Synopsis: Sediments dredged from harbors are frequently deposited on nearby beaches, as was done during the recent dredging of the Morro Bay Harbor. Before any such operation can take place, sediments must be tested to ensure that contaminants are within safety limits. However, the legally-required sediment tests do not cover a wide range of chemicals referred to as "emerging contaminants."
In addition, hydrogen sulfide, a naturally-occurring chemical that can be emitted from dredged sediments, can be harmful if exposure is significant. Several Morro Bay residents reported that the dredged material on the beach had a strong chemical odor that burned their eyes, noses, and throats. Residents of Santa Cruz reported major health impacts after exposure to dredged sediments placed on Twin Lakes Beach. Weaknesses in testing protocols and the experiences of these beach goers raise questions regarding the safety of depositing dredged sediments on our beaches.
In November, 2009, The U.S. Army Corps of Engineers (USACE) started work on the largest dredging operation in the Morro Bay Harbor in nearly ten years. A large quantity of sediment pulled up by the suction dredge was subsequently deposited on Morro Strand State Beach north of Morro Rock. Several residents reported that the material had a strong chemical odor that burned their eyes, noses, and throats.
Responding to a Morro Bay resident's inquiry, a USACE spokesperson stated that, "The organics in the dredged sand at the beach placement area can have a strong odor, which is a complaint we hear a lot. But luckily this odor dissipates rather quickly." The spokesperson also noted that "people should be aware that the beach placement area is a construction area and should be avoided for personal safety purposes."
Man-made Chemical Contaminants Might be Found in Dredged Material
The matter was dropped by the concerned residents until December, 2010, when the Journal reported that nonlyphenols are contaminating the Bay and the ocean. In their story, " Nonylphenol is Polluting the Water in Morro Bay and other Coastal Areas," Carol Georgi and Karl Kempton described the findings of SLOSEA scientists. Noting that nonylphenol is "a man-made chemical in treated effluent released from septic and other sewage processing systems." Georgi and Kempton reported that SLOSEA scientists had found nonylphenols in "significant concentrations in water, sediments and tissue samples from the bay."
The SLOSEA findings raised further concerns in the minds of some of the residents exposed to the dredged sediments on the beach. The USACE had conducted extensive testing of sediments in the harbor before the dredging operation commenced. Why had their tests not detected the high concentrations of nonylphenols identified by SLOSEA's tests? The USACE's testing protocols and test results provided the answer. The tests did not cover nonlylphenols.
Nonylphenols are part of a group of chemicals referred to as "emerging contaminants," compounds that have suspected or insufficiently-defined carcinogenic or toxicological risks. As discussed in the January, 2011 SLO Coast Journal story, "How Does Your Garden Grow," 1,000-2,000 new chemicals are introduced into the environment each year. Standard government testing requirements and protocols are challenged by the sheer volume of new chemical compounds and often do not keep up with the emergence of new threats. Although the USACE's tests were in conformance with all legal requirements, they did not include a number of substances in the emerging contaminants category.
The U. S. Geological Survey (USGS), Toxic Substances Hydrology Program has published a list of emerging contaminants found in U.S. streams. Included are several groups of "household and industrial wastewater products." Of the 39 substances in that list, 10 were covered by the USACE's tests of the Morro Bay Harbor sediments. With regard to what was in the sediments deposited on the beach during the recent dredging operation, there are some unanswered questions in the minds of residents, who will never know what chemicals might have been in the material.
According to a SLOSEA scientist interviewed for this report, some chemicals will dissolve more easily in water than others, and are easier for the body to eliminate after exposure. These are referred to as "hydrophilic" substances. Other chemicals, referred as "lipophilic" do not dissolve easily in water, adhere to organic matter, and have a tendency to accumulate in sediments. Those chemicals, which include such toxins as DDT, are more difficult for the body to eliminate.
Lipophilic chemicals can, according to the scientist, break down in the presence of oxygen and sunlight. However, in an environment where there is little or no available oxygen (referred to as an "anaerobic environment"), lipophilic chemicals can persist for many years. Such chemicals may be found in Bay and ocean sediments.
