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351.
Marine pollution from antifouling paint particles 总被引:3,自引:0,他引:3
Andrew Turner 《Marine pollution bulletin》2010,60(2):159-171
Antifouling paint particles (APP) are generated during the maintenance of boats and are shed from abandoned structures and grounded ships. Although they afford a highly visible, colourful reflection of contamination in the vicinity of the source, little systematic study has been undertaken regarding the distribution, composition and effects of APP in the wider marine environment. This paper reviews the state of knowledge in respect of APP, with particular emphasis on those generated by recreational boatyards. The likely biogeochemical pathways of the biocidal and non-biocidal metals in current use (mainly Cu and Zn) are addressed in light of recent research and an understanding of the more general behaviour of contaminants in marine systems.Analyses of paint fragment composites from recreational facilities in the UK reveal chemical compositions that are similar to those representing the net signal of the original formulations; significantly, dry weight concentrations of Cu and Zn of up to about 35% and 15%, respectively, are observed and, relative to ambient dusts and sediment, elevated concentrations of other trace metals, like Ba, Cd, Cr, Ni, Pb and Sn, occur. These metals leach more rapidly from APP than a painted surface due to the greater surface area of pigments and additives exposed to the aqueous medium. In suspension, APP are subject to greater and more rapid environmental variation (e.g. salinity, pH, dissolved oxygen) than painted hulls, while settled APP represent an important source of persistent and degradable biocides to poorly circulating environments. Through diffusion and abrasion, high concentrations of contaminants are predicted in interstitial waters that may be accumulated directly by benthic invertebrates. Animals that feed non-selectively and that are exposed to or ingest paint-contaminated sediment are able to accelerate the leaching, deposition and burial of biocides and other substances, and represent an alternative vehicle for contaminant entry into the marine foodchain. Clearly, an extensive understanding of biocide behaviour on painted surfaces is not sufficient for predictive or management purposes regarding APP. Greater caution is required by boaters and boatyards during the removal and disposal of solid wastes, and more awareness or stricter enforcement of relevant codes of practice or legislation is recommended. 相似文献
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Concerns about future supplies of raw materials demand careful examination of underlying assumptions and data. Flawed deposit information, ignored undiscovered resources and questionable assumptions about future consumption require a new look at copper resources.A careful compilation of 1978 copper-bearing mineral deposits totals 2700 million metric tons of copper including past production—considerably more than reported in previous studies. About 69% of the copper is in porphyry copper deposits and 12% in sediment-hosted copper, Magmatic sulfide (mostly intrusive Ni) deposits account for 5.1%, and IOGC adds about 4.7%. VMS deposits represent 45% of the 1978 deposits but only 4.9% of the copper.The largest 20% of the deposits account for over 92% of the total copper metal. In other words, total Cu content in the smaller 1600 deposits is only about 8% of all Cu known in all deposits. This is a consequence of highly skewed frequency distributions of deposit tonnages and contained metals in all kinds of mineral deposits. This relationship is critical if one is concerned about long-term supply of copper. Typically, distributions of contained metal can be modeled well by the lognormal distribution for individual types of deposits.Information used here and in many other studies on copper includes past production. Total past production through 2015 is about 667 million tons Cu. After subtracting past production from the total copper in known deposits, the remaining unproduced copper from known deposits is 2030 million tons. Known deposits inform us about undiscovered copper resources.Over 80% of known copper is in porphyry copper and sediment-hosted copper deposits. A reliable and robust USGS managed global assessment of 225 tracts for porphyry Cu and sediment-hosted Cu produced an expected value estimate of 3500 million tons Cu in undiscovered deposits. Deposit types not assessed such as IOGC are likely to have significant amounts of undiscovered copper. If the proportion of total Cu accounted for by the two major deposit types assessed is the same proportion in all undiscovered deposits, total Cu expected in these other deposit types would add an additional 850 million tons. The reasonable estimate of copper in undiscovered mineral deposits of 4350 million tons when added to the unmined 2030 million tons in known deposits provides an estimate of 6380 million of tons Cu, which far exceeds estimates published by other researchers.Growth in copper production appears to be exponential over time but appears to be linear with respect to population. Demand for copper is not driven by time, but rather by population and per capita income. Rates of population increases are slowing and incomes in many countries are increasing. Per capita consumption of copper will increase over the coming years as populous nations such as China and India develop increasing per capita incomes, but the demand will likely level off as their economies improve. The large estimated copper resources along with evidence of slowing demand for copper over the long term considerably extend the time of “peak copper” and the long mine life of large deposits means the decline in production after will not be rapid. The focus of copper supply concerns should be on important problems such as improving recovery rates, careful consideration of the benefits and costs of mining very large deposits, technologies to increase exploration success in covered areas and reducing costs of underground mining. 相似文献
354.
The Zijinshan high-sulfidation epithermal Cu–Au deposit is located in the Zijinshan ore field of South China, comprising porphyry–epithermal Cu–Au–Mo–Ag ore systems. The Cu ore body is more than 1000 m thick and is characterized by an assemblage of digenite–covellite–enargite–alunite. Digenite is the dominant Cu-bearing mineral, which makes this deposit unique, although the mechanisms of digenite formation remain controversial. To elucidate the genesis of digenite, this paper presents the Cu isotopic compositions of Cu-sulfides in the Zijinshan high-sulfidation Cu–Au deposit. The Cu isotopic values (65Cu relative to NIST 976) of all samples range from −2.97‰ to +0.34‰, and most values fall in a narrow range from −0.49‰ to +0.34‰, which is similar to the Cu isotopic signature of typical porphyry systems. Copper isotope ratios of each mineral decrease with increasing depth, a trend that is also typical of porphyry deposits. The variation tendency of δ65Cu values between sulfides is consistent with the sequence of mineral formation. These observations suggest that the Cu-sulfides in the Zijinshan Cu–Au deposit have a hypogene origin. 相似文献
355.
