Environmental Geochemistry and Health 1993 15(4) page 229
Trace metals in the roadside mountain soils of Sierra Nevada, Spain Ewa Panek 1 and Zbigniew Zawodny 2 1 Polish Academy of Sciences, Minerals and Energy Economy Research Centre, Wybickiego 7, PL-31261 Crakow, Poland 2 Academy of Mining and Metallurgy, AI. Mickiewicza 30, Crakow, PL-30059, Poland
Abstract
The investigations were made to determine the total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the roadside soils and rocks of the Sierra Nevada Mountains in Spain. There were differences in both the age and lithology of the bed-rock in the study area. The surface soil layer is primarily enriched with lead in relation to the bed-rock, but zinc, manganese, and cadmium also occur. Lead, zinc and cadmium concentrations show a decrease with increasing distance from the road, whereas the levels of iron, manganese, copper, nickel and chromium do not show such a variation. The change in lead and zinc concentrations with increasing distance from the road is related to the topography of the area immediately adjacent to the road. On the descending slopes the concentrations of these metals remain unchanged or increase with the increasing distance from the road, whereas on the ascending slopes they show a clear decrease.
Introduction
The present work aims to determine the content of selected trace metals in the roadside mountain soils of Sierra Nevada in Spain. The investigations were carried out on a study tour organised by the Cracow branch of the Society of Friends of the Earth in September, 1987. The subject of the tour was the ecological characteristics of mountain torrent biocenoses and the monitoring of heavy metal pollution of soils in mountain ecosystems. The pollution of roadside soils and plants by the combustion products of leaded petrol is localised and it is usually limited to a belt several metres wide on both sides of the road (Chow, 1970); Motto et al., 1970; Page et al., 1971, Wheler and Rolfe, 1979). For similar topography and vegetation, the level of pollution decreases with the distance from the road axis (Curzydlo, 1988; Lagerverff and Specht, 1970; Roszyk and Roszykowa, 1975). Materials and Methods
The study area was limited to the roads in the Sierra Nevada in southern Spain, and in particular the road from the town of Almeria in the east to the Granada-Motril road in the west. Figure 1 shows a map of the area where the eight sample points are marked. These roads carry light to moderate traffic. The altitude of the sample points varied between 500 m (points 1 and 8) and 1,000 m above sea level (points 5, 6 and 7). The area was unwooded and covered with grass and isolated bushes, with the exception of point 5 which was
located in a pine forest. The topography of the sample points differed in relation to the road: sample 1 was collected from ground level with the road, samples 2-5 were collected from ground higher than the road and samples 6-8 from ground lower than the road. Samples were taken from one side of the road only. Two topsoil samples (0-10 cm) were taken from each point at distances of 1 m and approximately 50 m from the road, together with samples of the bed-rock at each point. The bed-rock in the study area was varied. There were differences in both the age and lithology of bed-rock across the land sampled (Martin and Braga, 1987; Mapa Geologico, 1980). The u n d e r l y i n g rock type c o n s i s t e d largely of m e t a m o r p h i c rocks: Palaeozoic gneiss and crystalline schists (points 3 and 8), Permo-Triassic quartz and sandstone schists (points 2, 4, 5 and 6) and Triassic limestone and marl (points 0, 1 and 7). All the samples were taken from regosols characterised by shallow, stony profiles with little or no organic horizon. The soil material was digested with heated HC104. The total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the filtrate were determined using atomic absorption spectroscopy, using an AAS-1 produced by Carl Zeiss Jena. The bed-rock samples were crashed and analysed the same way. Results and Discussion The bed-rock The bed-rock consisting mainly of metamorphic rocks, is thought to be the primary source of Fe. The concentrations of iron in the
230
Trace metals in the roadside mountain soils
bed-rock were several times those of Mn, Zn or Pb, and were seen to vary between 3,300 and 25,800 mg kg-1. The lowest concentration of Fe was found in the sample from control point 0, a Permotriassic limestone and quartz sandstone schist, and the maximum concentration in the sample from point 8, a Palaeozoic schist. In all the rock types studied, the ranges of Mn, Zn, Pb, Cd, Cu, Ni and Cr in mg kg -1 were as follows: Mn, 37-807; Zn, 9-368; Pb, 6-115; Cd, 1-3; Cu, 4-40; Ni, 4-42; Cr, 1-20 (Table 1). These metal concentrations do not differ significantly from the average metal concentrations
Z
in rocks studied by Kabata-Pendias and Pendias (1979). The concentrations of metals in the bed-rock influence the natural concentrations of these metals in the soil, therefore the differentiation between the bed-rock derived metals and those from the combustion of leaded petrol is problematic in a study of this nature• The soil
The average concentrations of the heavy metals in the investigation were calculated for the 16 samples• They occur in the following decreasing sequence:
f
0
,
Trace metals in the roadside mountain soils of Sierra Nevada, Spain Ewa Panek 1 and Zbigniew Zawodny 2 1 Polish Academy of Sciences, Minerals and Energy Economy Research Centre, Wybickiego 7, PL-31261 Crakow, Poland 2 Academy of Mining and Metallurgy, AI. Mickiewicza 30, Crakow, PL-30059, Poland
Abstract
The investigations were made to determine the total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the roadside soils and rocks of the Sierra Nevada Mountains in Spain. There were differences in both the age and lithology of the bed-rock in the study area. The surface soil layer is primarily enriched with lead in relation to the bed-rock, but zinc, manganese, and cadmium also occur. Lead, zinc and cadmium concentrations show a decrease with increasing distance from the road, whereas the levels of iron, manganese, copper, nickel and chromium do not show such a variation. The change in lead and zinc concentrations with increasing distance from the road is related to the topography of the area immediately adjacent to the road. On the descending slopes the concentrations of these metals remain unchanged or increase with the increasing distance from the road, whereas on the ascending slopes they show a clear decrease.