Residents exposed to the "fumes" emanating from the dredged material on the beach have asked whether the seemingly-caustic odor might have been, at least in part, the result of a breakdown of chemicals – a breakdown triggered by the exposure to the plentiful oxygen available in the air, and to sunlight. According to, Handling and treatment of contaminated dredged material from ports and Inland Waterways , Volume I, published by the Permanent International Association of Navigation Congresses, "Removal of the dredged material can change the physical and chemical properties of the sediment, whereby the substances present in the sediment may become mobile or volatile (potentially dangerous for the dredging crew and the environment)" and, "The short term impact of suspended solids may include the migration of (contaminated) sediment from the dredging area to environmentally sensitive locations."
Some Specific Man-Made Chemical Contaminants of Concern
Like the USACE tests, the SLOSEA tests did not cover all of the emerging contaminants listed by the USGS, but the SLOSEA tests did include more of them. Emerging contaminants that were found in the goby fish tested by SLOSEA, but not covered by USACE sediment testing were:
- Nonylphenols: These chemicals are primarily used in the production of cleaning products such as detergents, but also in some pesticides. They are believed to affect the digestive system, eye, kidney, liver, reproductive system, skin, throat and the unborn child. They have been banned in European Union (EU) countries and are strictly monitored in many other countries such as Canada and Japan.
- Triclosan: This is an antimicrobial, a phenolic diphenol ether used as a preservative, an antibacterial, and an antifungal agent. It is found in numerous bar and liquid soaps and other personal care products as well as household products such as dishwashing soap. The Natural Resources Defense Council (NRDC) has asked the U.S. Food and Drug Administration to ban Triclosan, which breaks down into dioxins, and is a suspected endocrine disruptor. In animal tests, Triclosan was shown to interfere with male and female sex hormones, and with thyroid hormone. The Danish Environmental Protection Agency has reported that Triclosan bioaccumulates (builds up in higher concentrations over time) in fish, in factors thousands of times higher than those found in the surrounding water. According to a report by the Santa Clara Basin Watershed Management Initiative, "Environmental Emergence of Triclosan." Exposure to chlorine in wastewater treatment facilities can produce chlorinated Triclosan which, when exposed to sunlight, can break down into toxic dioxins, chemicals that readily accumulate in organisms. Dioxins are among the most toxic of chemicals, and are known carcinogens.
- Diazepam: This drug, first marketed under the name "valium," is used for treating a variety of medical problems including anxiety, seizures, and muscle spasms. A number of potentially-dangerous drug interactions have been documented, and experts have stated the drug is "contraindicated" for individuals with a variety of medical conditions, such as glaucoma and renal deficiencies, as well as for pregnant women and nursing mothers.
The above contaminants are believed to have entered the bay as components of wastewater. Potential sources include discharges from the Morro Bay/Cayucos wastewater treatment plant, the California Men's Colony wastewater treatment plant, leaking sewers in Morro Bay and Cayucos, and agricultural compost made from sewage sludge. As reported by the Journal in a June, 2010 article, "The Condition of Morro Bay Sewer Lines." "Local activists have alleged that the situation is serious, and that sewage leaking from the lines is contaminating ground water, City wells, and the Bay."
Two of the contaminants that SLOSEA researchers found in goby fish were also covered by the USACE tests. These are:
- DDT: This lipophilic contaminant is a pesticide found to have significant harmful effects on humans and wildlife. Most uses of DDT were banned in the United States in 1972, but it has remained in the environment in significant quantities. DDT is a known endocrine disruptor, and has been associated with the development of diabetes in some individuals. It is also believed to contribute to genotoxicity (damage to genetic material in cells).
- PCB's: These chemicals were once widely used in electrical components such as transformers and capacitors, and in a variety of other products such as adhesives, flame retardants, lubricating oils and sealants. PCB production was banned by the U.S. Congress in 1979. They are known endocrine disrupters and neurotoxins.
These chemicals are believed to have entered the Bay and the ocean from storm and agricultural runoff, and as components of wastewater.
