Portable, Accurate Toxicity Testing

Abstract

ABSTRACT Ever tightening environmental regulations, severe penalties for non-compliance, and expensive remediation costs have stimulated development of methods to detect and measure toxins. Most of these methods are bioassays that must be performed in the laboratory; none previously devised has been truly portable. The U.S. Army, through the Small Business Innovative Research program, has developed a hand-held, field deployable unit for testing toxicity of battlefield water supplies. This patented system employs the measurable quenching, in the presence of toxins, of the natural bioluminescence produced by the marine dinoflagellate algaPyrocystis lunula. The procedure's inventor used it for years to measure toxicity concentrations of chemical warfare agents - actually, their simulants, primarily in the form of pesticides and herbicides - plus assorted toxic reagents, waterbottom samples, drilling fluids, even blood. While the procedure is more precise, cheaper, and faster than most bioassays, until recently it was immobile. Now it is deployable in the field. The laboratory apparatus has been proven to be sensitive to toxins in concentrations as low as a few parts per billion, repeatable within a variation of 10% or less, and - unlike some other bioassays - effective in turbid or colored media. The laboratory apparatus and the hand-held tester have been calibrated with the EPA protocol that uses the shrimplike Mysidopsis bahia. The test organism tolerates transportation well, but must be rested a few hours at the test site for regeneration of its light producing powers. Development of a freeze-dried reagent, now under way, will make the portable tester even more convenient to use. Toxicity now can be measured confidently in soils, water columns, discharge points, and many other media in situ. Most significant to the oil industry is that drilling fluids can be monitored continuously on the rig. BACKGROUND A quick, precise, novel bioassay that uses the natural bioluminescence of the microscopic marine dinoflagellate Pyrocystis lunula was developed by a U.S. Navy scientist to detect and measure toxicity of, among other substances, chemical warfare agents. This work was conducted with CWA simulants, mostly in the form of commercial herbicides and pesticides. The inventor and associates disclosed the novel method to the scientific community in a 1985 report on the photometer used in the procedure (1) and in a 1986 paper on the detection of trichothecenes (2). The trichothecenes paper described a perfect qualitative correlation (Fig. 1) of the novel test with the Environmental Protection Agency protocol (3) that uses the tiny, shrimplike Mysidopsis bahia for testing drilling fluids toxicity. The novel method was announced to the petroleum industry as a development study in a 1990 Offshore Technology Conference paper (4). This work led to five Navy patents (5), to which a private environmental company has acquired exclusive marketing licenses under the government's technology transfer program..