Trace element levels in foetus-mother pairs of short-beaked common dolphins (Delphinus delphis) stranded along the French coasts

Tissues of foetus-mother pairs of common dolphins (Delphinus delphis) stranded along the French coasts (Bay of Biscay and English Channel) were analysed for their Cd, Cu, Hg, Se and Zn contents. In the kidneys, foetal Cd levels were extremely low, and strong relationships between Cu and Zn suggested the involvement of metallothioneins since early foetal life. The results also indicated a limited maternal transfer of Hg during pregnancy since levels in the tissues of foetuses were below 1 microg g(-1) w.wt. However, hepatic Hg levels in foetuses increased with body length, and were also proportionate to maternal hepatic, renal and muscular Hg levels. Lastly, affinities between Hg and Se in tissues would participate in Hg neutralisation in both mothers--through tiemannite granules--and fetuses--through reduced glutathione--counteracting the toxic effects linked to the particularly high quantities of methyl-Hg to which marine mammals are naturally exposed.     

Do ovarian scars persist with age in all Cetaceans: new insight from the short-beaked common dolphin (<Emphasis Type="Italic">Delphinus delphis</Emphasis> Linnaeus<Emphasis Type="Italic">,</Emphasis> 1758)

The determination of reproductive status and the reconstruction of individual reproductive histories are central to many ecological studies. In cetaceans, it has been assumed that ovarian scars accumulate with age and provide a lifetime record of female reproductive history. If ovarian scars persist, the number of scars should increase with age after puberty. To test this, we examined age, reproductive status and ovarian scars from 187 short-beaked common dolphins (Delphinus delphis) from the eastern North Atlantic. The number of Corpus Albicans (CA) present in ovaries did not increase with age after age at sexual maturity (ASM), suggesting that ovarian scars are not persistent and that their number at any one time would be a function of rates of ovulation and healing, the latter being defined here as the resorption or disintegration of CA tissue. Since female mammals stop ovulating when pregnant, inferences about healing rates could be made by using pregnant females. Pregnant females had ca. 40% fewer scars than non-pregnant females. This suggests that most CAs would heal quickly, with a half-life of less than 1 year, although larger scars may persist longer. Therefore, counting CAs would have limited potential for reconstructing individual reproductive lifetime histories in the common dolphin. A reassessment of the use of ovarian scars to reconstruct individual life reproductive histories in cetaceans is suggested.     

碳热还原电厂粉煤灰冶炼硅铝铁合金

电厂粉煤灰中主要含有SiO2和Al2O3,且含有一定量的残炭。采用粉煤灰和铝土矿等为主要原料进行了高温下制备硅铝铁合金研究,结果表明,利用电厂粉煤灰和铝土矿为主要原料,配加赤铁矿、硅石和添加剂CaF2,在1 880℃时经碳热还原可以制备硅铝铁合金,提高粉煤灰的利用价值,减少其环境污染。在1 750℃时,还原反应进行不完全,得不到硅铝铁合金。在1 880℃时还原出的合金主要成分为Si,Al和Fe,其平均含量分别为27.69%,8.75%和58.81%,合金的主要物相为Al0.3Fe3Si0.7,SiC,FeSi和FeC。     

Microalgal-bacterial granular sludge process outperformed aerobic granular sludge process in municipal wastewater treatment with less carbon dioxide emissions

Environmental Science and Pollution Research - The aerobic granular sludge (AGS) process and microalgal-bacterial granular sludge (MBGS) process were comparably applied for municipal wastewater...     

北川山区海拔和坡向对杂交玉米的影响

在φ（N）31°45′～31°50′,λ（E）104°20′～104°25′范围内,通过3个杂交玉米品种在海拔（h     

Bioaccumulation of persistent organic pollutants in female common dolphins (Delphinus delphis) and harbour porpoises (Phocoena phocoena) from western European seas: geographical trends, causal factors and effects on reproduction and mortality

Concentrations of polychlorinated biphenyls (PCBs) in blubber of female common dolphins and harbour porpoises from the Atlantic coast of Europe were frequently above the threshold at which effects on reproduction could be expected, in 40% and 47% of cases respectively. This rose to 74% for porpoises from the southern North Sea. PCB concentrations were also high in southern North Sea fish. The average pregnancy rate recorded in porpoises (42%) in the study area was lower than in the western Atlantic but that in common dolphins (25%) was similar to that of the western Atlantic population. Porpoises that died from disease or parasitic infection had higher concentrations of persistent organic pollutants (POPs) than animals dying from other causes. Few of the common dolphins sampled had died from disease or parasitic infection. POP profiles in common dolphin blubber were related to individual feeding history while those in porpoises were more strongly related to condition.     

Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific)

Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhynchus) and two pygmy sperm whales(Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu. Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd, Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 microg g(-1) dry wt. Only a very low percentage of the total Hg was organic. In both species,the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that G. macrorhynchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals.     

Do ovarian scars persist with age in all Cetaceans: new insight from the short-beaked common dolphin (Delphinus delphis Linnaeus, 1758)

The determination of reproductive status and the reconstruction of individual reproductive histories are central to many ecological studies. In cetaceans, it has been assumed that ovarian scars accumulate with age and provide a lifetime record of female reproductive history. If ovarian scars persist, the number of scars should increase with age after puberty. To test this, we examined age, reproductive status and ovarian scars from 187 short-beaked common dolphins (Delphinus delphis) from the eastern North Atlantic. The number of Corpus Albicans (CA) present in ovaries did not increase with age after age at sexual maturity (ASM), suggesting that ovarian scars are not persistent and that their number at any one time would be a function of rates of ovulation and healing, the latter being defined here as the resorption or disintegration of CA tissue. Since female mammals stop ovulating when pregnant, inferences about healing rates could be made by using pregnant females. Pregnant females had ca. 40% fewer scars than non-pregnant females. This suggests that most CAs would heal quickly, with a half-life of less than 1 year, although larger scars may persist longer. Therefore, counting CAs would have limited potential for reconstructing individual reproductive lifetime histories in the common dolphin. A reassessment of the use of ovarian scars to reconstruct individual life reproductive histories in cetaceans is suggested.