Guidelines for sampling in Flanders (Belgium)

In Flanders, sampling guidelines for investigations on contamination of soils are in development. One detailed sampling guideline is currently available with respect to the prospective investigation in the frame of the decree related to soil sanitation. Four strategies for sampling may be followed as a function of available information about pollution sources. Guidelines indicate what has to be sampled (top soil, deeper soil, soil water), how sampling points must be determined, how the number of samples and analyses is determined and what parameters need to be analysed. The example given shows that sampling guidelines will strongly depend on the ultimate goal of a particular sampling. A sampling procedure should be developed with close consideration of practical aspects and limitations, in order to be practical, realistic and cost-effective.     

European soil sampling guidelines for soil pollution studies

The soil sampling guidelines used in European countries (ESSG), as kindly provided by the national institutions which participated in the project, have been recorded, studied, evaluated and presented in this paper. The aim has been to ascertain what soil sampling guidelines exist in Europe; to detect similarities and differences (comparable results), advantages and deficiencies; to identify incompatible strategies and evaluate how methodologies might affect data quality; to investigate sources of deviations or uncertainties; to improve comparability and representativeness of soil sampling; to investigate the need for harmonised sampling guidelines; and to develop suggestions for standard operating procedures (SOP). Soil sampling guidelines throughout Europe differ as to whether they are applied by law, or used throughout the country. In some countries these are ISO/DIS related or based (ISO 10381-1, 1995; ISO 10381-2, 1995), or are produced by a scientific society or a standardisation body. As far as sampling strategy is concerned, not all sampling guidelines clearly describe the sampling scale, the specifications for contamination risk precautions, the sampling plan and protocol structure and the pre-analysis treatment of the soil samples. The purpose for sampling, in descending order of frequency, is soil pollution, soil fertilisation, general soil monitoring, background risk assessment, or else it is not specified. The majority of countries do not sample the top organic matter separately. Sampling depth is either related to the morphogenetic horizon or to ad hoc sampling depth, which is not specified in all cases. They suggest mass- and volume-related soil sampling, while the sampling pattern is not presented in all national guidelines. The criteria for area, site, unit, sub-unit, and point selection are mainly based on pedology and land use, following the history and pre-screening information or geology, or is site related. Some guidelines suggest the division of sampling units into sub-units. The sampling pattern is mainly grid sampling, grid and random sampling, or not mentioned. Sampling density inside the sampling unit either varies greatly or it is not mentioned, while the size of the sampling unit varies widely. Most guidelines require the collection of composite instead of simple samples, while some prefer sampling soil profiles. In the European SSG many technical details and steps are either not defined or vary, while in the pre-analysis treatment quality assurance (QA) and quality control (QC) approaches are used either both in the lab and in the field, or only in the field, or are not mentioned. The common points and the points in which harmonisation could be started or achieved are discussed.     

Comparative evaluation of European methods for sampling and sample preparation of soils--the Portuguese contribution

The main purpose of this work was to prepare a Portuguese sampling strategy, according to the existing Portuguese recommendations, for the soil sampling exercise at Dornach in the framework of the CEEM soil project of the SMT Programme of the EU. Within this project, the results obtained from the Dornach study were compared with the results obtained by other European participants and also with the reference sampling. The objective of this comparison was to validate the method used and to evaluate possible factors of uncertainty that may arise from the application of our national guideline as well as possible advantages. Another objective, also important, was to provide information regarding the need for a harmonised procedure within the European Union related to soil sampling and sample preparation of soils. The results obtained were consistent with the results obtained by other participants, however, in the Portuguese recommendations there is a general lack of specific information that may complicate its application to polluted scenarios. In fact, those guidelines are valuable to detect the average contamination of the soil, but they are not useful to identify hot spots or the edge influence in a contaminated land. As a conclusion, the results obtained by the CEEM soil project helped to evaluate the Portuguese sampling plan. This may provide a basis for further standardisation of soil sampling for specific purposes, e.g. contaminated land, and to establish a technical support for criteria used in the accreditation of laboratories for soil sampling.     

