Nobuyuki Miyazaki

Contamination profiles of antifouling biocides in selected coastal regions of Malaysia

The concentrations of butyltins (BTs) in sediment from Peninsular Malaysia along the Strait of Malacca and their spatial distribution are discussed. The concentrations of BTs were high in the southern part of Peninsular Malaysia where there is a lot of ship traffic, because trade is prosperous. The concentrations of monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) in sediment from the coastal waters of Peninsular Malaysia were in the range 4.1–242xa0μg/kg dry weight (dw), 1.1–186xa0μg/kg dw, and 0.7–228xa0μg/kg dw, respectively. A higher percentage of TBT was observed in the area where TBT concentrations were high. The concentrations of monophenyltin (MPT), diphenyltin (DPT), and triphenyltin (TPT) were in the rangexa0<0.1–121xa0μg/kg dw, 0.4–27xa0μg/kg dw, and 0.1–34xa0μg/kg dw in sediment from Peninsular Malaysia, respectively. MPT was the dominant phenyltin species. MBT, DBT, and TBT in green mussel (Perna viridis) samples were detected in the range 41–102xa0μg/kg, 3–5xa0μg/kg, and 8–32xa0μg/kg, respectively. A tolerable average residue level (TARL) was estimated at 20.4xa0μg/kg from a tolerable daily intake (TDI) of 0.25xa0μg TBTO/kg body weight/day. The maximum value of TBT detected in green mussel samples was the value near the TARL. TPTs were not detected in green mussel samples. The concentrations of Diuron and Irgarol 1051 in sediment from Peninsular Malaysia were in the rangexa0<0.1–5xa0μg/kg dw andxa0<0.1–14xa0μg/kg dw, respectively. High concentrations of these compounds were observed in locations where the concentrations of TBT were high. Sea Nine 211, Dichlofluanid, and Pyrithiones were not detected in sediment. The concentrations of antifouling biocides in Melaka and the Strait of Johor were investigated in detail. BTs were found in similar concentrations among all sampling sites from Melaka, indicating that BT contamination spread off the coast. However, Sea Nine 211, Diuron, and Irgarol 1051 in the sediment from Melaka were high at the mouth of the river. BT concentrations at the Strait of Johor were higher than those in Peninsular Malaysia and Melaka and were high at the narrowest locations with poor flushing of water. The concentrations of antifouling biocides were compared among Malaysia, Thailand, and Vietnam. A higher concentration and wide variations of TBT and TPT in sediment from Malaysia were observed among these countries. The Irgarol 1051 concentrations in sediment from Malaysia were higher than those in Thailand and Vietnam.

Monitoring the Organotin Contamination in the Taihu Lake of China by Bivalve Mussel Anodonta woodiana

As a part of the pilot study on “Freshwater Mussel Watch”, butyltin (monobutyltin, MBT; dibutyltin, DB; tributyltin, TBT), and phenyltins (monophenyltin, MPT; diphenyltin DPT; triphenyltin TPT) were analyzed in soft tissues of 15 bivalve mussels Anodonta woodiana sampled from five separate sites (Huzhou, Xueyan, Dapu, Sansandao, and Wulihu) around the Taihu Lake of China in 2004. The residue of total butyltins and total phenyltins in the all mussels ranged 142–1693 and 3.0–90xa0ngxa0Snxa0g−1 dry weight, respectively. Except for the mussels from Xueyan, DBT and MBT accounted more than 60% of total butyltins in those from other four sites. In contrast, TPT were usually almost 100% of the mussels studied. The present study provides most recent information about the organotin contamination in the Taihu Lake, and suggests Anodontaxa0woodiana can be used as a suitable bioindicator.

Concentrations of Organotin Compounds in the Stranded Killer Whales from Rausu, Hokkaido, Japan

We measured the concentrations of butyltin (BT) and phenyltin (PT) compounds in blubber, liver, lung, and muscle of seven stranded killer whales (Orcinus orca) collected from Rausu, Hokkaido, Japan. BTs in blubber (nxa0=xa06), liver (nxa0=xa04), lung (nxa0=xa01), and muscle (nxa0=xa04) of adult whale were in the range of 37–90, 385–676, 15, and 26–53xa0μg kg−1xa0wet weight, respectively. Concentrations of PTs in blubber, liver, lung, and muscle were <1 to 58, <1 to 14, 7 and <1 to 4xa0μg kg−1xa0wet weight, respectively. Detected frequencies of PTs were low in all tissues. Higher percentages of monobutyltin (MBT) in blubber, lung, and muscle were observed, while the percentage of dibutyltin (DBT) was high in liver. Detected frequencies of triphenyltin (TPT) were highest among tissues. Total BT concentrations in blubber and liver of a whale calf were lower than those in adult whales. MBT and DBT in the liver of the calf were the same (42%). MBT in blubber was the dominant compound among BTs.

Measurement of swimming speed in sperm whales

Cetaceans spend their entire life in the water. Hence these animals represent important models for studying adaptations for aquatic environment. Although many scientists have been interested in how fast they can swim, accurate swimming speed measurements of free-ranging cetaceans are rare because it is difficult to observe them continuously. In particular, little is known about routine swimming speed of deep diver, such as sperm whales. To measure swimming speed of the sperm whales, we attached two-type suction-cup-attached tags including a data logger to sperm whales. One type was similar to that employed in several other studies (Type A). The other type was modified by us to get more precious velocity data (Type B). We attached the two-type tag to a total of 11 sperm whales (8 Type A and 3 Type B) and, obtained accurate swimming speed with 8 whales of them (5 Type A and 3 Type B). A total of 136 hours of accurate swimming speed data including 137 dives was obtained. Average velocity during the dive was 1.77 plusmn 0.39 m s-1 (n =137). Maximum velocity of each whale was 4.2-9.6 m s-1 (n = 8). In addition, we found the oscillations caused by the tail beat in the time-series velocity data, which was obtained by modified suction-cup-attached tags (Type B). The modified tags provide us routine and maximum swimming speed of the whales as well as the information of the tail beat.

Metabolism of tributyltin and triphenyltin by Dall's porpoise hepatic microsomes.

The in vitro metabolism of tributyltin (TBT) and triphenyltin (TPT) by the hepatic microsomal cytochrome P-450 system enzymes of Dalls porpoises (Phocoenoides dalli) was comparatively elucidated with those enzymes of the Sprague Dawley rat in the present study. Our results suggested firstly a limited metabolic capacity for TBT and especially TPT to their metabolites in the Dalls porpoises, and documented a similar mechanism of a relatively stronger metabolic rate of TBT to its metabolites than that of TPT in the microsome of porpoises and rat. However, the metabolic capacity to degrade both TBT and TPT were much lower in the microsome of porpoises than that in the rats.

Baikal Seal: Pusa sibirica

Summary The Baikal seal, endemic to Lake Baikal, was derived from a ringed seal ancestor in the Arctic Ocean approximately 400 thousand years ago, as opposed to being a Paratethys relict. Males and females of this small, true seal species look very similar, but adult males are slightly larger than adult females. They are one of a few freshwater pinniped species. Baikal seals have been hunted for thousands of years and remain an important local resource. Recent viral outbreaks are a concern, but the population is thought to be at the lake’s carrying capacity and numbers over 100,000.