total contamination of the plants because of the deposition of contaminated dust. Discussion: The values of pollution in agricultural field and kitchen garden soils located near the smelter were respectively about 20 and 30 times above the agricultural regional reference values, probably due to the atmospheric emissions from a smelter that significantly increases the concentrations of metals in the upper horizons of the neighbouring soils. This pollution results in a high level of contamination of plants grown of these soils. Conclusions: The results showed that heavy metals in soils, particles (dust and soil) or plants of kitchen gardens, lawns or playgrounds could be potentially transferable to the users, and in particular to young children, and could then contribute, to a considerable share, to the exposure of the population living in a contaminated area around a smelter brought about through inhalation, direct ingestion of particles or consumption of plants. Recommendations and Perspectives: These results highlight that the consumption of home-grown vegetables can constitute a risk of exposure, in particular for cadmium, and especially in children. This work also underlined the role of the contaminated soil particles in the Pb contamination of the human food chains and their environment. Because of the complexity of the various methods of population exposure, it will be necessary to complete the data base, in partucular in urban areas. The main objective of this future work will be to relate the degree of environmental contamination with the lead level in child bood, and to integrate other environmental compartments like outdoor and indoor dust of the dwellings into the model of pathway exposure.

Should the Sediment Quality Triad Become a Tetrad, a Pentad, or Possibly even a Hexad?

Abstract: Goal, Scope, Background. The Sediment Quality Triad (SQT) as originally developed 20 years ago involved three lines of evidence (LOE): sediment chemistry, sediment toxicity, and benthic community structure. The first two LOE have been consistently included in all SQTs conducted to date, however the last LOE has been changed to 'alteration of resident communities' and, in some cases has been excluded or replaced. In other cases additional LOE have been added to the SQT. Main Features. This paper examines the history of different LOE used as part of the SQT, and provides recommendations regarding future use of various LOE in SQT studies. Results and Discussion. A total of 14 LOE replacing or additional to the alterations to resident communities LOE have been proposed and applied. These LOE fall into four categories: direct replacements for or additions to existing LOE; variations on existing LOE; additional LOE; and LOE to determine causation. An additional possible LOE not previously proposed or applied is determination of genetic diversity. Conclusion and Perspectives. Future applications of the SQT should ensure that LOE appropriately address all components of a risk assessment (Problem Formulation, Exposure and Effects Assessment), address causation, and also consider other (non-chemical) stressors. Choice of specific LOE will depend on the stressors of potential concern (SOPCs) and the receptors of potential concern (ROPCs), focusing on ecological relevance.

Comparison of Soil Clean-up Standards for Trace Elements Between Countries: Why do they differ? (9 pages)

Abstract: Goal, Scope and Background In the nineteen nineties most European countries issued legislation on soil protection, including soil contamination. In the case of a presumed contamination, soil investigation mostly follows a stepwise approach starting with a preliminary investigation, then an in-depth investigation and, finally, remediation. Soil clean-up standards are often foreseen as trigger criteria to determine the need for an in-depth soil investigation or for remediation. There are however large differences in soil clean-up standards. This is partly because of the different roles of soil clean-up standards in each legislative framework and partly because of differences in the soil clean-up standard (SCS) derivation procedures. Despites these differences there are large similarities in the concepts of the derivation procedures for clean-up standards. A better understanding of the differences in clean-up standards is needed. In order to clarify the variation, the background of the clean-up standards for a selected number of countries was investigated. The objective of this paper is to investigate the underlying reason why country-wide generic soil and groundwater clean-up standards of eight trace elements (cadmium, chromium (III), copper, mercury, lead, nickel, zinc and arsenic) differ between the selected countries.

Humic Acids Increase the Phytoavailability of Cd and Pb to Wheat Plants Cultivated in Freshly Spiked, Contaminated Soil (7 pp)

Abstract: Background, Aim and Scope Humic acids (HAs) are the most important humified component of dissolved organic carbon (DOC) present in sewage water used for irrigation. It is well known that HAs affect the toxicity and availability of heavy metals (HMs) in soil-plant systems, and may increase the human exposure to HMs in contaminated soil through plant uptake. This study was conducted to assess the effects of HAs on HM availability, plant growth and HM uptake. Materials and Methods: With wheat (Triticum aestivum) as a test plant, a greenhouse pot experiment was conducted to investigate the effects of HAs in irrigation water on the phytoavailability of cadmium (Cd) and lead (Pb) in soil. Cd and Pb were added to the soil at concentrations of 1.5 and 150 mg/kg, respectively. Wheat seedlings grown in Cd and Pb-contaminated soil were watered with 4 levels of HA solution (0, 140, 280 and 560 mg/kg of HAs, respectively). Results: In control and Pb treatments, both plant biomass and plant HM concentrations increased with increasing concentrations of HAs in the solution. Plant biomass was markedly decreased when metal concentrations in plants increased, particularly in Cd and Cd/Pb treatments. In the soil, extractable metals, and water soluble organic carbon (WSOC) and its fractions significantly increased with increasing HA concentrations. Discussion: The results suggested that the application of HAs in barren soils may improve plant nutrition by mobilizing soil nutrients and providing plants with carbon sources. On the other hand, HAs present in sewage water may increase both the availability and transfer of HMs in the soil-plant continuum and subsequently increase human exposure to HMs in polluted soil. Conclusions. Conclusions: HA solution as irrigation water significantly increased HM availability to plants cultivated in the HM-amended soil and may increase the environmental risk of sewage irrigation. Recommendations and Perspectives: These results suggested that, when assessing the effect of sewage irrigation on soil quality, HAs contained in sewage water should be taken into consideration.

