Particle size distribution in ground biological samples.

Modern trace and retrospective analysis of Environmental Specimen Bank (ESB) samples require surplus material prepared and characterized as reference materials. Before the biological samples could be analyzed and stored for long periods at cryogenic temperatures, the materials have to be pre-crushed. As a second step, a milling and homogenization procedure has to follow. For this preparation, a grinding device is cooled with liquid nitrogen to a temperature of -190 degrees C. It is a significant condition for homogeneous samples that at least 90% of the particles should be smaller than 200 microns. In the German ESB the particle size distribution of the processed material is determined by means of a laser particle sizer. The decrease of particle sizes of deer liver and bream muscles after different grinding procedures as well as the consequences of ultrasonic treatment of the sample before particle size measurements have been investigated.

Eel-pout (Zoarces viviparus L.) as a marine bioindicator.

Several elements and metal species were analyzed in eel-pout or viviparous blenny (Zoarces viviparus). The analytical data demonstrate that fish muscle is a suitable bioindicator for mercury (Hg) and arsenic (As). About 90% of the total Hg content is present in the fish muscle in the form of methyl mercury. Due to higher concentration levels, the liver is more useful for monitoring Pb and TI. No biomagnification of some trace elements, such as Cd, Ni or Co, were observed in eel-pout. More information is necessary to decide about the use of eel-pout for long-time monitoring programs.