If people are eating outdoors near windy soil on a windy day, airborne contaminants may land on food before it is eaten. When soils are uncovered, small particles can become airborne with wind or other disturbance. Construction or demolition work, mining operations, or poor landscaping efforts can make soil dust. Breathing in contaminated dust may cause physical or chemical damage to humans.
For example, asbestos fibers can puncture the lungs. Chemicals such as lead can hurt the nervous system, including the brain. Contaminants may also be absorbed through the skin.
Creosote is a common material used to preserve wood in the United States. This complex mixture of chemicals can leach out of treated wood and contaminate the soil. If creosote-contaminated soils are touched, then over time the skin may blister, peel or severely redden. Before you put a lot of work into your home or community garden, you want to make sure the soil is safe from contamination!
If you grow food in contaminated soil , there is a risk that your food will also be contaminated. Some housing developments and community garden are established in areas that served a different purpose historically. Read about one neighborhood's efforts here. Many vegetables and herbs can absorb contaminants as they grow.
That puts you at risk if you eat them. Also, vegetables and herbs can have soil dust on them. Without proper washing, contaminants remain. Some garden beds may also be lined with chemically-treated wood. Finally, gardens or farms may be located on uncontaminated soils near a site with contamination. In this case, dust may blow from the contaminated site and pollute the once uncontaminated soil. Industrial and manufacturing sites often have a range of contaminants polluting their soils.
The type of contaminant will depend on what the factory was producing. Contamination can occur when chemicals leak out onto the soil from buildings or trucks. Other times, the factory may have a waste stockpile or holding area that was once considered safe but now known to be a pollution problem. Industrial sites can also be quite large. This makes full-site soil remediation an expensive and challenging, but necessary, task.
In the first tier the research is simple, broad and generic. In later tiers more specific and complex tests and analyses may be used. For each of the LoE in the Triad there are a variety of analyses or tests that can be chosen. Some examples are:. Chemistry: Measurement of total concentrations, bioavailable concentrations, bioaccumulation, etc. Ecology: Field observations of vegetation, soil fauna, micro-organisms, etc. In Chapter 6, a number of tests or tools that are for suitable for use in each tier are presented for the chemistry, toxicology and ecology LoE.
This chapter is an attempt to present a decision support system, which can guide risk assessors in their assessment of site-specific ecological risk. A number of site-specific questions need to be answered before a final decision on performing an ecological risk assessment can be made. This chapter introduces a flow chart for ecological risk assessment of contaminated sites. The flowchart is presented as decision trees as shown in Figure 8 together with a more in-depth introduction to the relevant questions that needs to be addressed and answered when performing a site-specific ecological risk assessment.
The assessment of ecological risk is performed stepwise in tiers. Higher tiers represent gradually more and more complex studies, but also more expensive and laborious studies. The full site-specific risk assessment covers four tiers, i. The main principle in going from a simple screening over a more refined screening to a detailed assessment of the contaminated site is to minimize time and effort.
The actual performance of the risk assessment and use of the various tiers may be very site-specific. After deciding in the two first stages of the ERA that ecological concern needs special consideration, the risk assessment starts typically with a simple evaluation at the screening level. This is done in order to minimize costs until new information indicates the need for further assessment and more sophisticated studies. Therefore, the tools used in the first screening need not only to be reasonably quick and easy, but also relatively cheap.
On the basis of the results of instruments used in Tier 1 it is decided to either stop further assessment or continue to a higher tier. Tier 2, still considered being at the screening level, aims at refining the measurement of exposure and at the same time to provide further insight into the toxicological and ecological properties of the contaminated soil.
Tier 2 deviate from the conservatism normally associated with the use of total concentration in the risk assessment by taking rough estimations of bioavailability into consideration in the chemical LoE. A better screening of the toxicological and ecological properties of the soil compensates for the reduced conservatism in the Chemistry LoE of the Triad.
The tools for use in Tier 2 are described in more details in the toolboxes C2, T2 and E2. On the basis of the results in Tier 2 a decision should be made to either stop further assessment or continue to a higher Tier. The tools in Tier 3 differ from the ones used in Tier 1 and Tier 2 in that they are more laborious, costly and may take longer. The stakeholders should beforehand negotiate a minimum set of tests. Is it for example necessary to consider all trophic levels in the toxicological and ecological LoE?
