15:30 〜 17:00
[MZZ41-P04] Linking Land Use Pattern and Exposure Risk toward Harmonized Urban Development
キーワード：土地利用、重金属、アフリカ
Environmental pollution in urban areas is often thought to be a result of development activities themselves. In these cases, the distribution of pollutants according to the distance from the pollution source is featured. However, even at points relatively far from the pollution source, changes in the surrounding ground surface conditions may increase the exposure opportunities for organisms. In regions in developing countries where environmental pollution has already occurred due to industrial activities before urbanization, land use changes during city development activities should be paid attention to.
In Kabwe, in the Republic of Zambia, heavy metal pollution has been widespread due to lead and zinc mining activities that operated for nearly 100 years since the beginning of the 20th century, and even beyond the official cessation of industrial activities in 1994. In addition to environmental media such as soil, high concentrations of lead have also been detected in the biological media of humans, domestic animals, and wild rodents (Yabe et al. 2015, Nakata et al. 2017, Nakayama et al. 2011). To investigate the effect of the land use shift mentioned above, we have studied the use of a species of wild lizards (Trachylepis wahlbergii, Scincidae) as a target organism for biomonitoring. Lizards are suitable for biomonitoring because 1)they live in a relatively small home range, 2)their food is limited to insects, 3)they are widely distributed from residential areas to grasslands and wastelands, and 4)their density per point is relatively high. Our previous study based on a field survey in 2017 has shown that the relationship between the amount of lead detected in lizards and the distance to the site varies depending on the land use pattern based on satellite spectrum analysis. The categorization of land use was preliminarily performed based on vegetation status and the existence of buildings; “Green Field” as an area where there are plants throughout the year, “Bare Field” as an area where there are no plants throughout the year, “Open Field” as an area where there are plants only in the rainy season, and “Residential Area” as an area where architectures including houses and shop appear in the satellite image. The concentrations of lead in the liver of lizards living in Bare Field were higher than assumed from the distance (Doya et al., 2020). In 2021, a follow-up sampling was done in Kabwe to cover more geographical points and land use patterns to move the land-use-based analysis forward to develop a model to estimate the pollution level of each land use. Mapping and modeling of environmental contaminants to account for differences in land use are often used to identify sources of contamination. Inverse distance weighted (IDW ) interpolation and Kriging interpolation, which focus on the distance-dependent similarity between neighboring points (spatial autocorrelation) as described in Tobler's First Law of Geography, are widely used in wide-area surveys of soil pollutants such as heavy metals (Hou et al., 2017). The land use regression (LUR) model, which uses data from monitoring sites, is also widely used for exposure risk assessment of air pollutants (Beelen et al., 2013). Here, we report an evaluation of the validity of land use classification based on satellite spectrum data with the comparison of several combinations band sets, and the possibility of risk simulation/mapping based on data of lead concentrations in lizards.
In Kabwe, in the Republic of Zambia, heavy metal pollution has been widespread due to lead and zinc mining activities that operated for nearly 100 years since the beginning of the 20th century, and even beyond the official cessation of industrial activities in 1994. In addition to environmental media such as soil, high concentrations of lead have also been detected in the biological media of humans, domestic animals, and wild rodents (Yabe et al. 2015, Nakata et al. 2017, Nakayama et al. 2011). To investigate the effect of the land use shift mentioned above, we have studied the use of a species of wild lizards (Trachylepis wahlbergii, Scincidae) as a target organism for biomonitoring. Lizards are suitable for biomonitoring because 1)they live in a relatively small home range, 2)their food is limited to insects, 3)they are widely distributed from residential areas to grasslands and wastelands, and 4)their density per point is relatively high. Our previous study based on a field survey in 2017 has shown that the relationship between the amount of lead detected in lizards and the distance to the site varies depending on the land use pattern based on satellite spectrum analysis. The categorization of land use was preliminarily performed based on vegetation status and the existence of buildings; “Green Field” as an area where there are plants throughout the year, “Bare Field” as an area where there are no plants throughout the year, “Open Field” as an area where there are plants only in the rainy season, and “Residential Area” as an area where architectures including houses and shop appear in the satellite image. The concentrations of lead in the liver of lizards living in Bare Field were higher than assumed from the distance (Doya et al., 2020). In 2021, a follow-up sampling was done in Kabwe to cover more geographical points and land use patterns to move the land-use-based analysis forward to develop a model to estimate the pollution level of each land use. Mapping and modeling of environmental contaminants to account for differences in land use are often used to identify sources of contamination. Inverse distance weighted (IDW ) interpolation and Kriging interpolation, which focus on the distance-dependent similarity between neighboring points (spatial autocorrelation) as described in Tobler's First Law of Geography, are widely used in wide-area surveys of soil pollutants such as heavy metals (Hou et al., 2017). The land use regression (LUR) model, which uses data from monitoring sites, is also widely used for exposure risk assessment of air pollutants (Beelen et al., 2013). Here, we report an evaluation of the validity of land use classification based on satellite spectrum data with the comparison of several combinations band sets, and the possibility of risk simulation/mapping based on data of lead concentrations in lizards.