Field-Scale Assessment of Phytotreatment of Soil Contaminated with Weathered Hydrocarbons and Heavy Metals (9 pp)

Abstract: Phytoremediation is a remediation method which uses plants to remove, contain or detoxify environmental contaminants. Phytoremediation has successfully been applied for the removal of fresh hydrocarbon contamination, but removal of aged hydrocarbons has proven more difficult. Biodegradation of hydrocarbons in the subsurface can be enhanced by the presence of plant roots, i.e. the rhizosphere effect. Phytostabilization reduces heavy metal availability via immobilization in the rhizosphere. Soils contaminated by both hydrocarbons and heavy metals are abundant and may be difficult to treat. Heavy metal toxicity can inhibit the activity of hydrocarbon-degrading microorganisms and decrease the metabolic diversity of soil bacteria. In this experiment, weathered hydrocarbon- and heavy metal- contaminated soil was treated using phytoremediation in a 39- month field study in attempts to achieve both hydrocarbon removal and heavy metal stabilization. Materials and Methods: A combination of hydrocarbon degradation and heavy metal stabilization was evaluated in a field-scale phytoremediation study of weathered contaminants. Soil had been contaminated over several years with hydrocarbons (11400±4300 mg kg dry soil)-1 and heavy metals from bus maintenance activities and was geologically characterized as till. Concentrations of soil copper, lead and zinc were 170±50 mgkg-1, 1100±1500 mg kg-1 and 390±340 mg kg-1, respectively. The effect of contaminants, plant species and soil amendment (NPK fertilizer or biowaste compost) on metabolic activity of soil microbiota was determined. Phytostabilization performance was investigated by analyses of metal concentrations in plants, soil and site leachate as well as acute toxicity to Vibrio fischeri and Enchtraeus albidus. Results: Over 39 months hydrocarbon concentrations did not decrease significantly (P=0.05) in non-amended soil, although 30% of initial hydrocarbon concentrations were removed by the last four months of study. In soil amended with NPK fertilizer and municipal biowaste compost, 65 % and 60 % of hydrocarbons were removed, respectively. The soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Compost addition resulted in a slight increase in enzymatic activities. Diesel fuel utilization potential in Biolog MT2 plates inoculated with a soil suspension was enhanced by both compost and NPK compared to non-amended soil. Soil toxicity to V. fischeri and E. albidus was low. The leachate was not toxic to V. fischeri. Pine (Pinus sylvestris), poplar (Populus deltoides x Wettsteinii), grasses and clover (Trifolium repens) survived to varying degrees in the contaminated soil. All plants suffered from phytotoxicity symptoms and some trees died during the study period. Plants formed a dense cover over the compost-amended soil, whereas non-amended soil had areas devoid of vegetation throughout the study. Vegetation coverage in the NPK-amended quarter was about 50 % after the first four months of study, but increased gradually to 100 %. Heavy metals did not accumulate in plant tissue. Discussion: Removal of hydrocarbons from weathered unfertilized hydrocarbon-contaminated soil was not statistically significant despite the presence of a viable hydrocarbon-degrading microbial community. This effect is attributed to soil heterogeneity and low bioavailability of hydrocarbons. Hydrocarbon concentrations were not reduced to the desired level, i.e., 1500 mg hydrocarbons (kg of dry soil)-1, in any treatment. . The presence of clay minerals and organic matter within the compost may have limited heavy metal transfer to leachate and plant tissue. Conclusions: Weathered hydrocarbons were partly decomposed in soil fertilized with NPK fertilizer or biowaste compost, but not from unfertilized soil. The active hydrocarbon-degrading microbiota and low toxicity of soil to V. fischeri and E. albidus indicates low availability of contaminants to microorganisms. Despite high heavy metal concentrations, the soil contained metabolically diverse bacteria, measured as carbon source utilization and extracellular enzymatic activities. Heavy metals did not accumulate in test plants. Pine and poplar suffered from phytotoxicity symptoms in the soil and could not enhance hydrocarbon removal in compost-amended soil. Compost addition combined with a grass and legume crop is suggested for stabilization of combined hydrocarbon- and metal-contaminated soil. Recommendations and Perspectives: Both compost and NPK fertilizers can be used to enhance phytoremediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals; however, compost addition is recommended since it enables greater vegetative coverage. This in turn may decrease heavy metal mobility. Phytoremediation can be used for remediation of soil contaminated with weathered hydrocarbons in the presence of heavy metals. However, phytoremediation of weathered contaminants requires extended periods of time; thus, other remediation methods should be considered in the event of soil contamination posing an immediate public health and/or environmental threat.

Mineralogy and Arsenic Mobility in Arsenic-rich Brazilian Soils and Sediments (11 pp)

Abstract: Background. Soils and sediments in certain mining regions of Brazil contain an unusually large amount of arsenic (As), which raises concerns that mining could promote increased As mobility, and thereby increase the risks of contaminating water supplies. Objectives. The purpose of this study was to identify the most important factors governing As mobility in sediments and soils near three gold-mining sites in the State of Minas Gerais, Brazil. Methods. Surface and sub-surface soil samples were collected at those sites and characterized by chemical and mineralogical analyses. Oxalate (Feo) and citrate-bicarbonate-dithionite (Fed) iron contents were determined by atomic absorption spectroscopy (AAS). Arsenic mobilization was measured after incubating the samples in a 2.5 mM CaCl 2 solution under anaerobic conditions for 1, 28, 56, 84, or 112 days. The solution concentrations of As, Fe, and Mn were then measured by inductively coupled plasma-mass spectrometry (ICP-MS) and AAS, respectively. Results and Discussion. Results indicated that As mobilization is largely independent of both the total As and the Feo/Fed ratio of the solid phase. Soluble As is roughly controlled by the Fe (hydr)oxide content of the soil, but a closer examination of the data revealed the importance of other highly weathered clay minerals and organic matter. Large amounts of organic matter and a low iron oxide content should favor As leaching from soils and sediments. Under reducing conditions, As is mobilized by the reductive dissolution of Fe and/or Mn oxides. However, released As may be readsorbed depending on the sorptive properties of the soil. Gibbsite is particularly effective in adsorbing or readsorbing As, as is the remaining unreduced fraction of the iron (hydr)oxides. Conclusion and Outlook. In general, low soluble As is related to the presence of gibbsite, a large amount of iron oxides, and a lack of organic matter in the solid phase. This has environmental significance because gibbsite is thermodynamically more stable than Fe oxides under anaerobic conditions, such as those found in waterlogged soils and lake sediments.

