1、A review of the contamination soil with lead II. Spatial distribution and risk assessment of soil lead,Julie Markus*, Alex B. McBratney Department of Agricultural Chemistry and Soil Science, The University of Sydney Sydney, NSW, Australia,論文翻譯：柴元慶 陳紅 ppt制作講解：孫麗軍,1 Abstract,Contamination of soil with

2、 lead has occurred on a global scale. Exposure to lead may cause adverse effects to human health and the environment. It is therefore desirable to obtain a quantitative estimate of the potential risk of lead contamination. Numerous studies have been conducted collecting lead concentration data from

3、both natural and contaminated soil on a range of scales. Very few of these studies have made serious attempts to spatially describe the data. This paper reviews the multitude of data collected on soil Pb concentrations. Lead survey are discussed on the basis of land use, with Australian data present

4、ed separately.,Data from lead surveys of agricultural, urban and industrial areas, as well as nationwide surveys are summarised. A small but increasing number of studies have employed spatial prediction techniques such as kriging to map the distribution of lead concentrations in soil. These studies

5、are also summarised and a brief description of the basis for their use presented. Finally, environmental and health risk assessment is discussed and some methodologies in use around the world reviewed. D 2001 Elsevier Science Ltd. All rights reserved,Introduction,The adverse health effects caused by

6、 lowlevel expo-sure to Pb have been extensively document. Such health effects include neurological impairment and deficitsin the functioning of the central nervous system (Needle-man, 1983; Needleman et al., 1990). Comprehensivereviews on this subject may be found in Needleman and Landrigan and Need

7、leman and Bellinger(1991). In order to determine the potential risk to human health of Pb contaminated soil, it is essential to gain an understanding of the universal range of Pb concentrations and how they are spatially distributed.,2. The spatial distribution of Pb in soil,2.1. Soil Pb surveys of

8、agricultural, urban and industrial areas A summary of the Pb data from all surveys discussed below is given in Table 1. The data has been ordered according to location and mean Pb concentration.,The majority of studies have concluded that the concentration of Pb decreases with distance from the road

9、 (Singer and Hanson, 1969; Lagerwerff and Specht, 1970; Motto et al., 1970), however, Hafen and Brinkmann (1996) found only a weak relationship between concentration and distance. Microclimatic features including air turbulence and human disturbance of the soil profile were suggested as reasons for

10、the absence of a strong correlation (Hafen and Brinkmann, 1996). Hafen and Brinkmann collected 224 topsoil samples along 32 transects perpendicular to a major interstate highway in Florida, USA. While their results differ frommost other investigations of roadside soil, the number of samples collecte

11、d makes this the most detailed survey of Pb,concentrations surrounding a major roadway. Pb concentra- tions at distances greater than 1520 m from the road were found to approach constant values and were appreciably smaller than those within a few metres of the road (Singer and Hanson, 1969; Albasel

12、and Cottenie, 1985). Lagerwerff and Specht (1970) and Singer and Hanson (1969) also report a decrease in Pb concentrations with depth in the soil profile and an increase in Pb concentration with traffic density.,2.2. Soil Pb surveys in Australia,Australias research is mainly to study in southern Aus

13、tralia . That investigation of the lead in soil regional distribution and towns scattered pollution. Lead pollution can also occur in the orchard region, due to lead nitrate in the use of insecticide. The accumulated in orchard soil lead in also will happen, and these lead is not transfer. The conce

14、ntration of lead were foundat the distribution is.In these studies of the regionis found of lead concentration is negligible,2.3. Use of spatial prediction techniques to map contaminant distribution in soil,Geographic data analysis is a space independent model. And through the use of kriging to the

15、position sampling characteristic value evaluation. Kringing is a space forecasting method, in its simplest form is measured by the proportion of data points average.These data point is aposition or roughly a larger area.,More and more research kriging method has been used in soil lead concentration

16、in describing the spatial distribution. Geographic statistical method is more suitable for the determination of the pollutant dispersion, but for the determination of non-point source pollution requires more complex technology.,3. Environmental and health risk assessment for soil lead,Environmental

17、risk assessment is the in a series of specific condition assessment a chemical or physical factors on a specific ecosystems might affect process,some countries about health risk assessment for soil lead, the most widely recognised methodology for assessing the risk of environmental contaminant is th

18、at developed by the US Environment Protection Agency The USEPA have devised a sitespecific, quantitative methodology using a modelling approach to quantify human exposure, doseresponse and/or plant response relationships, The Netherlands also have well-developed criteria and guidelines for soil prot

19、ection and risk assessment. The Dutch policy is based on the idea of soil multifunctionality, which means that the number of functions that a soil can haveshould not be reduced by human activities, The risk assessment protocol in Australia is closelyrelated to the USEPA methodology although there ar

20、e someimportant differences. A key distinction is the semiquanti-tative nature of risk assessment in Australia.,Langley,Langley summarises important issues to consider prior to conducting risk assessment. Amongst other things he states that it is essential that the specific purpose of the risk assme

21、nt is clear and the critical receptors identified.,A basic framework exists through which risk assessmentsfor chemical contamination are typically conducted. This is depicted in Fig. 2.,kriging,The design of an appropriate sampling plan is an important part of the risk assessment process. A detailed

22、 spatial description of contamination maybe obtained by kriging to predict the concentration at locations between sampling sites. This may assist in identification of hot spots, for example Kriging also has the ability to predict the probability that a contaminant will have a concentration greater t

23、han a particular threshold concentration. As an example, Ginevan and Split- stone (1997) use probability kriging as part of an evaluation of the soil-related cancer risk at a site contaminated with hazardous waste.,4. Conclusions,Data describing the range of lead concentrations in soil around the wo

24、rld is abundant. Typical Pb concentrations found in agricultural, urban and industrial soil are well defined. To identify patterns in the location of a contami-nant and delineate areas that may be hazardous, it is essential to present survey data in the form of a map. Only a small proportion of studies have attempted to s