Results 



TDECF: The results of the analysis for As, Se, B and Mo are shown in figures 6.4 and 

 6.5. Arsenic is clearly very reactive (indicated by values less than the limit of quantitation) 

 especially at Barbizon and Peck ponds. Selenium (not detected at Barbizon pond) is slightly less 

 than predicted at Peck pond. The peculiar comparison that is portrayed at Pryse pond probably 

 arises from physical fluxes of Se rather than chemical fluxes. Boron is generally non-reactive 

 and is predicted fairly well by the TDECF. The TDECF calculation also indicates that Mo is 

 reactive for the selected conditions. 



For the TDECF formula to be valid, one assumption that needs to be approximately true 

 is that the ratio of chloride to solute be the same at both instances of time (i.e., initial and final). 

 This has been verified with a maximum change in the ratio to be 69%. Since no change is 

 unreasonable to expect, that value of 69% is deemed acceptable given the objectives of the 

 calculation. 



MCECF: The calculations for Peck pond (figure 6.6) generally support the observations 

 of the TDECF results. However, molybdenum clearly shows non-reactive behaviour which 

 suggests that it tends to leave and return to the water column according to season. Further 

 calculations using fall dates as initial and final time points should be able to verify this. Finally, 

 the prediction of boron appears to be excellent. There is a high level of confidence in these results 

 because they correspond well with the results that were previously calculated for a single year 

 (Fall 1986 to Summer 1987). 



Conclusions 



The evapoconcentration factors may be used in predicting solute concentrations assuming 

 that the solute exhibits non-reactive behaviour. Deviations from the predicted trend may be 

 taken as indications of reactivity. The actual significance of the deviations depends on the data 

 set used in the calculations. 



Boron has been found to accumulate in the water column whereas selenium appears to 

 undergo a partial removal from the water column. Arsenic tends not to accumulate in the water 

 column while molybdenum undergoes a cycle of removal and restoration according to seasons. 



page 6.4 



