摘要
为评价九龙江河口区的地下水输入量及其输送的营养盐数量，建立了天然存在的镭同位素”。Ra和”。Fla的质量平衡模型。镭的源项考虑了河流的输入、河流悬浮颗粒的解吸、沉积物再悬浮颗粒的解吸、沉积物扩散输入、涨潮时外海的输入和地下水的输入；镭的汇项考虑了镭的放射性衰变，以及退潮时河口水的输出。根据镭的质量平衡计算，地下水输入的镭通量约占河口区镭总输入通量的41．9％-56．9％，转换成地下水输入量为1．65亿-1．83亿m^3/d，该地下水输入量是河流径流输入量的4倍多。以陆源地下淡水占总的地下水输入量的10％考虑，计算获得营养盐输人通量分别为461万mol／d（DIN）、22万mol／d（DIP）、694万mol／d（DSi），它们分别约是河流输入营养盐通量的23％（DIN）、28％（DIP）、77％（DSi）。结果表明九龙江河口的地下水输入量及其所输送的营养盐相当可观，所输入的营养盐是海域富营养化的潜在影响因素，在未来的河口环境管理中应引起重视。
A mass balance model of naturally-occurring short-lived and long-lived radium isotopes （224Ra and 226Ra） for the Jiulong River Estuary is developed to estimate the submarine groundwater discharge （SGD） to the estuary. All likely source and sink terms are considered in the model establishment. The source terms for Ra include river discharge, desorption from riverine suspended particles, desorption from resuspended particles, diffusion from subtidal sediments, and input from open sea and SGD. Ra can also be removed through radioactive decay and with ebb tide. The modeling result shows that up to 41.9% to 56.9% of the total Ra input can be attributed to the contribution of submarine groundwater in the estuary, and this has to be sustained by a discharge of I. 65 x 10s to i. 83 x 10Sm3/d in groundwater input. Such groundwater amounts can be four times that of river discharge in the estuary. Assuming that fresh groundwater can account for 10% of the total amount of groundwater, then the model calculated inorganic nutrient fluxes are 4.61 x 106 mol/d for dissolved inorganic nitrogen （DIN） , 0.22× 10^6 mol/d for dissolved inorganic phosphate （DIP） , and 6.94 × 10^6 mol/d for dissolved inorganic silicon （DSi） , respectively. And such inorganic nutrient fluxes are 23% , 28% and 77% of that delivered by river discharge in the estuary, respectively. The result suggests that a considerable amount of nutrients in the Jiulong River Estuary is coming from the contribution of SGD. The latter itself is also significant in relation to the total river discharge in the estuary. Nutrients contributed by SGD could potentially cause environmental concerns of estuary and coastal marine eutrophication. Such an environmental issue must be considered in the future management plan.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2011年第1期118-125,共8页
Advances in Water Science
基金
国家自然科学基金资助项目(40672166)~~
关键词
地下水
海水
海底地下水排泄
放射性同位素
镭
营养盐
河口
九龙江
groundwater
seawater
submarine groundwater discharge
radioisotopes
radium
nutrients
estuary
Jiulong River
