Skip directly to search Skip directly to A to Z list Skip directly to site content

PUBLIC HEALTH ASSESSMENT

MESSER STREET MANUFACTURED GAS PLANT
LACONIA, BELKNAP COUNTY, NEW HAMPSHIRE


IV. DISCUSSION

Based on the review of environmental data for the site in the previous section, PAHs are present in the sediments and fish tissue of the Winnipesaukee River and Opechee Bay at levels above comparison values. Mobile coal tar and distinct coal tar globules are also present in the river sediments in several areas. However, for this chemical contamination to pose a public health hazard, there must be opportunities for exposure to the contaminated media.

In the following subsection, the available toxicological and epidemiologic information on PAHs and coal tar are summarized. Next, the pathways by which people could be exposed to chemical contamination on the Messer Street MGP Site are determined and then evaluated using the health information summarized previously. Finally, to complement this evaluation, available health outcome data for the community immediately adjacent to the site was reviewed and summarized.

(A) Properties of Site Contaminants

Many residents near the site requested information on the health effects associated with the chemical contaminants at the site. Consequently, the available toxicological and epidemiologic information on PAHs and coal tar are summarized in the following subsections. It is important to note that the pathways of exposure described in the scientific literature, which range from occupational exposures to medicinal treatments, are often substantially different than those that are possible at the Messer Street MGP Site. A specific evaluation of the health implications of exposures to these chemicals at the Messer Street MGP Site is provided in Section IV(C).

(i) Polycyclic Aromatic Hydrocarbons

PAHs are a class of over 100 different compounds that are found in and formed during incomplete combustion of coal, oil, wood, or other organic substances. In the environment, PAHs are found as complex mixtures of compounds, rarely as single compounds alone. Some uses for PAHs include the manufacture of medicines, dyes, plastics, and pesticides. More typically they are found in petroleum based products such as coal tar, asphalt, creosote, and roofing tar [17].

Because they are produced by combustion processes, PAHs are widespread in the environment. In rivers and lakes, the majority of PAHs will be bound to sediments. Degradation is slow (on the order of years) and can be slower in areas that are chronically contaminated like the Messer Street MGP Site. Accumulation of PAHs in fish tissue is not a major concern because most fish can metabolize PAHs and excrete them over a few days [17].

The greatest exposures to PAHs for the general population are from inhaling tobacco smoke, wood smoke, and contaminated air, as well as eating contaminated foods. For non-smokers, diet is the largest background exposure to PAHs. Food preparation methods that involve combustion, such as charbroiling or smoking meats or fish, increase exposures to PAHs in food [21]. Occupations where there are significant opportunities for exposure to PAHs include: working with coal tar, asphalt, or roofing materials; working in a foundry; working in a mine; or working as a chimney sweep [17].

Non-cancer adverse health effects associated with PAH exposure have been observed in animals but generally not in humans [17]. Based on the results of animal studies, ATSDR has established several minimum risk levels for oral exposure to individual PAHs. Minimum risk levels are estimates of daily human exposure to a contaminant that is unlikely to cause adverse non-cancer health effects over a lifetime. The minimum risk level for naphthalene of 0.02 milligrams per kilogram of body weight per day (mg/kg-d) is the lowest of all the individual PAHs. It is based on an animal study in which minimal effects on the liver were observed in mice after 90 days of intense exposure to naphthalene by the oral route [19]. For skin contact with PAHs, the main concern is for adverse reactions of the skin. For example, benzo(a)pyrene, the most toxic and best studied of the PAHs, was found to irritate skin lesions for people with pre-existing skin conditions and to make the skin of animals more sensitive to ultraviolet light [17].

The available evidence indicates that mixtures of PAHs can cause cancer in humans. The evidence in humans comes primarily from occupational studies of workers exposed to mixtures containing PAHs as a result of their involvement in such processes as coke production, roofing, oil refining, or coal gasification (e.g., coal tar, roofing tar, soot, coke oven emissions, soot, crude oil). However, PAHs have not been clearly identified as the causative agent. Cancer associated with exposure to PAH-containing mixtures in humans occurs predominantly in the lung and skin following inhalation and dermal exposure, respectively [17]. The mechanism of action for PAH carcinogenicity is thought to be that breakdown products formed when PAHs are metabolized by the body are highly reactive with DNA macromolecules, potentially resulting in genetic damage [22].

EPA currently classifies seven of the PAHs as probable human carcinogens based on the weight of toxicological evidence. Benzo(a)pyrene is the best studied of the carcinogenic PAHs, and is the only one for which an oral cancer potency factor has been determined by EPA (7.3 per mg/kg-d) [17]. The potencies of the other six carcinogenic PAHs can be estimated from the potency of benzo(a)pyrene and toxic equivalency factors [23]. The overall carcinogenic potential of a mixture of PAHs is often expressed as the benzo(a)pyrene toxic equivalent (TEQ) concentration. This is an estimate of the pure benzo(a)pyrene concentration that would have the same carcinogenic potential as the mixture of PAHs in the sample. Benzo(a)pyrene TEQ concentrations for sediments and fish tissues at the Messer Street MGP Site are shown on Tables 1 and 4. The available toxicological evidence indicate that there are no appreciable interactions between different PAH compounds so adding the effects of multiple PAHs is appropriate [22].