Membrane Dialysis Extraction (MDE): A Novel Approach for Extracting Toxicologically Relevant Hydrophobic Organic Compounds from Soils and Sediments for Assessment in Biotests

Abstract: Organic solvents are routinely used to extract toxicants from polluted soils and sediments prior to chemical analysis or bioassay. Conventional extraction methods often require the use of heated organic solvents, in some cases under high pressure. These conditions can result in loss of volatile compounds from the sample and the degradation of thermally labile target analytes. Moreover, extracts of soils and sediments also frequently contain substantial quantities of organic macromolecules which can act as sorbing phases for target analytes and in doing so interfere with both chemical analysis and bioassays. Membrane dialysis extraction (MDE) is described as a simple, passive extraction method for selectively extracting toxicologically relevant hydrophobic organic compounds (HOCs) from polluted soils and sediments and anaylzed for its applicability in ecotoxicological investigations. Toxicologically relevant hydrophobic organic compounds were extracted from wet and dry sediments by sealing replicate samples in individual lengths of pre-cleaned low-density polyethylene (LD-PE) tubing and then dialysing in n-hexane. The efficacy of the MDE method for use in ecotoxicological investigations was assessed by testing the concentrated extracts in the neutral red assay for acute cytotoxicity, in the EROD assay for the presence of dioxin-like compounds and in the Danio rerio fish egg assay for embryotoxic and teratogenic effects. Conditions of the sediment sample (with or without water content), dialysis membrane length and duration of dialysis were analyzed with respect to their impact on three endpoints. Results of the MDE investigations were compared to data obtained in samples prepared using conventional Soxhlet extraction. The membrane dialysis extraction was found to be at least as efficient as Soxhlet methodology to extract toxicologically relevant HOCs from sediment samples. In most cases, MDE-derived extracts showed a higher toxicological potential than the Soxhlet extracts. Lack of any significant effects in any MDE controls indicated these differences were not caused by contamination of the LD-PE membrane used. The elevated toxicological potential of MDE extracts is most likely the result of enhanced bioavailability of toxic compounds in consequence of lower amounts of organic macromolecules (i.e. sorbing phases) in the MDE extracts. This effect is probably the result of a size-selective restriction by the LD-PE membrane. Membrane dialysis extraction was found to be a simple, efficient and cost-effective method for the extraction of sediment samples. MDE can be used to extract toxicologically relevant hydrophobic organic compounds from both wet and dry sediments without the risk of loosing volatile and thermally labile target analytes. The size-selectivity of the LD-PE membrane also appears to have the capacity to increase the bioavailablity of potential target analytes in the resulting extracts by retaining much of the organic macromolecules present in the sample. Thus, results suggest that MDE may be particularly useful for the extraction of toxicologically relevant hydrophobic organic compounds from soils and sediments for bioassays and other ecotoxicological investigations. Further validation of MDE has been initiated and the applicability of the methodology to other sample types will be investigated. Of particular interest is the potential application of MDE to recover hydrophobic target analytes from biological samples such as muscle, other soft tissues and blood.

Assessment of Highly Polluted Fluvisol in the Spittelwasser Floodplain Based on National Guideline Values and MNA-Criteria (11 pages)

Abstract: Nearly all large European rivers have been used as disposal pathways for several unwanted substances. Deposition of the contaminated solids occurs in regions of slack water and also during floods in adjacent floodplains. As a result of the recurrent input, most of the floodplains in central Europe are contaminated by manifold inorganic and organic pollutants, representing a risk for both plants and groundwater at the site, and for areas downstream. The aim of the present paper is to demonstrate and assess the sink and source functions of a highly contaminated 'fluvisol' (= alluvial soil) for inorganic and persistent organic pollutants. The extent of contamination is described on the basis of national guidelines. These results are further discussed on the basis of the 'monitored natural attenuation' (MNA) potential, i.e., with respect to the requirements for the cheapest problem solution for large scale contamination of floodplains. The MNA potential is assessed according to several lines of evidence such as contaminant burial, mechanical and chemical mobility, transformation to less toxic forms, and dilution due to dispersion. The existing inorganic and organic pollutant status and the ecotoxicological potential of the Spittelwasser floodplain near Jesnitz was documented by analysing several element and compound depth profiles of a typical alluvial soil site. Geochemical analyses were performed on solid material and soil solution according to standard procedures. In laboratory experiments monoliths were continuously irrigated with deionised water and the leachate was analysed weekly. In addition to the geochemical, the ecotoxicological status of the samples was studied using different biotests for the dissolved and the solid phase. The measured alluvial soil profile is severely contaminated with numerous inorganic and organic pollutants. Highest enrichment factors according to the catchment based, element specific geological background were found for Hg (402), Pb (8.9), Cr (7.1) and Cd (6.3). Assessment was made of the hazard potential of both the solid material and the soil solution according to the German Federal Soil Protection and Contaminated Sites Ordinance (BBodSchV). Relating to the respective maximum contents in the soil profile, the overstepping of BBodSchV trigger values is highest for Hg with a coefficient of 49.0 followed by Cd (14.3), Pb (12.2), Zn (7.3), Cr (5.9) and Cu (3.6). Pollutant concentrations in the soil solution exceed the threshold values for Cd, Cu and Zn by factors of 6.3 to 12. While DDT is retained in the topsoil, there is a considerable translocation of HCH towards deeper horizons. The algae test confirms a strong toxicity in the top layer of the soil profile. In contrast, no such toxic reactions were indicated by the luminescent bacteria test and the Daphnia test at this depth. However, the deeper layers (10 - 100 cm) show a toxic reaction by the Daphnia test, thus indicating a relevant translocation of contaminants. The Spittelwasser floodplain represents a significant sink for inorganic and persistent organic pollutants. Simultaneously, the area is a relevant secondary source of dissolving contaminants like heavy metals and HCH. Although strict criteria in the lines of evidence for applying MNA are not fulfilled, it can be stated that the alluvial soil offers a high natural retention potential for As, Hg, DDT, and PCDD/F. These pollutants are firmly retained and are not found in the soil leachate. This meets the demands of the EC-WFD for pollutant retention close to their primary source. But for agricultural use and groundwater recharge the natural attenuation potential of the soils in the Spittelwasser area will not be sufficient to achieve acceptable conditions medium-term. The main problem for the dissemination of pollutants is not chemical stability but mechanical dispersion. This is particularly the case for PCDD/F, with concentrations of more than 10,000 ng/kg I-TEQ in the upper Spittelwasser soil layers. Dispersion processes can result in a wide spatial contamination of downstream floodplains.

Comparison of Fenton's Reagent and Ozone Oxidation of Polycyclic Aromatic Hydrocarbons in Aged Contaminated Soils (7 pp)

Abstract: Background, Aim and Scope Polycyclic aromatic hydrocarbons (PAHs) are formed as a result of incomplete combustion and are among the most frequently occurring contaminants in soils and sediments. PAHs are of great environmental concern due to their ubiquitous nature and toxicological properties. Consequently, extensive research has been conducted into the development of methods to remediate soils contaminated with PAHs. Fenton's reagent or ozone is the most commonly studied chemical oxidation methods. However, the majority of remediation studies use soils that have been artificially contaminated with either one or a limited number of PAH compounds in the laboratory. Hence, it is essential to extend such studies to soils contaminated with multiple PAHs under field conditions.

