Overview of Radioactive Waste Disposal at Sea

For hundreds of years, the seas have been used as a place to dispose of wastes from human activities. Although no high level radioactive waste has been disposed of into the sea, variable amounts of packaged low level radioactive wastes have been dumped at 47 sites in the northern part of the Atlantic and Pacific Oceans. in 1946 the first sea dumping operation took place at a site in the North-East Pacific Ocean. the last dumping operation was in 1982, at a site off the European continental shelf in the Atlantic Ocean. Between these two dates, an estimated 46 PBq (1.24 MCi) of radioactive waste coming from research, medical, military and industrial activities have been disposed of at sea. the present trend, through the Convention for the Prevention of Marine Pollution by Dumping of Wastes and other Matter and other Regional Conventions, points towards the prohibition of the dumping of any radioactive waste into the marine environment.     

海洋放射性污染生态风险评价研究进展

近年来,随着我国核电事业迅猛发展,海洋放射性污染的风险激增,放射物质的事故性污染将成为海洋环境一个重要问题。目前,海洋环境放射性污染风险评估的研究仍然较为薄弱,开展海洋放射性污染生态风险评价有助于了解事故对海洋生态的危害程度,为海洋与海岸带环境管理提供科学决策依据,维护海洋生态系统的健康与安全。梳理总结当前国内外海洋放射性污染生态风险评价的相关研究进展,结果表明:目前国内外对海洋放射性污染生态风险评价尚未做出科学的定义;现有海洋放射性污染生态风险评价的技术路线大体可归纳为基于经典风险评估框架和基于迭代的生态风险评价框架2种类型;ERICA Tool模型以及RESRAD-BIOTA模型是目前放射性风险评价中应用最多的方法 ,但存在海洋放射性污染标准限值少的问题;现有的研究主要集中于评估事故中后期均衡条件下的长期慢性暴露评价,对事故初期的高剂量、短期急性暴露的风险影响研究较少;我国海洋放射性污染的生态风险评价与环境影响评价的概念混淆,至今没有明确的海洋放射性污染生态风险评价的概念及技术框架。     

Disposal of Coal Fly Ash at A Deep Water Site in the Eastern Mediterranean Off Israel - Six Years of Monitoring

Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km² allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA.     

Disposal of Coal Fly Ash at A Deep Water Site in the Eastern Mediterranean Off Israel - Six Years of Monitoring

Coal fly ash (CFA) is dumped at a deep sea disposal site (1,500m water depth) in the eastern Mediterranean, ca. 70km off the Israeli shore. Since 1989, about one million tons of CFA were dumped at the 200km² allocated area. Six years of monitoring at the dump-site shows that the CFA is heterogeneously distributed; there are areas where CFA covers about 1.3cm depth of the sea floor while at others no CFA is found. CFA is present as a fine powder, small aggregates and even as large blocks both in the dump-site as well as at its peripheries. Cadmium, copper and zinc concentrations in the CFA decreased as a result of the prolonged contact with sea water at in situ conditions while inconclusive changes in mercury, iron and manganese were detected. No changes were observed for lead, iron and aluminium concentrations. A controlled long term field experiment, now in progress at the site, is expected to clarify further chemical changes occurring in the CFA.     

Fish Disease Monitoring in the Dutch Part of the North Sea in Relation to the Dumping of Waste From Titanium Dioxide Production

Gross pathologies were recorded in a total of 5942 individual common dab (Limanda limanda L.) at 5 sites in and around Dutch coastal waters, in spring, from 1986 to 1988. Two of these sites (an offshore dumping ground and an inshore site influenced by direct river discharge) received large quantities of diluted acids of titanium dioxide waste (TDW); the other three were selected as reference sites for comparison.

The main diseases recorded were epidermal hyperplasia/papilloma, lymphocystis, liver nodules (pre-neoplastic and neoplastic lesions), and infections caused by the protozoan Glugea sp. Frequencies of disease were analysed using a logit model. There was a consistently high prevalence of epidermal hyperplasia/papilloma in dab from the two sites that received TDW when compared to the other sites. However, no dear relationships were found between the prevalence of epidermal hyperplasia/papilloma and dumping-associated heavy metals or other relevant environmental and biological factors. No significant spatial trend was revealed for liver nodules, although there was a statistically significant association between the occurrence of epidermal hyperplasia/papilloma or of lymphocystis and that of liver nodules in individual fish. Prevalences of lymphocystis were usually higher at offshore sites than in inshore areas, while prevalences of Glugea showed the opposite trend.

