Enhanced chemiluminescence cannot predict the presence of Cryptosporidium parvum when applied to water-quality monitoring in an agricultural environment.

Adaptation of the enhanced chemiluminescent reaction (ECLOX test) to water-quality monitoring revealed that pollutants in industrial and domestic effluent and farmyard and dairy washings may suppress or completely inhibit enhanced chemiluminescent light emission. Inhibition or changes in the kinetics of light emission occur in the presence of a wide range of extraneous substances. Interaction of such substances with ECLOX reaction components or reaction intermediates can produce changes in light emission, allowing detection of a broad range of chemical pollutants. This work examined the suitability of the ECLOX test to differentiate between water quality at various points along a rural stream. In addition, the study was used to measure whether changes in water quality detected by the ECLOX test were consistent with measured levels of the protozoan parasite Cryptosporidium parvum. Seven locations along a stream and a farmyard drainage ditch were sampled on the basis of position, continuity of flow, permanence, and evidence of fecal contamination. The stream frequently contained C. parvum (75% of occasions tested), although according to the ECLOX test and other standard parameters (suspended solids and pH), it seemed relatively uncontaminated. The ECLOX test did, however, distinguish among a range of water qualities. The ECLOX test can be considered as a useful qualitative indicator of differing water qualities, but C. parvum can be present in water of any quality; therefore, ECLOX is not an appropriate method for detecting the presence of this parasite.