Contamination by Persistent Organochlorines in Small Cetaceans from Hong Kong Coastal Waters     

Tu Binh Minh  Mafumi Watanabe  Haruhiko Nakata  Shinsuke Tanabe  Thomas A. Jefferson 《Marine pollution bulletin》1999,39(1-12):383-392

Blubber samples of 2 cetacean species, the Indo-Pacific hump-backed dolphin (Sousa chinensis) (n=11) and finless porpoise (Neophocaena phocaenoides) (n=9), collected from Hong Kong coastal waters were analysed for persistent organochlorines. Mean concentration in the blubber of DDTs was ranked first (46 μg/g wet wt.), followed by PCBs (24 μg/g wet wt.), HCHs (0.76 μg/g wet wt.), chlordane compounds (0.38 μg/g wet wt.) and HCB (0.07 μg/g wet wt.). The present cetacean species may potentially be faced with high risk due to the elevated level of DDTs and PCBs. Relatively high concentrations of PCBs and DDTs can be attributed to the continuous environmental input of these compounds in the Far East region including Hong Kong. Highly chlorinated PCBs such as IUPAC Nos. 138, 153, 180 were the prominent congeners, accounting for 39% of the total PCBs. Mean concentrations of 6 non- and mono-ortho coplanar congeners were 2.1 and 2.8 μg/g wet wt. in the hump-backed dolphin and finless porpoise, respectively. Among highly toxic coplanar PCBs, mono-ortho congener IUPAC No. 118 and non-ortho congener IUPAC No. 126 were estimated to have the greatest toxicity contribution. Tris(4-chlorophenyl) methane (TCPMe) and tris(4-chlorophenyl) methanol (TCPMeOH), which have been the most recently identified microcontaminants, were also detected with the highest concentration of 290 and 300 ng/g (wet wt. basis), respectively. The concentrations of TCPMe relative to TCPMeOH in cetaceans from Hong Kong coastal waters were significantly higher than those found in various seals collected from other parts of the world, suggesting the different metabolic system of these two compounds between seals and cetaceans. Correlations between the concentrations of tris-chlorophenyl compounds with other persistent organochlorines such as HCHs, CHLs, DDTs and PCBs were significant, suggesting their accumulation nature similar to these organochlorines.  相似文献   

Particulate organic carbon fluxes to the ocean interior and factors controlling the biological pump: A synthesis of global sediment trap programs since 1983   总被引：2，自引：0，他引：2  

Susumu Honjo  Steven J. Manganini  Roger Francois 《Progress in Oceanography》2008,76(3):217-285

