Studies have demonstrated that spring tide conditions mobilize pollutants, enhance flushing, and create condi- tions which increase bacteria levels in coastal waters.36
Note the presence of significant wildlife habitat, salt marshes, and other wetlands that drain to the shoreline area. Habitat areas may be designated by the Natural Resources Protection Act or the Maine Natural Areas Program.
Is the area used by waterfowl or pets?
Animal waste from beavers, deer, waterfowl, cats, dogs, horses, etc. can contaminate surface waters and beach sand (see Table 1). The contribution of animal sources to elevat- ed bacteria levels is not well known, and more studies are needed to further explore this relationship.8, 37, 45 However, fecal contamination of recreational and drinking water by non-human sources can lead to water-related illnesses.
Note the type and number of animal(s) present, and the presence of droppings. Note whether dogs are allowed to access the shoreline (are there signs prohibiting them?) and record the presence/absence of dog waste stations and trash receptacles. Many communities ban dogs on the beach or restrict access to certain hours or months of the year.46
Conducting the Sanitary Survey
Note any factors that attract (or could attract) waterfowl to the area. Feeding seagulls and ducks may cause them to become a nuisance and increase their vulnerability to predators. It can also lead to overcrowding, increased concentrations of droppings, poor nutrition, increased spread of disease, and disruption of natural waterfowl migration patterns. Trash can attract waterfowl and other animals.
Is groundwater discharging to the beach?
Ground and sur- face waters are connected, and contaminated groundwater can contribute bacteria to coastal waters. Nutrient- and bacteria-enriched groundwater in septic effluent-affected watersheds can lead to high bacte- ria levels and the “freshening” of water quality, especially during low tides.47 Compared to surface water, groundwa- ter is more difficult to see and monitor; however, seepages resulting from pressure relief of an outgoing tide some- times can be visible.
Note any groundwater seepages visible on the shoreline. An unusual amount of green algae, slime, or discolored sand (usually black or gray) around the seepage face can indicate an upgradient discharge of wastewater.48 Collect a water sample at the seepage for bacteria analysis.
Groundwater pollution can come from a variety of sources. For example, beach sand can release bacteria into groundwater that comes in contact with it. Groundwater can be contaminated by inland sources (e.g., malfunction- ing septic systems) and also can contain dissolved organic matter and nutrients that stimulate the growth of bacteria in coastal waters.49, 50
Nicholas R. de Sieyes, Stanford University