Impacts of Fukushima Nuclear Accident on Freshwater Environments

Preface
Contents
Chapter 1: Introduction: Overview of Research with Dynamics of Radiocesium in Freshwater Environment
	1.1 Introduction
	1.2 Migration Behavior of Radionuclides in Freshwater
		1.2.1 River Systems
		1.2.2 Lakes
	1.3 Effects of Radiocesium on Ecosystem
		1.3.1 Fishes
		1.3.2 Insects and Another Species
	1.4 Integrated Research on Fate of Radiocesium in a Lake and a River System
	References
Part I: Rivers and Lake Environment
	Chapter 2: Differences in Radiocesium Export in River Systems 1 and 5 Years After the Fukushima Daiichi Nuclear Power Plant Ac...
		2.1 Introduction
		2.2 Materials and Methods
			2.2.1 Sampling Location Characteristics
			2.2.2 Sampling
			2.2.3 Analysis
		2.3 Results and Discussion
			2.3.1 Spatial and Temporal Variations in the Radiocesium Concentration in River Water
			2.3.2 Existing Forms of Radiocesium in River Water
			2.3.3 Factors Controlling Radiocesium Transport
			2.3.4 Effects of Precipitation on Export of Radiocesium in River Systems
		2.4 Conclusion
		References
	Chapter 3: Spatial and Temporal Fluctuations of Nuclear Accident-Derived Tritium Concentrations in the River Waters of Eastern...
		3.1 Introduction
		3.2 Materials and Methods
			3.2.1 Sample Collection and Analysis
		3.3 Results and Discussion
			3.3.1 Concentrations of 3H in River Water
			3.3.2 River Water 3H Concentrations Under Base Flow Conditions and During Flood Events
			3.3.3 Concentrations of 3H and 137Cs Inventory in the Watershed Area
		3.4 Conclusions
		References
	Chapter 4: Spatial and Temporal Changes of 137Cs Concentrations in River Waters and Correlation with the Radiocesium Inventory...
		4.1 Introduction
		4.2 Data and Methods
		4.3 Results and Discussion
			4.3.1 137Cs Concentration in River Water and Its Relationship with the 137Cs Inventory
			4.3.2 Temporal Change in Normalized Dissolved 137Cs Concentration
		4.4 Summary
		References
	Chapter 5: Inflow/Outflow of Radiocesium in a Dam Lake and Its Accumulation in Sediments
		5.1 Introduction
		5.2 Materials and Methods
			5.2.1 Study Site
			5.2.2 Temporal Changes in 137Cs in Suspended Solids and Particulate 137Cs Budget
			5.2.3 137Cs in the Matsugabo Dam Lake Sediment
		5.3 Results and Discussion
			5.3.1 Dynamics of 137Cs in the Inflow and Discharge of the Matsugabo Dam Lake
				5.3.1.1 Changes in the 137Cs of Suspended Solids in Water
				5.3.1.2 Inflow-Outflow Balance of Particulate 137Cs
			5.3.2 Sedimentary 137Cs Dynamics
				5.3.2.1 Temporal Changes in Vertical 137Cs Distribution
				5.3.2.2 Vertical 137Cs Profile Characteristics Among the Sites
				5.3.2.3 137Cs Storage in the Lake
		References
	Chapter 6: Concentrations and Fluxes of Radiocesium Activity in Lake Chuzenji, Japan, During 2014-2016
		6.1 Introduction
		6.2 Study Area
		6.3 Methods
		6.4 Results and Discussion
			6.4.1 Environmental Monitoring at the Center of Lake Chuzenji
			6.4.2 Contamination in Lake Chuzenji and the Inflowing and Outflowing Rivers
			6.4.3 Inventory of Radiocesium in the Sediments of Lake Chuzenji and Other Mountain Lakes in Japan
			6.4.4 Fate of 137Cs Deposited in the Aquatic Ecosystem of Lake Chuzenji After the 2011 FDNPP Accident
			6.4.5 Flux of 137Cs in the Aquatic Ecosystem of Lake Chuzenji
			6.4.6 Contamination Levels of Lake Water, Bottom Sediment, and Plankton
			6.4.7 Distribution of 137Cs in the Biotic Components of the Aquatic Ecosystems
		6.5 Conclusions
		References
Part II: Ecosystem
	Chapter 7: Relationship Between Air Dose Rate and Radiocesium Concentrations in Mountain Stream Fish in Fukushima Prefecture
		7.1 Introduction
		7.2 Materials and Methods
			7.2.1 Relationship Between Air Dose Rate in the River Area and 137Cs Concentrations in Masu Salmon
				7.2.1.1 Study Area, Sampling, and Measurement
				7.2.1.2 Radiocesium Measurements in Fish and Sediment Samples
				7.2.1.3 Data analyses
			7.2.2 Relationship Between Mean Air Dose Rate in the Water Catchment Area and 137Cs Concentrations in the Fish in Mountain Str...