Particulate organic carbon (POC) is vertically transported to the oceanic interior by aggregates and their ballasts, mainly CaCO₃ and biogenic opal, with a smaller role for lithogenic aerosols through the mesopelagic zone. Diel migrating zooplankton communities effect vertical transport and remineralization of POC in the upper layers of the ocean. Below 1.5 km, the presence of zooplankton is reduced and thus the aggregates travel mainly by gravitational transport. We normalized the fluxes of POC, CaCO₃, and biogenic opal from data published on samples collected at 134 globally distributed, bottom-tethered, time-series sediment trap (TS-trap) stations to annual mole fluxes at the mesopelagic/bathypelagic boundary (m/b) at 2 km and defined them as F_m/bC_org, F_m/bC_inorg, and F_m/bSi_bio. Using this global data set, we investigated (1) the geographic contrasts of POC export at m/b and (2) the supply rate of ∑CO₂ to the world mesopelagic water column. F_m/bC_org varies from 25 (Pacific Warm Pool) to 605 (divergent Arabian Sea) mmolC m⁻² yr⁻¹; F_m/bC_inorg varies from >8 (high latitude Polar Oceans) or 15 (Pacific Warm Pool) to 459 (divergent Arabian Sea) mmolC m⁻² yr⁻¹; and F_m/bSi_bio, the most spatially/temporally variable flux, ranges from 6 (North Atlantic Drift) to 1118 (Pacific Subarctic Gyre) mmolSi m⁻² yr⁻¹. The oceanic region exhibiting the highest POC flux over a significantly large region is the area of the North Pacific Boreal Gyres where the average F_m/bC_org = 213, F_m/bC_inorg = 126, and F_m/bSi_bio = 578 mmol m⁻² yr⁻¹. F_m/bC_org and F_m/bC_inorg are particularly high in large upwelling margins, including the divergent Arabian Sea and off Cape Verde. One of the data sets showing the lowest flux over a significant region/basin is F_m/bC_org = 39, F_m/bC_inorg = 69, and F_m/bSi_bio = 22 mmol m⁻² yr⁻¹ in the North Pacific subtropical/tropical gyres; Pan-Atlantic average fluxes are similar except F_m/bSi_bio fluxes are even lower. Where C_org/C_inorg and Si_bio/C_inorg are <1 defines the “Carbonate Ocean”, and where these ratios are ?1 defines the “Silica Ocean”. The Carbonate Ocean occupies about 80% of the present world pelagic ocean between the two major oceanographic fronts, the North Pacific Polar Front and the Antarctic Polar Front, and the Silica Ocean is found on the polar sides of these fronts. The total global annual fluxes of F_m/bC_org, F_m/bC_inorg, and F_m/bSi_bio at m/b calculated by parameterizations of the export flux data from 134 stations are surprisingly similar; 36.2, 33.8, and 34.6 teramol yr⁻¹ (120, 112, and 114 mmol m⁻² yr⁻¹), respectively, resulting in a near uniform binary ratio between the above three elements of about one. The global ternary % ratios estimated from 152 TS-trap samples of the three elements are 35:32:33. From our global F_m/bC_org and a published model estimate of the global export production, we estimate the regeneration rate of CO₂ through the mesopelagic zone by the biological pump is 441 teramolC yr⁻¹. Based on our global F_m/bC_inorg and recently estimated global primary production of PIC, 36-86 teramolC yr⁻¹ of PIC is assumed to be dissolved within the upper 2 km of the water column.  相似文献   

Integrative assessment of organotin contamination in a southern European estuarine system (Ria de Aveiro, NW Portugal): tracking temporal trends in order to evaluate the effectiveness of the EU ban   总被引：1，自引：0，他引：1  

Sousa A  Matsudaira C  Takahashi S  Tanabe S  Barroso C 《Marine pollution bulletin》2007,54(10):1645-1653

Organotin (OT) compounds have been used as biocide agents in antifouling paints since the mid 1960s and are now ubiquitous in the marine environment. Due to their high toxicity to non-target species they were banned from antifouling paints in the European Union in 2003 (2002/62/EC directive). The aim of the present work is to assess any obvious decline of the OT environmental levels at Ria de Aveiro (NW Portugal) after the ban. The organotins - monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPT), diphenyltin (DPT), triphenyltin (TPT), monoctyltin (MOT), dioctyltin (DOT) and trioctyltin (TOT) - were quantified in the gastropod Nassarius reticulatus, in the mussel Mytilus galloprovincialis and in sediments. Imposex (imposition of male characters on females of gonochorist gastropods) in N. reticulatus was additionally used as a biomarker of TBT pollution. Time comparisons show a slight decrease of imposex between 2003 and 2005 probably as a consequence of the EU ban, though in some cases this trend seems to have started earlier since 2000. The fraction of TBT relatively to its metabolites has been decreasing over the last years but still remains high suggesting that there are still recent inputs of this compound into the study area.  相似文献   

Isomer specific determination of hexabromocyclododecanes (HBCDs) in small cetaceans from the South China Sea--Levels and temporal variation   总被引：1，自引：0，他引：1  

Isobe T  Ramu K  Kajiwara N  Takahashi S  Lam PK  Jefferson TA  Zhou K  Tanabe S 《Marine pollution bulletin》2007,54(8):1139-1145

A diastereoisomer (alpha, beta, and gamma) specific analytical method for measuring hexabromocyclododecanes (HBCDs) was developed using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The method developed was applied to analyze blubber of small cetaceans to divulge the distribution and temporal variation of HBCDs in the Asian marine environment. HBCDs were detected in all the blubber samples of finless porpoises (Neophocaena phocaenoides) and Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea during 1990-2001. Concentrations of HBCDs were higher in humpback dolphins (31-380 ng/g lipid) than in finless porpoises (4.7-55 ng/g lipid), which can be attributed to habitat differences. Average concentrations of alpha-HBCD in finless porpoises increased from 9.5 ng/g lipid in 1990 to 35 ng/g lipid in 2000/01. alpha-HBCD was predominant among the three isomers with some exceptions in finless porpoises collected in 1990. This is the first report on HBCDs contamination in marine mammals from Southeast Asia.  相似文献   

