铀尾矿库周边农产品中镭-226及铀浓度调查分析

目的 对某退役铀尾矿库周边主要农产品中的放射性核素镭-226和天然铀含量进行调查,以了解尾矿库周边食品中的放射性水平。方法 2017—2021年在该尾矿库周边地区连续5年采集多份大米和豆角样品,用高纯锗γ谱仪检测镭-226和天然铀浓度,并运用间接法对当地标准人食入镭-226所致内照射年待积有效剂量进行估算。结果 大米中天然铀的检出率为96.0%,镭-226的检出率为74.0%;豆角中天然铀的检出率为96.7%,镭-226的检出率为73.3%,周围居民食入镭-226所致年待积有效剂量约为170.22μSv/a。结论 尾矿库周边主要农产品中镭-226和天然铀浓度均在国家标准限值以内,通过与国内相关领域内的研究结果对比,尾矿库周围居民食入镭-226所致辐射影响是可接受的。     

Uptake of 226Ra by established vegetation and black cutworm larvae, Agrotis ipsilon (class Insecta: order Lepidoptera), on U mill tailings at Elliot Lake, Canada

Radium-226 levels in samples from an inactive U tailings site at Elliot Lake, Ontario, Canada, were: 9,140 +/- 500 mBq g-1 dry weight in the substrate; 62 +/- 1 mBq g-1 dry weight in rye, Secale cereale, and less than 3.7 mBq g-1 dry weight in oats, Avena sativa, the dominant species established by revegetation of the tailings; and 117 +/- 7 mBq g-1 dry weight in washed and unwashed black cutworm larvae. Concentration ratios were: vegetation to tailings 0.001-0.007; black cutworms to vegetation 3.6 and black cutworms to tailings 0.01. The values are considered too low to be considered a hazard to herring gulls, Larus argentatus, which occasionally feed on cutworms.     

Distribution of inorganic and methylmercury among tissues in mink (Mustela vison) and otter (Lutra canadensis)

Total mercury and methylmercury concentrations were measured in brain, kidney, liver, and fur from several mink and otter collected in south-central Ontario. There was a large range in concentrations of both total and methylmercury. The percentage of the total mercury present as methylmercury varied among the various tissues; however, the percentage mercury found as the methyl form was relatively constant within a given tissue for all tissues in mink but highly variable in otter. For both species the highest percentage of methylmercury was found in the brain, whereas the lowest percentage was found in the kidneys for the otter and in the fur for the mink. Comparison of mercury concentrations in otter reveals that animals with higher body fat have higher mercury concentrations. Measurements of mercury in fur can be used as a general indicator of internal tissue concentrations.     

The effect of uranium mine tailings on radionuclide concentrations in Langley Bay,Saskatchewan, Canada

From 1955 to 1964 the Gunnar Uranium Mine (Canada) produced approximately 8×10³ tonnes of uranium oxide and about 5×10⁶ tonnes of waste rock tailings. Large quantities of fine tailings material washed into Langley Bay, a shallow bay opening onto Lake Athabasca. The limnoiogical characteristics of this bay make it an ideal site to study the movement and impact of some radionuclides in and on the northern environment. This paper describes the physical, chemical, and biological characteristics of Langley Bay and introduces a study of radionuclide movement begun in 1983.     

Levels of 226Ra, 210Pb and total U in fish near a Saskatchewan uranium mine and mill

Radionuclide levels in fish from the Beaverlodge Lake area, Saskatchewan, Canada, varied significantly among lakes, species and tissues, but did not vary with fish sex or age. Fish from lakes affected by an operating uranium mine and mill had radionuclide levels one to two orders of magnitude above levels in fish from an uncontaminated control lake. Concentrations were greatest in white suckers, intermediate in lake whitefish, and low in lake trout. Skin and bone contained the highest radionuclide levels; levels in flesh were much lower. The mean ash-weight concentration of 226Ra in non-control, eviscerated, whole fish was 9.3, 1.8 and 0.8 pCi X g-1 in white suckers, lake whitefish and lake trout respectively. Mean 210Pb levels for those species were 4.0, 1.4 and 0.5 pCi X g-1, while U content was 96.8, 28.2 and 5.8 micrograms X g-1, respectively. Radium-226 content in forage fish ranged from 9.7-70 pCi X g-1. Lead-210 levels ranged from 3.9-55.0 pCi X g-1, while U levels ranged from 15-119 micrograms X g-1. Bioconcentration factors varied among sites, species and tissues. The primary radionuclide transfer pathway appears to be via sediments, either through direct contact or through food organisms. Bottom-feeding species had the highest radionuclide levels while piscivorous fish had the lowest levels. The internal dose rate to non-control fish are comparatively low; any effects are likely to occur at the genetic level.     

