Republication or reproduction of this report or its storage and/or dissemination by electronic means is The determination of iodine species in environmental and biological samples (Technical Report)Abstract: Iodine is found in organic forms in plants and animals and in inorganic forms in natural water samples. Methods of identification and quantitative determination for iodine species are decided by the types of compound and the matrices in which they occur. Iodine is an essential element and specific radioimmunoassay methods have been devised for physiologically important compounds (thyroxine and related compounds) in which it is found. In addition, marine plants and animals have provided a rich source of varied and unexpected organic iodine compounds that occur, along with other organic halogen compounds, as secondary metabolites. Natural waters, particularly marine waters contain iodine chiefly in the forms of iodide and iodate. Organic iodine compounds in biological samples have been identified by classical natural products chemical techniques following their isolation, and by modem spectroscopic methods. Routine analysis of such compounds can be done by gas chromatography (GC) and high performance liquid chromatography (HPLC). Analysis of inorganic iodine species in waters is carried out by catalytic, electrochemical and spectrometric methods and by GC; possibly HPLC inductively coupled-mass spectrometry (ICP-MS) might be the method of choice in the future.

To understand the eutrophication phenomena in Lake Biwa, Japan, a research project for the water quality formation processes was executed. This paper presents phosphorus mass changes in water body in Lake Biwa from April 1995 to January 2000 and discusses the main factors of the change. Phosphorus mass ranged from 190 to 350 t, with an average of 260 t. DP mass in 1995, '97 and '98 showed seasonal change patterns, while non-periodical phenomena seemed to control the PP mass. Phosphorus mass was increased about 15 t in epilimnion from April to July while nitrogen showed a 50 t decrease. This disagreement suggests that some processes selectively accumulated phosphorus in epilimnion during this period. However, such an increase in phosphorus was not observed in 1996 and '99. Air temperature was lower and much snowfall was recorded in 1996 and '99, suggesting that coldness in winter season weakened the phosphorus accumulation process to depress the mass in epilimnion in summertime. Water temperature increase seemed to be delayed in proportion to total snowfall, but thermocline was formed independently of coldness. Hence, the idea was abandoned that the delay of thermocline formation encouraged the sedimentation process, and biological activities were considered to be the main factor controlling phosphorus mass in the epilimnion in Lake Biwa.