3.1 Assessing the risk of cyanobacterial proliferation and the system’s performance in controlling this risk

Please mark the fields you consider most appropriate for the water-body you are assessing. Then enter the reasons for your assessment and enter an estimate of the uncertainty of your assessment.

Were any of the following indications of cyanotoxin occurrence observed? Example for filling in this table

For this assessment, supporting expertise is recommended in the areas of public health, toxicology, and limnology, particularly phytoplankton.

	N	O	F	?	Your assessment of the situation	Description of the uncertainty of your assessment
Humans / animals: Illness indicating the presence of cyanotoxins? Link to background information
Cyanotoxins observed at > 1 µg/L, particularly microcystins? Link to cyanotoxin overview
Cyanobacteria – visual inspection: Visible blooms or discolouration; conspicuous olive-green or wine-red blooms? Don’t confuse with Lemna minor ("duckweed") Secchi disc readings or turbidity that indicate cyanobacterial proliferation?
Cyanobacteria in quantities > 1 mm³/L Biovolume detected by microscopy, or > 1 µg/l Chlorophyll-a, largely caused by cyanobacteria Link to an introduction to determining Microcystis spp., Planktothrix agardhii and P. rubescens, Aphanizomenon flos-aquae

N = not observed

O = observed occasionally

F = observed frequently

?= no information

Are cyanobacteria to be expected from water-body characteristics? Example for filling in this table

For this assessment, supporting expertise is strongly recommended in limnology particularly with a focus on phytoplankton ecology.

Note: the categories suggested here provide very rough first estimates, and entries performed without such expertise are subject to major uncertainty.

		N	P	Y	?	Your assessment of the situation	Description of the uncertainty of your assessment
Overall condition of the water-body	Is it eutrophic; deep with stable thermal stratification or shallow and usually mixed; not acidic; water retention time > 1 month ?
Current situation	· Is the water temperature high,? · If the water-body stratifies in summer, is it stably stratified now? · Are TP-concentrations > 10-30 µg/L ? · Is Secchi Disc transparency < 1 m ?

N = no, does not apply

P = applies partially

Y = yes, applies

? = no information

Are current and future nutrient loads under sufficient control in order to meet the target level for this water-body?

For this assessment, supporting expertise is needed in the areas of limnology or geoecology, particularly with a focus on estimating or modelling nutrient budgets in water-bodies. Without such expertise, entries are subject to major uncertainty.

	W	P	N	?	Your assessment of the situation	Uncertainty of this assessment
Assessment through site inspection					Example Dam Y
Assessment through modelling loads					Example Reservoir Z

W = well under control
P = partially under control
N = not sufficiently controlled
? = no information

On to è Evaluation of your assessment