Or does the land-use suggest otherwise? Is it necessary or possible to estimate the bioavailability of all the substances exceeding their SSL? If not, how are the non-investigated substances dealt with? The tools described for use in Tier 3 are described in more details in the toolboxes C3, T3 and E3. Depending on the results from Tier 3 a decision should be made to either stop further assessment or continue with an even more detailed assessment in Tier 4.
In Tier 4, the aim of the studies is to answer any remaining questions and to decrease existing uncertainties and this may often require more in-depth research. Tools in Tier 4 can be similar to tools of Tier 3, but more focus has to be on site-specific circumstances. For example bioassays should be done with organisms, which normally occur at the site.
Furthermore, it may be more relevant to consider ecological effects outside the contaminated area on e. This Tier requires specialised knowledge and experience with ERA, which implies that costs can be high and only a limited number of people may be able to perform the tests.
Generally only on a very limited number of site evaluations will include investigations at this level. If the results of Tier 4 still indicate risk there are basically two possible solutions.
Accept the risk and leave the contamination or remove parts of the contamination. In order to facilitate the selection of appropriate tools in the right context, the tools have been compiled in subclasses or toolboxes. Each of these is a collection of tools considered to be potentially useful in the designated tiers and LoE of the Triad, i. Furthermore, the tools are arranged according to their complexity, price and practicability or in other words depending on whether they are most useful for screening or detailed assessment, i.
At the very first stage of the ERA process, total concentrations of all relevant chemicals are individually compared to soil screening levels SSL in order to evaluate whether there is a need for a site specific assessment of ecological risk. In the current Stage III of the ERA, this first generic evaluation of risk is followed by a more site-specific screening of risk including information from all three lines of evidence in the Triad.
In the Chemistry part of the Triad more site-specific information is collected by:. Refining and targeting the comparison of soil concentrations with soil related benchmarks for site-specific purposes. Incorporation of the accumulative risk of a mixture of contaminants by calculating the toxic pressure TP of a mixture and by doing so generating more site-specific insight to the potential ecological impact of a contaminated site.
Each of these steps can be done separately or in combination, e. The approach entirely depends on the strategy taken by the stakeholder group and the availability of data. The main objective of the selected toxicity tests or bioassay at Tier 1 should be to screen the soil for presence of toxic compounds. This includes toxic degradation products or compounds, which are not routinely included in various national analytical programs for contaminated sites.
This Tier is the first screening level of the ERA and the cost in form of manpower and money should hence be relatively low. Equipment for measuring luminescence of Vibrio fischeri [ 94 ]. Ecological surveys or monitoring studies are generally considered a time consuming effort performed by experts. This is in most cases true, wherefore detailed surveys normally take place in higher tier assessment.
However, in order to ensure that also ecological information is collected and used in the Triad already in the screening phase, it is recommended to perform a limited examination of the site.
A survey of the area with special focus on visible changes in e. Simple survey of the site [ 95 ]. If any aerial pictures areavailable from the area these may give valuable information about the plant cover also historically, which may be helpful in identifying parts of the site where the impact may be highest hot spots.
At this stage the conclusion can in most cases only be indicative. Therefore if the results from the other line of evidence may cause any doubt or the survey indicated potential impact, it is recommended to either continue with a more refined screening in Tier 2 or go directly to the detailed assessment in Tier 3. Selective solvent extraction. It may be considered useful to adjust the estimate of exposure by taking bioavailability into consideration and hereby deviating from the conservatism normally associated to the use of total concentration in the risk assessment.
The principle in this refinement of the ecological risk assessment is to extract a more ecotoxicologically relevant fraction of the contamination than the total concentration. The latter generally tends to overestimate the risk of historically contaminated soils. In this screening phase no attempt is made to estimate the freely dissolved or readily bioavailable concentration of contaminants. Table 10 explains principal studies that employed chemical extractants to evaluate bioavailability.
Instead the fraction of the contaminants is extracted, which can be directly compared to the existing soil screening levels. This is considered to be a relatively simple and quick method to screen for potential risk of contaminants in a more realistic way than using total concentrations. The extracted concentration mg kg-1 is compared to the SSL and the result used in the Triad.
However, for most methods this still has to be fully validated. The method establishes preferential partitioning of hydrophobic contaminants to the extractant by increasing their solubility in the aqueous phase whilst removing pollutant compounds from soil surfaces establishing equilibrium conditions. No standard protocol has been adopted for mild chemical extractions in relation to bioavailability testing.
