Chemistry Reference
In-Depth Information
Walker,
Enache, and
Dearden,
2007
Quantitative
cationic activity
relationships for
predicting
toxicity of metal
ions from
physicochemical
properties and
natural
occurrence
levels
QSAR
Combin. Sci
.
26:522-527
Ag
+
, Al
3+,
Ba
2+,
Cd
2+
, Co
2+
, Cu
2+
,
Fe
3+
, Pb
2+
, Li
+
,
Mn
2+
, Ni
2+
, Zn
2+
Quantitative cationic activity relationships (QCARs) were developed to predict
the toxicity of metal ions from physicochemical properties and natural
occurrence levels. In vivo toxicity data for different concentrations of nitrate
salts of 17 metal ions were developed based on germination of sunflower seeds
(F.1.
Helianthus annuus
Sunspot) in distilled water. The EC50 data were
reported as the concentration giving 50% inhibition of radicle growth one day
after emergence. Stepwise regression of the toxicity data produced correlations
with some physicochemical properties and natural occurrence levels. For
physicochemical properties, good results were obtained with the density of the
elements, enthalpy of formation of metal sulfides, and the stability constants of
metal ions with sulfate (
r
2
adj. = 0.72−0.81). For natural occurrence levels, good
results were obtained with metal concentrations in soil, the median elemental
composition of soils and the calculated mean of the elemental content in land
plants (
r
2
adj. = 0.69 - 0.83).
Van Kolck,
Huijbregts,
Veltman,
and
Hendriks
2008
Estimating
bioconcentration
factors, lethal
concentrations
and critical body
residues of
metals in the
mollusks
Perna
viridis
and
Mytilus edulis
using ion
characteristics
Environ.
Toxicol.
Chem
.
27:272-276
Ag
+
, Cd
2+
, Co
2+
,
Cr
3+
, Cs
1+
, Cu
2+
,
Hg
2+
, Pb
2+
, Zn
2+
Regression equations were developed between individual metal ion
characteristics and toxicity data (LC
50
s) for two species of mollusks,
Perna
viridis
and
Mytilus edulis
. The four ion characteristics studied were: the
covalent index, softness index, hydrolysis constant, and ionic index.
A statistically significant relationship was observed between the covalent index
and toxicity to each species of mollusks (R
2
= 0.74 - 0.79; P = 0.03 - 0.04),
suggesting that covalent index is a good predictor of toxicity. Regressions
between the remaining metal ion characteristics and toxicity values did not
produce significant relationships.
(
Continued
)
