Heavy metals in soils and crops in Southeast Asia 2. Thailand
- 1 December 2004
- journal article
- research article
- Published by Springer Science and Business Media LLC in Environmental Geochemistry and Health
- Vol. 26 (3-4), 359-371
- https://doi.org/10.1007/s10653-005-4670-7
Abstract
A reconnaissance soil geochemical and concomitant plant survey based on 318 soil (0–15 cm) and 122 plant samples was used for the assessment of heavy metal pollution of agricultural soils and crops of Thailand. Arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) were determined in soils using aqua regia digestion, and in plants using nitric acid digestion. Organic carbon (C), pH, electrical conductivity (EC) and available phosphorus (P) were determined on the soil samples using appropriate procedures. Results indicated that concentrations of heavy metals varied widely among the different regions of Thailand. Regression analysis between the concentrations of metals in soil (aqua regia extractable) and edible plant parts indicated a small but positive relationship for Cd in all the plants sampled in the survey (R 2 = 0.081, p < 0.001). There was also a positive relationship between soil and plant Cd concentrations in rice (R 2 = 0.242, p < 0.010), and negative relationships for Zn in rice (R 2 = 0.385, p < 0.001), and Cu (R 2 = 0.355, p < 0.001) and Zn (R 2 = 0.122, p < 0.026) in glutinous rice. Principal component analysis of the soil data suggested that concentrations of As, Co, Cr, Cu, Hg, Ni and Pb were strongly correlated with concentrations of Al and Fe, which is suggestive of evidence of background variations due to changes in soil mineralogy. Thus, the evidence for widespread contamination of soils by these elements through agricultural activities is not strong. On the other hand, Cd and Zn were strongly correlated with organic matter and concentrations of available and aqua regia extractable P. This is attributed to input of contaminants in agricultural fertilisers and soil amendments (e.g. manures, composts).Keywords
This publication has 15 references indexed in Scilit:
- Cytotoxicity and oxidative mechanisms of different forms of chromiumToxicology, 2002
- Heavy metals and nutrients chemistry in sewage sludge amended Thai soilsJournal of Environmental Science and Health, Part A, 1998
- Arsenic in the Soil Environment: A ReviewPublished by Elsevier BV ,1998
- The Thai environment: prospering or suffering from development?TrAC Trends in Analytical Chemistry, 1997
- Environmental Monitoring and Impact Assessment of a Solid Waste Disposal SiteEnvironmental Monitoring and Assessment, 1997
- Review: the behaviour and environmental impact of contaminants in fertilizersSoil Research, 1996
- Analytical Problems in the Determination of Inorganic Soil ContaminantsPublished by Springer Science and Business Media LLC ,1993
- Urban soil contamination in AustraliaSoil Research, 1992
- A modified single solution method for the determination of phosphate in natural watersAnalytica Chimica Acta, 1962
- DETERMINATION OF TOTAL, ORGANIC, AND AVAILABLE FORMS OF PHOSPHORUS IN SOILSSoil Science, 1945