The budget of dissolved trace metals in Lake Biwa, Japan

Abstract

A comprehensive study on the dynamics of dissolved elements (Mg, Al, Si, P, Ca, V, Cr, Mn, Fe, Ni, Zn, As, Sr, Y, W, and U) in Lake Biwa was carried out using a clean technique. Lake water samples (n ϭ 523) were collected from six stations in the North Basin and three stations in the South Basin. River water samples (n ϭ 178) were collected from 14 major rivers flowing into the North Basin. Rainwater samples (n ϭ 89) were collected at Otsu. The river water was enriched with Mn, Al, Fe, P, and Zn and the rainwater was enriched with Zn, Al, Fe, and Mn compared to North Basin water during winter mixing. The residence times of dissolved species were estimated on the basis of input through the rivers and rain. The residence times for Ca, Mg, and Sr were about 8 years, the same as that for water. Mn, Al, Fe, and Zn showed the shortest residence times (0.05-0.19 year). A budget calculation suggested that more than 60% of the input of dissolved Si, P, V, Cr, Mn, Fe, Ni, and Zn was scavenged and retained in the lake sediments and/or discharged as suspended particles.

Geochemical behavior of trace elements in Lake Biwa

“…D-Fe concentrations in river waters that flow into Lake Biwa are generally higher than those in Lake Biwa itself (Itasaka 1974;Mito et al 2004). In the stagnation period, these river waters flow into the epilimnion only.…”

“…Of course, the chemical aspects of the lake also have been discussed frequently. However, there are few reports on the geochemical behavior of trace elements (Haraguchi et al 1998;Mito et al 2002Mito et al , 2004Takaku et al 2003) compared to the many studies of major elements and nutrients (e.g., Fujinaga and Hori 1982;Horie 1984;Somiya 2000).…”

Dissolved and labile particulate Zr, Hf, Nb, Ta, Mo and W in the western North Pacific Ocean

“…Molybdenum sulfide is added to gasoline as a lubricant. Our group reported the concentrations of W in rain water collected in Otsu City, which is contiguous with Uji City (Mito et al, 2004). The W concentrations varied from 9.5 to 2.2 × 10 3 pmol kg -1 .…”

Apparent increase in Mn and As accumulation in the surface of sediments in Lake Biwa, Japan, from 1977 to 2009

“…Given the average composition of the dissolved trace elements in Lake Biwa provided by Mito et al (2004), it seems impossible that the large amounts of Mn and As were supplied from the overlying lake water. Their report suggested that river flow is the dominant source of Mn and As in the lake water, with an annual influx of Mn and As through the river and rainfall of 2.0 × 10 6 and 4.6 × 10 4 mol/yr, respectively (Table 3).…”