Harmonisation and quality assurance in pre-analytical steps of soil contamination studies--conclusions and recommendations of the CEEM Soil project

The paper summarises the project's results and consequences including expert's statements. Based on sampling strategies and methodological details which have been recognised to be critical for the comparability of the results of soil contamination studies, recommendations are given towards harmonisation of soil sampling guidelines, improvement of quality assurance of pre-analytical steps and inclusion of soil sampling into accreditation systems. Recommended approaches to improve QA and QC in soil sampling are: harmonised guidelines; specified SOPs; written sampling (strategy) plans; defined qualification and experience of sampling personnel; sampling records; regular interlaboratory comparisons (proficency tests) for sampling; and inclusion of sampling and sample preparation into accreditation procedures. Needs for further research in the field of pre-analytical phases of soil contamination studies are outlined and further R&D projects are encouraged.     

Objectives, concept and design of the CEEM soil project

Within the member countries of the European Union, different strategies and guidelines for the sampling and the preparation of soils are used to investigate soil contamination. As a consequence, there is reasonable doubt that the results gained by applying these different strategies and methods are comparable. In general, the relative contribution of sampling and sample preparation to the total uncertainty in soil contamination studies is a subject of speculation than of knowledge. For this purpose, the first European soil sampling inter-comparison test was organised as a project under the Standards, Measurement and Testing Programme of the European Commission. The aim of this project was to analyse and to compare the existing guidelines, the degree and the state of standardisation in this field in the European countries, and to compare their results when applied on the same test area under comparable conditions by representative sampling teams. The results of the project in general demonstrate that sampling and sample preparation errors reach about the same order of magnitude as errors caused in the chemical analysis. However, there are great differences depending on the elements investigated and their concentration ranges, as well as on pedological and land-use conditions in the test area. Consequently, sampling and sample preparation require the same attentiveness and equivalent measures for quality assurance (QA) and quality control (QC) as the chemical analysis, which has not been the case up to now. Insufficient comparability of the results is illustrated by the fact that different participants arrive at different conclusions for up to 61% of tested soil quality criteria (e.g. threshold levels). The methods and results of the project are presented in detail in the six following papers within this volume. The following 13 papers present some key studies and specific contributions of the participants, as well as synoptical papers of the invited experts in standardisation and accreditation.     

Quantitative evaluation of the CEEM soil sampling intercomparison

The aim of the CEEM soil project was to compare and to test the soil sampling and sample preparation guidelines used in the member states of the European Union and Switzerland for investigations of background and large-scale contamination of soils, soil monitoring and environmental risk assessments. The results of the comparative evaluation of the sampling guidelines demonstrated that, in soil contamination studies carried out with different sampling strategies and methods, comparable results can hardly be expected. Therefore, a reference database (RDB) was established by the organisers, which acted as a basis for the quantitative comparison of the participants' results. The detected deviations were related to the methodological details of the individual strategies. The comparative evaluation concept consisted of three steps: The first step was a comparison of the participants' samples (which were both centrally and individually analysed) between each other, as well as with the reference data base (RDB) and some given soil quality standards on the level of concentrations present. The comparison was made using the example of the metals cadmium, copper, lead and zinc. As a second step, the absolute and relative deviations between the reference database and the participants' results (both centrally analysed under repeatability conditions) were calculated. The comparability of the samples with the RDB was categorised on four levels. Methods of exploratory statistical analysis were applied to estimate the differential method bias among the participants. The levels of error caused by sampling and sample preparation were compared with those caused by the analytical procedures. As a third step, the methodological profiles of the participants were compiled to concisely describe the different procedures used. They were related to the results to find out the main factors leading to their incomparability. The outcome of this evaluation process was a list of strategies and methods, which are problematic with respect to comparability, and should be standardised and/or specified in order to arrive at representative and comparable results in soil contamination studies throughout Europe. Pre-normative recommendations for harmonising European soil sampling guidelines and standard operating procedures have been outlined in Wagner G, Desules A, Muntau H, Theocharopoulos S. Comparative Evaluation of European Methods for Sampling and Sample Preparation of Soils for Inorganic Analysis (CEEM Soil). Final Report of the Contract SMT4-CT96-2085, Sci Total Environ 2001;264:181-186. Wagner G, Desaules A, Munatu H. Theocharopolous S, Quevauvaller Ph. Suggestions for harmonising sampling and sample pre-treatment procedures and improving quality assurance in pre-analytical steps of soil contamination studies. Paper 1.7 Sci Total Environ 2001b;264:103-118.     

