The role of pH in heavy metal contamination of urban soil

Abstract

The aim of this study to assess interdependence between urban soil pH and its accumulation of heavy metals. The article meant to be a contribution to a better knowledge of peculiarities and diagnostics of urban soil and its anthropogenic transformation. The hypothesis assumes that relationship between urban soil pH and its accumulation of heavy metals may be determined by the origin and age of parent material as well as the nature and degree of the anthropogenic impact. The spatial variability of topsoil pH level was performed in 100 points in eldership of Šnipiškės of the city Vilnius. Laboratory analysis was based on ISO 10390:2005. Samples were collected from 20 cm topsoil layer in the same sampling points where have been analysed concentrations of topsoil chemical elements using optical atomic emission spectrophotometry. The contamination of urban soils exhibits somewhat different compared to agricultural soils. In contradiction to earlier studies in Lithuanian agricultural soils where strong correlation between soil pH and Cr, Cd, Pb, Ni, Cu and Z_d found, the conducted analysis shows a statistically reliable, but very weak (<0.3) correlation between the soil pH and concentration of contaminants. The proof to this correlation is provided by an existing relationship between pH and the concentration of copper (r = 0.20), mercury (r = 0.15), strontium (r = –0.12) and the overall contamination index (r = 0.12). The applied statistical analysis, however, failed to reveal the nature of interdependence between the soil pH and its contamination with studied heavy metals there concentration of contaminant chemical elements depends on the pH range of the soil and, conversely, the chemical reactivity of the soil changes affect on the concentration of studied chemical elements.

Keywords:

• soil pH
• soil contamination
• correlation analysis

Additional information

Notes on contributors

Asta Kazlauskaitė-Jadzevičė

Asta KAZLAUSKAITĖ-JADZEVIČĖ. She is a PhD student, working at the Lithuanian Research Centre for Agriculture and Forestry. Her research interests include renaturation, GIS, and soil carbon modelling.

Jonas Volungevičius

Jonas VOLUNGEVIČIUS. He is a Doctor of Physical Sciences (Geography) and works as a Docent at the Department of Geography and Land Management, Faculty of Natural Sciences in Vilnius University, and also is a President of Lithuanian Soil Science Society at the Lithuanian Academy of Science Agricultural and Forest Sciences Department. He is the author and co-author of ∼14 scientific papers and other scientific publications and has attended 2 international and 11 local conferences. His research interests include geography of landscape management, soil geography, environmental policy, and application of GIS in geography.

Virginija Gregorauskienė

Virginija GREGORAUSKIENĖ. She is a Doctor of Physical Sciences (Geography), works as a Senior technician at the Subdivision of Engineering Geology and Processes, Geological Survey of Lithuania, and is also a Lector at Mykolas Riomeris University. Her research interests include environmental geochemistry, soil science, soil contamination, soil quality standards, air borne contamination, methods of geochemical mapping at different scales, and medical geology.

Saulius Marcinkonis

Saulius MARCINKONIS. He is a Doctor of Biomedical Sciences (Agronomy), working as a Head of Strategic Development Department at the University of Applied Sciences (Vilniaus kolegija). He is the author and co-author of ∼33 scientific papers and has attended 40 conferences. His research interests include soil chemical degradation, liming, fertilization, soil pollution, renaturation, and GIS.