›› Imperial Beach Ocean Water Quality and Community Health

Key Health Messages

Swimming, surfing and playing in the surf zone

Eating fish caught at Imperial Beach Pier


Since 1971 Imperial Beach Community Clinic (dba Imperial Beach Health Center) has been helping residents of Imperial Beach stay healthy.  We are concerned with the health of each individual patient, but also, as a Federally Qualified Health Center, we are concerned with health issues that affect our whole community.

One persistent question about public health in Imperial Beach is the effect of ocean pollution on our swimmers, surfers and fishers. As a longstanding member of the Imperial Beach community we have heard many and conflicting statements about the health effects of ocean water quality at Imperial Beach and we have wondered what the truth of the situation is.

In 2007, Imperial Beach Health Center became especially concerned about ocean water quality and public health in Imperial Beach because we learned that:

In July 2008, Imperial Beach Health Center received a grant from the Networking for Community Health program of the Community Clinics Initiative, which is a joint project of the TIDES Foundation and the California Endowment. The program goals were to address community and environmental health issues and strengthen community partnerships. The three primary partners of this Networking for Community Health project were Imperial Beach Health Center, a community health center; Professor Rick Gersberg of the Graduate School of Public Health at San Diego State University who is a specialist in ocean water quality at Imperial Beach; and WiLDCOAST, a grassroots environmental organization located in Imperial Beach.

From 2008-2010 the project examined how the quality of our ocean water affects the people who swim, surf, fish and play at the beach here. Our objectives were to identify health risks, to treat and prevent ocean related illness, and to provide accurate information to ocean users and pier fishers so they can enjoy the ocean and its bounty safely, given the environmental factors that affect us.

To identify health risks to recreational ocean users we conducted a community survey, interviewing people at the beach or who were just coming out of the ocean. We wanted to identify the activities they do at the beach and surf zone, how often they are in the water, and if they believed they had become sick from being in the ocean. 

Our survey confirmed that people who go into the ocean when there are no beach advisories or closures and don’t put their face in the water appear to have a very low chance of becoming sick from IB ocean water. Those who go into the water year round, even when and where there are beach closures and advisories, and who put their face in the water by swimming or surfing, have the highest chance of experiencing illness from water contact. 

Until the source of the pollution is eliminated, the best way for the public to stay healthy and enjoy the ocean is to stay out of the water whenever and wherever there are beach advisories or closures. Imperial Beach has a proactive and effective system for warning recreational ocean users about unhealthy ocean water quality. It is important that the public is aware that when the beach is closed, the ocean water quality contains high levels of bacteria and viruses that are unhealthy for humans, or it may contain chemicals that are presumed to be unhealthy. When the beach is open the water quality meets the same standards as all other beaches in the county and is considered safe for recreation. It is important to note that some parts of the beach from the US-Mexico border to the north end of Imperial Beach may be closed while others are open.

Another project concern was the safety of eating fish caught at Imperial Beach Pier. Project volunteers surveyed people fishing at the pier and asked about what they caught, how much they ate, and if women and children also ate the fish they caught. We also wanted to know if fish caught at the pier were healthy to eat, and if so, for whom, and how much? We analyzed fish caught at the IB Pier for toxic heavy metals including mercury, chlorinated pesticides, and Polychlorinated biphenyls (PCBs) toxic substances previously used in many commercial applications.

Testing of sports fish from Imperial Beach Pier had not previously been done so there were no guidelines about the safety of consuming them. The fish that we tested had levels of toxins in the same range as fish sold in supermarkets, indicating that they are considered safe for most people to eat several times a week.  Women of childbearing years and small children should be especially cautious and follow US Food and Drug Administration recommended limits for consuming fish because mercury can harm a baby or child’s developing nervous system.  For most healthy people it appears to be safe to eat two meals a week of fish that are low in mercury.

Two public health problems presented themselves: a binational problem of pollution and a local problem of health behaviors. Eliminating the source of the pollution is the most effective way to eliminate the health threat. In pursuit of our mission to help improve the overall health status of residents of Imperial Beach and South San Diego, Imperial Beach Health Center supports WiLDCOAST and the efforts of many other individuals and organizations working to solve the problem of Tijuana River pollution reaching the ocean at Imperial Beach. We recognize that the problem will likely take many years or decades to resolve, and that in the mean time we have a role to play in safeguard public health by influencing IB residents and visitors to enjoy the ocean safely, given current environmental conditions.


Forces Behind the Issue

For decades, sewage from the city of Tijuana, Mexico has flowed into the Tijuana River and across the international border into the Tijuana Estuary and then out into the ocean just south of city of Imperial Beach, CA.  Such cross-border pollution is a result of the lack of a proper sewage infrastructure in the city of Tijuana, Mexico, and its inability to keep up with rapid population growth and industrialization. During rain events particularly, such sewage contamination moves north along the coast. As a result the beaches of Imperial Beach can be heavily impacted, so that water quality at these beaches is extremely poor after rains, or when the Tijuana River is flowing. Such pollution of the Tijuana River not only affects people in Mexico, but also adversely impacts ocean water quality for those living in the United States (particularly in Imperial Beach), where many people have regular contact with the ocean either through recreational uses such as swimming and surfing, or by eating fish caught in the area.