Comparability of and Alternatives to Leaching Tests for the Assessment of the Emission of Inorganic Soil Contamination (11 pp)

Abstract: Goal, Scope and Background The suitability of leaching tests for the assessment of soil water concentrations is a controversial issue. The aim of this paper is to review and critically discuss the applicability and comparability of leaching tests in the scope of groundwater risk assessment of inorganic contamination and to discuss soil water sampling methods as alternative.

Control of Rainfall-Induced Soil Erosion with Various Types of Polyacrylamide (8 pp)

Abstract: Several types of organic polymers with various molecular weights and surface charges are produced for various industrial and agricultural purposes, and recent studies have shown that high molecular weight anionic polymers are the most effective in reducing runoff and soil loss. However, anionic polyacrylamide (PAM) is marketed under various commercial names with variable molecular weight and length according to its chemistry (Barvenik 1994). Consequently, its interactions with soil and efficiency in reducing soil erosion are expected to vary. Moreover, types of PAM other than those recommended for erosion control may also be effective in reducing soil erosion. The objective of this research is to test the influence of 9 types of polyacrylamide (PAM) on water infiltration and soil loss of an arid silt loam soil under simulated rainfall conditions. logy. Nine types of organic polymers varied in surface charge, ranging from +20 to –75, and molecular weight ranging from very low to very high were used in this study. Soil plots with dimensions of 60 cm by 120 cm having moderate slope of3 to 5% were constructed in the field and equipped with runoff collection installations. A specific type of PAM was spread on soil plots at a rate of 10 kg/ha. Rainfall was supplied from a drip type rainfall simulator at constant intensity and duration of 80 mm/h and 50 min, respectively. Runoff, infiltration and soil loss were measured for each plot subjected to a specific type of PAM and compared to control plots. Land application of PAMs significantly increased infiltration prior to runoff but had insignificant effect on total infiltration volume and final infiltration rate under the present experimental conditions. Experimental results confirmed that anionic polymers were more effective in reducing soil loss than that of non-ionic or cationic polymers. In fact the cationic, low molecular weight and low surface charge non-ionic PAMs had insignificant effect on soil loss. High molecular weight anionic PAM with 30% surface charge (A-130) was more effective(46% reduction) than those having a high molecular weight and a lower surface charge of 20% (A-110 and A-120) with an aver-age soil loss reduction of 24%. The PAM A-836, described assoil erosion polymer with 20% surface charge and high molecular weight, reduced soil erosion by 41%. Unexpectedly, the anionic PAM with low molecular weight but very high surface charge was also effective in reducing soil loss (47% reduction). Land application of PAM improves water infiltration and highly reduces soil erosion thus improving agricultural production. Application of PAM could be the only viable way to improve arid land farming. It seemed that various types of PAMs, other than those specifically produced for erosion protection can be used to combat soil erosion. This means that farmers in poor countries can use any type of PAM that is available to them to improve agricultural production.

Optimisation of the Solid-Contact Test with Arthrobacter globiformis (7 pp)

Abstract: Background, Aim and Scope A number of biotests are available for the characterisation of solid matters such as soil or sediment. Among these, bacterial biotests using single test species often analyse the toxicity of water-soluble contaminants in aquatic extracts, but there is also a need for a fast and inexpensive bacterial solid-contact test. In this study, a solid contact test with added bacteria (Arthrobacter globiformis) was optimised (through miniaturization) for the development of a test kit with conserved bacteria. As in other tests, the results can be influenced by natural soil factors, often masking anthropogenic impacts. For this reason, a further goal of this study was the investigation of the influence of natural soil characteristics on the result of the solid contact test. The project is part of the joint research project 'Optimization of ecotoxicological test methods for routine use' (abbreviated as ERNTE-Forschungsvorhaben: 0330305). Materials and Methods: This method is based on an existing German standard (DIN 38412 L 48) using Arthrobacter globiformi for testing whole soils and sediments. The test principle is the measurement of the dehydrogenase activity of the test organism A. globiformis after an incubation time of two hours with the solid material. To attain the miniaturization in microplates, dye measurement was changed from spectrophotometrical determination of the substrate resazurine to the fluorimetric measurement of the product resorufin. A second step towards optimisation was the use of freeze-dried bacteria. Seven selected uncontaminated soils were tested in order to determine the influence of natural soil characteristics on the results of the solid contact test with A. globiformis. Freshly spiked and polluted field soils were analysed in order to obtain information about the sensitivity of the test. Results: It is possible to perform the contact test in microplates. The fluorimetric dye measurement can be carried out in the presence of the solid material, so the work-intensive step of centrifugation and filtration is no longer necessary. The measurement in the optimised contact test is based on the kinetics of the enzyme reaction. The investigation showed that conserved bacteria have the same activity and sensitivity as cultivated bacteria. Discussion: The study of the uncontaminated soils demonstrated the influence of various soil characteristics on the results of the solid contact test. This information is the basis for the selection of the control and reference soils and is crucial for setting the threshold value in toxicity testing. The investigation of freshly spiked and contaminated soils showed a different sensitivity dependent on the kind of the contamination. Conclusions: The solid contact test was successfully optimised using microplates, whereas now less than six hours are necessary for the analysis. The optimised test is rapid and sensitive, requiring small samples and no stock culture of the bacteria A. globiformis if using freeze-dried bacteria. In this study, the effect of natural soil factors such as pH-value was shown. This information is used to define the threshold value for toxicity. Therefore, the optimised contact test can be used for an efficient assessment of soil or soil substrates. Further studies will clear up if this optimisation is also valid for aquatic sediments and waste. Recommendations and Perspectives: Due to its short analysis time, the test is suitable for screening different kinds of solid matter and can be used for on-site analysis. - The optimised contact test with freeze-dried bacteria as part of a battery of tests is appropriate for the assessment of contaminated soils, sediments and waste.