A recent study found that PAHs can pass through the placental barrier between a pregnant woman and the developing fetus [26]. There is also some evidence from experiments with animals that exposures to certain PAHs in utero can affect reproduction and development; however, the available studies show contradictory results. In Mackenzie and Angevine [24], pregnant mice were exposed to benzo(a)pyrene by the oral route during gestation. At the highest dose level, the number of mice giving birth was significantly decreased. Progeny (i.e., offspring) of mice from all the dose levels experienced reproductive problems ranging from decreased fertility to sterility. These results were contradicted by a study performed by Rigdon and Neal [25] in which mice were exposed to benzo(a)pyrene in their diet during mating, gestation, and childbirth at levels comparable to the first study, but no effects were observed.

Certain people are more susceptible to the toxic effects of PAHs than the general population. Of primary concern are developing fetuses, children, and the elderly, because the detoxification mechanisms used by the body to mitigate the effects of exposure are either immature or declining in function. People with nutritional deficiencies, pre-existing skin or liver disease, genetic diseases that inhibit DNA repair, or compromised immune systems may also be at increased risk. Finally, anyone who is exposed to PAH from other sources than exposures at the site (e.g., smoking, working with asphalt or coal tar) would be more susceptible because exposures to PAHs are cumulative [17].

(ii) Coal Tar

Coal tars are byproducts of the carbonization of coal to produce coke and/or natural gas. Physically, they are usually viscous liquids or semi-solids that are black or dark brown with a naphthalene-like odor. Coal tars are complex combinations of polycyclic aromatic hydrocarbons, phenols, heterocyclic oxygen, sulfur and nitrogen compounds [18]. Coal tar can be refined to form creosote for preserving wood products. It is also used as a pesticide, a pharmaceutical agent for the treatment of psoriasis, and as a component of some anti-dandruff shampoos. Because the composition of coal tar is variable, there is little information on the rates of degradation for coal tar in the environment [18].

Aside from exposures to coal tars at hazardous waste sites, people can come into contact with coal tars or creosotes by handling creosote-treated wood products or using anti-dandruff shampoos that contain coal tar. Workers that manufacture coal tar creosotes, use creosotes to preserve wood, or handle creosote-treated wood products have the potential to be exposed to coal tars at work [18,20].

The major chemicals of health concern in the coal tar at the Messer Street MGP Site are PAHs [5]. Therefore, the health effects previously discussed for PAHs are also of concern for coal tars. However, coal tar has a far greater capacity to produce dermal and ocular effects than PAHs alone. Effects on the skin range from mild to severe and include burns, rashes, and lesions. Coal tar products are also capable of making the skin sensitive to ultraviolet light. Conjuctivitis and other eye irritation (e.g., burning, redness, swelling, watering) have been observed in humans and animals after exposures to coal tars and their volatile components [18].

(B) Pathways of Human Exposure

To determine whether nearby residents and visitors could be exposed to contaminants at the site, the pathways by which exposure might occur must be identified. Exposures to environmental contamination are only possible through completed exposure pathways. A completed exposure pathway exists when all of the following five elements are present: a source of contamination, transport through an environmental medium, a point of exposure, a route of human exposure, and an exposed population (See Figure 4 for an example).

There are three completed pathways by which people could be exposed to contamination at the site: (1) swimming and wading in the Winnipesaukee River; (2) eating fish caught near the site; and (3) using the boat ramp on the site (Table 6a). Current, past, and future exposures along these pathways are possible. The public health implications of exposures along each of these completed pathways will be evaluated and discussed in Section IV(C).

Two additional pathways are not completed currently but have the potential to be completed in the future. These are: (1) using groundwater from the site for drinking; and (2) contacting contaminated soils beneath the site during construction (Table 6b). These pathways are incomplete because groundwater and subsurface soils on the site are not accessible at present; hence, people do not have opportunities for exposures to contamination in these media. As part of the Remedial Action Plan for the site, permanent restrictions on the use of the property will be established to ensure that these pathways are not completed in the future. Therefore, exposures along these pathways were not evaluated in the public health assessment.

Finally, one pathway was eliminated from consideration because it had already been evaluated by DHHS. In 1994, surface soils on the site were tested for chemical contamination. No compounds were found above health-based comparison values or, in the case of arsenic, above background concentrations for New Hampshire. Therefore, in 1995, DHHS determined that contact with surface soils on the site would not present a public health risk [12]. Since there are no new data for surface soils at the site, it was not necessary to reevaluate this exposure pathway in the public health assessment.

