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Harford AJ Hogan AC Tsang JJ Parry DL Negri AP Adams MS Stauber JL van Dam RA 《Marine pollution bulletin》2011,62(3):466-473
Ecotoxicological studies, using the tropical marine diatom, Nitzschia closterium (72-h growth rate), were undertaken to assess potential issues relating to the discharge from an alumina refinery in northern Australia. The studies assessed: (i) the species’ upper thermal tolerance; (ii) the effects of three signature metals, aluminium (Al), vanadium (V) and gallium (Ga) (at 32 °C); and (iii) the effects of wastewater (at 27 and 32 °C). The critical thermal maximum and median inhibition temperature for N. closterium were 32.7 °C and 33.1 °C, respectively. Single metal toxicity tests found that N. closterium was more sensitive to Al compared to Ga and V, with IC50s (95% confidence limits) of 190 (140-280), 19,640 (11,600-25,200) and 42,000 (32,770-56,000) μg L−1, respectively. The undiluted wastewater samples were of low toxicity to N. closterium (IC50s > 100% wastewater). Environmental chemistry data suggested that the key metals and discharge are a very low risk to this species. 相似文献
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A regression model to estimate regional ground water recharge 总被引:1,自引:0,他引:1
A regional regression model was developed to estimate the spatial distribution of ground water recharge in subhumid regions. The regional regression recharge (RRR) model was based on a regression of basin-wide estimates of recharge from surface water drainage basins, precipitation, growing degree days (GDD), and average basin specific yield (SY). Decadal average recharge, precipitation, and GDD were used in the RRR model. The RRR estimates were derived from analysis of stream base flow using a computer program that was based on the Rorabaugh method. As expected, there was a strong correlation between recharge and precipitation. The model was applied to statewide data in Minnesota. Where precipitation was least in the western and northwestern parts of the state (50 to 65 cm/year), recharge computed by the RRR model also was lowest (0 to 5 cm/year). A strong correlation also exists between recharge and SY. SY was least in areas where glacial lake clay occurs, primarily in the northwest part of the state; recharge estimates in these areas were in the 0- to 5-cm/year range. In sand-plain areas where SY is greatest, recharge estimates were in the 15- to 29-cm/year range on the basis of the RRR model. Recharge estimates that were based on the RRR model compared favorably with estimates made on the basis of other methods. The RRR model can be applied in other subhumid regions where region wide data sets of precipitation, streamflow, GDD, and soils data are available. 相似文献
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通过比较各段中每个准层序的进积规模和各次层序海相上倾终端的位置,在犹他州上白垩统布莱克霍克组的段内建立了两种独特的重复出现的堆叠地层模式。在同一段内,不论层序界面是否分隔开准层序,最虫的准层序总是比较晚的准层序进积较远。其结果是在各段中,进积距离的样式导致了从先进积到后加积的地层堆叠模式。 相似文献
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^137Cs法测算黄土高原土壤侵蚀速率的初步研究 总被引:16,自引:0,他引:16
核尘埃~(137)Cs降落到地表后,被土壤胶粒强烈吸附,集中分布于0—25cm的土壤表层。土壤剖面的~(137)Cs总量随土壤的流失而减少。根据黄土农耕地和非农耕地土壤的~(137)Cs流失模式,推导了它们的流失量和侵蚀速率的相关公式。根据陕西洛川黑木沟和山西离石羊道沟的13个土壤剖面的~(137)Cs含量测试结果,求得的黑木沟草坡覆盖的老谷坡和新谷坡的侵蚀速率分别为1400 t/km~2·a和5700t/km~2·a;羊道沟梁峁坡农耕地的侵蚀速率为3270—6030 t/km~2·a;裸露新谷坡的侵蚀速率大于8000 t/km~2·a。 相似文献
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Dehn LA Follmann EH Rosa C Duffy LK Thomas DL Bratton GR Taylor RJ O'Hara TM 《Marine pollution bulletin》2006,52(3):301-319
Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). Delta15N and delta13C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health. 相似文献