Implications of soil complexity for environmental monitoring

International proposals for national soil and environmental monitoring lack adequate awareness of the diversity and complexity of soils. These need to be considered in sampling and reporting. This paper provides examples of the diversity and complexity of soil and environmental conditions in Bangladesh and Ghana, including differences between physiographic regions, within soil toposequences, between and within neighbouring fields, and in areas of shifting cultivation. These examples show that large numbers of sites would need to be sampled and monitored to provide the information required for the national environmental accounting envisaged. Detailed studies are needed in countries with relevant soil monitoring capacities to determine the scale of sampling required and the feasibility of conducting national monitoring. Where the latter is considered infeasible, the contribution that more limited measures could make to environmental monitoring needs to be examined. There is scope for useful academic studies to be made of environmental variability and practical monitoring techniques.     

The effect of sampling design on extensive bryomonitoring surveys of air pollution

In this study, we investigated if the different sampling designs normally used in extensive bryomonitoring surveys of air pollution allow compliance with the objectives proposed in the 'Heavy Metals in European Moss' project. For this, we have used data on concentrations of As, Cu, Se and Zn from five moss sampling surveys carried out in Galicia (NW Spain), using three types of sampling design: regular grid, sampling sites inside squares and the strategy recommended in the guidelines for European surveys. To study the effect of the interaction between the sampling design and the spatial pattern of the presence of contaminants, we have used a simulated and a real pattern onto which we superimposed the three sampling designs considered. We found that only random sampling and grid sampling allow compliance with the proposed objectives, and we discuss the advantages of the latter over the former. The data corresponding to studies using different sampling designs are not comparable, and in future large-scale surveys, the same design must be used if the results are to be compared and if valid conclusions are to be reached. The scale of the grid determines the scale to which the objectives are complied with, so that for correct standardization of the technique, and taking into account the most commonly used grid sizes, we recommend a grid size of 30 x 30 or 32 x 32 km. When additional samplings are required, the size of the grid size should be 30/2(n) or 32/2(n) km.     

The distribution and fixation of trace elements by the Vertisols of Malaga, southern Spain

The response of Vertisols to contamination by heavy metals (As, Cd, Pb, Hg) and micronutrients (Co, Cu, Cr, Ni, V, Zn) in toxic concentrations was studied in a series of experiments undertaken with soil samples from the province of Malaga, in Southern Spain. The soil samples were placed in methacrylate columns, passing through a contaminant solution of selected elements in order to study their distribution and fixation the soil. Systematic sampling and sequential extraction analysis show that the Vertisols behave as a buffer to all elements, except cadmium.     

Indicators of change in the organic matter in arid soils

Soil organic matter is a key component in ecosystems, as it is the essential part of a set of relevant processes and constitutes an important carbon pool contributing to Global Change. The design of environmental monitoring programmes should include indicators of the current status of ecosystems, alerting to incipient changes in them. In this context, a sampling scheme has been designed taking into account the main processes and soil uses affecting the dynamics of soil organic matter. Well-tested parameters were determined in order to assess which of them are most useful as indicators of soil organic matter evolution in arid soil, such as that in the "Cabo de Gata-Níjar" Natural Park (SE Spain). The parameters characterising the lability of the different fractions indicate changes in soil organic matter triggered by changes in soil use and soil dynamics. Changes in soil use, when drastic, are best reflected by those fractions comprising a high percentage of the total soil carbon, while the processes having slower dynamics are best demonstrated by the labile fractions. As a result of the sensitivity analysis of parameters versus changes, and taking into account the operational difficulties for determining them, the following indicators are proposed for a monitoring programme: total organic carbon, active fraction of the organic carbon and ratios of this fraction versus total organic carbon (%) (as given by the lability index proposed).     

Analytical investigation of disturbance of seabed-sampled soil specimens and its influence on unconfined strength

In view of the need to utilize ocean space and to develop seabed resources, the assessment of the stability of deep seabed soil has emerged as an important challenge in the field of geomechanics. To study seabed stability, the strength and stiffness of the natural ground must be ascertained. Accordingly, it is necessary either to conduct laboratory testing on soil specimens sampled from the seabed or to estimate the strength and stiffness by in-situ tests. While in the future it may be reasonable to conduct in-situ tests to estimate the stiffness and strength of seabed soil, it will still be necessary to compare the physical properties measured by in-situ testing with those measured by laboratory testing in advance of these determinations. In short, soil specimens must be sampled from the actual deep seabed, and laboratory mechanical tests must be conducted on the sampled soil specimens. However, soil sampled from the ocean bottom is subject to effects that differ from those exerted on soil sampled from the earth. More specifically, the non-negligible effects of disturbance are expected with soil sampled from the ocean bottom. The effects of disturbance occur during the sampling process due to the vaporization of dissolved gases, as these soil specimens are under relatively higher pressure and contain pore water with a high amount of dissolved gases. Therefore, numerical simulations were conducted in the present study to investigate the effects of vaporized dissolved gases on the mechanical behavior of soil specimens during sampling and on the undrained shear strength as determined by laboratory tests. The analyses revealed that the combination of the decreasing effective stress caused by the sampling and factors such as overconsolidation and unsaturation is attributable to the difference between the soil strength ascertained by laboratory testing and the in-situ soil strength.     