(C) Health Evaluation of Completed Exposure Pathways

(i) Swimming and Wading in the Winnipesaukee River Near the Site

People who swim or wade in the Winnipesaukee River near the site could be exposed to coal tar and PAHs in the sediments and surface water. PAHs in sediments and water could be absorbed through the skin, and coal tar could adhere to the skin itself. Small amounts of water and sediment may also be incidentally ingested while swimming or wading. Concern about this exposure pathway prompted DHHS to post "No Swimming" signs in the river in 1995. However, nearby residents report that children continue to swim in the area. Adolescents are the most likely population to be involved in this type of activity. During the summer months when school is out of session, adolescents could swim in the river several times per week. It is unlikely that anyone would swim or wade in the river during the rest of the year when the weather is cold.

The sediments that swimmers or waders would have opportunities to contact are from areas of the river where the bottom is within five feet of the typical water level in the river. In surface sediments in these areas, distinct coal tar globules may be present, and PAH concentrations average 91 mg/kg and reach as high as 1,755 mg/kg (Table 1). During a short period each fall, the water level in the river is lowered by approximately three feet for dam maintenance. The PAH concentrations in deeper sediments potentially made accessible during this draw down period reach as high as 20,210 mg/kg (Table 1). Therefore, even though autumn is not typically a time for swimming in New Hampshire, lowering the water level would theoretically provide access to these more contaminated sediments for a brief period of time.

People who had skin contact with coal tar at work have experienced mild-to-severe skin irritation and lesions. The types of symptoms experienced (e.g., burns, sensitization to light, redness, rashes) are typically reversible and short lasting. Eye irritation and conjunctivitis have also been noted after exposures to coal tar and volatile emissions from coal tar. Skin contact with pure PAHs has resulted in some cases of skin inflammation or warts [17,18]. Therefore, there is convincing evidence that people who contact coal tars while swimming or wading would be at high risk for short-term, reversible, skin and eye irritation. It is important to note that, while there is considerable evidence for irritant effects, some PAHs and coal tars have been used beneficially to treat skin illness, particularly psoriasis [18].

In contrast to external irritant effects, non-cancer health effects for internal organs (e.g., the liver) would not be expected to result from swimming in the contaminated area. The likely amount of PAHs that would be ingested or absorbed through the skin while swimming would be one hundred times lower than the minimum risk levels established for individual PAHs.

It is unlikely that pregnant women would knowingly swim or wade in the contaminated stretch of the river because the area is clearly posted with warning signs. However, if this were to occur, the potential exposure from swimming and wading in this area would be approximately one million times lower than levels at which developmental effects were observed in animal studies.

Chronic skin contact with coal tar may increase an individual's risk of developing skin cancer [18]. The greatest risk factor for skin cancer is exposure to ultraviolet radiation in sunlight. Some animal studies have shown that exposure to benzo(a)pyrene enhances the effects of ultraviolet radiation on the skin [17]. However, the available evidence from studies of people who either worked with coal tar products or who used coal tar to treat skin illnesses is contradictory [18]. In old case reports, the development of non-melanoma skin cancer was observed after chronic exposures to coal tar at work. More recent studies of psoriasis patients who were treated with coal tar applications and others have mostly not found an association between exposures and skin cancer. Based on estimates of ingested and absorbed doses, there is no apparent increased risk of developing cancers of the internal organs from exposures while swimming or wading.

Therefore, people who ignore the "No Swimming" signs and swim or wade in the river would be at risk for short-term skin or eye irritation if they were to contact coal tar in the sediments. Chronic exposures of this nature may increase an individual's risk of developing skin cancer. Noncancerous effects on internal organs or developmental effects are not expected. Residents near the site who do not swim or wade in the river are not exposed to coal tars and, hence, are not at risk for adverse health effects. The remedial actions that are underway should eliminate this opportunity for exposure by removing coal tar contamination from the river sediments.

(ii) Eating Fish Caught near the Site

Neighbors have reported that people fish in the vicinity of the site. During a site visit, DHHS staff observed and talked with one man who was fishing from the Messer Street bridge. Eating fish caught from this area would result in exposure to PAHs in the fish tissue. Adults and children are equally likely to fish in the area. The activity could persist throughout the year as the Lakes Region of New Hampshire has a tradition of ice fishing. Also, pregnant women could be exposed to PAHs through this activity by eating fish either caught themselves or by family members.

