Evaluation of mine tailings effects on a benthic marine infaunal community over 29 years

Benthic infaunal and sediment data collected over 29 years were used to examine the extent and geographic range of effects and recovery from submarine tailings deposition. Empirical data were used to determine extreme and moderate effects, and identify near-, mid- and far-field zones. A simple probability test using overlap in frequency distributions was then used to determine less obvious effects, identify "normal" or "reference" conditions, and verify the geographic range of effect zones. Tailings thickness and sediment particulate copper were elevated from the outfall to 16-20 km distant, particularly below discharge depth (50 m). Changes in tailings thickness and copper levels before, during and after mining showed three distinct impact zones below discharge depth: near-field (<5 km from outfall); mid-field (5-16 km); and far-field (20 + km). Consistent faunal declines during mining were noted at sediment particulate copper levels >300 microg g(-1), and sediment tailings thickness > 15-20 cm. Extreme impoverishment at these sediment levels were; < 100 animals/m2, <2.5 g/m2 biomass and <7 taxa per station. No stations with >300 microg g(-1) copper and 20 cm tailings had more than 40 taxa. Amphipods were particularly affected by tailings, with distributions reflecting the instability in sediments from heavy deposition and/or shifting of tailings due to resuspension. The probability testing method assumed that reference conditions existed in far-field stations. There was no difference in abundance distributions between near-, mid- and far-field zones. Total taxa per station during mining was significantly reduced (<45) in both near- and mid-field stations compared with far-field (less than 10% overlap in distributions). One midfield station in Quatsino Sound (23) was in reference condition throughout the study period. Post-closure stations in the near- and mid-field had total taxa numbers approaching far-field conditions (overlap of 62% in distributions). Within 3 years following closure, total taxa values were within the far-field range for all stations sampled. Biomass showed a distinct decline in the near-field during mining, but with more overlap in near-field and far-field distributions (27%) than for total taxa per station, and was returning to far-field conditions in the post-closure years. A multivariate (Bray-Curtis) measure of dissimilarity indicated that the near- and mid-field infaunal compositions were distinct from the far-field during mining (< 10% overlap in distributions). The mid-field composition overlapped more with the far-field in the post-closure years, but the near-field composition did not, suggesting that the mine tailings are still affecting the fauna. The most abundant taxon in each of the reference and near-field station groups both showed significantly distinct relative abundance distributions between near- and far-field stations. In summary, the probability method showed that species richness, biomass, species composition and indicator taxa were useful for differentiating affected and non-affected stations. Polychaetes recolonize stable tailings most quickly, and have dominated the tailings stations in the post-closure years. Amphipods have recolonized sporadically, but seem to be highly sensitive to tailings stability. There was no evidence of recovery in dominant bivalves or echinoderms within three years after mine closure.     

Estrogenic responses of larval sunshine bass (Morone saxatilis x M. Chrysops) exposed to New York City sewage effluent

To determine the estrogenicity of effluents from sewage treatment plants (STPs) to larval fish, 2-day-old sunshine bass were exposed to effluents from three STPs serving New York City (NYC), varying in size and treatment level. Estrogenic response was evaluated by measuring vitellogenin (VTG) and estrogen receptor (ER) expression in cytosolic fractions of whole body homogenates. Concentrations of the presumptive endocrine disruptors in the effluents were also measured. VTG and ER levels in sewage-exposed fish were 3-5 times that observed in controls. Combined concentrations of estradiol and estrone ranged from 5 to 13 ng/l and nonylphenol-ethoxylate metabolites (NPEOs: 4-nonylphenol, and 1-, 2-, and 3-nonylphenol-ethoxylates) ranged from 180 to 470 microg/l in chlorinated effluent. Results indicate that both ER and VTG can be used as biomarkers for endocrine disruption in larval fish, and that 4-day exposure to sewage effluent is sufficient to elicit significant expression of these markers in sunshine bass larvae. The extremely higher concentrations of NPEOs found in effluent relative to hormones (approximately 40,000-fold) indicates that surfactant metabolites may be contributing significantly to the estrogenic effects observed.     

苏联出版的三本俄文版地震专业书简介

经苏联乌兹别克苏维埃社会主义共和国科学院地学部和地震研究所学术委员会批准,由“苏联科学院分院”出版社(塔什干)出版的三本俄文版地震专著,介绍了乌兹别克斯坦地震研究的成果,以及塔什干大地震和两次加兹利地震的研究成果。现将主要内容简介如下:1.《乌兹别克斯坦的地震研究》此书于1979年出版,全书分为4章,即:①地震活动性和地震区划;②震源区研究;③震源参数特征;④观测仪器和方法。2.《1966年4月26日塔什干地震》此书于1971年出版,全书分为4个部分。第一部分含5章,即;①地震效应和地震显     

日本的一次大地震预报

未来20年在日本首都所在地区范围内可能发生一次震级达里氏7级的强烈地震。这个结论是内阁总理大臣竹下登领导的防灾委员会做出的,该委员会1988年5月24日在东京举行了会议。共同社指出,像这样的预报,首次以政府名义正式做出。防灾委员会的委员们根据大量的地震资料     

德奎利亚尔发布自然灾害报告

最近20年间,因自然灾害死亡约300万人,最少有8亿人无家可归,患了各种疾病,遭受到严重的经济损失,包括数百亿美元的直接损失。这些资料是在今天发布的联合国秘书长关于国际减轻自然灾害十年的报告中提到的。1987年联合国大会通过一项宣布90年代为“国际社会在联合国保护下将特别关注在减轻自然灾害危险性方面加强合作”的十年的决议。     

超深源地震的性质

地震观测资料表明,深源地震基本上都发生在大平洋地震带的岛弧地区,其深度不超过700公里。深源地震的震源分布在从深海沟向岛弧下面俯冲的(即俯冲带的)较狭窄的(约100公里)冷岩石圈板块内。在过渡区至下地幔的界面上(深度670—700公里)地震活动性急剧降低或者甚至停止。对这一事实的传统的地球物理学解释与下列假说有关。这一假说是:或者由于化学势垒的缘故(例如,在下地幔物质的总成分中二氧化硅的含量增多),或者由于在约700公里深     

1989年世界地震遇难人数减少

美国地质调查局的研究资料指出,尽管在旧金山发生过造成大量人员遇难的破坏性地震,但去年仍是地球上地震活动最平静的年份之一。在1989年期间,世界上因地震造成526人死亡,这个数字大大低于平均遇难人数——每年1万人。在加利福尼亚1989年10月17日的悲惨事件中死亡62人,约3500人受伤。那次地震