Cryptosporidium parvum oocyst inactivation in field soil and its relation to soil characteristics: analyses using the geographic information systems

The need exists to understand the environmental parameters that affect inactivation of Cryptosporidium parvum oocysts in soil under field conditions. The inactivation of C. parvum oocysts placed in the natural environment was studied at a dairy farm in western New York State, USA. Seventy sampling points were arranged in a grid with points 150 m apart using the Geographic Information System. The sampling points were distributed among three distinct areas: woodland, corn field and pasture. Purified oocysts were inoculated into chambers filled with soil from each sampling point, and buried in the surface of each respective sampling point. To compare C. parvum oocyst survival with another organism known to survive environmental stresses, Ascaris suum eggs were also placed in soil contained in chambers and buried at the same sampling points as the oocysts. As controls oocysts and eggs in distilled water were also placed at each sampling point. Oocyst and egg viability, soil pH and percent gravimetric water content were measured at all sampling points at 0, 60 and 120 day sampling periods. Soil organic content was determined for each sampling point. At 120 days after placement, mean viability of C. parvum oocysts was 10% although at a few sampling points, 30% of oocysts were still potentially infective; whereas 90% of A. suum eggs were viable at all sampling points. Statistically significant differences were not observed among the three different sampling areas, and no statistically significant predictors were found by regression analysis. Results exemplified the heterogeneity of soil parameters and oocyst viability across a landscape; such results make predictive models for C. parvum inactivation problematical. The long-term survival of C. parvum oocysts in soil under field conditions, as this study demonstrated, emphasizes their potential as a risk to contaminate surface waters.     

An empirical approach to estimate soil erosion risk in Spain

Soil erosion is one of the most important factors in land degradation and influences desertification worldwide. In 2001, the Spanish Ministry of the Environment launched the ‘National Inventory of Soil Erosion (INES) 2002-2012’ to study the process of soil erosion in Spain. The aim of the current article is to assess the usefulness of this National Inventory as an instrument of control, measurement and monitoring of soil erosion in Spain. The methodology and main features of this National Inventory are described in detail. The results achieved as of the end of May 2010 are presented, together with an explanation of the utility of the Inventory as a tool for planning forest hydrologic restoration, soil protection, erosion control, and protection against desertification. Finally, the authors make a comparative analysis of similar initiatives for assessing soil erosion in other countries at the national and European levels.     

Derivation of risk based wipe surface screening levels for industrial scenarios

The environmental characterization of building interiors and other surfaces has generally been performed with wipe-sampling because it is a non-destructive technique. There is no consensus, however, as to the interpretation of the results of wipe-sampling. Specifically, there is not a standardized method to determine if chemicals found at sampled levels pose a threat to human health. A methodology was developed, based on acceptable health risk levels, to derive screening levels for evaluating wipe-sampling results pertaining to industrial scenarios. The methodology was based on the United States Environmental Protection Agency (USEPA) Region IX Preliminary Remediation Goal (PRG) approach; a multi-exposure methodology commonly used for evaluating soil concentrations. PRGs are the USEPA determined health based goals for soil preliminary remediation efforts. Probabilistic techniques were used to conduct a sensitivity analysis of the methodology to determine which variables drive the ultimate screening levels. Discrete values were then selected based on standard industrial scenarios common to the US Army. The wipe surface screening levels reported are for use as preliminary guidelines which help to determine whether further sampling or cleanup are necessary. The levels are not meant as cleanup or compliance criteria.     

