Impact of herbicides used in olive groves on waters of the Guadalquivir river basin (southern Spain)

► The first and unique scientific long monitoring study of herbicides used in olives. ► Herbicide water concentrations relate with properties and field application guide of chemicals. ► The herbicide presence in waters is related to rain and soil transport processes. ► The PCA analysis confirmed all the above relationships for the two last years. ► The suitability of the ad hoc government regulation developed meanwhile is shown.