Health Issues and the Bouchard No. 120 Spill
Human Health Issues
When the No. 6 fuel oil first landed in quantities on some beaches in Buzzards Bay, a strong asphalt odor was detectable some distance away. Adverse symptoms by some responders and cleanup workers in densely oiled areas included headaches and nausea. No persistent effects or symptoms were reported.
The Coast Guard released a (Genium) Material Safety Data Sheet (MSDS) for Number 6 fuel oil. As noted on the fact sheet, acute inhalation effects include headache, nausea, vomiting, among others. In the first few days, one worker exhibited vomiting, but this was determined to be from dehydration. Skin contact can cause irritation and rash.
Although the oil was treated as “hazardous material” when first spilled, after a couple of months the oil was considered weathered, lost many of its more volatile hydrocarbons, and was no longer present in such pervasive concentrations. The weathered oil is generally in the form of “tar balls” which typically form after a No. 6 oil spill. These tar balls generally adhered to rocks or accumulated in beach wrack, or in some cases, washed into salt marshes. Three weeks after the spill, very little oil was either in or floating in the water, but in some heavily impacted areas, oil mixed with sand, and accumulated in the intertidal.
After the initial spill and cleanup, human exposure was most likely through contact (typically stepping on) occasional tar balls. At this point, the oil was no longer considered a hazardous risk to people. However, at affected beaches, the oil was difficult to remove from bathing suits, and conceivable it could still cause a rash in those with allergic reactions petroleum products. Residents were advised to remove the oil with baby oil.
All public sandy swimming beaches were quickly cleared of oil within a few weeks after the spill. Because the spill occurred in the spring before beaches had opened for the summer, no Town or State beaches were officially closed due to oil; residents were discouraged from using beaches near active rock cleaning areas during the summer. No area Board of Health issued a health advisory against swimming in Buzzards Bay. By a couple of months after the spill, the oil had lost its most volatile (and generally more toxic) constituents. Any remaining oil on surfaces is tar-like in nature.
In July, some oil remained on rocks and jetties in a few isolated areas that were not yet cleaned, and residents are cautioned to stay off those areas. Occasional tar balls (pea size to hand size lumps) were found in some areas through the summer (mostly in the vicinity of heavily oiled sites). Residents were advised to remove oil on skin by using baby oil. The Command Center and the citizen group, the Buzzards Bay Coalition provided residents and beach goers with information packets at the start of the beach season at beaches that were heavily oiled. Some of these packets included samples of baby oil for cleaning.
The MSDS posted was not specific to this fuel. Number 6 fuel oil is a highly variable petroleum product. This particular No. 6 was high in various Naphthalene compounds, which are toxic to many animals. The simplest type of naphthalene compound (pure naphthalene C10H8) is sold commercially as “moth balls.”
NOAA tar ball fact sheet (web page with pdf flyer).
Dogs and Cats
Some dogs that frequented beaches were oiled during this spill. It was recommended that light oiling on pets could be removed with vegetable oil instead of baby oil (because dogs lick their fur). Because of the higher risk of ingestion, residents with oiled cats and dogs were encouraged to contact a veterinarian if the animal was seriously oiled, and to save any receipts to file a claim.
We did not scan the Coast Guard No. 6 fuel oil MSD sheet, which does not appear to be from Bouchard, and we do not know the manufacturer of this fuel. For comparison, review these two No. 6 MSDSs for No. 6 oil from two companies which are similar:
Chevron No. 6 MSDS -web version
Amarada Hess No. 6 MSDS, pdf version
Shellfish Consumption Issues
As noted elsewhere on this website, all sections of Buzzards Bay that were at least “lightly oiled” remained closed to shellfishing between May 21 and October 10. The reason for the prolonged delay is complicated, and was not well explained in newspaper articles.
The crux of the issue is that there is an unresolved debate about what threat hydrocarbons in shellfish pose to human health, how to characterize complex mixtures of hydrocarbons in seafood, and how to establish acceptable risk levels needed to protect human health. The issue is exacerbated by the fact that there are few national regulatory standards for low level hydrocarbon contamination of seafood, and each state may adopt its own standards (particularly if interstate commerce is not involved).