PAHs are not expected to accumulate in the tissues of fish because most fish have the capacity to metabolize and excrete these compounds [17]. Data from the Messer Street MGP Site are consistent with this prediction. Total PAHs were detected in fish near the site at concentrations (0.220 mg/kg) that were about four times higher than from the reference area (0.046 mg/kg) on average. However, carcinogenic PAHs were only found in one fish sample at concentrations greater than 0.008 mg/kg. Shellfish from near the site had PAHs in their tissues at the same levels as shellfish from uncontaminated areas of Opechee Bay (Table 4). It is important to note that coal tar may be toxic to fish even if it does not accumulate in their tissues [18]. The ecological health of fish and other aquatic organisms was evaluated in the Ecological Risk Assessment [6].

DHHS has a state-wide advisory for the consumption of freshwater fish from New Hampshire water bodies to protect the public from mercury, a contaminant that is found in fish throughout the state. The general population is advised to limit their consumption to four 8-ounce meals per month. Young children (6 years old or younger) and women of child-bearing age are recommended to eat only one 8-ounce meal per month. However, it is important to remember that fish is still an important part of a healthy diet. Fish are high in protein and low in saturated fat and cholesterol.

Recreational fishers typically eat approximately 30 grams of fish that they have caught per day [28], which is equivalent to the state-wide fish consumption advisory for the general population (four 8-ounce meals per month). This is likely an overestimate of fish consumption near the site given that most anglers fish from different waterbodies during the year. Regardless, at this consumption rate, exposures to PAHs in fish near the Messer Street MGP Site would be hundreds of times lower than minimum risk levels for individual PAHs, and over one million times lower than the levels at which developmental effects were seen in animals. Furthermore, consumption of fish from near the site would not result in an appreciably increased cancer risk.

Therefore, eating fish caught near the site is not expected to result in adverse health effects. Anglers should adhere to the existing state-wide fish consumption limits set by DHHS. Remedial actions at the site should clean up coal tar in the sediments thereby reducing exposures via this pathway.

(iii) Using the Boat Launch Area on Opechee Bay

The northern portion of the Messer Street site is currently used for a parking lot and boat launch area onto Opechee Bay. Aside from a dirt and gravel driveway and parking area near the boat launch, the site is covered with grass. Concentrations of chemicals in surface soils on the site are less than health-based comparison values for residential soils. DHHS previously reviewed data for surface soils on the site and concluded that surface soil contamination on the site did not pose a public health risk [12]. However, people wading in the water to launch their boats may come into contact with PAHs in the sediments and surface water by the boat ramp. PAHs in sediments and surface water could be absorbed through the skin or incidentally ingested in small amounts. Presumably, this type of exposure would be limited to weekly visits during the summer months.

The sediments near the boat ramp are considerably less contaminated with PAHs than those found in the Winnipesaukee River. For example, the PAH concentrations range only as high as 338 mg/kg near the boat ramp compared to maximum values of 1,755 mg/kg in the shallow areas of the river and 20,210 mg/kg in deeper areas (Table 1). More importantly, unlike the river, distinct coal tar globules are not present in the sediments of Opechee Bay, and active discharge of coal tar from the site into the bay is not occurring [11].

Intermittent use the boat ramp during the summer months would result in exposures to PAHs that are one hundred times lower than minimum risk levels for individual PAHs, and one million times below the levels at which developmental effects have been observed in animal studies. This level of exposure would not present an appreciably increased risk of developing cancer.

Therefore, use of the boat launch area is not expected to result in exposures to contaminants at levels of health concern. Planned remediation of the area in the future should further reduce opportunities for exposure to site contaminants.

(D) Health Outcome Data Evaluation

(i) Methodology

The health outcome data review for the Messer Street MGP Site in Laconia, New Hampshire, encompassed an analysis of available cancer information from the New Hampshire State Cancer Registry (NHSCR). The NHSCR is located at Dartmouth Hitchcock Medical Center in Lebanon, New Hampshire. The NHSCR maintains statistics regarding twenty-three types of cancer in New Hampshire.

Cancer information for Laconia, NH, was requested for all 23 types of cancer in a five-year time period of the most recent years that cancer incidence rates were available (1993 through 1997) from the Bureau of Health Statistics and Data Management, which maintains a close working relationship with the NHSCR. The five-year time period is an arbitrary number of years that is most commonly used in the evaluation of cancer trends in a community.

Once the data was received, a descriptive cancer epidemiological analysis was conducted using the standardized incidence ratio technique (SIR). A detailed discussion of this technique is available in Appendix C. The data were reviewed, for each type of cancer reported in Laconia, according to the following factors: sex and age (0-14, 15-24, 25-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and 85+ years). This process enabled us to review the observed number of specific cancer cases, per cancer type, in Laconia and compare that value to the expected number of cancer cases based on average rates for the State of New Hampshire.