Metal concentrations measured in the organs of beached whales are published regularly. Few of these, however, describe metal levels in nursing females. In the present study, mercury, lead, copper and zinc levels were measured in the milk and tissues of a female Bottlenose dolphin. Results reveal that metal pollutants pass from the tissue into the milk. 相似文献
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Experiments were conducted to assess the effects of copper on larval development in the barnacle Balanus amphitrite. In the first experiment, we compared the sensitivity of three naupliar stages to copper stress. Molting inhibition occurred at copper concentrations ranging from 32 μg l−1 in nauplius II to 128 g l−1 in nauplius VI. EC50 for molting ranged from 97 μg l−1 in nauplius II to 129 g l−1 in nauplius VI. Decreased survival occurred at 128 μg Cu l−1 in all of the naupliar stages tested, with LC50 ranging from 145 in nauplius II to 213 μg l−1 in nauplius VI. In the second experiment, we examined effects of copper on the development from nauplius II to cyprid. The larvae reached cypris stage only in treatments of 16 μg Cu l−1. Our study therefore showed that molting was a more sensitive endpoint than survival, nauplius II was the most sensitive naupliar stage, and that whole larval development assay was more sensitive than assays using a particular larval stage. The results were discussed with respect to the use of this species in toxicity tests. 相似文献
359.
Calcium alginate immobilized marine microalgae: experiments on growth and short-term heavy metal accumulation 总被引:3,自引:0,他引:3
Growth of 11 calcium alginate immobilized marine microalgal species belonging to eight taxonomical groups has been checked in the present work. Cellular densities inside the calcium alginate beads were monitored during 17 days. Good growth and maintenance of the structure of the beads were both found for some of the assayed species. One of those species (Tetraselmis chui, Prasinophyceae) was selected in order to perform a short term (up to 24 h) heavy metal accumulation experiment. Beads of calcium alginate containing (or not) cells of T. chui were exposed to 820 μg L−1 Cu and 870 μg L−1 Cd separately during a 24 h period, and accumulation of heavy metals in the beads was measured after this time and compared. Concentration of each metal in the supernatants was monitored at 5, 10, 60 min and 24 h from the beginning of the experiment. After 24 h, practically all Cu was removed by the beads. Beads with immobilized algae removed around 20% of total Cd, while beads without algae removed half of that percentage. 相似文献
360.
The Canatuan and Malusok massive sulfide deposits are located near Siocon, Zamboanga del Norte, in southwestern Mindanao, Philippines. The Canatuan–Malusok area is underlain by the Jurassic–Cretaceous Tungauan schists, which form much of the Zamboanga Peninsula. The volcanic strata at Canatuan and Malusok can be traced for >7 km along strike and is host to at least three discrete massive sulfide bodies: Canatuan, Malusok and SE Malusok. Basal basaltic andesite volcanic rocks are generally chemically uniform and show only moderate alteration. The massive sulfide deposits occur in overlying rhyolitic to rhyodacitic volcanic rocks that are altered to a schistose assemblage of quartz, sericite, chlorite and pyrite. The alteration is texturally destructive but graded clastic beds are locally observed. Despite tropical saprolitic weathering, four lithogeochemical subunits of the felsic package are identified. Stratigraphic interleaving, however, has made correlation of these units over any significant distance difficult. The sulfide lenses are overlain by a few metres of felsic schists which locally contain manganese-bearing silicates and oxides that serve as a stratigraphic marker. Hangingwall andesitic volcaniclastic rocks are discontinuously preserved, although where present, they consist of regularly bedded mafic volcanic sandstones. The lateral continuity of a manganese-bearing marker and flanking felsic volcaniclastic intervals indicate that locally the volcanic strata form a homoclinal sequence. The Canatuan Au–Ag–Cu–Zn deposit consists of a gossan overlying a massive sulfide lens. The sulfides and gossan are flat lying and hosted within felsic volcanic rocks. The gossan is gold–silver-rich, and was formed by a combination of oxidation and volume collapse of the original sulfide lens. The sulfide minerals present below the current water table, are auriferous massive pyrite with base metal sulfides, with some supergene chalcocite. The transition from gossan to sulfides is very sharp, occurring at the water table. Massive sulfide deposits at Malusok are hosted in the same felsic sequence as Canatuan and they have similar base and precious metal contents. Only limited gossan has been found at Malusok. The bimodal nature of the volcanic rocks at Canatuan, together with their low HFSE contents, near-flat REE patterns and tholeiitic affinities, suggest that they formed in an intra-oceanic arc setting above a depleted mantle source. Mafic and felsic volcanic rocks of similar composition have been recovered from the Tonga-Kermadec and Izu-Bonin-Marianas island-arc systems in the western Pacific. Mafic rocks at Canatuan show no evidence for LILE enrichment that characterizes melts derived from metasomatized mantle under more mature arcs, suggesting that they are the product of a nascent, rather than a mature arc. There is no evidence from the REE, or other incompatible trace elements, that continental crust or evolved arc crust was involved in the generation of the Canatuan-Malusok volcanic rocks. Although it has been proposed that the Zamboanga metamorphic complex comprises microcontinental fragments of Eurasian affinity, our data do not support an evolved crustal setting for the Canatuan-Malusok volcanic rocks, which we suggest were derived from an intra-oceanic arc and subsequently accreted to the eastern Mindanao terrane.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00126-003-0350-7Editorial handling: R.R. Large 相似文献