Formation of the Japan Sea basin: Reassessment from Ar–Ar ages and Nd–Sr isotopic data of basement basalts of the Japan Sea and adjacent regions     

Susumu Nohda 《Journal of Asian Earth Sciences》2009,34(5):599-609

Many studies have examined the Japan Sea basalts recovered during Ocean Drilling Program (ODP) Leg127/128. Of these, the ⁴⁰Ar–³⁹Ar dating undertaken is important in constraining the timing of the formation of the Japan Sea; however, the implications of their results do not appear to be fully appreciated by the geological community. In this paper, I reassess the ⁴⁰Ar–³⁹Ar age data of the basalts with reference to Nd–Sr isotopic data. The ⁴⁰Ar–³⁹Ar dating was performed on basalts somewhat enriched in large-ion lithophile elements and recovered from ODP Sites 794, 795 and the lower part of 797, yielding the plateau ages of 21.2–17.7 Ma. These basalts show the Nd–Sr isotopic signature of a moderately depleted mantle source (ε_Nd: 0.6–6.9). In contrast, the basalts from the upper part of Site 797 have yet to be dated due to their low K content, although their Nd isotopic compositions are similar to that of MORB (ε_Nd: 8.4–10.4). By analogy to the secular Nd–Sr isotopic trends reported for Sikhote-Alin and northeast Japan, the age of the upper basalts at Site 797 may be inferred to be younger than the lower basalts, probably around 16 Ma. The Nd–Sr isotopic compositions of the Japan Sea basalts have been interpreted in terms of eastward asthenospheric flow, as have the lavas of the Sikhote-Alin and northeastern Japan. The timing of volcanic activity in the Japan Sea region (i.e., from 21.2 to 14.86 Ma) is consistent with the timing of rotational crustal movements inferred from paleomagnetic studies of the Japanese Islands (i.e., 14.8–4.2 Ma for southwest Japan and 16.5–14.4 Ma for northeast Japan).  相似文献   

Contamination status of POPs and BFRs and relationship with parasitic infection in finless porpoises (Neophocaena phocaenoides) from Seto Inland Sea and Omura Bay, Japan     

Isobe T  Oshihoi T  Hamada H  Nakayama K  Yamada TK  Tajima Y  Amano M  Tanabe S 《Marine pollution bulletin》2011,63(5-12):564-571

Contamination status of brominated flame retardants (BFRs) and persistent organic pollutants (POPs) in blubber of finless porpoises (Neophocaena phocaenoides) stranded along the coasts of Seto Inland Sea and Omura Bay in Japan were investigated. Levels of PCBs, DDTs and CHLs were significantly higher than those of HCHs, HCB, PBDEs and HBCDs. Concentrations of PBDEs and HBCDs, as well as organochlorine compounds in males increased with body length (p<0.05). Among 14 PBDE congeners analyzed, BDE-47 was the predominant, which is similar to those generally reported in biota. PBDEs, HBCDs and PCBs showed no obvious temporal trend in concentrations during the study period, suggesting continuous environmental release of these chemicals. On the other hand, levels of DDT, CHLs and HCHs have decreased. Concentrations of PCBs in liver trematode infected individuals were significantly higher than those in not infected individuals, implying there could be a relationship between contaminant levels and parasitic infection.  相似文献   

Contamination status and spatial distribution of organochlorine compounds in fishes from Nansei Islands, Japan     

Malarvannan G  Takahashi S  Ikemoto T  Isobe T  Kunisue T  Sudaryanto A  Miyagi T  Nakamura M  Yasumura S  Tanabe S 《Marine pollution bulletin》2011,63(5-12):541-547

