Week 4a- Water

1.15. Marine Systems

We have discussed freshwater systems in lots of details in the previous pages but many of the water quality assessment tools are not as relevant for the marine environment.  For activities affecting the marine environment, you would need to obtain and coastal and potentially a discharge permit.  In terms of testing for baseline quality, you may want to consider that many of the chemical tests used for freshwater e.g for BOD/COD and nutrients are less helpful in the marine environment (in part because the dilution is so high that the BOD/COD levels will be very low and because phosphorus is not a limiting nutrient in the oceans for excessive plant growth (nitrogen and iron).

For marine regions, consider:

• Sediment Contaminant Assessment (using ANZECC standards or Auckland council guidelines)- if you are disturbing the bottom. This will look at substances like heavy metals and petroleum based hydrocarbons.
• Marine ecological survey (to determine the presence of any species (flora or fauna)which are vulnerable/rare etc and to establish bio-diversity).
• Specific chemical testing if required from known contaminant and from a single point source (e.g one discharge into the coastal region).  It is really hard to get valuable data from multiple discharges once mixed with the seawater as dilution occurs so quickly.  For example, this could be a leak from a chemical cleaning tank into the ocean which discharges a cleaning product which may be detected. As hazardous substances must be considered in an AEE – this may be appropriate depending on the project.