Prognosis of Methane Formation by River Sediments (9 pp)

Abstract: Under anoxic conditions typically prevailing in disposal sites for dredged sediment, methanogenesis is the terminal step during microbial degradation of sediment organic matter. Sediment gas production may pose several problems to site management and post-closure utilisation. Depending on the magnitude of gas/methane formation and the intended utilisation of the site, countermeasures will have to be effected during and after deposition of the dredged material. For this purpose it may be of interest to pre-estimate the extent of gas formation from simple sediment variables. Therefore, the aim of the investigations presented here was to analyse the interrelations between gas formation and sediment physical, chemical and biological qualities. Freshly sampled riverbed sediment from nine German federal waterways was analysed for standard solid physical and chemical parameters, pore water composition, cell counts of methanogenic and sulfate-reducing bacteria, and gas formation over a period of 500 days. Particle size and density fractionation were carried out in order to characterise organic matter quality. Correlations between methane formation and sediment chemical, physical and microbiological characteristics were tested using linear and multiple correlation analysis. The selected sediments, including two with marine influence, differed strongly regarding texture, chemical parameters, pore water composition, and methanogen cell counts. The course of methane formation was found to follow distinct phases. The commencement of methane formation was preceded by a lag phase of variable duration. The lag phase was followed by a strong increase of the methane formation rate up to a sediment-characteristic maximum of 5–30 nmol CH4 h–1 g dw–1. Eventually, the rate of methane formation decreased and reached a more stable, long-term level. The extent and amplitude of each phase varied strongly between sediments and could be correlated well with only a few standard analytical parameters, despite the strong heterogeneity of sediment with respect to chemical, physical, and biological characteristics. Lag phase duration depended strongly on the content of inorganic electron acceptors and also on the number of methanogens present at the beginning of the experiment. Maximum and steady state methanogenesis were mainly determined by sediment total nitrogen. As analysis of sediment density fractions revealed that total nitrogen reflected the share of readily degradable macroorganic matter. The results imply that the observed methane formation is a function of the temporally changing balance of the availability of electron acceptors and H2, and the share of easily degradable organic matter. For fresh riverbed sediments, the latter may be deduced from total nitrogen content. Overall, the results showed that methane formation by freshly dredged material may well be pre-estimated from standard analytical data within the first few years of deposition. However, the differently degradable organic matter pools will change over time with respect to size, chemical nature and association with the sediment mineral phase. It can thus be expected that the correlations found in this study will not be readily transferable to older materials. Further studies on the gas formation and organic matter quality by older sediments, e.g. from older dredged material disposal sites of known age, should be conducted and results should be combined with existing organic matter degradation models in order to improve the prediction of sediment gas formation over time.

Sustainable Management of Nutrients in Forage-Based Pasture Soils: Effect of Animal Congregation Sites (5 pp)

Abstract: Background, Aim and Scope Grazing animals have a dominant effect on the movement and utilization of nutrients through the soil and plant system, and thus on the fertility of pasture soils. Grazing can accelerate and alter the timing of nutrient transfers, and increase the amount of nutrients cycled from plant to soil. Long periods, position of shade, and water resources for grazing cattle can influence the spatial distribution of soil biochemical properties including soil organic carbon (C), total extractable inorganic nitrogen (TEIN), and Melich 1 extractable total phosphorus (TP). The objective of this study is to test whether cattle congregation sites typical on most Florida ranches, such as mineral feeders, water troughs, and shade areas are more nutrient-rich and may contribute more nutrients to surface and groundwater supply than in other pasture locations under Florida conditions. Materials and Methods: Baseline soil samples around and beneath three congregations sites in established (>10 yr) grazed beef cattle pastures at the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Subtropical Agricultural Research Station (STARS), Brooksville, FL, were collected in 2003, 2004, and 2005. Results: The levels of soil TEIN and TP were significantly (p ≤ 0.001) affected by the interaction of congregation sites and distance away from the center of the sites. Mineral feeders had the highest concentration of TP followed by shades and water troughs. The concentrations of soil TP decreased almost linearly with distance (x = meter) away from the center of the mineral feeders (-5.24x + 55.10; R2 = 0.92; p ≤ 0.001) and the shades (-6.25x + 57.21; R2 = 0.85; p ≤ 0.001). However, the level of TP around the water troughs (-0.25x + 16.91; R2 = 0.09) does not appear to change significantly with distance, staying close to about 13-18 mg kg-1. The levels of TEIN decreased linearly with distance away from the mineral feeders from the center of the shades. A linear model can describe the relationship between TEIN and distance away from the center of shades: -11.3x + 78.2; R2 = 0.95; p ≤ 0.001. The shaded sites (34.25 ± 1.7 mg kg-1) had higher levels than the mineral feeders (7.22 ± 0.60 mg kg-1) or water troughs (10.06 ± 0.8 mg kg-1) sites. Discussion: The higher soil TP near and around the mineral feeders can be attributed to the presence of phosphorus in the supplemental feeds. The average level of soil TP in the mineral feeders of 34.05 ± 0.44 mg kg-1 was not high enough to be of environmental concern. Losses of soil phosphorus by overland flow are becoming a big concern when the concentrations for soil phosphorus exceeded 150 mg kg-1 in the upper 20 cm of soils. With TN, the shaded sites (34.25 ± 1.7 mg kg-1) had either higher levels than the mineral feeders (7.22 ± 0.60 mg kg-1) or water trough (10.06 ± 0.80 mg kg-1) sites. Higher TEIN content at the shade sites may have been more likely due to frequent urination of animals and lack of vegetation immediately adjacent to shades. The lack of vegetation within and/or near the shades then had no uptake mechanism for removal of inorganic nitrogen, unlike the heavy demand for inorganic nitrogen by bahiagrass in other areas of the pasture. An accumulation of TEIN immediately adjacent to shades could lead to a potential point source that would be susceptible to leaching or gaseous losses to the environment. Conclusions: Early results of the study are suggesting that cattle congregation sites in beef cattle operations in Florida are not nutrient-rich, therefore may not contribute more nutrients to surface and groundwater supply under Florida conditions. Recommendations and Perspectives: Since there is no apparent vertical build up or horizontal movement of TEIN and TP in the landscape, we can then surmise that cattle congregation sites may be considered not a potential source of nutrients at the watershed level, at least on the sand ridge soils in Florida. Further research is continuing, including sampling at cattle congregation sites at other locations in north and south Florida, which started in July 2004.