Although at first sight the pattern of disease prevalence would appear to furnish a strong case for a cause-and-effect relationship between TDW and epidermal hyperplasia/papilloma, interpretation of the data is complicated by interference from riverine inputs, long-distance dispersion of discharged wastes, local hydrographic conditions, and possible local migration of dab. On the basis of present results, therefore, the possibility that discharges of TDW contributed to the occurrence of this disease cannot be proven or discounted.     

Nuclear Wastes in the Arctic Ocean. the Consequences of Past Dumping and Opportunities for Future Prevention

The view is expressed that the assessment of disposal of nuclear waste in the ocean (specifically the Arctic and Kara Seas) is critical to understanding Arctic pollution. Much needs to be done in deciding what we should do, even though many wastes are long-standing and persistent. in 1993, disclosures about Russian dumping of submarine nuclear reactors, nuclear fuel, and other radioactive wastes into the Arctic Ocean brought this region and its problems into the world spotlight and raised public concerns about the resulting health and environmental risks. As a result of this concern, the Congressional Office of Technology Assessment published a 1995 study, Nuclear Wastes in the Arctic (US Congress Office of Technology Assessment, 1995). This paper summarises and updates that study.     

Nuclear Wastes in the Arctic Ocean. the Consequences of Past Dumping and Opportunities for Future Prevention

The view is expressed that the assessment of disposal of nuclear waste in the ocean (specifically the Arctic and Kara Seas) is critical to understanding Arctic pollution. Much needs to be done in deciding what we should do, even though many wastes are long-standing and persistent. in 1993, disclosures about Russian dumping of submarine nuclear reactors, nuclear fuel, and other radioactive wastes into the Arctic Ocean brought this region and its problems into the world spotlight and raised public concerns about the resulting health and environmental risks. As a result of this concern, the Congressional Office of Technology Assessment published a 1995 study, Nuclear Wastes in the Arctic (US Congress Office of Technology Assessment, 1995). This paper summarises and updates that study.     

城市垃圾处理与管理对策研究

对北京、天津、上海、重庆、广州等１７个城市垃圾的调查,结果表明,近１０年,上述城市垃圾总量的增长城市化关系密切,城市垃圾的组分受经济发展,生活水平、消费行为方式的影响,地域差异显著;城市垃圾处理技术欠完善,管理体制不合理,急需通过市场化动作国吧改善。     

我国涉汞危废处置企业中汞分布特征及风险评价

为了解涉汞危废企业对周边环境的影响及其潜在风险,加强涉汞危险废物的监督管理,通过2007年至2013年对13个持环保部发证的涉汞危废处置企业每年一次的监督性监测,分析了我国涉汞危废处置企业不同环境介质中汞分布特征及其风险。研究结果显示,2007年至2013年我国涉汞危废处置企业土壤、地下水、无组织排放气体中汞的浓度范围分别为0.75~28.4 mg·kg-1、1.0×10-5~1.3×10-4mg·L-1、3.9×10-4~4.0×10-3mg·m-3。利用风险商的方法对不同介质中汞进行初步的生态风险评价,结果显示土壤中汞存在较高的风险(RQ≥1),除2009年和2012年,其他所有年份高风险的企业超过50%,风险商的范围为0.44~56.8,呈逐渐上升趋势。地下水中汞存在潜在的风险(0.1RQ1)。无组织排放气体中汞的风险较低(RQ≤0.1),可以忽略。     

The Application of A Tiered Testing Approach to the Management of Dredged Sediments for Disposal at Sea in Canada

Canada, and other signatories to the London Convention 1972 on the prevention of marine pollution by dumping, are preparing to ratify a 1996 Protocol to this convention. Among the improvements to this international agreement, is a new process for the Assessment of Waste and Other Matter, which is to be adopted by signatory parties. the process includes a step in which material considered potentially acceptable for sea disposal must be characterized by chemical, physical and biological properties. Canada's interpretation and intended implementation of this characterization step is presented for the assessment of dredged sediments. This tiered testing approach involves using chemical screening limits for contaminants, and biological testing when screening levels are exceeded. Dredged material containing specified substances (e.g., cadmium, mercury, PAHs, PCBs, etc.) below or at screening levels would generally be considered of little environmental concern for disposal at sea. Wastes above the screening levels would require more detailed assessment before their suitability for disposal at sea could be determined.     