Following this analysis, any cancers that were found to be statistically elevated for Laconia were evaluated using an odds ratio (OR) analysis. The OR for a type of cancer estimates the approximate odds of developing that cancer among an exposed group as compared to the same odds in a control (non-exposed) group. This analysis is only appropriate if there is a biologically plausible association between the cancer type and the chemical exposure. The exposed and the nonexposed groups, for the purposes of this analysis, were arbitrarily defined as residents living inside and outside of a one-quarter mile (1,320 feet) radius, respectively, of the Messer Street MGP Site. These groupings were selected based on the localized nature of the contamination as well as neighboring residents' concerns about potential exposure to site contaminants. Although this determination of the exposed group is crude, it is unbiased in that the sample of population considered the exposed group is based on an arbitrary circle drawn around the Messer Street MGP Site as opposed to a specifically designated area. Further explanation of the OR technique is provided in Appendix C.

It is important to note that the quality of the NHSCR cancer data is heavily relied upon to conduct a thorough descriptive epidemiological analysis for both the SIR and OR calculations. There were no independent interviews of persons living in Laconia, therefore these analyses are subject to random misclassification. The SIR and OR analyses performed are descriptive in nature and should not be confused with an in-depth epidemiological study. However, while these methods have limitations, they satisfy the objective of the health outcome data review in that they can determine whether or not potential health impacts around the site would warrant further investigation.

(ii) Results

The findings from our descriptive epidemiological analyses are illustrated in Table 7 titled, "Cancer Incidence in Laconia, New Hampshire (1993-1997)". The data is presented, by gender, in tabular form with the heading of each column describing the type of cancer, the expected number of cases for that particular type of cancer, followed by the observed number of cases for that specific cancer. A standardized incidence ratio (SIR) and 95% confidence interval (statistical tests)have been calculated for each type of cancer. Any types of cancer that have been omitted from the table, have been excluded due to a value of less than 4 observed cases over the five-year time period (1993-1997). This is done to conform to the Bureau of Health Statistics and Data Management's protocol on confidentiality in the release of cancer data. Finally the bottom of the table shows odds ratios and corresponding confidence intervals that have been calculated for all cancers in Laconia and any cancers that were found to be elevated using the SIR calculation.

After completing the SIR calculations, it was found that the rates for all cancer types except one were within the expected range at a 95% confidence interval. The only cancer that was found to be statistically elevated in Laconia between 1993-1997 was melanoma skin cancer (SIR 2.03 in males and 2.59 in females). However, after conducting an odds ratio analysis on this cancer, it was found that there was no statistically significant difference in melanoma rates between those people living within a one-quarter mile radius of the Messer Street MGP Site and the population in the rest of Laconia.

(iii) Discussion

Laconia, NH: Melanoma - Skin Cancer

Melanoma is a malignant tumor formed from a pigment cell (melanin) in the skin. Melanoma is the most dangerous type of skin cancer in that, unlike other types of skin cancers, melanoma tumors have the ability to metastasize (spread) to other organs in the body. This type of cancer can occur at any age, however is most common in people between the ages of 50 to 70 years old [29].

According to the American Cancer Society, an estimated 44,200 cases of melanoma will be diagnosed in 1999 throughout the United States, with 200 of those being diagnosed in New Hampshire [30]. Rates of melanoma incidence have steadily increased approximately 4% per year, over the past several decades from 5.7 per 100,000 in 1973 to 13.8 per 100,000 in 1996. Nationally there has been an increase in the incidence of melanomas over the past two decades. This increase may be partially due to increased diagnostic screening to detect this type of cancer over this same time period [31]. However, there is currently a debate among researchers as to whether or not this increase is due to an increase in detection of disease, or a true increase in the incidence of the disease for unknown reasons [32]. An estimated 7,300 melanoma related deaths will occur in the United States in 1999. Death rates from melanoma have remained relatively stable over the past several decades at approximately 2 per 100,000. The five-year survival rate for melanoma is 88% with the majority of patients detected early enough to provide adequate treatment [30].

The risk factor that can be attributed to the majority of diagnosed melanoma cases is that of excessive exposure to ultraviolet (UV) radiation [29,30,34]. Other risk factors for melanoma are: severe sunburn in childhood; fair complexion; light hair/blue eyes; family history; having multiple atypical moles; freckling; immune system suppression, and exposure to some environmental contaminants (coal tar, pitch, creosote, arsenic compounds or radium) [29,30].

The incidence of melanoma in the United States in 1996 was 13.8 per 100,000 according to data from the National Cancer Institute's Surveillance Epidemiology End-Results (SEER) review [33]. In Laconia, the incidence rate for melanoma is 17 per 100,000 over the period of 1993 through 1997. However, the incidence rate for melanomas in Belknap County, where Laconia is situated, is even higher at 25.9 per 100,000 over the same time period. In looking at this county in relation to the other nine counties in the state of New Hampshire, it can be seen that Belknap county exhibits the highest rate of melanoma cancer cases (the range among the nine other counties is 7.8 per 100,000 to 15.9 per 100,000) [35]. This is most likely due to the fact that Belknap County is located within New Hampshire's Lakes Region, where residents tend to participate in outdoor recreational activities involving excessive sunlight exposure.

