Artificial neural networks (ANN) are modelling tools that can be of great utility in studies of microbial water quality. The ability of ANNs to work with complex, inter-related multiparameter databases and provide superior predictive power in non-linear relationships suits their application to microbial water quality studies. To date ANNs have been successfully applied (a) for the prediction of peak microbial concentrations, (b) to sort land use associated faecal pollution sources and relative ages of runoff and (c) towards the selection and study of surrogate parameters. Predictions of peak microbial contamination or faecal pollution sources have been greater than 90% accurate. The importance of a subgroup of organisms that are isolated by the total coliform membrane filter test on m-Endo media in defining faecal sources was revealed through parameter selection exercises. The result is the definition of a new bacterial ratio that can be directly related to the age of faecal contamination in animal impacted runoff.

Objective: To determine whether Paducah Gaseous Diffusion Plant workers had mortality patterns that differed from the general US population and to investigate whether mortality patterns were associated with job title or workplace exposures. Methods: A retrospective occupational cohort mortality study was conducted on 6759 workers. Standardized mortality ratio analyses compared the cohort with the referent US population. Internal comparisons producing standardized rate ratios were conducted by job title, metal exposure, and cumulative internal and external radiation exposures. Results: Overall mortality and cancer rates were lower than the referent population, reflecting a strong healthy worker effect. Individual not significant standardized mortality ratios and standardized rate ratios were noted for cancers of the lymphatic and hematopoietic tissue. Conclusions: Although relatively low exposures to radiation and metals did not produce statistically significant health effects, no significant elevations for lymphatic and hematopoietic cancers were consistent with previous studies of nuclear workers.