S. Sharmasarkar et Gf. Vance, CHARACTERIZATION AND CORRELATION OF SOIL AND PLANT SELENIUM IN SOME RANGE AND COAL-MINE ENVIRONMENTS OF WYOMING, Communications in soil science and plant analysis, 26(15-16), 1995, pp. 2577-2591
Selenium (Se) has been recognized as an element of environmental conce
rn because of its natural occurrence and potential toxicity to plants,
animals, and humans. Range and coal mine (reclaimed and abandoned) so
ils were studied using various soil extracts, including saturated past
e, hot water, ammonium bicarbonate-DTPA (AB-DTPA), and phosphate in or
der to compare the Se extraction efficiency of these reagents and to c
haracterize the soil-plant Se correlations in these environments. Soil
extraction data indicated the order of Se extractability was phosphat
e > AB-DTPA > hot water > saturated paste. The saturated paste-extract
able Se was found to be typically very low. Statistically significant
correlations between phosphate, AB-DTPA-, and hot water-extractable Se
were observed irrespective of the type of environment. Selenium extra
cted by these reagents indicated certain relationships, such as phosph
ate approximate to 2 AB-DTPA, phosphate approximate to 5 hot water, an
d AB-DTPA approximate to 3 hot water. Selenium content of shrub vegeta
tion was approximately half of that of grass and forb. Soil-plant Se c
orrelations were found to be dependent on land type as well as vegetat
ion type; the regressional values for soil suitability limit (SSL) of
Se corresponding to 5 mg/kg plant Se varied accordingly. For a particu
lar type of vegetation, the SSL values followed the same order as the
extraction efficiency of the different reagents. The AB-DTPA-extractab
le Se was found to be the best predictor of soil-plant Se correlations
under field conditions, though phosphate-, hot water-, and saturated
paste-extractable soil Se were also related to the Se concentrations i
n different types of vegetation. Selenate was found to be the potentia
l aqueous specie for plant uptake. A comparison of different soil envi
ronments containing various vegetation types also suggested that, for
a plant containing 5 mg/kg Se, the soil Se status would be highest in
abandoned mine lands, followed by reclaimed mine and undisturbed range
environments, respectively.