Common methodology in literature primarily includes a soil sample to which a volume of chemical extractant is added generally 1 — 10 g soil,15 — 25 ml extractant.
This is followed by a period for mixing, e. Therefore, since convincing relationships between the chemical and biological tests were found it may indicate a potential for such extraction methods to predict bioavailability. In Tier 2 relatively simple tests with soil dwelling species are used for a more refined screening of the soil samples, i. Organisms screening in soil [ 98 ]. The habitat function of soils is often assessed using the reproduction test with Eisenia fetida.
The avoidance test with Eisenia fetida is a suitable screening test, which is less cost-intensive in terms of duration and workload than the reproduction test, and at the same time normally more sensitive than the acute test with the same species.
In Tier 2 the observations from the survey may be expanded by simple on-site assessment of the overall soil functioning or biological activity of the soils.
Bait-lamina sticks [99]. The main principle for tests at this level is to be relatively simple and cheap but at the same time to give valuable information whether or not the soil has lost some of its main services. Bait-lamina sticks for example have been demonstrated useful for describing biological activity of the soils in a general matter. The objective of the tools found in this toolbox is to assess the bioavailable and freely dissolved fraction of pollutants found in pore water of soils from contaminated sites.
The methods should in principle be able to mimic the fraction of organic pollutants available for uptake in biota. The collection of methods includes various non-depleting and depleting pore water extractions. Very few terrestrial ecotoxicity data are yet expressed as e.
Instead, the outcome of the methodologies in this toolbox is compared with water quality standards. The objective of the tools found in this toolbox is to evaluate the potential impact of contaminated soils to fauna and plants and hereby the entire ecosystems. Some of the methods use introduced, and not intrinsic, species. The benefit of this is a higher degree of standardisation, as the species used in these bioassays is easy to maintain in laboratory cultures compared to naturally occurring species.
The drawback may be that their ecological relevance is less obvious. For example the compost worm Eisenia fetida is used as a surrogate to evaluate risk to soil dwelling earthworms. Two sets of bioassays are presented. One for directly assessing potential risk for soil dwelling species, including micro-organisms, plants and soil invertebrates, and one for assessing indirectly risk to aquatic species through e.
It is often anticipated that soil organisms are exposed to pollutants mainly through uptake from pore water. Therefore it may also be possible to evaluate, or at least to compare or rank, the risk of contaminated soil samples to soil dwelling organisms on the basis of the outcome of the aquatic test using elutriate or pore water.
The choice of bioassays depends on a number of variables, e. Simple plant tests [ 91 ]. In this late tier of the Triad, the objective of the activities is community or population response analysis, typically by conducting field surveys. As these studies most often are time consuming, costly and dependent on ecologically, taxonomically and statistical expertise they are most frequently done on large-scale sites with a long-term- remediation perspective. In fresh water ecosystem community surveys have been widely used with relative success.
The absence of species from places where they would be expected to occur could be a strong identification of unacceptable levels of contaminants. However, this type of studies has only seldom been used for the terrestrial environment. The reasons for this are many. No world-wide accepted guideline on how to plan and perform a terrestrial field survey is available and hence no straight-forward and easy-to-follow description can be given.
The decision on when, where and how to conduct field surveys depends on a number of issues, e. Nevertheless, a number of general considerations have to be made in the planning phase of a successful field survey. These include but are not limited to :. Use statistical power analyses to determine the minimum number of samples or replicates needed to emonstrate the decided difference, e. In order to establish a cause-effect relationship, a number of confounding parameters need to be characterized both at the reference and the test site, e.
As no single description on how to perform ecological surveys for contaminated sites can be given, some general considerations and useful references for this tier of the ecological risk assessment are given below for:.
Reference data from reference sites, reference samples and literature. A crucial factor in a risk assessment is the quality of reference data, because the results of the site-specific ecological measurements or calculations are compared against these data. This is true for as well chemical information i. Litter bags [ 94 ]. The reference soil should in principle resemble the contaminated soil in all relevant parameters, e. In practice, these ideal spots are difficult to find. If there is no or inadequate reference information, effects can only be determined in relative terms by comparison with other sites.
Reference data can be obtained by including reference sites preferably more than one in the sampling scheme, including reference measurements in the experimental set-up, or by obtaining reference data from the literature or by expert based judgment. Higher tier assessment of the impact on biological activity and organic matter breakdown.