While seafood inspectors reject conspicuously “tainted” seafood that may cause immediate illness (the human nose can detect fairly low concentrations of certain hydrocarbons), most states have not adopted low level hydrocarbon contamination standards that address risks of cancer associated with lifelong consumption of seafood. In the US FDA’s recently implemented Seafood Hazard Analysis and Critical Control Point program (HACCP), contamination of seafood by hydrocarbon mixtures is not even addressed (the program addresses certain metals, pesticides, and classes of chlorinated hydrocarbons, like PCBs). In Massachusetts, in the absence of established federal and state standards and policies for low level hydrocarbon contamination, state officials find themselves simultaneously grappling with seafood safety issues revolving around the Bouchard No. 120 spill, together with the broader issue of hydrocarbon contamination found in many harbors and estuaries derived from boat engines, street runoff, atmospheric deposition of soot, and old creosote pilings to name a few sources.
Establishing contaminant limits
Federal and State governments have generally adopted a chemical-specific approach to regulating toxic compounds in the environment and in food sources. Under this approach, the concentration of a particular contaminant is applied to a specific numeric criteria or standard for that contaminant. For example, everyone agrees that lead in drinking water is not good for child health and development, and the US EPA has set a Maximum Contaminant Level (MCL) of 15 parts per billion (ppb or ng/L) of lead in drinking water supplies. Similar drinking water standards apply to pesticides and hydrocarbons. For example, the limit for the pesticide Chlordane in drinking water is 5 parts per billion (ppb), and single hydrocarbon contaminants like benzene, a constituent in gasoline, has a limit of 2 ppb.
These standards are based on current knowledge of human health and scientific studies and adopted acceptable risk levels (ARLs. These recommended standards sometimes change over time as new health studies are published (nearly always lowering). For example, the drinking water limit for arsenic is currently 50 ppb, but the EPA has proposed changing the limit to 10 ppb by 2006. This proposed rule change has caused considerable debate because of the expected expense to municipal governments associated with removing low-level arsenic from water supplies in some parts of the country. This has lead to questions over the validity of the arsenic studies, and whether certain naturally occurring arsenic compounds pose the same risk as arsenic compounds used in laboratory studies.
Like drinking water, the EPA and the FDA have proposed certain contaminant levels in seafood. These “action limits” are generally higher than allowed in drinking water because the amount of seafood ingested is much smaller than compared to drinking water. For example, while the EPA limits Chlordane in drinking water to 5 parts per billion (Massachusetts limits are now 2 ppb), the FDA recommended a maximum Chlordane level in seafood of 300 parts per billion.
When it comes to oil spills, a standard for lifelong consumption exposure is considerably harder to adopt, because petroleum products are composed of hundreds or even thousands of individual compounds, and common oil mixtures like “No. 6” fuel oil are highly variable among refineries. Some of the individual compounds in these oil mixtures are not well studied. Because of this complexity and variability of petroleum mixtures, regulatory agencies do not use single “indicator” compounds (e.g. benzene) to assess risk. Rather, some measure of total hydrocarbon content and risk is evaluated instead.
Sometimes Total Petroleum Hydrocarbons are evaluated in seafood, but in evaluating human risks, it has long been recognized that not all hydrocarbons should be considered equally. For example, hydrocarbons associated with the combustion of oil and fuels (from autos, furnaces, etc., called “pyrogenic” hydrocarbons) are considered more carcinogenic than hydrocarbons from natural seeps, crude oil, or even refined oil products like fuel oil (called “petrogenic” hydrocarbons). Hydrocarbons composed of multiple fused six-carbon rings (called Polycyclic Aromatic Hydrocarbons, or PAHs, or sometimes called Polynuclear Aromatics) are also viewed as a greater threat to human health. One of these PAH compounds, called Benzo[alpha]Pyrene (BaP), is particularly carcinogenic, and has been well studied. One recent trend has been to characterize complex hydrocarbon mixtures found in seafood by assigning a BaP-equivalency to characterize carcinogenic risks associated with all the PAHs in the mixture. However, for practical reasons, BaP equivalency analyses are really based on only quantifying 14 specific PAH compounds that may be found in seafood.
Several states have used BaP-equivalency to evaluate seafood, or contamination after an oil spill, some have used Total PAH. What values of BaP-equivalency or Total PAH are considered “safe?” In different states, and in different oil spills, different values have been selected. Sometimes different standards are used in different species. Why is this the case? In the last decade, a very specific equation has been used to calculate the acceptable contaminant concentration in seafood. However, the calculated acceptable concentration limit depends on several assumptions used with this equation. The three key assumptions that health officials make that most affect the calculation of the action limit concentrations are as follows:
1) What is the Acceptable Risk Level (ARL)? For drinking water, the ARL often adopted is one cancer in one million over a 70-year lifetime for the average weight adult. However, for foods, states often adopt a lifetime risk of one cancer in one hundred thousand over 70 years.
