Human activities, including industrial manufacturing and road travel, contaminate the soil with heavy metals such as zinc, chromium, nickel and mercury. However, contamination poses very little or no risk to human health in many situations because the way the land is used does not expose people to the metals.
Combining data on heavy metal pollution with information about land use is one way of identifying which areas do pose a significant risk to human health. In the study, EU-funded researchers, working under the TUSEC-IP project1, used this approach to assess the suitability of land use plans in the Grugliasco region of Torino in northwest Italy.
There are plans in Grugliasco to turn a large area, currently used primarily for agriculture, into an urban park which incorporates a 'naturalistic park', new university spaces and areas for playing sport, as well as small areas for allotment gardens and swamp. The aim of the research was to show how the land use change could have an impact on exposure to toxic chemicals.
The researchers used Geographic Information System (GIS) software to map soil contamination and estimate human health risk based on land use. GIS is a well-established mapping method which combines different types of information linked to location.
The study's results suggest that the planned park will help reduce the health risks posed by heavy metals in Grugliasco. Using a scale of 1-5, where 1 is low risk and 5 is relatively high risk, the maps illustrate how risk varies across the region. Currently, human health risk across most of Grugliasco is in class 3 or higher, but should fall to less than 1 with the construction of the park. However, areas that will remain in agricultural use will still be high risk because heavy metals could enter the food chain through food production.
So far, GIS has not been widely used in risk modelling for heavy metals, but the researchers claim it could be a powerful tool for decision making in land use planning and minimising the health risks of pollution faced by citizens.
- TUSEC-IP (Techniques of Urban Soil Evaluation in City Regions-Implementation in Planning Procedures) was conducted under Project-Interreg IIIB-Alpine Space Programme, supported by the European Commission. See: http://www.tusec-ip.org/
Source: Poggio, L. and Vršcaj. (2009). A GIS-based human health risk assessment for urban green space planning - An example from Grugliasco (Italy). Science of the Total Environment. 407: 5961-5970.