A MASS of unidentifiable toxic substances remains in waters and on shores long after oil spills appear to have cleared up. The mystery compounds can cause long-term harm to marine creatures, disrupting their feeding habits and damaging their general health.
To identify the constituents of organic mixtures such as crude oil, scientists use a method called gas chromatography. However, this only picks out certain compounds. Thousands of hydrocarbons cannot be distinguished, leaving an ungainly “hump” in the chromatograph trace (see Graphic).
When crude oil is “weathered” – digested by bacteria and battered by storms – the identifiable compounds tend…
