Resistant desorption of hydrophobic organic contaminants in typical chinese soils: implications for long-term fate and soil quality standards.
Soil contamination is an enormous problem in China and severely threatens environmental quality and food safety. Establishing realistic soil quality standards is important to the management and remediation of contaminated sites and must be based on thorough understanding of contaminant desorption from soil. In the present study, we evaluated sorption and desorption behaviors of naphthalene, phenanthrene, atrazine, and lindane (four common soil contaminants in China) in two of the most common Chinese soils. The desorption of these compounds exhibited clear biphasic pattern-a fraction of contaminants in soil was much less available to desorption and persisted much longer than what was predicted with the conventional desorption models. The unique thermodynamic characteristics associated with the resistant-desorption fraction likely have important implications for the mechanism(s) controlling resistant desorption. Experimental observations in the present study are consistent with our previous work with chlorinated compounds and different adsorbents and could be well modeled with a biphasic desorption isotherm. We therefore suggest that more accurate biphasic desorption models should be used to replace the conventional linear sorption/desorption model that is still widely adopted worldwide in contaminant fate prediction and soil quality standard calculations.
Yang
Weichun
W
College of Environmental Science and Engineering/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, People's Republic of China.
Duan
Lin
L
Zhang
Nan
N
Zhang
Chengdong
C
Shipley
Heather J
HJ
Kan
Amy T
AT
Tomson
Mason B
MB
Chen
Wei
W
D000327:Adsorption; D001280:Atrazine; D002681:China; D001556:Hexachlorocyclohexane; D057927:Hydrophobic and Hydrophilic Interactions; D009281:Naphthalenes; D009930:Organic Chemicals / Q000032:analysis / Q000737:chemistry; D010616:Phenanthrenes; D012987:Soil / Q000592:standards*; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D013816:Thermodynamics
D009281:Naphthalenes; D009930:Organic Chemicals; D010616:Phenanthrenes; D012987:Soil; D012989:Soil Pollutants; C031721:naphthalene; C031181:phenanthrene; D001556:Hexachlorocyclohexane; D001280:Atrazine