Accumulation of COGEMA-La Hague-derived Reprocessing Wastes in French Salt Marsh Sediments

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• 作者：Andrew B. Cundy ; Ian W. Croudace ; Phillip E. Warwick ; Jung-Suk Oh ; and Simon K. Haslett
• 刊名：Environmental Science & Technology
• 出版年：2002
• 出版时间：December 1, 2002
• 年：2002
• 卷：36
• 期：23
• 页码：4990 - 4997
• 全文大小：221K
• 年卷期：v.36,no.23(December 1, 2002)
• ISSN：1520-5851

文摘

Over the past five decades, authorized low-level dischargesfrom coastal nuclear facilities have released significantquantities of artificial radionuclides into the marineenvironment. In northwest Europe, the majority of thetotal discharge has derived from nuclear reprocessingactivities at Sellafield in the United Kingdom and COGEMA-La Hague in France. At the Sellafield site, a significantamount of the discharges has been trapped in offshore finesediment deposits, and notably in local coastal andestuarine sediments, and much research has been focusedon understanding the distribution, accumulation, andreworking of long-lived radionuclides in these deposits. Incontrast, there are few high-resolution published dataon the vertical distribution of radionuclides in fine-grainedestuarine sediments near, and downstream of, COGEMA-La Hague. This paper therefore examines the verticaldistribution of a range of anthropogenic radionuclides indated salt marsh cores from two estuaries, one adjacent to,and the other downstream of, the COGEMA-La Haguedischarge point (the Havre de Carteret at Barneville-Carteretand the Baie de Somme, respectively). The radionuclidesexamined show a vertical distribution which predominantlyreflects variations in input from COGEMA-La Hague(albeit much more clearly at Barneville-Carteret than atthe Baie de Somme site), and Pu isotopic ratios are consistentwith a La Hague, rather than weapons' fallout, source.Because of sediment mixing, the marshes apparently retainan integrated record of the La Hague discharges, ratherthan an exact reproduction of the discharge history. Sorption of radionuclides increases in the order ⁹⁰Sr < ¹³⁷Cs< ⁶⁰Co < ^239,240Pu, which is consistent with K_d values reportedin the literature. In general, the radionuclide activitiesobserved at the sites studied are low (particularly incomparison with salt marsh sediments near the Sellafieldfacility), but are similar to those found in areas of finesedimentation in the central Channel. These marshes arenot major sinks for discharged reprocessing wastes.