Impact of pulp and paper mill effluent on egg hatchability of pike (Esox lucius L.)
Toxicants affect reproduction often at concentrations well below lethal levels. Also, the acidification of fresh waters has been shown to cause extinction of teleost fish populations usually through a failure of recruitment from younger generations. Both field and laboratory studies have documented that the greatest susceptibility to low pH occurs in the early developmental stages (e.g. Lee et al. 1983; Peterson 1984). Also low concetrations of metals (Horning & Neisel 1979; Ozoh 1979, 1980) and environmental accumulation of xenobiotics (Ozoh 1979; yon Westerhagen et al. 1981) diminish egg hatchability. In numerous toxicological studies egg hatchability has been a more sensitive indicator of toxic action than the other parameters studied (e.g. Henderson et al. 1981; DeGraeve et al. 1982; Lewis & Wee 1983). However, only relatively recently have the effects of bleached kraft pulp mill effluent (BKME) on fish reproduction (zebrafish Branchydanio rerio) been studied (Viktor et al. 1980; Viktor 1982) and no recipient species have been used.
Effects of reversible incubations of zebrafish eggs in copper and lead ions with or without shell membranes
The purpose of this paper is to demonstrate that reversible incubations of Brachydanio rerio eggs with or without their shell membranes did not affect the malformation due to copper ions. Inhibitory tendencies of both copper and lead to hatchings of zebrafish were not affected. Rather new defects on the yolks and the integuments which sustend the hearts were detected. Dechorionated embryos reversed from copper to lead ions survived the 24-hours' exposure but those from lead to copper did not. Copper appears to confer some tolerance to lead, while the shell membranes appear to provide some protective action against the toxicity of copper.
An Internet-based Real-time Heavy Rainfall Display System
A new storm warning system, which can be accessed through the Internet and by cellular phones is described. At the time of a heavy rainfall for disaster prevention, it is important that every resident understand how heavy is that rainfall. A real-time heavy rainfall display system designed for all of Japan provides such information (http://www.disaster-i.net/rain/). In that system values for 1-hour precipitation, 24-hour accumulated precipitation, etc. are displayed at every observatory. Advantages are that not only the latest observations but differences from the historical highest records can be seen. Almost all information is displayed by characters so that users have easy access to the system even when the communication network is crowded. Access date for the six months after the system opened shows that the average daily number of accesses of the top page was 306, and the largest number 3078. The maximum number for daily access to all the pages was about 21,500. This is about 2% of the number obtained on the same day for a similar system operated by the Ministry of Land, Infrastructure and Transport (http://www.river.go.jp/).