776 BRADT 



station 28 was 12.3°C (SD = 6.4), and the mean temperature at 

 station 2 was 13.2°C (SD = 5.0). 



Table 1 lists the means and standard deviations for the chemical 

 parameters. Variation in pH at the eight stations reflects the change 

 in the geological formations which the stream traverses: shale and 

 slate at stations 28, 23, and 21 and limestone at stations 13 through 

 2. Stations 13 and 12.5 are located at the beginning of the limestone 

 area. 



The total alkailinity increases downstream, especially at stations 

 10 and 2, and was correlated with the downstream station 2 

 (r = 0.72*). 



Conductivity also increased downstream, reflecting an increase in 

 the concentration of the ions of mineral salts. Conductivity was 

 correlated with pH (r = 0.41*), total alkalinity (r = 0.64*), and the 

 downstream station (r = 0.44*), reflecting the relationship between 

 the three parameters and the increase downstream. 



The concentration of nitrate in the stream increased downstreaim 

 and was correlated with alkalinity (r=0.43*), conductivity 

 (r = 0.36*), and the downstream station 2 (r = 0.39*). 



Orthophosphate increased slightly downstream. The mean level 

 at station 28 was 0.05 mg/liter, and the mean level at station 2 was 

 0.14 mg/liter. The highest mean levels of orthophosphate were 

 recorded at station 13 (x = 0.30 mg/liter), a tributary receiving 

 sewage effluent. Orthophosphate levels were correlated with pH 

 (r = 0.23*) and conductivity (r = 0.28*). 



An increase in chlorides was also observed as the stream 

 approached the mouth. Chloride levels were correlated with alkalin- 

 ity (r = 0.43*), conductivity (r = 0.42*), nitrate (r = 0.30*), and the 

 downstream station (r = 0.31*), reflecting the increase in all these 

 parameters toward the mouth. 



Total iron levels remained similar at stations 28 through 10 and 

 increased slightly at station 2. The higher levels at station 2 probably 

 reflect the entrance of iron-containing compounds from a mineral- 

 pigment manufacturer 2.4 km upstream of station 2. Total iron was 

 correlated with alkalinity (r = 0.25*), conductivity (r = 0.22*), and 

 the downstream station (r = 0.49*). 



Levels of calcium ailso increased downstream. The mean level at 

 station 28 was 35 mg/liter, at station 12.5, 68.6 mg/liter, and at 

 station 2, 118 mg/liter, reflecting the impact of the limestone areas. 



*P < 0.01, df = 241. 



