Marine water quality criteria for metals are largely driven by the extremely sensitive embryo-larval toxicity of Mytilus sp. Here we assess the toxicity of four dissolved metals (Cu, Zn, Ni, Cd) in the mussel Mytilus trossolus, at various salinity levels while also examining the modifying effects of dissolved organic carbon (DOC) on metal toxicity. In 48 h embryo development tests in natural seawater, measured EC50 values were 6.9-9.6 microg L(-1) (95% C.I.=5.5-10.8 microg L(-1)) for Cu, 99 microg L(-1) (86-101) for Zn, 150 microg L(-1) (73-156) for Ni, and 502 microg L(-1) (364-847) for Cd. A salinity threshold of >20 ppt (approximately 60% full strength seawater) was required for normal control development. Salinity in the 60-100% range did not alter Cu toxicity. Experimental addition of dissolved organic carbon (DOC) from three sources reduced Cu toxicity; for example the EC50 of embryos developing in seawater with 20 mg C L(-1) was 39 microg Cu L(-1) (35.2-47.2) a 4-fold increase in Cu EC50. The protective effects of DOC were influenced by their distinct physicochemical properties. Protection appears to be related to higher fulvic acid and lower humic acid content as operationally defined by fluorescence spectroscopy. The fact that DOC from freshwater sources provides protection against Cu toxicity in seawater suggests that extrapolation from freshwater toxicity testing may be possible for saltwater criteria development, including development of a saltwater Biotic Ligand Model for prediction of Cu toxicity.

Toxicity of dissolved Cu, Zn, Ni and Cd to developing embryos of the blue mussel (Mytilus trossolus) and the protective effect of dissolved organic carbon.

Methods for determining microcystins (peptide hepatotoxins) and microcystin-producing cyanobacteria.

Liquid chromatography-electrospray ionisation-mass spectrometry based method for the simultaneous determination of algal and cyanobacterial toxins in phytoplankton from marine waters and lakes followed by tentative structural elucidation of microcystins.

Copper, an essential element, is toxic at elevated concentrations, and as a result of anthropogenic activities is becoming increasingly prevalent in marine environments. In this study, we examined the effects of copper on early life stages of the blue mussel, Mytilus trossulus. We assessed the impacts of increasing copper concentrations on embryo development, egg viability, sperm fertilization capacity and, in particular, on sperm swimming speed using computer-assisted sperm analysis. Sensitivity to copper followed the pattern: embryos > sperm > eggs. A dramatic increase in abnormal embryo development was observed following exposure to copper concentrations exceeding 10 microg/L. Sperm swimming speeds decreased significantly when exposed to 100 microg/L of copper, but lower doses did not influence sperm swimming speed. Copper exposure (at any tested concentration) did not affect sperm flagellum length, or alter egg viability. Based on our results, we suggest that exposure of sperm to copper may interfere with mitochondrial activity, which reduces sperm swimming speed during the extended duration of sperm motility in blue mussel.

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The relative sensitivity of sperm, eggs and embryos to copper in the blue mussel (Mytilus trossulus).

Groundwater may contain high concentrations of fluoride. In most countries, however, information on the fluoride content is scarce and anecdotal. The aim of the present study was to make a comprehensive assessment of F- in the groundwater of a representative area of Norway, thereby establishing a more solid basis for appropriate health counseling. Relevant technical information was collected, together with water samples from 1063 underground water sources in 31 municipalities in the county of Hordaland. One thousand and two water samples were analyzed for F- and pH with an F(-)-selective electrode and a pH electrode, respectively. Mean F- was 0.30 mg/l (range, or = 0.50 mg/l. In three municipalities well water had a mean F- concentration > 0.07 mg/l; in one instance the mean was as high as 1.45 mg/l. In 10 municipalities maximum F- values were > 1.50 mg/l. F- values showed a positive correlation with the pH of the water and the depth of the wells (P < 0.01) and a negative correlation with the age of the well (P < 0.05). The results indicated that low-capacity wells deliver water with a higher F- value than high-capacity wells. This trend, however, was not statistically significant. The results show that high-F groundwater is prevalent and emphasize that information on domestic water supply must be available before supplementary fluoride is prescribed for caries prophylactic purpose.

