As noted in a previous blog (“Oil Spills”), the interdisciplinary number for oil spills is 363.7382 Oil as an environmental pollutant.
What Table 2 Geographic Areas notation should be added for a work on the Deepwater Horizon oil spill? That depends on the scope and focus of the work. A work that focuses on the impact of the spill on the Mississippi Delta region of Louisiana would be classed in 363.7382097633 Oil as an environmental pollutant in Southeastern parishes of Louisiana (built with 363.7382 plus T1—09 Geographic treatment plus T2—7633 Southeastern parishes of Louisiana, which has the class-here note “Class here Mississippi Delta,” following instructions at T1—093–T1—099 Treatment by specific continents, countries, localities; extraterrestrial worlds). A work that focuses on the impact of the spill on the waters of the Gulf of Mexico would be classed in 363.73820916364 Oil as an environmental pollutant in the Gulf of Mexico (built with 363.7382 plus T1—091 Treatment by areas, regions, places in general plus 6364 from T2—16364 Gulf of Mexico, following instructions at T1—091). Works on oil spills that treat the impact on both the water and the coast usually give fuller treatment to the effects on the shorelands (shorelands include coastal wetlands and intertidal zones). The “Introduction to the DDC,” section 5.7 (B), says: “Class a work on two subjects with the subject receiving fuller treatment.” Thus a work on the Deepwater Horizon oil spill that treats the impact on both the waters of the Gulf of Mexico and the U.S. Gulf Coast—with fuller treatment of the coast—would be classed with the land in 363.73820976 Oil as an environmental pollutant in Gulf Coast states (built with 363.7382 plus T1—09 plus T2—76 Gulf Coast states, following instructions at T1—093–T1—099). If the U.S. Gulf Coast and the Gulf of Mexico are given equal treatment, then the first-of-two rule would apply, and T2—16364 Gulf of Mexico would be used instead of T2—76 Gulf Coast states. See the “Introduction to the DDC,” section 5.7 (C).
Works that focus on the effect of an oil spill on a specific subject (e.g., a specific animal) are classed with the subject according to the rule of application. An example from studies of the effects of the Exxon Valdez Oil Spill may illustrate. Population, Reproduction, and Foraging of Pigeon Guillemots at Naked Island, Alaska, before and after the Exxon Valdez Oil Spill is classed in 598.33 Charadriiformes. Since pigeon guillemots do not approximate the whole of 598.33, no further addition is allowed.
How does a classifier know which subdivision of 598 Aves (Birds) to choose, given that pigeon guillemots are not mentioned in the DDC? In its introduction, the work being classified identifies the pigeon guillemot as being in the family Alcidae, and “Alcidae” is in the Relative Index linked to 598.33 and in the including note at 598.33. Also, the LCSH for “Pigeon guillemot” has “Cepphus” as broader term, and the LCSH “Cepphus” has “Alcidae” as broader term. Similar information is available in many reference sources, e.g., the Cornell Lab of Ornithology Bird Guide at “Pigeon Guillemot.”
The potential effect of the Deepwater Horizon oil spill on the brown pelican has been in the news, e.g., “Oil Threatens Brown Pelican Off of Louisiana Coast” (NPR) and “La.'s [Louisiana’s] State Bird, Brown Pelican, Imperiled by Oil” (AP). Works on the effect of the oil spill on the brown pelican will be classed with other works on the brown pelican in 598.43 Pelecaniformes, which has an including note that begins: “Including Pelecanidae (pelicans). . . . .” An example of a work classed in 598.43 is Brown Pelican: Pelecanus Occidentalis.