Some studies have indicated that chronic exposures to certain chemical contaminants, including some found at the Messer Street MGP Site, are related to the development of melanoma and other types of skin cancers. However, statistically significant elevated rates of melanoma were not observed in the population with the greatest potential for exposure to site contaminants (i.e. the residents living within one-quarter mile of the Messer Street MGP Site). Therefore, the elevated rates of melanoma in Laconia are not likely related to exposures to contamination at the Messer Street MGP Site.

The results of this health outcome data review complement the health evaluation of potential exposures to contaminants at the Messer Street MGP Site. Based on the toxicological properties of coal tar, people who contact coal tar in the sediments of the river while swimming or wading would be at risk for short-term skin or eye irritation. Chronic exposures of this nature may increase an individual's risk of developing skin cancer. However, while some people reportedly swim or wade in the contaminated section of the river, this is probably not common behavior because the affected area is clearly posted with "No Swimming" signs. Residents in the vicinity of the site who do not swim or wade in the river would not have the opportunity for exposure to site contaminants at levels of health concern.

(iv) Conclusions

The rates of 22 of 23 cancer types in Laconia, New Hampshire between 1993 and 1997 were within their expected ranges at the 95% confidence level.

Melanoma skin cancer (SIR 2.03 in males and 2.59 in females) was the only cancer found to be statistically elevated for Laconia. However, after conducting an OR analysis, it was found that there was no statistically significant difference between people living within a one-quarter mile radius of the Messer Street MGP Site and the rest of the population of Laconia.

The elevated rates of melanoma in Laconia appear to be part of a regional trend of increased melanoma incidence in Belknap County. This is likely due to outdoor activities involving excessive exposure to sunlight, the main risk factor for the development of melanoma.

(v) Recommendations

For the prevention of excessive sunlight induced melanoma, we suggest the residents of Laconia limit or avoid sun exposure during the hours of 10:00 AM through 4:00 PM, when ultraviolet rays are most intense. Limited exposure to the sun could include such protective activities as covering skin with clothing, hats, or shades for the face, neck and ears. Use of a topical sunscreen with a solar protecting factor (SPF) of 15 or higher, is also an effective means for limiting sunlight exposure [29]. We support the recommendations of the American Cancer Society in that we advocate a lifestyle in which limited exposure to sunlight, use of a protective sunscreen, or thorough covering of the skin when outdoors is the most effective way to prevent the development of melanoma [30]. We also support the National Institutes of Health Consensus Statement regarding screening for people with first-degree family members who have had a previous diagnosis of melanoma [31]. In New Hampshire, if melanoma is suspected, after a patient has performed a self-examination, he can contact his primary care physician for a screening test. Further, we recommend routine self monitoring for changes in the skin that include the recognition of the melanoma A,B,C,D categories [31]. A warning sign for melanoma skin cancer is a change in appearance of the skin involving one of the following:

  1. Asymmetry: Melanoma tumors tend not to be symmetrical. In other words, they look different on one side as compared to the other side.

  2. Border: The border of a melanoma tends to be irregular and often is scalloped in appearance.

  3. Color: Melanomas can be black, brown, blue or white or have a variegation of all of these.

  4. Diameter: Most melanomas are at least 1 centimeter in diameter and may not look that different from non-melanoma moles. However, one of the first signs and symptoms of melanoma skin cancer is when the size or height of a mole increases over time.

For further information on melanoma please see the following websites:
Melanoma Patients Information Page
http://www.mpip.org/

National Cancer Institute
http://cancernet.nci.nih.gov

American Cancer Society
http://www2.cancer.org/crcGateway/index.cfm
1-800-ACS-2345

(E) ATSDR Child Health Initiative

Children are at a greater risk than adults from certain kinds of exposure to hazardous substances emitted from waste sites. They are more likely to be exposed for several reasons (e.g., they play outdoors more often than adults thus increasing the likelihood that they will come into contact with chemicals in the environment). Due to their smaller stature, children may breathe dust, soil, and heavy vapors close to the ground. Children are also smaller, resulting in higher doses of chemical exposure per body weight. The developing body systems of children can sustain permanent damage if certain toxic exposures occur during critical growth stages. Most importantly, children depend completely on adults for risk identification and management decisions, housing decisions, and access to medical care.

The Messer Street MGP Site may pose a significant health hazard to children and young adults since people in these age groups are more likely to swim or wade in the river and, therefore, would have an increased opportunity for exposure to coal tar in the sediments. DHHS specifically evaluated children's exposures to site contaminants as well as the potential for developmental effects due to exposures in utero in Section IV(C).