A recent study by SDSU public health professor Rick Gersberg showed that within 72 hours after rainfall, coastal waters near the U.S.-Mexico border almost always harbor harmful viruses, in addition to the bacteria that are usually measured to detect health threats.  Gersberg et al. (2006) detected both hepatitis A virus (HAV) and a variety of enteroviruses that can cause human disease. At the Tijuana River mouth, HAV was detected 86 percent of the time, and enteroviruses were found in 100 percent of the samples, while at Imperial Beach (near the pier), HAV and enteroviruses were detected 79 and 93 percent of the time, respectively during rain events.

Aside from sewage, contamination by chemicals has also worsened in recent years with intensive industrial development associated with the maquiladora (in-bond manufacturing and assembly plants) program in Mexico. Unfortunately, an industrial pretreatment program similar to one implemented in the U.S. has not been initiated in Mexico. Moreover, in Mexico there is no program equivalent to the U.S. EPA’s National Pollutant Discharge Elimination System (NPDES) permitting program, so the threat of contamination of the nearshore coastal waters to Imperial Beach by toxic industrial chemicals is particularly pronounced. Indeed, although discharges from the Tijuana River account for only a small percentage of total gauged runoff into the Southern California coastal ocean, it contains the highest concentrations of the toxic metals - cadmium, copper, nickel, lead, zinc, and the toxic organic compound PCB,  among the eight largest creeks and rivers in Southern California (SCCWRP, 1992). Moreover, it remains the single greatest source of lead loading to the coastal ocean of the Southern California region.  The shoreline pollution is a multidimensional problem impacting the health, economy and well-being of Imperial Beach and adjacent coastal communities.

Project Partners

Imperial Beach Health Center is a Federally Qualified Community Health Center that has been serving Imperial Beach and surrounding areas of southwest San Diego County for 37 years. Federally qualified health centers are community-based and patient-driven organizations that serve populations with limited access to health care. Imperial Beach Health Center serves primarily low-income, uninsured or underinsured, and limited English proficient patients.

Imperial Beach Health Center (IBHC) is located in and serves a high need community. IBHC provides comprehensive primary health care services as well as supportive services (education, translation and transportation, etc.) that promote access to health care; provides services available to all with fees adjusted based on ability to pay; and meets other federal performance and accountability requirements regarding administrative, clinical, and financial operation.

Professor Rick Gersberg, Division of Occupational & Environmental Health of the Graduate School of Public Health at San Diego State University, has been studying the Tijuana River Estuary and sewage pollution since 1990. In 2002-2003 Dr. Gersberg was the principal investigator of a human health risk assessment for enteroviruses and Hepatitis A virus in runoff from the Tijuana River and in bathing waters of nearby Imperial Beach.

 Dr. Gersberg has extensive knowledge about human health risks in waters off Imperial Beach, and the resources and knowledge to develop research-based evidence. This research–based evidence will be used to inform the public and influence health policy about the ocean waters near Imperial Beach. If public health policy can be influenced to improve public health in Imperial Beach, the precedent may be used to promote positive policy changes for environmental health at other beach locations nearby.

WiLDCOAST is an Imperial Beach based non-profit organization addressing environmental health threats posed by Tijuana River pollution. With support from the California Endowment, Alliance Healthcare Foundation and The California Wellness Foundation, WiLDCOAST has made significant progress in documenting the health risks to area ocean users, carrying out environmental health education, and building the capacity of community leaders to advocate for clean water solutions.

WiLDCOAST has an active volunteer base in Imperial Beach, experience conducting media campaigns, has political strength, and an extensive and practical understanding of our local ocean water quality, ocean water users, and community dynamics surrounding ocean water policies.


Imperial Beach Ocean
Water Quality

Imperial Beach ocean water is recognized as safe for swimming and surfing when the weather is dry and the beach is open.

However, if beach closure or beach advisory signs are posted, stay out of the water and keep yourself safe. In the rainy season when the Tijuana River is flowing, it affects ocean water quality. Ocean water affected by the Tijuana River outflow is not considered safe for swimming or surfing because of bacterial, viral, and chemical contamination. The most heavily affected area is the ocean shoreline from the U.S. / Mexico border to the north end of the Tijuana Sloughs (the south end of Seacoast Drive).

Beach closure signs are posted when the water is contaminated, and the signs are removed when the water meets county guidelines.

For the CURRENT STATUS on coastal water closures or advisories in San Diego County, call (619) 338-2073.

Water Quality and the Science of Beach Closures (Imperial Beach Patch, December 13, 2010)


Ocean related illness

If you think you have been getting sick from ocean use at Imperial Beach, please make an appointment with a medical provider at Imperial Beach Health Center. Call (619) 429-3733 for an appointment. Let your doctor know you have recently been in the ocean.

For uninsured individuals a sliding fee scale based on income and family size will determine the cost of the visit. Most low-income individuals qualify for a visit with a fee of $30 that is paid at the time of the visit.