High Population Density Pollutes Beaches (Sometimes)

Published on July 20th, 2017

Around the world, one of the typical consequences of high human population density in coastal zones is polluted beaches, or to be more precise, polluted water at those beaches.

This water pollution puts swimmers and surfers at risk of catching stomach flu, ear infections, upper respiratory infections, rashes – and even more serious infectious diseases such as dysentery, typhoid fever, cholera, and hepatitis A – from exposure to pathogens that tend be associated with high fecal coliform counts. Fecal coliform bacteria are found in the guts and feces of humans, mammals and birds.   
Many of California’s most popular and iconic beaches face this threat. While the state’s many advanced wastewater treatment plants kill bacteria and pathogens as part of the treatment process (disinfection), during periods of high rainfall and runoff (such as the winter just passed), nonpoint sources of bacterial contamination can cause beach water quality to plummet…and bacterial contaminants to peak.     
This is the conclusion of the 2016-2017 Beach Report Card, released annually by the Santa Monica-based group Heal the Bay. According to the report, released in June, bacterial pollution spiked dramatically at many of California’s most heavily visited beaches during the winter of 2016-2017. 


Analysts from Heal the Bay rated more than 400 beaches along the California coastline during the 2016-2017 reporting year, assigning letter grades ranging from A to F based on levels of bacterial contamination. While 96 percent of beaches were awarded A or B grades during the busy summer season (April-October), wetter winter months were a different story altogether.
Responding to the many storms that barreled into California this past winter, huge volumes of polluted runoff poured off impervious streets and sidewalks and funneled into storm drains, which discharged the polluted waters into the near-shore ocean. As a result, almost half (48 percent) of California’s beaches were graded from C to F, about 12 percent higher than the five-year statewide average. Physical contact with water graded C or worse substantially increases the risk of contracting infectious diseases.      
According to Heal the Bay, the 10 most polluted California beaches in 2016-2017 were evenly divided between Northern and Southern California:
Clam Beach County Park, McKinleyville (Humboldt County)
San Clemente Pier, San Clemente (Orange County)
Cowell Beach, West of Wharf, Santa Cruz (Santa Cruz County)
Lakeshore Park, Marina Lagoon, San Mateo (San Mateo County)
La Jolla Cove, La Jolla (San Diego County)
Santa Monica Pier, Santa Monica (Los Angeles County)
Capitola Beach, Capitola (Santa Cruz County)
Luffenholtz Beach, Trinidad (Humboldt County)
Mother’s Beach, Marina del Rey (Los Angeles County)
Monarch Beach, North of Salt Creek, Dana Point (Orange County)

In less densely populated parts of the state, such as Humboldt County in the north, bacterial pollution at beaches tends to occur as a result of too many poorly regulated and functioning septic systems. Areas like these do not even have centralized sewage collection and treatment systems. 
A 2006 study (“Regional Public Health Cost Estimates of Contaminated Coastal Waters: A Case Study of Gastroenteritis at Southern California Beaches”) in the technical journal Environmental Science and Technology found that, in Los Angeles and Orange counties alone, the public health cost of gastrointestinal illnesses caused by recreation in contaminated ocean waters was between $21 and $51 million annually.

crowds on a beach
La Jolla Cove in San Diego County, a new addition to the list
of the 10 most polluted California beaches.

American beaches attract nearly two billion visitors a year and contribute $90 billion annually to the tourism economy. Beaches and their water quality are not just an important ecological asset, they are an important economic asset as well. What can be done to protect them from this scourge?
Increasing California and American populations, and even faster rates of population growth near the coast, will undoubtedly place greater pressures on water quality, especially from burgeoning nonpoint sources of pollution. Nonpoint sources are those that, instead of being discharged from a specific pipe or outfall, are widely dispersed across impervious surfaces in ever more developed landscapes within rapidly growing watersheds. They include everything from dog poop and oil to grease, toxic chemicals, pesticide residues, salts, sediments and nutrients (from fertilizers).
In Southern California, Heal the Bay recommends developing new infrastructure to capture, cleanse and reuse the tens of billions of gallons of storm water that pour out of the region many winters. 
There are a number of physical measures that can and should be taken to protect our beaches. At the same time, over the long term, population stabilization will help to ease the ever-increasing pressures to which we subject our vulnerable beaches, water quality, and human health.    


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