Two species of fishes (n=52; tilapia and mullet) from industrialized and urbanized areas of Okinawa Island (Manko-Noha river, Hija river and Shikaza river) and from a remote area of Ishigaki Island (Anparu mudflat), Japan were collected between August 2005 and July 2006, and analyzed for five organochlorine compounds (OCs), viz., DDTs, PCBs, CHLs, HCHs and HCB. Concentrations and the contamination patterns of OCs in fishes varied between locations. Considerable residue levels of OCs, especially CHLs and DDTs were found in both fishes from the main Okinawa Island. These levels were relatively higher than the reported values for seafood from Japanese coasts, indicating that even now pollution sources of these contaminants still exist in this region. On the other hand, lower concentrations of OCs were detected in fishes from Ishigaki Island waters than those of other Japanese coastal waters, suggesting that this region is less contaminated by OC contaminants.  相似文献   

Accumulation of trace elements in harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada     

Agusa T  Nomura K  Kunito T  Anan Y  Iwata H  Tanabe S 《Marine pollution bulletin》2011,63(5-12):489-499

Nineteen trace elements were determined in liver, muscle, kidney, gonads, and hair of 18 harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada. Concentrations of V, Mn, Fe, Cu, Mo, Ag, and Hg in the liver, Co, Cd, and Tl in the kidney, and Ba and Pb in the hair were significantly higher than those in other tissues. Significant positive correlations between Hg concentrations in the hair, and liver, kidney and testis imply usefulness of the hair sample for non-destructive monitoring of Hg in the harp seals. It is suggested that whereas Hg preferentially accumulates in the liver, the accumulation in other tissues is induced at higher hepatic Hg levels. In contrast, Se may not be accumulated in other tissues compared with the liver even at higher hepatic Hg levels because of the presence of excess Se for Hg detoxification in other tissues.  相似文献   

Spatial distribution and corresponding determining factors of metal concentrations in surface sediments of Beppu Bay, southwest Japan     

Amano A  Kuwae M  Agusa T  Omori K  Takeoka H  Tanabe S  Sugimoto T 《Marine environmental research》2011,71(4):247-256

This study determined the factors contributing to the spatial distribution of 14 metal concentrations in the surface sediments of Beppu Bay on the basis of comparisons of the organic geochemical properties and environmental parameters through principal component analysis (PCA) and redundancy analysis (RDA). The results of PCA and RDA showed that the concentrations of V, Cr, Co, and As were closely related to the distances between the sampling sites and the Oita River. This indicated that these metals originated from the river's drainage area. The Mn, Cu, Mo, and Cd concentrations were related to the water depth. These results indicated that the Mo, Cd, and Cu deposition processes were controlled by oxygen depletion, and that these elements accumulated in the deeper parts of the bay under anoxic conditions.  相似文献   

Degree of impactor fragmentation under collision with a regolith surface—Laboratory impact experiments of rock projectiles     

Hiroki Nagaoka  Susumu Takasawa  Akiko M. Nakamura  Kazuyoshi Sangen 《Meteoritics & planetary science》2014,49(1):69-79

Some meteorites consist of a mix of components of various parent bodies that were presumably brought together by past collisions. Impact experiments have been performed to investigate the degree of target fragmentation during such collisions. However, much less attention has been paid to the fate of the impactors. Here, we report the results of our study of the empirical relationship between the degree of projectile fragmentation and the impact conditions. Millimeter‐sized pyrophyllite and basalt projectiles were impacted onto regolith‐like sand targets and an aluminum target at velocities of up to 960 m s^?1. Experiments using millimeter‐sized pyrophyllite blocks as targets were also conducted to fill the gap between this study and the previous studies of centimeter‐sized rock targets. The catastrophic disruption threshold for a projectile is defined as the energy density at which the mass of the largest fragment is the half of the original mass. The thresholds with the sand target were 4.5 ± 1.1 × 10⁴ and 9.0 ± 1.9 × 10⁴ J kg^?1, for pyrophyllite and basalt projectiles, respectively. These values are two orders of magnitude larger than the threshold for impacts between pyrophyllite projectiles onto aluminum targets, but are qualitatively consistent with the fact that the compressive and tensile strengths of basalt are larger than those of pyrophyllite. The threshold for pyrophyllite projectiles and the aluminum target agrees with the threshold for aluminum projectiles and pyrophyllite targets within the margin of error. Consistent with a previous result, the threshold depended on the size of the rocks with a power of approximately ?0.4 (Housen and Holsapple 1999). Destruction of rock projectiles occurred when the peak pressure was about ten times the tensile strength of the rocks.  相似文献