The Application of A Tiered Testing Approach to the Management of Dredged Sediments for Disposal at Sea in Canada

Canada, and other signatories to the London Convention 1972 on the prevention of marine pollution by dumping, are preparing to ratify a 1996 Protocol to this convention. Among the improvements to this international agreement, is a new process for the Assessment of Waste and Other Matter, which is to be adopted by signatory parties. the process includes a step in which material considered potentially acceptable for sea disposal must be characterized by chemical, physical and biological properties. Canada's interpretation and intended implementation of this characterization step is presented for the assessment of dredged sediments. This tiered testing approach involves using chemical screening limits for contaminants, and biological testing when screening levels are exceeded. Dredged material containing specified substances (e.g., cadmium, mercury, PAHs, PCBs, etc.) below or at screening levels would generally be considered of little environmental concern for disposal at sea. Wastes above the screening levels would require more detailed assessment before their suitability for disposal at sea could be determined.     

Potential health impacts of heavy-metal exposure at the Tar Creek Superfund site,Ottawa County,Oklahoma

The potential impact of exposure to heavy metals and health problems was evaluated at the Tar Creek Superfund site, Ottawa County, Oklahoma, USA. Observed versus expected mortality was calculated for selected conditions in the County and exposed cities. Excess mortality was found for stroke and heart disease when comparing the exposed County to the state but not when comparing the exposed cities to the nonexposed rest of the County. However, sample sizes in the exposed area were small, population emigration has been ongoing, and geographic coding of mortality data was incomplete. In an exposed community, 62.5% of children under the age of 6 years had blood lead levels exceeding 10 μg/dl. The relationships between heavy-metal exposure and children’s health and chronic disease in adults are suggestive that a more thorough investigation might be warranted. A number of possible environmental and health studies are suggested, including those focusing on possible central nervous system impacts. Unfortunately, the exposed population is dispersing. One lesson learned at this site is that health studies need to be conducted as soon as possible after an environmental problem is identified to both study the impact of the most acute exposures and to maximize study sample size—including those exposed to higher doses—and minimize the loss of individuals to follow-up.     

Distribution of nutrients and AOU in the Mediterranean Water (North Atlantic Ocean)

Water samples were collected in the Northeast Atlantic Ocean (33-37^° N and 11-16^° W) in May 1983, and vertical profiles of chemical and physical parameters allowed us to identify the different water masses. A significant difference in salinity and its maximum can be found at different places and depths, as a consequence of the spreading of the Mediterranean Water (MW) from the Strait of Gibraltar. The apparent oxygen utilization shows a correlation with nutrients in North Atlantic Central Water. The relative percentages of water masses were assessed in order to examine the depth of maximum influence of MW as a function of latitude and to apply this knowledge to the black scabbard fish long-line strategy. The long-line fishing depth location was adapted to the specific MW distribution of the different banks with improvements in the mean catch efficiency. The thickness of the MW prevalence layer has a pronounced decrease to the south. MW influence clearly sinks and decrease to south-west. The highest percentage of the MW was found in the Gorringe Bank area and the lowest in the Madeira area.     

铅锌尾矿废弃地的化学性质研究

凡口铅锌尾矿废弃地的不同区位及不同深度的尾矿中铅锌含量存在着较大的差异 ,总锌为 70 3～ 19657mg/ kg、总铅 10 4 13～ 94 988mg/ kg。正常尾矿中 ,有效态锌含量达到 151.6～ 84 1.7mg/ kg,有效态铅含量很低 ( 0 .75～ 2 .50 mg/ kg) ,有机质、总氮、有效磷及速效钾等营养物质缺乏。当尾矿酸化后 ,p H降低 ,有效态 Pb、Zn含量升高 ,有效锌达到 175.8～ 2 82 8.0 mg/ kg,有效铅含量最高为 10 0 .0 mg/kg,而有机质、总氮和有效磷为零 ,使尾矿更加贫瘠。在尾矿库的边缘区位和尾矿表面的覆盖土壤区位 ,基质中营养物质含量增加 ,但是营养状况的改善又引起了有效态的 Pb、Zn含量升高。     

Radioactive Isotopes of Strontium,Caesium and Plutonium in Sediments of the Northern Adriatic Sea

Changes in nitrification rates of an acid grassland soil with and without air drying have been monitored over 9 days, after first flushing native nitrate from the soils with deionised water. The results confirmed that full re-establishment of nitrification after air drying takes several days, supporting the hypothesis that any immediate first flush of nitrate from air-dried soils originates from cell lysis or flushing of ‘stored’ nitrate. Ammonium spiking confirmed that nitrification was not ammonium substrate limited. It was also found that ammonium accumulates in the soil during the drying process, providing a substrate pool once the population of nitrifiers has re-established. Over the first week of incubation, nitrate immobilisation was less conspicuous in the soil that had been rewetted after air drying compared with the incubated field moist soil.     

