Bromadiolone (BRD), a second generation anticoagulant often applied to the living environment to control rodents, is usually considered to have low environmental toxicity due to its poor solubility in water. In this study of the effect of humic acid (HA) on BRD using electronic absorption spectroscopy, it has been observed that BRD is appreciably solubilized even in low concentrations of aqueous HA solutions. The BRD solubilization efficiency of aqueous HA was found to be $2.39{pm}0.14$ ($4.53{pm}0.26{mu}M;ppm^{-1}$). It was also seen that BRD is reasonably solubilized in aqueous extract of farm soil.