Selenium Accumulation in Sea Ducks Wintering at Lake Ontario

Numbers of wintering sea ducks, including buffleheads (Bucephala albeola; BUFF), common goldeneyes (Bucephala clangula; COGO), and long-tailed ducks (Clangula hyemalis; LTDU), increased substantially at Lake Ontario after Dreissenid mussels (Dreissena bugensis and D. polymorpha) colonized the Great Lakes. Invertebrates, including Dreissenid mussels, are major diving duck prey items that can transfer some trace elements, such as selenium (Se) to higher trophic levels. Se can be problematic for waterfowl and it often has been detected at elevated levels in organisms using the Great Lakes. There are, however, few data on hepatic Se concentrations in sea ducks, particularly during the winter at Lake Ontario. In this study, we evaluated interspecific differences and temporal trends in hepatic Se concentrations among BUFF (n = 77), COGO (n = 77), and LTDU (n = 79) wintering at Lake Ontario. All three species accumulated Se throughout winter, but COGO did so at a higher rate than did BUFF and LTDU. Overall, Se concentrations were higher in LTDU [ [`(\textx)] = 22.7 {\bar{\text{x}}} = 22.7; 95% CI = 20.8–24.8 μg/g dry weight (dw)] than in BUFF ( [`(\textx)] = 1 2. 3 {\bar{\text{x}}} = 1 2. 3 ; 95% CI = 11.6–13.1 μg/g dw) and COGO ( [`(\textx)] = 1 2.0 {\bar{\text{x}}} = 1 2.0 ; 95% CI = 10.7–3.5 μg/g dw) throughout the winter. Se concentrations were deemed elevated (>33 μg/g dw) in 0%, 5%, and 19% of BUFF, COGO, and LTDU, respectively. Presently there are no data on Se toxicity end points for these species, so it is unclear how acquiring concentrations of these magnitudes affect their short- and long-term health or reproduction.     

Naturally occurring 226Ra concentrations in bone at various ages and alpha doses in adults.

Radium-226 concentrations of bone from the fetus and stillborn and from subjects aged 0 to 87 y, especially those older than 15 y, were determined by alpha spectrometry after an ion exchange separation. The median and mean 226Ra concentrations in bone of the adults, 20 to 69 y, were 0.35 and 0.42 Bq (kg bone ash)-1, respectively, and those for ages 15 to 87 y were 0.35 and 0.41 Bq (kg bone ash)-1, respectively. For fetal bones, mean content was 0.29 Bq (kg bone ash)-1. Annual dose equivalents in cells near bone surfaces and active red bone marrow, received from alpha radiation emitted from 226Ra and its decay products in mineral bone, were estimated using the ICRP dosimetric model for bone and assuming masses of source and target tissues for a Japanese Reference Man.     

Accumulation of organic contaminants in sentinel mallards utilizing confined disposal facilities at Hamilton Harbour,Lake Ontario,Canada

Organochlorine analysis was performed on adult and juvenile farm-raised mallards (Anas platyrhynchos) released and collected at three experimental sites in southern Ontario: Hamilton Harbour Confined Disposal Facility (CDF); Winona Sewage Lagoons (SL); and Big Creek Marsh, Canada. Collections were scheduled at 10, 30, and 70 days after release. Hamilton Harbour CDF and Winona SL are known to be contaminated whereas Big Creek Marsh is a relatively clean, natural site. All sites are important resting and feeding areas for migratory and resident waterfowl. Breast muscle concentrations of polychlorobiphenyls (PCBs) in ducks collected 10 days after release (160.8 g/kg, wet wt) at Hamilton Harbour CDF were more than 5300 times greater than day 0 birds (0.03 g/kg). All ducks collected from Hamilton Harbour CDF had PCB concentrations exceeding Health and Welfare Canada and United States Food and Drug Administration (FDA) guidelines for edible poultry. Concentrations of DDE (216.9 g/kg), hexachlorobenzene (0.9 g/kg), dieldrin (1.9 g/kg), and 1,2,4,5,-tetrachlorobenzene (24.9 g/kg) were significantly elevated in ducks utilizing Winona SL. Concentrations of 1,2,3,4-tetrachlorobenzene, mirex, and photomirex were elevated at one or more of the sites. Ducks from Big Creek Marsh had lower contaminant concentrations than ducks from the other study sites. It is not clear whether bioaccumulation of organochlorines at these sites would pose a potential hazard to migratory and resident mallards; however, other duck species such as diving ducks that have more contact with sediments and sediment-derived foods would probably be at much higher risk.     

