Environmental profiles of agricultural chemicals in a river flowing into Lake Teganuma were surveyed. Their dissolution and adsorption were investigated by using indoor experiments, and their behaviors were discussed from a viewpoint of molecular structure in the compounds. The herbicides detected in the river contained CNP and Benthiocarb were at high concentration at the time of spraying, but decreased sharply thereafter. The CNP had lower concentration than Benthiocarb in the river, indicating little amount flowing out from paddy fields. These differences in the environmental profiles should be attributable to natures of the herbicides. An indoor experiment has revealed that Benthiocarb has lower solubility and higher absorption strength than CNP. It was found with respect to the chemical structures that polarity increases if hetero atoms and hydrophilic substituents exist in moleculars; the solubility of Benthiocarb grows higher than that of hydrocarbons; and adsorption power relates to the area of contact with absorbing media, and absorption rate relates to the solubility, absorption power, and three-dimensional structure. 23 refs., 7 figs., 4 tabs.