V. COMMUNITY HEALTH CONCERNS

When performing any public health assessment, DHHS gathers health concerns from people living in the vicinity of the site. The list of health concerns that people have expressed are then used to direct the focus of the public health assessment so that questions from community members are answered. In March 1999, DHHS held a public availability session at the Laconia City Hall. This was an opportunity for community members to speak to health officials about their concerns one-on-one and in confidence. Later, in July 1999, DHHS distributed a survey to residents living in the immediate vicinity of the Messer Street MGP Site. The following sections are a compilation of questions and comments that DHHS received at the public availability session and on the surveys. Please see Appendix D for a detailed analysis of the responses to the surveys.

Questions on the nature and extent of contamination at the site

  • "I'm not familiar with chemicals that have been found."

Response: Coal tar contamination has been found beneath the site and in sediments of the Winnipesaukee River from the Messer Street bridge to a point 1,000 feet downstream. The coal tar contains primarily polycyclic aromatic hydrocarbons (PAHs), as well as some volatile organic compounds. PAHs are a class of over 100 different compounds that are found in and formed during incomplete combustion of coal, oil, wood, or other organic substances. Lesser amounts of these compounds have also been detected in water, sediment, and fish from areas of the Winnipesaukee River and Opechee Bay near the site. Surface soils on the site do not contain contamination at levels of health concern. For more information on these chemicals, please see Sections IV(A)(i) and IV(A)(ii).

  • "Does this problem effect the Messer Street boat launch area?"

Response: Sediments near the Messer Street boat launch area contain some PAHs, but at relatively low concentrations. Importantly, distinct coal tar globules are not present in this area [11]. Therefore, using the boat launch area should not result in exposures to contaminants at levels of health concern. For more information on DHHS' evaluation of this area, please see Section IV(C)(iii).

  • "The whole area has been disgusting (since we became homeowners)...the entire area was a dump site many years ago and often we find objects leaching through the soil in our backyard & can only wonder what else is really there & how close."

Response: This public health assessment has focused on chemical contamination at the Messer Street MGP Site. DHHS is confident that the environmental site investigations [1-7] have characterized the nature and extent of contamination at the site with regards to human health concerns. The effects of other sources of contamination (e.g., old dumps) cannot be determined without additional information. However, the former MGP facility was presumably the major source of contamination in the area. If you are concerned about other potential sources of contamination in the area, please contact DES at (603) 271-3503.

  • "I spent 20 years living on Messer St. and am very interested with this survey and outcome. The boat launch area was formally known by the locals as the "Pole Yard" because telephone poles were soaked in creosote. Also when they lowered the lake water there was a lot of black sludge on the shoreline."

Response: Indeed, there are reports of a "tar pool" on the northern section of the property during the former MGP operations. Coal tar contamination has been found beneath this area during the site investigations [5]. Due to the properties of the soils beneath the site, coal tar beneath this area appears to be flowing south towards the Winnipesaukee River, not north into Opechee Bay [11].

Questions about adverse health effects associated with site contamination

  • "What type of illness may be linked to what's in the water, fish etc."

Response: Short-term irritation of the skin and eyes could result from exposures to coal tar in sediments near the site. These effects are only possible for people who swim or wade in the section of the Winnipesaukee River where coal tar has been found in the sediments. In contrast, other typical activities (e.g., fishing in the area, using the Messer Street boat launch area) would not present opportunities to contact coal tar and, hence, would not present a risk for skin or eye irritation. For more information, please see Section IV(C)(i).

  • "Is coal tar contamination linked to cancer in humans..."

  • "I was diagnosed with a cancer...*...any connection?" (*personal medical information withheld to maintain confidentiality)

  • "Are any of these chemicals harmful to people and could they cause any long term illness?"

  • "My questions will be based on the information about these particular carcinogens, and their long term effects."

Response: All of these questions pertain to the potential for exposure to site contaminants to result in long-term illness or cancer. The available evidence indicates that mixtures of PAHs and coal tars can cause cancer in humans. Therefore, chronic exposures to coal tars and PAHs while swimming or wading in the contaminated section of the river may increase an individual's risk of developing cancer, particularly skin cancer. Due to the possible carcinogenicity of the site contaminants and because of concerns expressed by local residents, DHHS reviewed and summarized cancer incidence data for Laconia between 1993 and 1997. No cancers were found to have significantly elevated rates among the people who live within one-quarter mile of the site. Besides cancer, other types of long-term illness from exposures to coal tars or PAHs (e.g., effects on the liver) have been observed in animals but generally not in humans. For more information, please see Sections IV(A)(i), IV(A)(ii), and IV(D).

  • "Since moving to Messer St. 2 years ago we have enjoyed walking, fishing & swimming in the area. We would certainly like to be informed about chemicals, health effects & risks as we 'utilize' our neighborhood to the fullest."

  • "How will this site affect my children and my cat who wanders the neighborhood on occasion. The children fish off the bridge and we all swim at Opechee Point."

  • "People still swim in the river sometimes, and some neighborhood kids play on the banks."

  • "People are still using this area for both swimming and fishing."