Spatial distribution and temporal variation of metals in the vicinity of a municipal solid waste incinerator after a modernization of the flue gas cleaning systems of the facility

In June 1994 and 1997, the concentrations of a number of elements were determined in soil and herbage samples collected in the vicinity of a municipal solid waste incinerator (MSWI) (Tarragona, Catalonia, Spain). In August 1997, an adaptation to the EU legislation on pollutant emissions from the stack was carried out to the incinerator. In June 1999, soil and herbage samples were collected again at the same sampling points and the levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni) and vanadium (V) were measured by ICP-MS or AAS with graphite furnace. The results are compared with those obtained in the 1994 and 1997 surveys. In the period 1997-1999, the only significant changes in soil levels corresponded to Cd and Pb, with decreases of 21.0% and 53.5%, respectively. In vegetation, only Mn levels showed a significant reduction, which contrasts with the notable increases found in the concentrations of As, Hg and Ni. According to the results of this survey, it seems evident that other metal emission sources in the same area of study are masking the environmental improvements carried out in the MSWI.     

Soil water erosion on road embankments in eastern Spain

Road embankments erosion is a serious problem in Spain. By means of simulated rainfall experiments (45 mm h(-1) during one hour on 0.41 m(2) plots) soil and water losses were measured on five road embankments located on the SW of the Valencia province, Spain. The bare road embankments, still under construction, contributed with 30 times more soil erosion than the vegetated ones. The measurements here presented demonstrate that road embankments are an important source of sediments, especially during the construction works, and it is recommended that restoration works should be undertaken after the road construction to reduce sediment removal, protect the road and avoid traffic accidents.     

Accreditation and recognition of soil sampling evidence of competence for testing laboratories in Germany

Quality assurance is an essential requirement in many areas of soil testing. Soil sampling plays an important role in soil investigation. One important quality assurance measure is evidence of the competence of institutions offering sampling services (testing laboratories) to carry out appropriate sampling. A special quality assurance procedure has been developed in the course of the investigation and assessment of suspected and contaminated sites on federal property. Testing laboratories are granted official recognition by an independent competent institution, based on well-defined criteria with regard to testing methodology and the qualifications held by the personnel. A prerequisite for such recognition is an effective accreditation procedure. Currently only testing laboratories with recognised status are commissioned for work on contaminated sites on federal property.     

Assessing the Integration of Landscape Connectivity into Comprehensive Spatial Planning in Spain

The integration of landscape connectivity criteria into spatial planning through ecological networks formed by coherent open space systems has received increasing attention in Europe in the last few decades. In Spain, such integration began recently, in parallel with the development of a supralocal comprehensive spatial planning policy, which was practically non-existent a decade ago. An assessment of such integration is reported here, specifically on ecological networks inclusion within the spatially explicit zoning regulations of 11 regional and 66 subregional plans which had been approved in Spain until the end of 2012. At the same time, a survey was conducted among 22 Spanish and 14 European practitioners in order to detect possible deficiencies and opportunities to optimise this integration in Spain through a comparison with other European countries. An increasing integration of ecological networks into supralocal plans was observed, especially in subregional plans approved in the last five years, coinciding with a period of greater development in supralocal spatial planning policy, the end of the Spanish speculative housing bubble and new national legislation which encourages the promotion of ecological networks. However, the integration process is very uneven because homogeneous guidelines are not applied in the different regions. Spanish practitioners discerned wide room for improvement. The integration of ecological networks into multiscale spatial planning should be optimised in Spain, including improvements in local planning, strategic environmental assessment and training of planners in this topic.     

Farmers’ perception of soil fertility change and their preferences for soil fertility management techniques for different land use types in Arsamma Watershed,Southwestern Ethiopian Highlands

This study aimed to assess farmers’ perception of soil fertility change and their priorities for soil fertility management techniques for different land use types in Arsamma Watershed, Southwestern Ethiopian Highlands. A three-stage random sampling technique was employed to select the sampled households. A smaller proportion of farmers perceived soil fertility decline in perennial cropland than in annual cropland as the farmers appeared to be less aware of below-ground processes of soil degradation. The farmers used physical, chemical and biological indicators to evaluate soil fertility changes. The rate of soil fertility decline and the occurrence of the contributory factors were land use specific. Increasing fertilizer requirement of croplands and decreasing yield per unit of land were the main indicators of soil fertility decline in annual and perennial cropland, respectively. Farmers’ preference for soil fertility management techniques was also found to depend on the type of land use. Integrated soil fertility management (ISFM) and agroforestry were the top priorities of the farmers, respectively, for annual and perennial cropland management. Farmers lack knowledge of below-ground processes of soil degradation by leaching, nutrient mining and soil acidity; and agricultural extension services should respond to this need. Further, ISFM for annual cropland and agroforestry for perennial cropland need to be encouraged in the study catchment.