Occurrence of 224Ra, 226Ra, 228Ra, gross alpha, and uranium in California groundwater

One hundred and twelve groundwater wells sampled from all the major aquifers in California were analyzed for 224Ra, 226Ra, 228Ra, gross alpha, and uranium. The results showed that radium is found in relatively low concentration, 1.56 x 10(-2)-1.23 Bq L(-1) (0.42-33 pCi L(-1)) for 224Ra, 2.2 x 10(-3)-0.81 Bq L(-1) (0.06-22 pCi L(-1)) for 226Ra, and 8.5 x 10(-3)-1.31 Bq L(-1) (0.23-35 pCi L(-1)) for 228Ra in California groundwater. Uranium was found at the highest concentration on both mass and activity basis and was correlated with the gross alpha measurement. Short-lived radioisotopes showed no significant contribution to gross alpha measurements. There was a strong correlation between 224Ra and 228Ra activities, suggesting the latter to be an indicator for the occurrence of the former. Comparison of 226Ra to 238U, 224Ra to 226Ra, and 226Ra to 228Ra showed scattered data indicating no correlation between each of these isotope pairs. Approximately 4% of the wells were found to exceed the U.S. Environmental Protection Agency (EPA) established maximum contaminant level for total radium of 0.185 Bq L(-1) (5 pCi L(-1)). Analysis of 228Ra by gamma-ray spectroscopy was in good agreement with the U.S. EPA-approved procedure.     

Emerging pollutants in the North Sea in comparison to Lake Ontario, Canada, data

In the present study, the concentrations and fate of contaminants such as organophosphate flame retardants and plasticizers, musk compounds such as galaxolide (HHCB), tonalide (AHTN), musk ketone and musk xylene, the bactericide triclosan, as well as the metabolites HHCB-lactone and triclosan-methyl were compared in the aqueous phase of the German Bight (North Sea). The concentrations of these compounds were around 1 to 10 ng/L in nearshore areas, and the concentrations were lower in the more pristine areas. The highest concentrations were determined for tris-(2-chloro-isopropyl) phosphate in the North Sea with concentration exceeding 10 ng/L even for the offshore samples. The samples contained 1 to 20 ng/L chlorinated organophosphates, approximately 1 ng/L nonchlorinated organophosphates, and 0.3 to 3 ng/L fragrance compounds. Some samples from Lake Ontario (Canada) were analyzed in comparison. Per capita emissions were calculated for both regions. These emissions were compared and turned out to be very similar for the Canadian and German locations. For the North Sea, some observations concerning stability, dilution, and degradation, as well as sources of the respective substances, were performed. These data indicate that the chlorinated organophosphates and some musk fragrances exhibit half lives exceeding the residence times and thus can be considered to be persistent in this ecosystem. In the German Bight, the river Elbe is the dominating source for the more hydrophilic compounds, such as chlorinated organophosphate flame retardants, which are diluted only into the North Sea. However, for the more lipophilic compounds such as the musk fragrances, different input patterns as well as distribution patterns are relevant, though the river Elbe is still a major source of pollution to the German Bight of the North Sea. The data seem to indicate either relevant inputs further west of the sampling area or mobilization from the sediments.     

Ambient air particulate dry deposition, concentrations and ionic species study at Taichung Harbor near Taiwan Strait

The characterization for watersoluble species of dry deposition flux, total suspended particulate (TSP), fine particle (particle matter with aerodynamical diameter 2.5 microm, PM2.5), coarse particle (particle matter with aerodynamical diameter 2.5-10 microm, PM(2.5-10)), and dry deposition velocity were studied at Taichung Harbor sampling sites of central Taiwan during February-August 2004. The average downward dry deposition flux, TSP, PM10 concentrations obtained in Taichung Harbor were about 0.51, 0.3, and 3.4 times more than those values obtained by traffic sampling site in central Taiwan. Average dry deposition velocity for mass, Cl-, NO3-, SO4(2-), Na+, NH4+, Mg2+, and Ca2+ were 9, 3.8, 0.3, 0.25, 0.46, 0.18, 0.51 and 2.28 cm respectively at the harbor sampling site. In general, average particle mass dry deposition velocity was about 1.8 times more than those values obtained at the traffic sampling site. Chemical analysis, also indicated that three major soluble inorganic species concentrations (sulfate+nitrate+ammonium) accounted for 59.8% and 80.6% of the PM2.5 and PM(2.5-10) mass concentrations, respectively at the Taichung Harbor sampling site.     

Heavy metals concentrations in the sediments from Kolleru Lake,India

Kolleru Lake is the largest natural freshwater lake of Andhra Pradesh in India. It is situated between the latitudes 16 degrees 32(1) and 16 degrees 47(1)N and longitude 81 degrees 05(1) and 81 degrees 21(1) E. The catchment area of the lake is 4763 sq. km. The sediment samples were collected at different points from Kolleru Lake in three seasons a year over a period of three years and analyzed for heavy metals and organic matter. Concentrations of Cu, Pd, Cd, Mn, Ni, Co, Fe and Zn in the sediments were analysed by using Atomic absorption spectrometer (AAS) and selected sediments samples were analysed for Be, Sr, Ba, B, Mo, Tl, V, Cr, Ag, Bi, As and Se by using inductively coupled plasma Mass Spectrometer (ICP-MS).