HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Jing, Y. D. Articles by Yang, X. E. PubMed PubMed Citation Articles by Jing, Y. D. Articles by Yang, X. E. Agricola Articles by Jing, Y. D. Articles by Yang, X. E. Related Collections Toxic Trace Metals Sorption/Exchange Heavy Metals Soil Pollution Soil Chemistry

TECHNICAL REPORTS

Heavy Metals in the Environment

Adsorption–Desorption Characteristics of Mercury in Paddy Soils of China

^a MOE Key Lab. of Environ., Remediation and Ecosystem Health, College of Natural Resource and Environment Sciences, Zhejiang Univ., Hangzhou 310029, China
^b Dep. of Resources and Planning, Qufu Normal Univ., Jining 273165, China
^c Univ. of Florida, Inst. of Food and Agricultural Sciences, Indian River Research and Education Center, Fort Pierce, FL 34945, USA

^* Corresponding author (zhe{at}ufl.edu).

Received for publication May 2, 2007. Mercury (Hg) has received considerable attention because of its association with various human health problems. Adsorption–desorption behavior of Hg at contaminated levels in two paddy soils was investigated. The two representative soils for rice production in China, locally referred to as a yellowish red soil (YRS) and silty loam soil (SLS) and classified as Gleyi-Stagnic Anthrosols in FAO/UNESCO nomenclature, were respectively collected from Jiaxin County and Xiasha District of Hangzhou City, Zhejiang Province. The YRS adsorbed more Hg²⁺ than the SLS. The characteristics of Hg adsorption could be described by the simple Langmuir adsorption equation (r² = 0.999 and 0.999, P < 0.01, respectively, for the SLS and YRS). The maximum adsorption values (X_m) that were obtained from the simple Langmuir model were 111 and 213 mg Hg²⁺ kg^–1 soil, respectively, for the SLS and YRS. Adsorption of Hg²⁺ decreased soil pH by 0.75 unit for the SLS soil and 0.91 unit for the YRS soil at the highest loading. The distribution coefficient (kd) of Hg in the soil decreased exponentially with increasing Hg²⁺ loading. After five successive desorptions with 0.01 mol L^–1 KCl solution (pH 5.4), 0 to 24.4% of the total adsorbed Hg²⁺ in the SLS soil was desorbed and the corresponding value of the YRS soil was 0 to 14.4%, indicating that the SLS soil had a lower affinity for Hg²⁺ than the YRS soil at the same Hg²⁺ loading. Different mechanisms are likely involved in Hg²⁺ adsorption–desorption at different levels of Hg²⁺ loading and between the two soils.

Abbreviations: CEC, cation exchange capacity • SLS, silty loam soil • YRS, yellowish red soil