Variability in fluoride content of subsurface water reservoirs.

A simple and rapid coprecipitation method for the determination of several trace metals in seawater is presented. These metals are coprecipitated with lanthanum hydroxide, the precipitate is dissolved, and then the metals are determined by atomic absorption spectrometry. Lanthanum hydroxide was chosen as a coprecipitant for the following reasons, (a) lanthanum hydroxide has a sufficiently low solubility and forms an easily filterable flocculate at about 80‡C, and (b) lanthanum has an absorption wavelength that is sufficiently separated from those of the other elements to be analysed, i.e., Mn, Fe, Ni, Cu and Zn. Experimental results show that these metals are coprecipitated by the present method with excellent recoveries.

The determination of Mn, Fe, Ni, Cu and Zn in seawater by atomic absorption spectrometry after coprecipitation with lanthanum hydroxide

Purification of microcystins by DEAE and C18 cartridge chromatography

The determination of dissolved Mn in sea water was carried out using a Chelex 100 resin and graphite furnace atomic absorption spectrophotometer. The nearshore surface layer waters off the Straits of Kii had the highest Mn concentration of 6.40 n mol kg−1 at these stations. Mn concentration of intermediate and deep water off the Straits of Kii ranged between 0.18 and 1.42 n mol kg−1. Mn concentration in deep and bottom waters at the Mariana Trough were between 0.71 and 2.48 n mol kg−1. Sharp increases of Mn concentration near the bottoms were observed at two stations near the hydrothermal vents of the central ridge of the Mariana Trough.

Behavior of Mn in the western north pacific

Sea water samples, still hot from volcanic emanations were taken in a bay of Nishinoshima-Shinto Island just after volcanic activity had ceased and were analysed for borate-B, fluoride-F and bromide-Br. The hot water is considered to be formed by the conservative mixing of volcanic emanations with sea water, and the emanations containedCl, B, F andBr in the ratio of 1∶1.84×10−3∶0.474×10−3∶6.47×10−3 by weight.

Chemical modification of sea water by submarine volcanism at Nishinoshima-Shintô Island

海水中の浮遊懸濁物を三保半島沖合, 相模湾とその南方海域および薩南海域の各地点において100l 以上の海水を表層から500m層まで採水してただちにHA形ミリポアフィルターでロ過して採取した。この浮遊懸濁物中のモリブデンを定量してつぎの結果を得た。浮遊懸濁物の重量は陸岸に近い海域で300～1000mg/100l にも達するが, 外洋ではこの約1/2を示し, モリブデン含有量は0.5～4.0μgであった。表層から底層に浮遊懸濁物が沈降し分解する過程で, モリブデンがケイ酸鹿, リン酸塩および硝酸塩とともに水中に溶出したとしても, その値は0.01～0.04μg/l で海水中のモリブデン含有量に変化を与えるとは考えられない。ロ過しない海水とロ過した海水のモリブデン含有量の差は定量誤差範囲内で浮遊懸濁物の影響はみられなかった。この懸濁物の構成成分はモリブデン含有量から考えても大部分は植物プランクトンであろうと推定した。

Yoshimasa Toyota

Papers

The determination of Mn, Fe, Ni, Cu and Zn in seawater by atomic absorption spectrometry after coprecipitation with lanthanum hydroxide

Purification of microcystins by DEAE and C18 cartridge chromatography

Behavior of Mn in the western north pacific

Chemical modification of sea water by submarine volcanism at Nishinoshima-Shintô Island

Molybdenum Contents in Suspended Matters in the Sea Water