Effect of Overlying Windrowed Harvest Residues on Soil Carbon and Nitrogen in Hoop Pine Plantations of Subtropical Australia (6 pp)

Abstract: Harvest residues were formed into windrows to prevent nitrogen (N) losses through volatilisation and erosion that occurred following pile and burn operations in hoop pine (Araucaria cunninghamii Aiton ex A. Cunn.) plantations of subtropical Australia. We selected second rotation (2R) hoop pine sites where the windrows (10-15 m apart) had been formed 1, 2 and 3 years prior to sampling in order to examine soil carbon (C) and N in the areas beneath and between the windrows. Materials and Methods: We used conventional chemical methods, anaerobic incubation assay, 13C and 15N natural abundance analyses and, solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Results: Percent mineralisable N (PCMN) was the only parameter in the underneath windrow position at the Year 1 site that did not show a significant difference to the rest of the positions along the transect. However, positions adjacent to windrows did have significantly greater PCMN at the Year 1 site than other positions along the transect. PCMN, total N and total C were significantly greater underneath the windrows at the Year 3 site, whilst d13C was significantly more negative in the underneath windrow positions. Discussion: PCMN was the most sensitive biological indicator of the changes occurring in the soil due to decomposition of the windrows, with the beneath-windrow position having a significantly higher PCMN than the inter-windrow position (p<0.001) at the Year 3 site. Isotopic natural abundance for both 13C and 15N was able to detect the influx of labile materials from new residues. Solid-state 13C NMR was able to detect inputs of labile C from the windrows at the Year 1 site, whilst the increase in aromatic C at the Year 3 site was indicative of the more advanced stages of windrow decomposition. Conclusions: Decomposition of windrowed residues had a beneficial effect on soil N and C pools. However, the effect remained localised after 3 years, indicating that trees needed to be planted close to the windrows to gain any benefit from residue decomposition Recommendations and Perspectives: The use of windrows allows a clear planting area and provides a good barrier against soil erosion. However, trees can only gain access to the nutrients from the decomposing residues if they are planted close to the windrows. Limiting the width of the cleared areas to allow for only 2 planting rows will give the maximum benefit to the developing trees.

A Novel Particle Contact Assay with the Yeast Saccharomyces cerevisiae (8 pp)

Abstract: Goal, Scope and Background Numerous xenobiotics released into surface waters are transferred to suspended particulate matter and finally attached to sediments. Aquatic organisms may be exposed to them by direct particle feeding, by physical contact with contaminated surfaces as an exposure route, and by the uptake of dissolved contaminants after equilibration via the free water phase. In order to assess potential sediment toxicity, each of these exposure routes has to be addressed. This paper presents a newly developed particle contact assay that uses the fermentation performance of a specific Saccharomyces cerevisiae strain for the assessment of toxic effects in sediments. The test procedure is based on the characteristic feature of growing yeast cells to attach to sediment particles, which are also relevant for the accumulation of contaminants. The physical contact with lipophilic contaminants mirrors an exposition pathway for the direct uptake into the cells. In order to quantitatively characterize the toxic effects of particle attached pollutants on the fermentation performance, unpolluted native reference sediment was spiked with representatives for widely distributed anthropogenic contaminants.

Occurrence of Polycyclic Musks in Sewage Sludge and their Behaviour in Soils and Plants. Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter (5 pp)

Abstract: Background, Aim and Scope Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter Part 2: Investigation of Polycyclic Musks in Soils and Plants

Comparing Deterministic and Probabilistic Risk Assessments. A case study at a closed steel mill in southern Sweden (7 pp)

Abstract: Background, Aims and Scope. Contaminated land is a high priority environmental problem in most of Europe and North-America. Sweden is no exception and generic guideline values have been developed f ...

Sensitivity Studies of the Common Bean (Vigna unguiculata) and Maize (Zea mays) to Different Soil Types from the Crude Oil Drilling Site at Kutchalli, Nigeria (7 pp)

Abstract: The economic growth that Nigeria has enjoyed as a result of oil revenue has its drawback through exposure of people in the oil producing areas to environmental contamination, due largely to the increase in the movement of oil. Activities associated with oil well drilling on agricultural lands have led to serious economic losses on the communities affected. The local people in most of these communities are peasants who do not know how to react to drilling wastes or polluted fields where they have their crops. A case under study is the Kutchalli oil drilling area. Waste pit soil from drilling waste dumps in Kutchalli oil drilling area was tested whole and in combinations with 'clean' soil for their abilities to support plant growth and development in common bean (Vigna unguiculata) and maize (Zea mays). Seed germination, plant height, leaf area, biomass accumulation, respiratory activity as well as soil chemical analysis were used to access the ability of waste pit soil to support plant growth and development in the test plants. Discussion and Conclusions. Waste pit soil completely inhibited the germination of bean and maize seeds. Waste pit soil in combinations with different proportions of Kutchalli soil gave growth (germination, height of plants, number of leaves, leaf area, etc.) values that were inferior to the control soil (Kutchalli) and the independent control soil (Monguno). Seeds planted in the test soil combinations containing waste pit soil showed significantly low respiratory activity. Waste pit soil seems to be toxic to plant growth and development. Drilling mud in combination with native Kutchalli soil significantly enhanced plant growth and development. The seed germination, growth and development inhibition by waste pit soil suggests its toxicity. We want to suggest the need for strict control and monitoring of waste pit soil in oil drilling sites.

Nitrogen and Phosphorus in Coastal Sediments Covered by Cyanobacteria Mats (9 pp)

Abstract: Background. Biocommunities of phototrophic microorganisms (principally cyanobacteria) developing on the surface sediments of shallow, warm and semi-isolated coastal environments, bind or trap small particles on their polysaccharide sheaths creating organosedimentary structures. Those structures are called algal mats and they are commonly flat and laminar in shape. They are also called recent stromatolites due to their remarkable similarity to the fossil ones. Objectives. Not many geochemical studies exist concerning cyanobacterial mats in Mediterranean coasts, in comparison with the biological ones. Considering the importance of nitrogen and phosphorus in the cyanobacteria mat development, the present study aims to contribute to the knowledge of their chemical behaviour in such environments. Methods. Sediment cores of about 10 cm length along with water samples were collected during the course of a year from two Greek coastal areas. Sediments were fractionated in three distinct layers according to their structure. A wet oxidation method for the simultaneous determination of total nitrogen and total phosphorus was applied to all sediment samples. The total organic carbon (TOC), the total inorganic phosphorus and the natural pigment content in the sediment samples were also determined. Standard spectrophotometric methods were used for the determination of the concentration of dissolved nutrients. In situ measurements of pH, temperature and salinity were also carried out. Results and Discussion. The sampling areas were found to be in the mesotrophic level. The group of aerobic filamentous cyanobacteria dominated the sediment biocommunities. The pH of the sediment showed a gradual reduction downwards. The highest content of TOC, total nitrogen and total phosphorus were detected in the surface layer of the sediment samples. The contribution of organic phosphorus to the total phosphorous ranged between 0% and 50% with an average value of 26.6%. A depletion of organic phosphorus in the anoxic middle layer of the sediment was detected. A good positive correlation between total nitrogen and chlorophyll-a, as well as total nitrogen and TOC in the surface sediment layer, was observed. A good negative correlation between total phosphorous in sediments and dissolved phosphates in seawater was also observed. Conclusions. The high content of total nitrogen recorded in the surface sediments indicate that cyanobacteria accumulate nitrogen acquiring it from the sediment, the marine environment

Managing European Sediments: Can We Expand Our Ecological Risk Assessment Paradigms?