Naturally-Occurring Hydrogen Sulfide Gas Produced by Dredged Material
In addition to man-made chemicals, the dredged material on the beach may have also been emitting hydrogen sulfide gas, a substance commonly produced by the breakdown of organic matter. According to a Port of Seattle document prepared by Windward Environmental and Anchor Environmental, "Hydrogen sulfide is a chemical that is naturally produced as a gas from the sediments that is potentially toxic via inhalation, ingestion, and skin and eye contact. Inhalation can result in respiratory irritation, rhinitis, and edema of the lungs. Subacute exposures to hydrogen sulfide may result in headache, dizziness, staggering gait, and agitation. Acute exposure at higher concentrations may result in immediate coma and possibly death as a consequence of respiratory failure."
Health-related problems related to hydrogen sulfide exposure were reported by residents and visitors who were exposed to dredged sediments at Twin Lakes Beach in Santa Cruz, California. In an In an October 14, 2005 open letter to the Monterey Bay Air Board, the Community Solutions Group in Santa Cruz reported that, "Adverse health complaints include nausea, headaches, eye and throat irritation, dizziness, loss of balance, mood change, and neurological problems." The letter alleged that thousands exposed to the gas had lacked adequate protection, and that the problems during the prior dredging season had been much worse than reported by the Santa Cruz Port District to the Air District Board and staff. The letter further stated that, "Hydrogen sulfide emissions exceeded the Air District standard 39% of the days during beach disposal. Peak emissions reached 200 times the Air District's standard in the hydrogen sulfide protocol." and, "Emissions repeatedly exceeded California's health standard for "acute" exposure."
Some Santa Cruz residents said that they had been examined by a local physician who administered a battery of neurological examinations to determine possible impacts of the residents' exposure to the dredged material. The residents reported that the doctor stated that they had sustained permanent neurological damage due to the hydrogen sulfide gas exposure, and that the doctor had told them that if they continued to live in close proximity to the dredging activities, they would be at risk.
In 2007, the California Department of Health Services (CDHS), Environmental Health Investigations Branch investigated and reported its findings. The report noted that, "Community concerns related to H2S were reported by a variety of individuals, including residents, visitors to the beach, and some who made anonymous complaints. Community members reported health concerns such as red and burning eyes, blurry vision, conjunctivitis, headaches, agitation and shakiness, heart palpitations, dizziness, nausea, vomiting, bloody nose, sinus infections, worsening asthma, and being mentally "foggy." One person reported having a metallic taste in their mouth. Some were concerned that infants and children (i.e., sensitive populations) who play on the beach might be exposed to H2S or other chemicals related to the dredging. Some community members were concerned when they saw "clay balls" on the beach near the discharge pipe. They were concerned that exposure to H2S was affecting their health in the short and long term."
The study authors indicated that findings were not conclusive due to the fact that, "The identification and analysis of environmental exposure is difficult and inexact. This health consultation was prepared using different sources. There are varying degrees of uncertainty associated with each source of information"
Summarizing the results of the evaluation, and noting problems with lack of certain kinds of information, the study authors said, "Are the health effects that the nearby neighbors (and beach visitors) are experiencing caused by hydrogen sulfide? While it's possible the health effects the nearby neighbors and beach visitors are experiencing could be related to the H2S from the dredge material, it would be difficult to make this determination without a more complete understanding of the chemical's toxicity. It should be stated that CDHS did not medically evaluate anyone as a part of this health consultation. Based on our analysis of the H2S monitoring data, CDHS can not conclude that the health effects were caused by the releases of H2S from beach discharge of the dredged material."
The CDHS stated that its findings did not support a conclusion that the hydrogen sulfide emissions from the dredged material were a public health hazard but nevertheless, the agency made the following recommendations:
- the port district should comply with the hydrogen sulfide protocol and establish a clear understanding with their dredging contractors that the dredging should stop for the day when the action levels are exceeded;
- the port district should continue the hydrogen sulfide sampling for the upcoming dredging seasons;
- the port district, with the assistance of the other regulatory agencies, ensure the dredging is performed off shore and under water as much as possible to dissipate the hydrogen sulfide;
- the harbor should post additional signs on the beaches, warning of possible health implications during dredging;
- the port district should create a better delineation around the discharge area;
- the air district should start a policy where they archive their inspector notes; and
- the dredging crew should indicate on their field notes when the operations on the beach are being conducted under emergency conditions or emergency variance.
