Takaomi Arai

EMISSIONS AND ENVIRONMENTAL IMPLICATIONS OF MERCURY FROM ARTISANAL GOLD MINING IN NORTH SULAWESI, INDONESIA

In artisanal gold mining practiced in North Sulawesi Island, Indonesia, gold is separated from ore by the use of mercury, which forms an amalgam with gold. All related processes are undertaken with a low level of technical knowledge and skills, no regulation, and with disregard for the safety of human and environment health. The situation is generating serious potential health and environmental risks in the area. As part of an ongoing monitoring program, total mercury concentrations were examined in water, bottom sediment and fish samples from three main rivers in Talawaan Watershed, which receives drainage from gold mining practices. Monitoring began in May-June 2000, almost 2 years after artisanal gold mining had begun. At that time, the mercury concentration in the sediment was generally low, except in places close to the gold processing plants. In the present study, a more systematic sampling and analysis was conducted in May-June 2001. Bottom surface sediments, water, and fish samples were collected at 12 sites along the three main rivers in the watershed. In addition, one site outside the watershed was sampled to serve as a control. Sample collections were conducted in three phases in duplicate, with two-week intervals between each phase. The mercury concentration observed in this study indicated that an increase took place along the three main rivers in the watershed. Solutions to this problem must be formulated as soon as possible in order to avoid a major health, economic, and ecological disaster arising from the continuing discharge of Hg. The present study proposes that mercury dispersion occur downstream of the mining.

Occurrence of sea eels of Anguilla japonica along the Sanriku Coast of Japan

Abstract The age and migratory history of the Japanese eel, Anguilla japonica, collected along the Sanriku Coast of Japan, were examined using otolith microstructure and analysis of strontium (Sr) and calcium (Ca) concentrations. The mean Sr : Ca ratios from the elver mark to the otolith edge indicated that there were eels with several general categories of migratory history, including sea eels that never entered freshwater and others which had entered freshwater for brief periods but returned to the estuary or bay. This first evidence of the occurrence of sea eels in this northern area indicates that Japanese eels of the Sanriku Coast do not necessarily migrate into freshwater rivers.

An assessment of selected trace elements in intertidal surface sediments collected from the Peninsular Malaysia

Concentrations of 11 trace elements (V, Cr, Co, Ni, Cu, Zn, As, Ag, Cd, Pb, and U) were determined in the intertidal surface sediments of Peninsular Malaysia. The average trace element concentrations are ranked as follows: Zn>V>As>Cr>Pb>Cu>Ni>Co>U>g>Cd. Interim Sediment Quality Guidelines (ISQGs) employed in present study are the Australia and New Zealand joint guideline (ANZECC/ARMCANZ), and the Hong Kong authorities. From the pooled data, none of these trace elements have the average concentration above the ISQG-high values. However, As and Ag average concentrations were over the ISQG-low values. Some elements were found to have the average concentration above the ISQG-high and/or ISQG-low in certain locations, including Kampung Pasir Putih (JPP), Lumut Port (ALP), Kuala Perai (PKP), Port Dickson (NPD), and others. The lowest and highest concentrations in a specific sampling location and maritime area varied among the elements, variations that were greatly affected by natural and anthropogenic activities in a given area. For each trace element, there were various levels of concentration among the sampling locations and maritime areas. These patterns indicated pollutant sources of an element for each area perhaps derived from nearby areas and did not widely distributed to other locations. It is necessary for Malaysia to develop an ISQG for effective quick screening and evaluation of the coastal environment of Peninsular Malaysia.

