This study compared the relative sensitivity of five inexpensive, rapid toxicity tests to the sensitivity of five standard aquatic acute toxicity tests through literature review and testing. The rapid toxicity tests utilized organisms that require little culturing or handling prior to testing: a freshwater rotifer (Branchionus calyciflorus); brine shrimp (Artemia salina); lettuce (Lactuca sativa); and two microbial tests (Photobacterium phosphoreum–Microtoxr̀ test, and a mixture of bacterial species–the Polytoxr̀ test). Standard acute toxicity test species included water fleas (Daphnia magna and Ceriodaphnia dubia), green algae (Selenastrum capricornutum), fathead minnows (Pimephales promelas), and mysid shrimp (Mysidopsis bahia). Sensitivity comparisons between rapid and standard acute toxicity tests were based on LC50/EC50 data from 11 test chemicals. Individually, the lettuce and rotifer tests ranked most similar in sensitivity to the standard tests, while Microtox fell just outside the range of sensitivities represented by the group of standard acute toxicity tests. The brine shrimp and Polytox tests were one or more orders of magnitude different from the standard acute toxicity tests for most compounds. The lettuce, rotifer, and Microtox tests could be used as a battery for preliminary toxicity screening of chemicals. Further evaluation of complex “real‐world” environmental samples is recommended.

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Trichloroethylene (TCE) was found as a contaminant in the well supplying water to an aquatic testing laboratory. The groundwater was routinely screened by a commercial laboratory for volatile and semivolatile compounds, metals, herbicides, pesticides, and polychlorinated biphenyls using U.S. Environmental Protection Agency methods. Although TCE was the only reportable peak on the gas chromatograph, with average concentrations of 0.200 mg/l, other small peaks were also present, indicating the possibility that the contamination was not limited to TCE alone. A chronic 6-month carcinogenicity assay was conducted on-site in a biomonitoring trailer, using the Japanese medaka fish (Oryzias latipes) in an initiation-promotion protocol, with diethylnitrosamine (DEN) as the initiator and the TCE-contaminated groundwater as a promoter. Study results indicated no evidence of carcinogenic potential of the groundwater without initiation. There was, however, a tumor-promotional effect of the groundwater after DEN initiation. A follow-up laboratory study was conducted using reagent grade TCE added to carbon-filtered groundwater to simulate TCE concentrations comparable to those found in the contaminated groundwater. Study results indicated no promotional effects of TCE. These studies emphasize the necessity for on-site bioassays to assess potential environmental hazards. In this instance, chemical analysis of the groundwater identified TCE as the only reportable contaminant, but other compounds present below reportable limits were noted and may have had a synergistic effect on tumor promotion observed with the groundwater exposure. Laboratory toxicity testing of single compounds can produce toxicity data specific to that compound for that species but cannot take into account the possible toxic effects of mixtures of compounds.ImagesFigure 2

This study evaluated the use of Nothobranchius guentheri as a novel organism for rapid acute toxicity screening. A major advantage of the species is that there is no need to maintain a continuous culture to have organisms immediately available for testing. Rather, the embryos are viable under long-term storage conditions and can be hatched within a few hours. The tests require only 24 h with standard laboratory equipment. Sensitivity levels for 11 representative toxicants were comparable to those reported for five of the standard U.S. Environmental Protection Agency test species requiring continuous culture.

Two new anthracyclinone antitumor antibiotics, maggiemycin (6, NSC-D344012) and anhydromaggiemycin (8) have been isolated from a culture of an unspeciated Streptomyces (ATCC No. 39235). Bioautography against Bacillus subtilis was used for the preliminary detection of these anthracyclinones. Structures were proposed based on their UV-visible, IR, *H NMR,13C NMR spectra, electron impact (El) and high-resolution EI-MS and confirmed by partial synthesis and a direct correlation with e-rhodomycinone. Both the anthracyclinones are active against KB, P388 and L1210 murine tumor cell lines; however, anhydromaggiemycin was more active than maggiemycin. A number of related anthracyclinones have also been prepared and their biological activity has been determined. The structure-activity relationship of these new anthracyclinones is also discussed.