Abstract: provide the substrate for benthic and plant communities critical to aquatic food webs, and as suspended sediment can affect the functional health of pelagic and shore ecosystems, sediment status, dynamics, stability and type are all critical factors of ecosystem health, whether or not contaminants are part of the picture. There is a need for research in various aquatic habitats to provide better scientific understanding of mechanisms linking anthropogenic activities and the biological community function that may be the focus of protection, at various spatial, temporal, trophic, and organizational scales. One FP-6 funded research programme, Coastal Ocean Benthic Observatories (COBO; www.cobo.org.uk) is developing the tools for multidisciplinary in situ experimentation and biogeochemical observation and measurement to simulate anthropogenic disturbances and measure their effects on benthic community function. This work should help improve ecosystem models and inform management decisions. European ocean observatories being considered under ESONET should have coastal nodes and inland analogues to evaluate baseline and evolving aquatic ecosystem function.

A Chronic Plant Test for the Assessment of Contaminated Soils. Part 1: Method development (9 pp)

Abstract: - PREAMBLE According to the German Federal Soil Protection Act (BBodSchG 1998), the habitat function of soils must be protected. Despite the fact that in the Federal Soil Protection Ordinance (BBodSchV 1999) it has not been established how this goal can be reached reliably, it is clear that such a biological function can only adequately be assessed using biological test methods. This is especially true when a soil is contaminated by a mixture of often unknown chemicals. In such a case the use of chemical analysis aiming at a small range of known substances is not sufficient and must therefore be supplemented by biological methods. For this reason, several standardised test methods are available (e.g. using earthworms, collembolans or plants; Rombke and Knacker 2003; ISO 2003). Since acute tests are usually not sensitive enough for the assessment of potentially contaminated soils (e.g. Hund-Rinke et al. 2002), chronic tests like the earthworm reproduction tests (ISO 1998) are recommended for this purpose.

Technical Recommendations for the Update of the ISO Earthworm Field Test Guideline (ISO 11268-3) (5 pp)

Abstract: Background, Aim and Scope Background, Aims and Scope. The earthworm field test firstly was developed by the German Federal Biological Research Centre for Agriculture and Forestry (BBA) for testing of pesticides and later internationally standardised by the International Organization for Standardization (ISO) as a tool for characterizing soil quality. It is mainly used for the assessment of effects of pesticides on earthworms under field conditions. Growing experience has shown that the practical performance of the test can be improved. Main Features: In two meetings organised by the Federal Biological Research Centre for Agriculture and Forestry (Braunschweig, 2002) and later the German Federal Agency for Consumer Protection and Food Safety (Lille, 2005) an ad-hoc working group of experts from various countries and institutions discussed the practical performance and recommendations that should be taken into account in a revised draft following the current ISO guideline after the proposed revision has been approved by voting in the periodical review. Results: The outcome of the discussions and the background of the recommendations of the ad-hoc working group are briefly summarised in this paper. These are mainly methodological details in order to improve the test performance (e.g. by decreasing variability or increasing practicability). Discussion: These recommendations are proposed to be considered for the next update of the current ISO guideline. They should be seen as technical amendments still waiting for their approval by standardisation organisations. Conclusions: Although this method focuses on the assessment of effects of pesticides on earthworms, the recommendations will also be valuable for testing contaminated soils. The recommendations presented may also be a first step for splitting the current guideline into two fields of application, one for testing of chemicals and pesticides (i.e. within the scope of OECD) and another one for testing soil quality (i.e. within the scope of ISO). Perspectives: Nevertheless, there is still a major need for guidance concerning the interpretation of effects determined in such complex field tests.

Handling sediments in Dutch river management: The planning stage of the Maaswerken river widening project

Abstract: Goals, Scope and Background. Faced with higher peak discharges in the foreseeable future, the Dutch government has decided to increase the discharge capacities of the Dutch Rhine and Meuse rivers. Instead of raising the dikes, river widening measures are to be undertaken, in and along the riverbed. Such measures include surface level lowering along the rivers, channel deepening, the addition of high-discharge channels and the removal of hydraulic obstacles. To cover or reduce the costs of river widening, a coupling with aggregates (sand and/or gravel) extraction has been considered. Although the rationale of this concept is basically sound, it has met with considerable resistance, especially along the southernmost stretch of the Dutch Meuse River, in the Maaswerken project area. Main Features. The Dutch river widening projects are quite unique in size and occurrence, and the number of publicly documented case histories available for the planning of such works is inevitably few. We review the planning and decision-making process for the Maaswerken project, which is in a more advanced stage than that of the corresponding project for the Rhine. Sediment handling and aggregates extraction are focused on, which are key issues to this case. Analysis and Discussion. In the study area, there is a conflict of interests between the extractive industry and the local communities. The industry faces a policy of phasing out mineral extraction; river widening presents the last significant prospects in the area. The general public, however, has come to resent mineral extraction because of its historical impacts. Aiming at a manageable process, the Maaswerken project management kept most stakeholders in a basically reactive position: the general public was kept informed and enabled to submit formal reactions to draft planning decisions. Aggregate extraction plans and extraction volumes were only discussed with the industry. Despite not being represented, the public influenced this negotiation process by expressing dissatisfaction with interim outcomes through the media and political channels. Plans had to be reconsidered, and this closed process turned out to be only seemingly efficient. Conclusions and Recommendations. The level of public concern regarding the Maaswerken project suggests that the overall level of stakeholder involvement may have been insufficient, even though it complied with pertinent environmental and planning legislation. A participation deficit seems to have mainly occurred when defining the project's preconditions: a predefined, controversial role for the extractive industry was implicit in self-financed river widening. As planning and decision making in large projects such as the Maaswerken are prone to be affected by a negative public opinion, it is recommended that social feasibility is assessed and addressed at the very outset. © 2006 ecomed publishers (Verlagsgruppe Huthig Jehle Rehm GmbH).