In addition to the general information about biological activity in soils generated in Tier 2 from the bait-lamina test, other, slightly more laborious, tests may give additional information about the overall biological activity in soil, e. A review paper from Van Gestel et al. Knacker et al. All of these simple tests only give insight into the overall activity in soils and the breakdown of organic material.
They are hence most suitable on their own in cases of land-use with low sensitivity, e. For land-uses where structural endpoints, e. Higher tier assessment of the impact on the microbial community. The number of microorganisms, especially bacteria, in soil is extremely large. They differ widely in their function and sensitivity to chemicals. Besides more classical and simple measures of the microbial community like total bacterial biomass, the number of colony forming units and substance induced respiration rate SIR , more advanced methods for assessing the impact of contamination on soil microorganisms have recently been made available.
Microbial community [ 96 ]. Higher tier assessment of the impact on the plant community. Plants interact dynamically with the physical and chemical characteristics of soils. Soil types and site characteristics, therefore, greatly influence the occurrence of plants and their total aboveground biomass also called, Net Primary Production, i.
NPP within given climatic conditions and human management. Vegetation cover is an important indicator of soil quality and a diverse plant community is normally a good indication of essential soil functions such as the decomposition process, the mineralisation rate, and the occurrence of soil dwelling animals associated to fresh organic matter.
Vascular plants are easy to sample. They are immobile and hence associated to soil contamination and airborne pollution. Plant survey [ 95 ]. Higher tier assessment of the impact on the soil invertebrate community. Survey of soil biota in order to evaluate the effect of various sources of pollution on soil communities on historically contaminated sites have not yet been used on a larger scale by e.
However, numerous monitoring studies by various research groups can be found in the open literature. Methods of surveying include:. Extraction or collection of organisms in the field, e.
Trapping surface dwelling animals by the use of e. Monitoring species includes earthworms, snails, oribatid mites, nematodes, springtails, ants, ground-living beetles and spiders. Most of the studies have been done on metal contaminated sites see references below. A substantial amount of work has been put into the challenge of developing a soil invertebrate system for evaluating risk of pollutants. The only soil invertebrate system that is used on a regularly basis in the context of ecological risk assessment of contaminated soils is most likely the nematode Maturity Index MI.
The system is based on the evidence, that rapid colonising species dominate nematode communities in disturbed ecosystems. Soil fauna sampling [ 98 ]. The final assessment in the ERA process is not likely to be initiated for many contaminated sites. The choice of additional tests or monitoring at this level of the ERA is bound to be very site-specific and hence an issue for negotiation between stakeholders and experts.
Accumulation in biota is included in this toolbox as the internal concentration in biota is believed, at least to some extend, to reflect uptake and then bioavailability. An alternative in this final tier could also be to model uptake in biota provided sufficient data is available [ 98 ]. Detailed field survey [ 93 ]. The aim is to investigate whether the land has been contaminated, and if contamination has occurred whether the contamination presents a significant risk of harm.
The commonly encountered international practice consists of three distinct reporting phases. It progresses from Phase 1 desktop and site walkover assessments with limited investigation and testing to a Phase 2 detailed invasive investigation and testing for site characterisation to a comprehensive Phase 3 report with an evaluation of remediation objectives and a proposed remediation plan, supported by control and monitoring measures for the activities.
A phase approach for the assessment and remediation of contaminated land. The reporting system requires norms and standards of practice to be strictly applied, but also must retain flexibility to allow for decisions on the contaminated status of sites to be made in the most beneficial manner considering ecological, social and economic aspects also taking into account timeframes.
In some cases, urgent priority works may require that the phased approach to reporting has to move forward in a concurrent single report. Nature and extent of contamination, contaminants of concern and historic activities that may be sources of contamination. List all present and past activities at the site that involves storage and production, use, treatment or disposal of hazardous material that could contaminate the site.
Describe current condition of the site and contents and the results of any previous assessment report. All data may not be available, or data may vary in terms of uncertainty, it is thus important to recognize gaps in the knowledge base and to decide whether additional data must be obtained on the site characterisation. This may trigger the commencement of Phase 2 Investigations. The Phase 1 report must make clear recommendations on the status of the contamination risk posed by the site. If a complete site history clearly demonstrates that the site activities do not pose a contamination threat then no further investigation is warranted and the site should be recommended as suitable for reuse.
A limited investigation of certain subsurface activities, for example, underground storage tanks, would be necessary to obtain a waiver on the contamination status of a site at a Phase 1 level of reporting. If soil contaminants are found at concentrations that exceed the applicable standards specified in the approval, the approval holder is required to implement a soil management program. The program must first address source control to stop on-going contaminant releases. After the sources of contamination have been stopped, further assessment and delineation of the contaminated area may be necessary.
