Lithological and land-use based assessment of heavy metal pollution in soils surrounding a cement plant in SW Europe.
We study the influence of phasing out a cement plant on the heavy metal (Hg, Pb and Cr) content in the surrounding soils, taking into account factors often neglected, such as contributions due to local lithology or land use. The range of total Hg was 10-144µg kg(-1), reaching up to 41 and 145mgkg(-1) for total contents of Pb and Cr, respectively. Forest soils showed higher concentration of Hg than prairie soils, indicating the importance of land use on the accumulation of volatile heavy metals in soils. In forest soils, total Hg showed a trend to decrease with soil depth, whereas in prairie soils the vertical pattern of heavy metal concentrations was quite homogeneous. In most cases, the distance to the cement plant was not a factor of influence in the soils content of the analyzed heavy metals. Total Pb and Cr contents in soils nearby the cement plant were quite similar to those found in the local lithology, resulting in enrichment factor values (EF's) below 2. This suggests that soil parent material is the main source of these heavy metals in the studied soils, while the contribution of the cement plant to Pb and Cr soil pollution was almost negligible. On the contrary, the soils surrounding the cement plant accumulate a significant amount of Hg, compared to the underlying lithology. This was especially noticeable in forest soils, where Hg EF achieved values up to 36. These results are of relevance, bearing in mind that Hg accumulation in soils may be an issue of environmental concern, particularly in prairie soils, where temporal flooding can favor Hg transformation to highly toxic methyl-Hg. In addition, the concurrence of acid soils and total-Cr concentrations in the range of those considered phytotoxic should be also stressed.
Department of Plant Biology and Soil Science, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain.
Laura
L
Cutillas-Barreiro
Department of Plant Biology and Soil Science, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain.
Paula
P
Pérez-Rodríguez
Department of Plant Biology and Soil Science, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain.
Antía
A
Gómez-Armesto
Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Universidade de Santiago de Compostela, Lugo 27002, Spain.
María José
MJ
Fernández-Sanjurjo
Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Universidade de Santiago de Compostela, Lugo 27002, Spain.
Esperanza
E
Álvarez-Rodríguez
Department of Soil Science and Agricultural Chemistry, Engineering Polytechnic School, Universidade de Santiago de Compostela, Lugo 27002, Spain.
Avelino
A
Núñez-Delgado
Department of Plant Biology and Soil Science, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain.
Manuel
M
Arias-Estévez
Department of Plant Biology and Soil Science, Faculty of Sciences, Universidade de Vigo, Ourense 32004, Spain. Electronic address: edjuanca@uvigo.es.
Juan Carlos
JC
Nóvoa-Muñoz
D003252:Construction Materials; D004784:Environmental Monitoring; D005060:Europe; D019216:Metals, Heavy / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis*
D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants
Enrichment factors; Forest; Lead; Mercury; Prairie; Soil; Soil pollution