Differences in sorption behaviour of carbaryl and phosalone in soils from Australia, Pakistan, and the United Kingdom
Date
2001
Authors
Ahmad, R.
Kookana, R.
Alston, A.
Bromilow, R.
Editors
Advisors
Journal Title
Journal ISSN
Volume Title
Type:
Journal article
Citation
Soil Research, 2001; 39(4):893-908
Statement of Responsibility
Conference Name
DOI
Abstract
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Sorption of 2 nonionic pesticides, carbaryl (1-naphthyl methylcarbamate) and
phosalone (S-6-chloro-2,3-dihydro-2-oxobenzoxazol-3-ylmethyl O,O-diethyl
phosphorodithioate), was investigated for 48 soils from Australia, Pakistan,
and the United Kingdom. A wide variation in sorption affinities of the soils
to carbaryl and phosalone was observed. The sorption coefficient (K
d) values for carbaryl ranged from 0.19 to 23.0 L/kg
in Australian soils, from 0.99 to 59.7 L/kg in Pakistani soils, and from
1.09 to 23.0 L/kg in the UK soils. The K d values
for phosalone ranged from 4.8 to 443 L/kg in Australian soils, from 15.5
to 1182 L/kg in Pakistani soils, and from 18.1 to 205 L/kg in the UK
soils. To eliminate the effect of variation in organic carbon content among
the soils, the K d values were normalised to the
fraction of soil organic carbon (K oc ). However, K oc
values for both pesticides varied by about an order of magnitude across the
soils, decreasing in the following order: Pakistani > Australian
> UK soils. Correlation between K d and organic
carbon content of the soils was poor (r
2 = 0.44 and 0.46). The particulate organic C
(53 µm–2 mm) was only slightly better correlated with K
d than the total organic C in the <2 mm fraction
of the soils. Thus soil organic C content alone is not a good predictor of
sorption even for nonionic pesticides such as carbaryl and phosalone. Caution
is needed during extrapolation of overseas data to predict sorption under
local conditions.
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