When the extent of contamination is understood, remediation objectives, as described below, must be adopted for the area. Once remediation objectives have been agreed to, appropriate treatment or containment technologies can be chosen and the management plan finalized. Remediation objectives may be developed in a variety of ways ranging from generic guidelines to site-specific risk assessment. Generic guidelines are numerical concentration limits that are applicable under a variety of site conditions.
When neither Environmental Protection nor the agency has a guideline for a particular substance, four options are available. First, the remediation objective may be based on the ambient background concentration for the site. Second, the guideline development protocol may be applied. Third, a remediation objective may be adopted from another jurisdiction if the proponent can show that the remediation objective is consistent with the environmental protection goals of the approval.
Finally, a remediation objective may be developed by the proponent using site-specific risk assessment procedures. A risk assessment for an approved facility will focus on human health concerns but fundamental ecological concerns must also be addressed. Site-specific risk assessment is a means of quantifying the likelihood that soil contamination will have a harmful effect under conditions found at a specific site. The essential components of human health and ecological risk assessments are similar; however, ecological risk assessments tend to be more complex than those for human health because a wide variety of receptors may have to be considered.
Very briefly, a site-specific risk assessment may be described as consisting of the following steps or components as shown in Figure 20;. Problem formulation involves developing a conceptual model of the possible contaminant effects on receptors at the site.
The conceptual model describes contaminant distribution and concentration in relation to the receptors and their patterns of activity on the site. The exposure assessment describes the pathways by which soil contaminants may be taken up by the receptor.
This information is combined with receptor characteristics in order to estimate the contaminant uptake. The toxicity assessment describes the adverse effects that the contaminants may cause and the dose at which these effects occur. Risk Assessment Framework. Humans can be affected by soil pollution through the inhalation of gases emitted from soils moving upward, or through the inhalation of matter that is disturbed and transported by the wind because of the various human activities on the ground.
Soil pollution may cause a variety of health problems , starting with headaches, nausea, fatigue, skin rash, eye irritation and potentially resulting in more serious conditions like neuromuscular blockage, kidney and liver damage and various forms of cancer. Soil acts as a natural sink for contaminants, by accumulating and sometimes concentrating contaminants which end up in soil from various sources. Tiny amounts of contaminants accumulate in the soil and - depending on the environmental conditions including soil types and the degradability of the released contaminant - can reach high levels and pollute the soil.
If the soil is contaminated, home-grown vegetables and fruits may become polluted too. This happens because most of the soil pollutants present in the soil are extracted by the plants along with water every time they feed. Thus, it is always prudent to test the soil before starting to grow anything edible. This is especially important if your garden is located near an industrial or mining area, or within 1 mile of a main airport, harbor, landfill, or foundry.
March 30, Read by users. April 13, Read by users. April 14, Read by users. Natural Pollutants Natural processes can lead to an accumulation of toxic chemicals in the soil. Man-Made Pollutants Man-made contaminants are the main causes of soil pollution and consist of a large variety of contaminants or chemicals, both organic and inorganic.
Types of Soil Pollutants Soil pollution consists of pollutants and contaminants. Whatsapp Whatsapp. Soil pollution, its effects on our future and what we can do to reduce it We tend to look skywards when talking about pollution, but this problem is not confined to our skies. Carousel of images and videos. Moreover, the FAO distinguishes between two types of soil pollution: Specific pollution: accounted for by particular causes, occurring in small areas the reasons for which can be easily identified.
Land pollution such as this is normally found in cities, old factory sites, around roadways, illegal dumps and sewage treatment stations. Widespread pollution: covers extensive areas and has several causes the reasons for which are difficult to identify. Cases such as these involve the spreading of pollutants by air-ground-water systems and seriously affect human health and the environment.
The most important effects of soil pollution according to IPBES and the FAO are indicated below: Damage to health Soil pollutants enter our body through the food chain, causing illnesses to appear. Poorer harvests Soil pollution agents jeopardise world food security by reducing the amount and quality of harvests. Climate change In the first decade of the 21st century, soil degradation released between 3.
Water and air pollution Soil degradation affects the quality of air and water, particularly in developing countries. Population displacement Soil degradation and climate change will have driven between 50 and million people to emigrate by
0コメント