Geology (from the Ancient Greek γῆ, gē, i.e. "earth" and -λoγία, -logia, i.e. "study of, discourse") is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also refer to the study of the solid features of any terrestrial planet or natural satellite, (such as Mars or the Moon).
Andrew Herbert Knoll. Gaidos E, Knoll AH. Frontiers of Astrobiology. Cambridge: Cambridge University Press; 2012. Our evolving planet: From dark ages to evolutionary renaissance. pp. 132–153.
Josiah Gilbert Holland, in Rev. S. Pollock Linn Golden Gleams of Thought from the Words of Leading Orators, Divines, Philosophers, Statesmen and Poets, A.C. McClurg & Company, 1881, p. 280.
Pesticides are used around the world but can persist in the environment, contaminating drinking and irrigation water with toxic organic compounds. One example is Vietnam where herbicides and dioxins applied during the Vietnam war entered the water cycle, possibly leading to cancers and abnormalities in newborn babies.