Introduction
The present work aims to determine the content of selected trace metals in the roadside mountain soils of Sierra Nevada in Spain. The investigations were carried out on a study tour organised by the Cracow branch of the Society of Friends of the Earth in September, 1987. The subject of the tour was the ecological characteristics of mountain torrent biocenoses and the monitoring of heavy metal pollution of soils in mountain ecosystems. The pollution of roadside soils and plants by the combustion products of leaded petrol is localised and it is usually limited to a belt several metres wide on both sides of the road (Chow, 1970); Motto et al., 1970; Page et al., 1971, Wheler and Rolfe, 1979). For similar topography and vegetation, the level of pollution decreases with the distance from the road axis (Curzydlo, 1988; Lagerverff and Specht, 1970; Roszyk and Roszykowa, 1975). Materials and Methods
The study area was limited to the roads in the Sierra Nevada in southern Spain, and in particular the road from the town of Almeria in the east to the Granada-Motril road in the west. Figure 1 shows a map of the area where the eight sample points are marked. These roads carry light to moderate traffic. The altitude of the sample points varied between 500 m (points 1 and 8) and 1,000 m above sea level (points 5, 6 and 7). The area was unwooded and covered with grass and isolated bushes, with the exception of point 5 which was
located in a pine forest. The topography of the sample points differed in relation to the road: sample 1 was collected from ground level with the road, samples 2-5 were collected from ground higher than the road and samples 6-8 from ground lower than the road. Samples were taken from one side of the road only. Two topsoil samples (0-10 cm) were taken from each point at distances of 1 m and approximately 50 m from the road, together with samples of the bed-rock at each point. The bed-rock in the study area was varied. There were differences in both the age and lithology of bed-rock across the land sampled (Martin and Braga, 1987; Mapa Geologico, 1980). The u n d e r l y i n g rock type c o n s i s t e d largely of m e t a m o r p h i c rocks: Palaeozoic gneiss and crystalline schists (points 3 and 8), Permo-Triassic quartz and sandstone schists (points 2, 4, 5 and 6) and Triassic limestone and marl (points 0, 1 and 7). All the samples were taken from regosols characterised by shallow, stony profiles with little or no organic horizon. The soil material was digested with heated HC104. The total contents of Fe, Mn, Zn, Cu, Pb, Cd, Ni and Cr in the filtrate were determined using atomic absorption spectroscopy, using an AAS-1 produced by Carl Zeiss Jena. The bed-rock samples were crashed and analysed the same way. Results and Discussion The bed-rock The bed-rock consisting mainly of metamorphic rocks, is thought to be the primary source of Fe. The concentrations of iron in the
230
Trace metals in the roadside mountain soils
bed-rock were several times those of Mn, Zn or Pb, and were seen to vary between 3,300 and 25,800 mg kg-1. The lowest concentration of Fe was found in the sample from control point 0, a Permotriassic limestone and quartz sandstone schist, and the maximum concentration in the sample from point 8, a Palaeozoic schist. In all the rock types studied, the ranges of Mn, Zn, Pb, Cd, Cu, Ni and Cr in mg kg -1 were as follows: Mn, 37-807; Zn, 9-368; Pb, 6-115; Cd, 1-3; Cu, 4-40; Ni, 4-42; Cr, 1-20 (Table 1). These metal concentrations do not differ significantly from the average metal concentrations
Z
in rocks studied by Kabata-Pendias and Pendias (1979). The concentrations of metals in the bed-rock influence the natural concentrations of these metals in the soil, therefore the differentiation between the bed-rock derived metals and those from the combustion of leaded petrol is problematic in a study of this nature• The soil
The average concentrations of the heavy metals in the investigation were calculated for the 16 samples• They occur in the following decreasing sequence:
f
0
,