Concentrations of booster biocides in sediment and clams from Vietnam

An analytical method for the simultaneous determination of five booster biocides (Sea-Nine 211, Dichlofluanid, Duiron, Irgarol 1051 and Pyrithiones) and degradation product of Irgarol 1051 (Ml) in sediment from Vietnam was developed by LC/MS-MS. The recovery rates and relative standard deviation of the booster biocides in the sediment were in the range of 71-108% and 1.5-12%, respectively, and the detection limits were in the range of 0.04-2 μg kg -1 dry. An analytical method for the simultaneous determination of three booster biocides (Sea-Nine 211, Duiron and Irgarol 1051) and Ml in clams was also developed by LC/MS-MS. The recovery rates and relative standard deviations of the booster biocides in the biological samples were in the range of 60-99% and 3.4 -6.8%, respectively, and the detection limits were in the range of 0.24-1.1 μg kg -1 . The booster biocides in sediment from the coastal area of northern and central Vietnam were measured using this analytical method. Sea-Nine 211, Dichlofluanid, Duiron, Irgarol 1051, Ml and Pyrithiones were detected in the range of 0.09-1.3 μg kg -1 dry, <0.10 13 μg kg -1 dry, 0.11-3.0 μg kg -1 dry, 0.05-4.0 μg kg -1 dry, <0.1 -0.43 μg kg -1 dry and < 2-420 μg kg -1 dry, respectively. The detection frequencies of Dichlofluanid, Ml and Pyrithiones were low. The species and levels of detected booster biocides varied between sampling stations. Irgarol 1051 and its degradation product Ml were not detected in clams.

Serological evidence of transmission of human influenza A and B viruses to Caspian seals (Phoca caspica)

Seroepidemiological surveillance of influenza in Caspian seals (Phoca caspica) was conducted. Antibodies to influenza A virus were detected in 54% (7/13), 57% (4/7), 40% (6/15) and 26% (11/42) of the serum samples collected in 1993, 1997, 1998 and 2000 by enzyme‐linked immunosorbent assay (ELISA). In an hemagglutination‐inhibition (HI) test using H1‐H15 reference influenza A viruses as antigens, more than half of the examined ELISA‐positive sera reacted with an H3N2 prototype strain A/Aichi/2/68. These sera were then examined by HI test with a series of naturally occurring antigenic variants of human H3N2 virus, and H3 viruses of swine, duck, and equine origin. The sera reacted strongly with the A/Bangkok/1/79 (H3N2) strain, which was prevalent in humans in 1979–1981. The present results indicate that human A/Bangkok/1/79‐like virus was transmitted to Caspian seals probably in the early 1980s, and was circulated in the population. Antibodies to influenza B virus were detected by ELISA in 14% (1/7) and 10% (4/42) serum samples collected from Caspian seals in 1997 and 2000, respectively. Our findings indicate that seal might be a reservoir of both influenza A and B viruses originated from humans.

Ecological Aspects of the Japanese Eel, Anguilla japonica, Collected from Coastal Areas of Japan

Abstract The ecological characteristics of 597 yellow and silver-stage Japanese eels, Anguilla japonica, were examined and compared among collection sites located at three different latitudes of Japan (Amakusa Islands, Mikawa Bay, and Sanriku Coast) to provide basic data on this unusual catadromous fish species. Eels were sexed and their total length, body weight, age, and growth rate based on otolith analysis was compared among sexes, stages, and collection sites. The overall sex ratio favored females (94%), but the sex ratio differed among the three locations. The frequency of females was highest in the coastal waters at Sanriku in the north (100%), next highest at Mikawa Bay in central Japan (95%), and lowest in the Amakusa Islands in the south (70%). Silver eel males ranged from 41.2–66.3 cm in length and 4–10 years in age, and silver eel females from 44.3–97.2 cm in length and 5–17 years in age. Female eels generally grew faster (8.7±2.2 cm/year) than males (6.4±2.6 cm/year), and the growth rate slowed in the older eels. The growth rate of A. japonica at all three sites was much faster than that of other temperate anguillid species (<4 cm/year), and their age at maturation was younger than that of other temperate species (~7 to >50 years), suggesting this species has important ecological differences from other similar species.

Migratory histories of three types of Cottus pollux (small-egg, middle-egg, and large-egg types) as revealed by otolith microchemistry

