Barge Alaska; Wrangell, Alaska

Wrangell, Alaska | 1997-Dec-24

Initial Notification: DATE: December 24, 1997 1400 PDT - TO: NOAA SSC Ed Levine - FROM: NOAA/Hazardous Materials Response Team, Seattle, WA 98115 - - SUBJECT: Barge Alaska - - FOR ADDITIONAL INFORMATION, PLEASE CONTACT JIM MORRIS, NOAA/HAZMAT SEATTLE, WA 98115. PHONE (206) 526-6317. - _ - Per your request we have looked at trajectory implications of the urea that has been released from the barge Alaska. These notes are based on the following information:- - A barge located at 56? 28'N, 132? 23'W (Wrangell, Alaska) is reported to have cracks in the starboard and portside. The vessel is carrying an unknown amount of urea stored as a bulk product. At this time, the vessel is not leaking product.- - If any of this initial information is incorrect, please let us know ASAP as it would affect any trajectory implications. - _ - 1) WEATHER - Today, the winds are forecast from the south at 30 knots with rain. Tomorrow, the rain is expected to continue with winds from the south at 25 knots. - - 2) GENERAL DESCRIPTION OF UREA - Urea is a white crystal or powder with very faint odor. It has a density of 1.3 (it would sink in water) and is soluble in water. Urea is commonly present in nature, in urine and other body fluid. As a fertilizer, urea contains 45-46% nitrogen, and is usually in the form of small pellets or granules. It is shipped in bags or in bulk. - - 3) TRAJECTORY ANALYSIS - The harbor is generally shallow and is rapidly flushed due to tidal action. Any dissolved product will be quickly diluted by water exchange through the harbor entrance. The dissolved urea will not affect the pH of the water much, the effect, if there is any, will be localized, and given the tidal current present any effect will quickly dissipated because of the flushing effect in the harbor. - - 4)FATE AND EFFECT OF UREA - Solubility - Urea is very soluble in water. In the case of a capsized vessel, the urea pellets will sink to the ocean floor while dissolving in the water column. Water currents facilitate the dissolution process of urea in the same way that stirring a cup of coffee helps dissolve the sugar faster. Since the urea was stored in bulk, the granules may disperse as a "cloud" of fertilizer, each granule sinking independently while coming in full contact with the water. - Effect on pH - When urea dissolves in water it forms a weak base. The pH of the ocean water varies between 6.5 to 8.5. Usually it tends to be somewhat basic. In addition, the ocean has a substantial buffering capacity. In the past even large urea spills had minimal effect on the pH and we would expect the similar process during this incident. - Effect on the environment - We would not expect to see any algae bloom or other nutrient driven changes. The spilled urea dissolves quickly, eventually turning into carbon dioxide which escapes as gas and dissipates, and ammonia, which dilutes in the prevailing tidal current and quickly drops to ambient concentration. It is quite possible that the concentration of available nitrogen (in the form of ammonia) may be elevated for a short period of time at the immediate location of the spill. However, considering the rapid dilution and dispersion into the water column, exposure to organisms is predicted to be short-term. The biological literature focuses on phytoplankton effects and these seem to be mediated by light. At this time of the year, the phytoplankton population is relatively small, and the amount of daylight minimal. Adverse effects are expected to be minimal and confined to the harbor. USCG district 17.