Quality Criteria for Re-Use of Organotin-Containing Sediments on Land (7 pp)

Abstract: Background, Aim and Scope The use of organotin compounds as antifouling agents on ships is prohibited at EU level since 1 July 2003. Because of its persistence, the presence of organotin compounds in harbour sediment will however remain a problem for years. Dumping of dredged sediment in sea is subject to very strict quality criteria, stimulating the exploration of re-use alternatives, such as re-use on land. Within the TBT Clean project (EU LIFE Project 02/ENV/B/341) an assessment framework for re-use of organotin containing treated sediment on land as secondary granular building material was developed. Three scenarios were considered: free re-use on land, re-use above groundwater level with cover layer, and re-use under groundwater level (the latter two scenarios are referred to as restricted re-use). Receptors considered were humans, ecosystem and groundwater. Generic upper concentration limits and sediment leaching limits were calculated. Materials and Methods: Upper concentration limits were calculated with the Vlier-Humaan model. This model allows to calculate soil remediation values according to the Flemish legal framework. The focus of the methodology is the protection of human health, although a check for ecotoxicity was included in the project. The soil remediation value for residential land-use was selected within the scenario for free re-use; for restricted re-use (no direct contact possible), the soil remediation value for industrial land-use was selected. Leaching values were calculated with an analytical soil and groundwater transport model. The reference scenario behind the leaching criteria of the European Landfill Directive was modified to fit the project objectives. Default values for application height and length were used. The point-of-compliance was situated at 20 m distance in the groundwater. Physicochemical properties were taken from literature; sorption characteristics were taken from literature and were measured on 6 treated sediment samples during the project. Plant-uptake values were taken from the literature. Toxicological criteria were taken from EFSA. Results: The assessment framework provided an upper limit (SedUL) and an leaching value (SedLV) for each scenario, expressed as mg/kg dm in the sediment. Criteria were calculated for tributyltin (TBT) and dibutyltin (DBT); too few data were available for monobutyltin (MBT). The SedUL equalled 0.51 mg TBT/kg dm and 0.07 mg DBT/kg dm for free re-use and 195 mg TBT/kg dm and 205 mg DBT/kg dm for restricted re-use (two scenarios). For free re-use the SedLV was only limiting for TBT at Kd of < 2000 l/kg in the sediment. Under re-use above groundwater level with coverage SedLV values ranged from 6.9 – 29 mg TBT/kg dm and from 12 – 33.3 mg DBT/kg dm (Kd ranging from 100 – 10000 l/kg); under re-use below groundwater level SedLV values ranged from 0.007 – 0.77 mg TBT or DBT/kg dm (Kd ranging from 100 – 10000 l/kg). Discussion: Results are subject to large uncertainties because of variation in input data; the model output is sensitive to variation in plant uptake (SedUL for free re-use), Koc or Kd (SedUL for restricted re-use, SedLV for re-use with coverage), Henry's law coefficient (SedUL for restricted re-use); all these parameters show orders of magnitude variation. Conclusions: A feasible and consistent framework for evaluation of the re-use of treated organotin containing sediment was developed. However, the resulting quality criteria are still subject to large uncertainties, due to uncertainties in input data. Recommendations and Perspectives: High-quality data on plant uptake and soil sorption of organotin compounds, the influence of soil properties on these processes, and long-term terrestrial toxicity data are needed to refine the calculations. The quality criteria should be reviewed when these data become available.

A Chronic Plant Test for the Assessment of Contaminated Soils. Part 2: Testing of contaminated soils (10 pp)

Abstract: PREAMBLE According to the German Federal Soil Protection Act (BBodSchG 1998), the habitat function of soils must be protected. Despite the fact that in the Federal Soil Protection Ordinance (BBodSchV 1999) it has not been established how this goal can be reached reliably, it is clear that such a biological function can only adequately be assessed using biological test methods. This is especially true when a soil is contaminated by a mixture of often unknown chemicals. In such a case the use of chemical analysis aiming at a small range of known substances is not sufficient and must therefore be supplemented by biological methods. For this reason, several standardised test methods are available (e.g. using earthworms, collembolans or plants; Rombke and Knacker 2003; ISO 2003). Since acute tests are usually not sensitive enough for the assessment of potentially contaminated soils (e.g. Hund-Rinke et al. 2002), chronic tests like the earthworm reproduction tests (ISO 1998) are recommended for this purpose. A chronic plant test for the determination of phytotoxicity was missing until quite recently. The term phytotoxicity is understood here as the capacity of a compound or a contaminated soil to cause temporary or long-lasting damage to plants (EPPO 1997). Therefore, the German Ministry for Education and Research sponsored a project (1997 – 1999) in which – based on existing standardised methods – such a chronic plant laboratory test was developed and partly validated (Kalsch and Rombke 2000). The new test can be used for the evaluation of single chemicals (see Part 1 of this mini-series) as well as for the assessment of contaminated or remediated soils (see Part 2 of this mini-series). ABSTRACT Background and Scope. A new chronic plant test system which is based on experiences with various acute plant tests (e.g. published by OECD or ISO) and existing North American Plant-Life-Cycle Bioassays was standardised in a project sponsored by the German government. Characteristic properties of the test system, which can be performed either with Brassica rapa (turnip rape) or Avena sativa (oat), are described in Part I of this mini-series. This new test was used to assess the effects of natural soil samples contaminated with TNT (2,4,6-Trinitrotoluene) or PAHs (poly-aromatic hydrocarbons). The soils were tested after taken from the field as well as after being remediated. Different control and reference soils were used to evaluate the test results. In addition, they were compared with the results of tests in which either TNT or Pyrene was spiked to field and standard soils (see Part I of this mini-series). All contaminated soils showed clear effects in the Chronic Plant Test (usually B. rapa was more sensitive than A. sativa). LUFA 2.2 standard soil and OECD artificial soil are well-suited as control and mixture substrates, while reference soils collected at uncontaminated sites were several times phytotoxic. In most of the latter cases, soil properties could be identified as the main cause of these effects (e.g. the pH value). While in general the sensitivity of the reproduction and biomass endpoints did not differ much, it is recommended to measure different endpoints (i.e. biomass and reproduction) due to the different mode-of-action of contaminants. In the case of TNT a good agreement between the results of single chemical tests and tests with TNT-contaminated soils was found (due to the minimal effects of Pyrene the same statement is not possible for PAHs). The results of this work have been used to prepare a draft test guideline, which has recently been standardised by the International Organisation for Standardisation (ISO). Based on these experiences, recommendations are given how this chronic test system could be used as part of a test battery for the assessment of contaminated soils.