Taste and Odor in the New York City's Supplies

Abstract

In New York City's supplies, despite the diversity of its sources, the only organisms which have given offense from taste or odors have been Asterionella, Tabellaria, Anabaena, Aphanizomenon (with admixtures of Coelosphaerium, Microcystis and Clathrocystis), Uroglena, Synura, Dinobryon and Peridinium. Asterionella produces a slightly aromatic odor when present in 500 to 1000 standard units per cubic centimeter. At 1000 units, and rarely less, the odor is distinctly similar to that of the geranium. The intensity of odor increases with increasing numbers until a fishy odor is produced by several thousand. The fishy odor may also be produced when smaller quantities die or are destroyed. Tabellaria, and similarly Asterionella, may produce an earthy odor when present in very small amounts (produced also by large amounts of Synedra). The odor passes through the aromatic, geranium and fishy stages with about the same relative quantities of organisms as Asterionella. At times the odor of Tabellaria has suggested illuminating gas, no other organism being present. Anabaena and Aphanizomenon, when present in 500 to 1000 units, produce a faintly grassy odor, like freshly-cut grass. With larger numbers the odor increases until it becomes pungent like nasturtium, or even onions. Upon decay the odor is of vile, pig-pen character. Uroglena produces an oily fishy taste and odor, first noticeable in probably 500 to 1000 units. In larger quantities it is very disagreeable, the flavor being that of cod-liver oil. Synura may cause trouble apparently in any amount judging from our recent experience, at least as little as 50 units. This organism is by far the most persistent and disagreeable of them all. The taste is variously described as cucumber, muskmellon, fishy, etc. It leaves a bitter after-taste when the undestroyed organisms are in the