PB-210 AND PO-210 IN SEDIMENTS AND SUSPENDED MATTER IN THE TAGUS ESTUARY, PORTUGAL - LOCAL ENHANCEMENT OF NATURAL LEVELS BY WASTES FROM PHOSPHATE ORE PROCESSING-INDUSTRY

被引:68
作者
CARVALHO, FP
机构
[1] International Atomic Energy Agency, Marine Environment Laboratory, MC 98012 Monaco Cedex
关键词
NATURAL RADIOACTIVITY; PO-210; PB-210; PHOSPHATE; INDUSTRIAL WASTES; ESTUARIES; ENHANCEMENT OF RADIOACTIVITY;
D O I
10.1016/0048-9697(95)04332-U
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
Results of analyses of uranium series radionuclides in phosphate ore and in wastes released by the phosphate fertilizer industry confirm their potential for the enhancement of environmental radioactivity levels. Therefore, concentrations of Pb-210 and Po-210 were measured in bottom sediments and suspended matter in the Tagus estuary, Portugal, to assess the enhancement of radioactivity due to wastes from the phosphate industry. The concentration of Pb-210 in surface sediments in the estuary increased inversely with sediment grain-size; conversely, increased percentage of sand has a dilution effect on the concentration of Pb-210 measured in bulk sediment samples. By normalizing the data to the < 63-mum fraction, the naturally-occurring Pb-210 in sediments was found to be 68 +/- 19 Bq kg-1 (dry wt.) in background sediments. Higher Pb-210 levels, up to 1580 Bq kg-1 (dry wt.), were measured in some bulk sediment samples. It was verified that this radionuclide has been introduced by the discharge of wastes from a phosphate fertilizer plant but enhanced concentrations are localized near the point of discharge. In other zones of the estuary, the concentrations of Pb-210 in sediments and suspended matter were generally below those measured in the zone of phosphatic releases at the Barreiro Peninsula. Concentrations higher than the predicted average concentration of unsupported Pb-210 from natural sources (atmospheric deposition, river input) were also measured in the upper estuary, both in bottom sediments and in suspended matter. It is suggested that these relatively elevated concentrations are due to the highly efficient scavenging of soluble naturally-occurring unsupported Pb-210 onto suspended matter and to co-precipitation with iron-manganese hydroxides in the fresh water-salt water mixing zone.
引用
收藏
页码:201 / 214
页数:14
相关论文
共 25 条
[1]  
Carvalho F. P., 1990, THESIS U NICE SOPHIA
[2]  
CARVALHO FP, 1988, RADIAT PROT DOSIM, V24, P113
[3]  
CARVALHO FP, 1991, 12 P NAT S PORT SOC, P451
[4]  
CARVALHO FP, UNPUB J GEOPHYS RES
[5]  
CASTANHEIRO J, 1986, ESTUARINE PROCESSES, P73
[6]  
Duinker J.C., 1980, CHEM BIOGEOCHEMISTRY, P121
[7]   ACCUMULATION AND CELLULAR-DISTRIBUTION OF AM-241, PO-210, AND PB-210 IN 2 MARINE-ALGAE [J].
FISHER, NS ;
BURNS, KA ;
CHERRY, RD ;
HEYRAUD, M .
MARINE ECOLOGY PROGRESS SERIES, 1983, 11 (03) :233-237
[8]   DETERMINATION OF LOW LEVELS OF POLONIUM-210 IN ENVIRONMENTAL MATERIALS [J].
FLYNN, WW .
ANALYTICA CHIMICA ACTA, 1968, 43 (02) :221-&
[9]  
Galehouse J. S., 1971, PROCEDURES SEDIMENTA, P69
[10]   A REGENERATION MODEL FOR THE EFFECT OF BIOTURBATION BY FIDDLER-CRABS ON PB-210 PROFILES IN SALT-MARSH SEDIMENTS [J].
GARDNER, LR ;
SHARMA, P ;
MOORE, WS .
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY, 1987, 5 (01) :25-36