Trace elements may also be directly involved in biological processes, either as limiting nutrients or potential toxins. Analytical techniques for the determination of picomolar levels of dissolved metals in seawater are developed. Detection limits in the low pM range are attained by these techniques. New techniques are continually under investigation in order to increase sensitivity, facilitate sample handling, or selectively analyse for various metal species. Methods that can be portable, to allow for ship-board determinations, are especially desirable for monitoring contamination at the time of sample collection.
Multielemental techniques are also highly desirable.