Abstract Migratory histories of three types of Cottus pollux, the small-egg type (SE type), middle-egg type (ME type), and large-egg type (LE type), were studied by examining strontium (Sr) and calcium (Ca) in their otoliths with wavelength dispersive X-ray spectrometry on an electron microprobe. The Sr : Ca ratios in the otoliths changed both with ontogenetic development and with salinity of the habitat. Otolith Sr : Ca ratios of LE-type samples and the ME-type samples from the Honmyo River, Kyushu Island, showed consistently low ratios, averaging 1.8 × 10−3 and 2.4 × 10−3 from the core to the edge, respectively. In contrast, otolith Sr : Ca ratios of SE-type samples and the other four ME-type samples from Hokkaido and Honshu Islands fluctuated strongly along the life history transects in accordance with migration patterns from freshwater to the sea and vice versa. The otolith Sr : Ca ratios of SE-type samples showed low ratios from the core to a point around 15 μm, averaging 1.5 × 10−3, and subsequently increased sharply with a high Sr : Ca ratio phase to a point around 400 μm, averaging 5.5 × 10−3, and followed again a low ratio phase to the edge with averages of 3.1 × 10−3. Similar fluctuation patterns in otolith Sr : Ca ratios were found for the four ME-type samples. These findings clearly demonstrated that otolith Sr : Ca ratios reflected the sculpins life histories, as being fluvial for the LE type and the Honmyo River ME type and amphidromous for the SE type and the other four populations of ME type.

Chronic effects of tributyltin on the caprellid amphipod Caprella danilevskii

In order to examine the biological effects by TBT exposure, experiments involving the exposure of five levels of TBT concentrations (0, 10, 100, 1000 and 10,000 ngl(-1)) were conducted on the caprellid amphipod Caprella danilevskii, over a generation after hatching. Marked delays in growth and molting during the early developmental stage and maturation were found in both 100 and 1000 ng TBTCl l(-1) concentrations in spite of the sex. All specimens died in 10,000 ng TBTCl l(-1) within 4 days after hatching. Inhibition of maturation and reproduction such as delaying in the achievement of maturity and a decrease in the number of juveniles hatched was apparent in 10 and 100 ng TBTCl l(-1) concentrations. Furthermore, brood loss, and failure in egg formation and hatching were observed as the TBT concentration became higher. No significant changes in sex ratio were seen at any of the TBT exposure levels during hatching and maturation in the present study. This phenomenon was different from a previous study in which the proportion of females was increased with an increase in TBT concentrations in the embryonic exposure experiment. This suggests that sex disturbance is induced during the embryonic stage of the species. A drastic decrease in survival rate was observed at 10 ng TBTCl l(-1) (25%) which corresponds to the mean level in coastal waters. Therefore, the present encountering ambient TBT concentration may influence populations of C. danilevskii in the coastal environment.

Evidence of downstream migration of Sakhalin taimen, Hucho perryi, as revealed by Sr:Ca ratios of otolith

The migratory history of Sakhalin taimen, Hucho perryi, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith by using wavelength dispersive X-ray spectrometry on an electron microprobe. Otolioth Sr : Ca ratios of freshwater-reared samples remained consistently at low levels throughout the otolith. The Sr : Ca ratios of samples from Lake Aynskoye of Sakhalin Island showed a low value from the core up to a point of 700–2140 µm. Thereafter, the ratios increased sharply and remained at higher levels up to the outermost regions. The difference in Sr : Ca ratio might be the result of the presence of individuals that underwent seawater and freshwater life history phases, probably reflecting the ambient salinity or the seawater–freshwater gradient in Sr concentration. Otolith Sr : Ca ratio analysis revealed downstream migration history in H. perryi.

Identifying sea-run brown trout, Salmo trutta, using Sr : Ca ratios of otolith

Abstract The migratory history of the brown trout, Salmo trutta, collected from Japanese rivers, was examined in terms of strontium (Sr) and calcium (Ca) uptake in the otolith, by means of wavelength dispersive X-ray spectrometry on an electron microprobe. Sea-run (anadromous) and freshwater-resident (nonanadromous) types of S. trutta were found to occur sympatrically. Otolith Sr concentration or Sr : Ca ratios of anadromous S. trutta fluctuated strongly along the life history transect in accordance with the migration (habitat) pattern from sea to freshwater. In contrast, the Sr concentration or the Sr : Ca ratios of nonanadromous fish remained at consistently low levels throughout the otolith. The higher ratios in anadromous S. trutta, in the otolith region from the core to 1500 μm, corresponded to the initial seagoing period, probably reflecting the ambient salinity or the seawater–freshwater gradient in Sr concentration. The findings clearly indicated that otolith Sr : Ca ratios reflected individual life histories, enabling the sea-run S. trutta to be distinguished from the freshwater-resident brown trout.