2) How much seafood is consumed each month? Sometimes unlimited consumption is considered one 8 ounce serving every day. Sometimes 16 days of consumption per month are used. Few people consume this much shellfish, so lower average consumption rates may be used, which in turn will raise the acceptable concentration.
3) What is the BaP Cancer Slope Factor? This is a technical term derived from cancer and epidemiological studies, but health officials have a little flexibility in defining how conservative a measure this will be, which in turn affects the seafood action limit concentration.
Bottom Line Numbers
The methods discussed above relate to fish consumption advisories (how often an adult should consume a particular species). This discussion does not address the regulatory opening and closing of shellfish beds, which historically has only been prompted when there is an overt immediate health risk (e.g. avoiding sickness and death from pathogens or “red tide” toxins). In the case of finfish, to address life-long exposure issues, the trend among regulators during the past decade has been to issue health advisories as to how many meals of a particular fish species should be consumed each month. This helps many states avoid closing freshwater ponds to fishing because of high mercury or pesticides levels that exist in some areas. However, in the case of shellfish, which may be harvested in various “open ” areas, and sold to the public, there has been a strong desire by health officials to simply define areas open and closed to shellfishing, and avoid issuing health advisories on shellfish consumption. Because shellfish beds in enclosed embayments and harbors typically are closed first to bacteria before they show elevated hydrocarbon levels, and because shellfish do not have high lipid (fat) content which would bioaccumulate certain contaminants, the reliance on bacterial classifications to protect human health has been a reasonable policy.
One recent EPA seafood advisory recommended that health officials adopt a 6-ppm (parts per million) limit of PAHs for seafood. If this limit were adopted as the basis of shellfish bed open status, many harbors along the East Coast of the US would be closed to shellfishing, because, unlike fish, shellfish to not metabolize (break down) PAHs, and the compounds may bioaccumulate in their tissues. After the Exxon Valdez oil spill, BaP-Equivalency advisory levels for subsistence consumers (using only a ten-year exposure period) were 3 ppb BaPE for salmon, 5 ppb BaPE for finfish,11 ppb BaPE for crustaceans, and 120 ppb BaPE for bivalve mollusks. Following the Kure oil spill, the California Department of Health Services adopted advisory action levels of 34 ppb BaPE for the average shellfish consumer and 5 ppb BaPE for frequent shellfish consumption. These levels were not used to establish the opening or closing of shellfish beds, and other values have been adopted by other states.
What will the Massachusetts Department of Public Health and the Division of Marine Fisheries establish as the standard to open and close shellfish beds due to the Bouchard No. 120 spill? Will that action limit have implications for unoiled bays in the Commonwealth affected by non-point sources of PAH? Will there be a lower threshold PAH consumption advisory level? These questions remain unresolved.
Whatever decisions are made, the public could find the decisions contentious or confusing. As noted in one NOAA publication: “The public wants to know whether the seafood is safe to eat; yet the answers given are typically posed in terms of ‘acceptable risk’ or ‘not a significant risk.'” The same document pointed out that Alaskan village residents became upset when it was pointed out that samples of smoked fish contained carcinogenic hydrocarbon levels hundreds of times higher than any shellfish samples collected from oiled beaches, and nearly 10,000 times higher than found in wild salmon. The report noted, “residents considered eating smoked salmon to be an acceptable, voluntary risk, and eating oil-contaminated seafood to be an involuntary, unacceptable risk.” Even the meaning of the analytical results can seem questionable when it was pointed out that the leafy vegetable Kale shows a PAH concentration (from naturally occurring plant compounds) three to fifty times higher than smoked fish. With this kind of information, the report concluded “risk comparisons should be made carefully.”
Additional Reading
NOAA Document: Managing Seafood Safety after an Oil Spill. A key document being used by health officials (1 MB pdf file).
U.S. Food and Drug Administration Seafood Hazard Analysis and Critical Control Point site.
EPA mid-Atlantic study page showing EPA recommended tissue concentration limits used in issuing fish advisories.