Radioactive Isotopes of Strontium, Caesium and Plutonium in Sediments of the Northern Adriatic Sea

Sediment samples of different strata (0-3 and 12-15 cm) were collected between 1990 and 1992 during seasonal cruises in the Northern Adriatic Sea. A complete mapping of the Sr-90, Cs-137, Pu-238 and Pu-239(240) concentrations was obtained for samples covering a wide area, stretching from the Gulf of Trieste towards the Ancona shoreline. Sr-90 concentrations varied between 1.5 and 6.5 Bq kg^-1 dw, Cs-137 was in the range 0.9-38.9 Bq kg^-1 dw, Pu-239(240) in the range 0.08-1.5 Bq kg^-1 dw and Pu-238 around 0.03 Bq kg^-1 dw. Special reference was also put on the comparison between the off-shore environment and data obtained from samples collected inside the Po river delta. in spite of the major accumulation of Cs-137 inside the estuarine environment, higher concentrations of strontium and plutonium isotopes were detected in the offshore environment.     

Dredged Material Disposal at the Edge of the Florida Current

A field data collection project was undertaken to investigate the short-term fate of dredged material discharged in the designated Miami Ocean Dredged Material Disposal Site (ODMDS) before dredging of the Miami River and the Miami Harbor Turning Basin begins. the designated ODMDS is located in relatively deep water for discharge sites with a typical bottom depth of 150 metres and is also located in the western boundary region of the Gulf Stream current off Miami. Acoustical backscattering, current, particulate, temperature and salinity data were gathered over a three day period from April 24, 1990 through April 26, 1990. the major generic features of shallow-water discharge plumes were observed to be present: (a) the presence of a rapid convective descending plume portion; (b) impact of that plume portion with the ocean bottom and concomitant generation of a bottom surge; (c) rapid horizontal width growth of the descending plume through entrainment; and (d) retention of a residual plume portion within the water column. A well-mixed upper water column layer extending to a depth of 40 to 60 metres below the surface of the ocean permitted measurements of the plume entrainment coefficient free from bottom boundary, water column density gradient, and vertical current shear effects which are usually present in relatively shallow, e.g. less than 40 metres bottom depth, coastal ocean discharge studies. Entrainment coefficient estimates obtained in this study were between 0.5 to 0.7. the residual water plume material was tracked over one-half hour during each of eight discharge events and was transported in a north-northeast direction.     

Dredged Material Disposal at the Edge of the Florida Current

A field data collection project was undertaken to investigate the short-term fate of dredged material discharged in the designated Miami Ocean Dredged Material Disposal Site (ODMDS) before dredging of the Miami River and the Miami Harbor Turning Basin begins. the designated ODMDS is located in relatively deep water for discharge sites with a typical bottom depth of 150 metres and is also located in the western boundary region of the Gulf Stream current off Miami. Acoustical backscattering, current, particulate, temperature and salinity data were gathered over a three day period from April 24, 1990 through April 26, 1990. the major generic features of shallow-water discharge plumes were observed to be present: (a) the presence of a rapid convective descending plume portion; (b) impact of that plume portion with the ocean bottom and concomitant generation of a bottom surge; (c) rapid horizontal width growth of the descending plume through entrainment; and (d) retention of a residual plume portion within the water column. A well-mixed upper water column layer extending to a depth of 40 to 60 metres below the surface of the ocean permitted measurements of the plume entrainment coefficient free from bottom boundary, water column density gradient, and vertical current shear effects which are usually present in relatively shallow, e.g. less than 40 metres bottom depth, coastal ocean discharge studies. Entrainment coefficient estimates obtained in this study were between 0.5 to 0.7. the residual water plume material was tracked over one-half hour during each of eight discharge events and was transported in a north-northeast direction.