The study did not evaluate other contaminants that might have been in the dredged material. However, it did note that, "Community members were concerned about the contents of the dredging when it originates from the upper harbor. They say this dredged material is black, and they are concerned about exposure to chemicals such as pesticides, heavy metals, and chlordane. "
Potential Impacts of Exposure to Multiple Contaminants
The USACE's tests of Morro Bay sediments indicated that most of the contaminants evaluated were within safe limits, but is this a guarantee that the tested contaminants pose no hazards to humans and wildlife? In their study, "Geographical Distribution and Potential for Adverse Biological Effects of Selected Trace Elements and Organic Compounds in Streambed Sediment in the Connecticut, Housatonic, and Thames River Basins." Robert F. Breault and Sandra L. Harris stated, "The presence of multiple contaminants is important for the assessment of the toxicity of the sediment, or of the water from which they are collected because of possible synergistic effects among the contaminants. Synergistic effects could cause a combination of contaminants to be more toxic than any single contaminant."
The increased risk of illness as a result of exposure to multiple contaminants seems intuitively obvious, but another associated risk factor may not be. Bioaccumulation of toxins is a related problem of major concern to scientists and health professionals. As defined by the International Union of Pure and Applied Chemistry, bioaccumulation is "Progressive increase in the amount of a substance in an organism or part of an organism which occurs because the rate of intake exceeds the organism's ability to remove the substance from the body." The manual, Evaluation of Dredged Material Proposed for Ocean Disposal Testing, published by the EPA and the USACE, defines bioaccumulation as "The accumulation of contaminants in the tissues of organisms through any route, including respiration, ingestion, or direct contact with contaminated sediment or water."
The manual also states that, "It is difficult to quantify either the ecological consequences of a given tissue. Concentration of a bioaccumulated contaminant or the consequences of that body burden to the animal. This manual does not provide quantitative guidance on interpreting the ecological meaning of the bioaccumulation observed. Instead, measured bioaccumulation is considered to be potentially unacceptable if animals exposed to the dredged material bioaccumulate statistically greater amounts of contaminants than do animals exposed to reference sediments."
As previously noted, lipophilic chemicals are the most difficult for the body to eliminate. With repeated exposures, the amount of a chemical contaminant in the body can increase. So, multiple exposures to a contaminant in a concentration considered safe could result in accumulation of an unsafe amount of the substance within the body. This contributes to the total "chemical body burden," described in Scientific American as the "presence of hazardous chemicals and their residues in humans".
A PBS report on body burden reveals some disturbing facts: "As part of a study of pollutant loads in the human body sponsored by the Mount Sinai School of Medicine in New York, samples of Bill Moyers' blood and urine were analyzed. Eighty-four distinct chemicals were found. His test results–much like a chemical fingerprint–revealed evidence of hazardous chemicals in common use–as well as compounds banned for more than a quarter century–and others so obscure that almost no public information is available to identify what products might have resulted in Moyers' exposure."
As Many Questions as Answers
The PBS report also states that, "The health effects of chronic exposure to low levels of chemicals are only beginning to be studied." This, combined with the fact that testing protocols do not cover many potentially-harmful contaminants, leaves us with some critical questions for which there are no well-defined answers.
One of those questions is, "If we don't know exactly what's in it, and we don't know how exactly chemicals that might be in it can affect us, but we do know they may be very harmful . . . is dredged material something we should be putting on our beaches?
The experience of Santa Cruz residents and visitors would seem to be a wake up call. What other toxins might have been emanating from the dredged material at Twin Lakes Beach, besides the hydrogen sulfide? What role, if any, did they play in the symptoms experienced by those exposed?
Until we do know exactly what is in the sediment dredged from our Harbor, and exactly what it can do to us, should it be treated as a form of hazardous waste? It might be easier and, from a financial standpoint, cheaper, to put it on the beach, but what is the potential cost in terms of our health?
Some are not inclined to wait until we find the answers to these questions before taking action. Steps recommended by residents include implementing protective measures to prevent the public from being exposed to dredged material and accelerating efforts to clean up the sources of the contaminants. Recommended steps include halting the use of sewage sludge for compost, fixing our leaky wastewater collection systems and replacing our inadequate wastewater treatment facilities with modern systems capable of dealing more effectively with chemical contaminants.
