3.2 Evaluation of your assessment of the risk of cyanotoxin intake and breakthrough
and your system’s performance in controlling it

In assessing the risk of cyanobacterial proliferation your result was that this occurs or cannot be safely excluded. Subsequently you have assessed the performance of your further barriers – offtake strategy and treatment. Again, to evaluate this assessment, please check which colours you marked most frequently in the questionnaire.

Note: The outcome of this assessment supports you in positioning the human health risk from cyanotoxins in relation to other health risks from exposure to the same water in a matrix for relative ranking of health risks. This is a basis for setting priorities in controlling these risks.

• Option A:

You have always marked green fields: Your risk of cyanobacterial intake and/or cyanotoxin breakthrough is low, and you aim to maintain this good situation.

Therefore, the next important step is to identify the control measures in your system which currently are decisive for this level of safety and should have priority for maintenance and operational monitoring. For these, you should develop a management plan as key element of your Water Safety Plan which would particularly define the operational monitoring system to indicate the potential of break-through and thus provide an early warning.

è Continue with control measures for drinking-water offtake and/or control measures for drinking-water treatment.

• Option B:

You have frequently marked orange or red fields. Your risk of cyanobacteria being drawn into the offtake and/or cyanotoxin breakthrough is high:

1. Immediate action to establish early warning for cyanobacterial bloom situations is adequate. This should trigger the provision of water from an alternative supply while blooms last. Continue with early warning and contingency planning.
2. Rapid improvement of your offtake strategy (if possible) and/or your treatment chain is important for protecting public health from cyanotoxins in drinking-water.

Your Water Safety Plan will include a management plan for operational monitoring of those control measures already in place in your system. It will have a strong focus on upgrading the control measures that your assessment identified as necessary but currently insufficient, and/or for implementing new ones (i.e. investments).

è Continue with control measures for drinking-water offtake and/or control measures for drinking-water treatment.

• Option C:

You have frequently marked grey fields. Your assessment is uncertain due to lack of information, and a risk of cyanobacterial intake and cyanotoxin break-through cannot be safely excluded.

1. Until the information gaps are closed and longer-term solutions are established, consider establishing early warning for cyanobacterial bloom situations which would trigger the provision of water from an alternative supply while blooms last. Continue with early warning and contingency planning.
2. Assess whether decisions on implementing new control measures or upgrading ones can already be made on the basis of the information available, or whether this risks misguided investment, and the first priority should be to collect the missing information.
3. Improvement of your offtake strategy (if possible) and/or your treatment chain may nonetheless be immediately adequate for protecting public health from cyanotoxins in drinking-water.

Your Water Safety Plan will include a management plan for operational monitoring of those control measures already in place in your system. It will have a strong focus on closing information gaps as basis for making investiment decisions.

è Continue with control measures for drinking-water offtake and/or control measures for drinking-water treatment.

On to è documentation of your system and risk assessment

Back to è Assessing risks and the system’s performance in controlling them, part II

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