				7.2.2.1 Grouping of Branch Streams of the Abukuma River
				7.2.2.2 Sample Collection, Processing, and Radiocesium Measurement
				7.2.2.3 Calculating the Radiocesium Contamination Index for the Water Catchment Area in Mountain Streams
		7.3 Results
			7.3.1 Relationship Between Air Dose Rate in the River Area and 137Cs Concentrations in Masu Salmon
			7.3.2 Relationship Between Mean Air Dose Rate in the Water Catchment Area and 137Cs Concentrations in the Fish in Mountain Str...
		7.4 Discussion
			7.4.1 Relationship Between Air Dose Rate in the River Area and 137Cs Concentrations in Masu Salmon
			7.4.2 Relationship Between Mean Air Dose Rate in the Water Catchment Area and 137Cs Concentrations in the Fish in Mountain Str...
		7.5 Conclusion
		References
	Chapter 8: Annual Changes in 137Cs Concentrations in Freshwater Fishes
		8.1 Introduction
		8.2 Materials and Methods
			8.2.1 Study Location and Capture of Samples
			8.2.2 Treatment of Fish Samples
			8.2.3 Analysis of 137Cs Activity
			8.2.4 Effective Half-Life
			8.2.5 Statistical Analysis
		8.3 Results and Discussion
			8.3.1 Activity Concentrations of 137Cs in Freshwater Fishes
			8.3.2 Seasonal Change
			8.3.3 Long-Term Trends of 137Cs Concentrations
			8.3.4 Decline of 137Cs Activity Concentrations in Future
		8.4 Conclusion
		References
	Chapter 9: Source of Variation of 137Cs Concentrations in Brown Trout in Lake Chuzenji After the Fukushima Daiichi Nuclear Pow...
		9.1 Introduction
		9.2 Study Site (Lake Chuzenji)
		9.3 The Size Effect and Seasonal Pattern of Radiocesium Contaminations in Brown Trout
		9.4 Ontogenetic and Seasonal Feeding Pattern of Brown Trout
		References
	Chapter 10: Body Size Effect of Radiocesium Concentrations in Wakasagi (Hypomesus nipponensis)
		10.1 Introduction
		10.2 Materials and Methods
			10.2.1 Study Area
			10.2.2 Wakasagi Sampling and Weight Classification
			10.2.3 Wakasagi Age Estimation
			10.2.4 Pretreatment and Measurements of Radiocesium Concentrations in Wakasagi
			10.2.5 Relationship Between 137Cs Concentration and Wakasagi Body Weight
			10.2.6 Calculation of Teff for 137Cs in Wakasagi
		10.3 Results and Discussion
			10.3.1 Wakasagi Body Weight, Age, and Radiocesium Concentrations
			10.3.2 Teff of Wakasagi at Age 0+
		10.4 Conclusions
		References
	Chapter 11: Characteristics of 137Cs Concentration and Radioactivity Transfer in Large Aquatic Insect Species
		11.1 Introduction
		11.2 Life Cycle of S. marmorata and P. grandis
		11.3 Study Site and Sample Treatment
		11.4 The Radioactive Material Monitoring Surveys of the Water Environment by the Ministry of the Environment
		11.5 Definitions of Concentration Factors
		11.6 Result and Discussion
			11.6.1 Radioactivity of 134+137Cs of SPM and S. marmorata
			11.6.2 Radioactivity of 134+137Cs of P. grandis
			11.6.3 Concentration Factors of the 137Cs Concentrations for S. marmorata and P. grandis
		References
	Chapter 12: Relationships Between Stomach Contents and Radiocesium Contamination of Fish by Fukushima Radioactive Accident in ...
		12.1 Introduction
		12.2 Materials and Methods
		12.3 Results
		12.4 Discussion
		References
Part III: Case Studies at Different Watershed Environments
	Chapter 13: The Dynamics of Radiocesium in the Lake Onuma Ecosystem, Mt. Akagi
		13.1 Introduction
		13.2 Study Area (Lake Onuma)
		13.3 137Cs Concentration and Seasonal Variation in Lake Water
		13.4 137Cs Concentration in Inflow Water (Spring and River Water) in Lake Onuma
		13.5 Material Balance of 137Cs in Lake Onuma
			13.5.1 Amount of 137Cs in Lake Water
			13.5.2 Amount of Outflowing 137Cs
			13.5.3 Amount of Inflowing 137Cs
			13.5.4 Calculating the 137Cs Material Balance in Lake Onuma
		13.6 Variation in 137Cs Concentrations in Dominant Fish Species
		13.7 Variation in 137Cs Concentrations in Other Aquatic Organisms
		13.8 Concentration Factor (CF) of Aquatic Organisms
		13.9 Conclusions
		References
	Chapter 14: Radiocesium Transfer from Forest Catchment to Freshwater Fish Living in Mountain Streams Estimated from Environmen...
		14.1 Introduction
		14.2 Environmental Monitoring Data on Radiocesium Migration from the Forest to Fish via Rivers
			14.2.1 Forest Monitoring Data
			14.2.2 River Water and Freshwater Fish Monitoring Data
		14.3 Model
			14.3.1 Model Description
			14.3.2 Parameters
		14.4 Evaluation of Radiocesium Transport Pathways from Forest to Fish
		14.5 Conclusions
		References