Section Page 



10 Gross photosynthesis in a water-body treated with diurone 



at the time of a blue-green algal bloom 106 



10 Tests on DDT content in storage tissues of fish 108 



10 Increase in sensitivity of biological tests on survival 



of aquatic organisms at 30 °C 109 



11 Analysis of well water values expressed in mg/1 115 



11 96-hour and threshold LC50 of hydrogen sulfide (mg/1) 



for brook trout, bluegill, fathead minnow and goldfish . . 116 



11 Chronic effect of sublethal concentrations of hydrogen 

 sulfide (mg/1) on trout, bluegill, fathead minnow and 

 goldfish 117 



11 Increment in weight and survival of bluegill started as 

 young-of-the-year and exposed to varied concentrations 

 of hydrogen sulfide for 826 days at O2 of 6.0 mg/1 iter 

 and mean temperature of 17.8-18.5 °C varied seasonally . . 118 



11 Weight and reproduction of adult bluegills exposed to 

 varied concentrations of hydrogen sulfide for 97 days 

 at 23.5-23.9 °C 118 



11 Growth of fathead minnow in 112-day exposure to hydrogen 

 sulfide at 23 °C, pH 7.7, 02 6.4-7.3 mg/liter - expressed 

 as mean weight in grams of three replications at the end 



of succeeding 28-day periods 119 



12 Symptoms of intoxication in carp exposed to the short- 

 term action of toxic substances 125 



12 Toxicity of some substances for medicine leech and their 

 threshold concentrations (mg/1) producing avoidance 



reaction 128 



13 Classification of asbestos 134 



15 Relative chlorophyll content of seston in clean and 



polluted parts of rivers 151 



