Verification of aquatic dilution factors for liquid effluents released from a nuclear power plant.

Dilution factors for liquid effluents released from the Fermi 2 Power Plant into Lake Erie were verified using updated liquid effluent release data, and currently available aquatic dispersion models. A near-field dilution factor of 5 currently used by Fermi 2 appears to be a reasonable assumption as supported by two models and site-specific data. Previously assumed dilution factors for shoreline points outside the near field are of the same order of magnitude as those calculated by this study. The dilution factor of 77, currently used by Fermi 2, at the Monroe water intake point is very conservative when compared with values calculated by this study. More accurate values could be generated by tracer studies as recommended by Regulatory Guide 1.113. Such studies can predict plume behavior and are more accurate than aquatic models. These new values would probably be less conservative than those currently in use, and their use would make it less likely that Fermi 2 will reach technical specification limits for liquid effluent dose.

A statistical analysis of the third UKEMS collaborative trial.

In the third UKEMS collaborative trial, nine laboratories optimized protocols for a variety of mammalian cell mutagenicity assays and used these protocols to test three reference mutagens. Data from the trial have been deposited with Mutagenesis under the scheme of the journal for a database of results of extensive mutagenicity testing programmes. A preliminary examination of the data using procedures advocated by the UKEMS guidelines on statistical evaluation of mutagenicity test data confirms that the assays are capable of giving clear, convincing data, in a form amenable to statistical analysis. The utility of the methods of analysis proposed by both the plate and fluctuation test statistical working groups was confirmed. In almost all cases variation between plates or trays from the same replicate treatment was little greater than Poisson or binomial, whereas variation between replicate treatments was substantially larger, confirming the recommendation of both groups for true independent replicates of each treatment. In six out of nine laboratories part of this variation between replicates was consistent for both viability and mutation, which might cause the guide-lines procedure for fluctuation test data to underestimate significance. In about half the cases examined, variation between experiments was significantly greater than variation between replicates within an experiment, which may create problems of interpretation. Supplementary tests, using the statistical package GLIM, suggested that although factors such as choice of expression time, level of S9, zero dose cloning efficiency or spontaneous mutation frequency might have an effect, they would not have been likely to interfere with detection of a mutagenic effect in the present data set.

A monoclonal antibody to (S)-abscisic acid: its characterisation and use in a radioimmunoassay for measuring abscisic acid in crude extracts of cereal and lupin leaves.

A monoclonal antibody produced to abscisic acid (ABA) has been characterised and the development of a radioimmunoassay (RIA) for ABA using the antibody is described. The antibody had a high selectivity for the free acid of (S)-cis, trans-ABA. Using the antibody, ABA could be assayed reliably in the RIA over a range from 100 to 4000 pg (0.4 to 15 pmol) ABA per assay vial. As methanol and acetone affected ABA-antibody binding, water was used to extract ABA from leaves. Water was as effective as aqueous methanol and acetone in extracting the ABA present. Crude aqueous extracts of wheat, maize and lupin leaves could be analysed without serious interference from other immunoreactive material. This was shown by measuring the distribution of immunoreactivity in crude extracts separated by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC), or by comparing the assay with physicochemical methods of analysis. Analysis of crude extracts by RIA and either, after TLC purification, by gas chromatography using an electron-capture detector or, after HPLC purification, by combined gas chromatography-mass spectrometry (GC-MS) gave very similar ABA concentrations in the initial leaf samples. However, RIA analysis of crude aqueous extracts of pea seeds resulted in considerable overestimation of the amount of ABA present. Determinations of ABA content by GC-MS and RIA were similar after pea seed extracts had been purified by HPLC. Although the RIA could not be used to analyse ABA in crude extracts of pea seeds, it is likely that crude extracts of leaves of several other species may be assayed successfully.