Response: All these questions ask whether certain activities in the vicinity of the site would result in exposures to site contaminants. The four activities specifically mentioned are: (1) walking/playing on the river banks; (2) using the boat launch on Opechee Bay; (3) fishing; and (4) swimming/wading in the river. Each of these activities will be addressed individually. First, the banks of the river are not contaminated, hence, walking or playing on them does not pose a health risk. Second, while there are some PAHs in the sediments at the boat launch area, use of this area would not result in exposures at levels of health concern. Third, with regard to fishing, because PAHs do not tend to accumulate in the tissues of fish, eating fish caught in the area should not result in significant exposures. However, people are reminded that there is a state-wide advisory on consumption of fish from New Hampshire waterbodies*. Fourth, in contrast to the previous three activities, swimming or wading in the contaminated section of the Winnipesaukee River could result in significant exposures to coal tar and PAHs in the sediments. Thus, DHHS strongly recommends that people do not engage in this activity. The contaminated area begins at the Messer Street bridge and extends 1,000 feet downstream. This area is clearly posted with permanent "No Swimming" signs. For more information, please see Sections IV(C)(i), IV(C)(ii), and IV(C)(iii).

* The general population is advised to limit their consumption of freshwater fish from New Hampshire waterbodies to four 8-ounce meals per month. Young children (6 years old or younger) and women of child-bearing age are recommended to eat only one 8-ounce meal per month.

  • "We are interested in any knowledge about this area because our children were raised here nearby & were exposed to it all."

Response: In this public health assessment, DHHS paid special attention to the potential effects of exposures to children because children are more susceptible to environmental exposures than adults. Our analysis revealed that the only significant route of exposure to site contamination is swimming and wading in the contaminated section of the river. Therefore, simply being raised in the neighborhood would not necessarily result in exposures to site contaminants at levels of health concern. For more information on ATSDR's Child Health Initiative, please see Section IV(E).

Questions on ways to prevent exposure to contamination on the site

  • "What are some of the steps we could apply to our everyday lives to prevent further damage?"

  • "How can I be sure I am protected?"

Response: There are three steps you can take to prevent exposures to chemicals on the site. First, do not swim or wade in the section of the Winnipesaukee River starting at the Messer Street bridge and extending 1,000 feet downstream to where the river narrows. Second, follow the recommendations of DHHS' state-wide fish consumption advisory. The general population is advised to limit their consumption of freshwater fish from New Hampshire waterbodies to four 8-ounce meals per month. Young children (6 years old or younger) and women of child-bearing age are recommended to eat only one 8-ounce meal per month. DHHS issued this advisory to protect the public from exposures to mercury in fish tissues, which is common throughout the state. Third, do not enter restricted areas of the site while remedial actions are underway.

Questions on notification and posting of site hazards

  • "I was not aware of this problem."

  • "The only question I have is how or why haven't I heard anything about this subject prior to this questionnaire."

  • "Do not see or hear anything about this problem until last year. If there is some hazardous problem there, why isn't there some signs up -- like no swimming in the area, no fishing?? Lots of people fish from the bridge, evenings & weekends."

  • Should there be signs posted in the field, not just the water?

Response: Since these questions all pertain to notification, they will all be addressed with one response. The section of the river that is contaminated with coal tar is well posted with permanent signs. DES, DHHS, and the parties who have assumed responsibility for the site remediation cooperate to maintain the signs every few years. DHHS is also planning to conduct an educational campaign about the state-wide fish consumption advisory before the beginning of the fishing season in 2000. Finally, in order to keep those people who are interested in the site better informed, DHHS will provide copies of this public health assessment to everyone who completed the needs assessment survey.

Questions about adverse health effects for pets

  • "How do the chemicals effect the wildlife?"

  • The respondent experienced the death of two family dogs from cancer. The pets "were not aged" but they "drank the river water and swam in it".

  • "After moving to the area, one family dog died, and the other became ill."

  • "Most of my trees along the rivers edge seem to be sick & dying - does it have anything to do with these chemicals?"

Response: All of these questions are about the effect of site contamination on pets or the ecosystem in general. For the purpose of the public health assessment and consistent with its mandate, DHHS has focused on issues related to human health. In many cases, humans and animals react to exposures to chemicals in different ways, so this evaluation of human health risks is not necessarily relevant to pets. Regardless, it would be prudent to keep pets from swimming or wading in the contaminated section of the river to reduce their opportunities for exposures to contamination. The effect that site contamination is having on the ecology in the river has been evaluated as part of the remedial design process. For more information on this evaluation, the technical report on the ecological risk assessment for the site [6] is available at the Laconia Public Library at 695 Main Street.

Questions on upcoming remedial actions

  • "If we are planning to build a wall to contain the contaminants I think this is a mistake. The contaminants must be removed."

Response: As part of the remedial design, a sheetpile barrier will be built to prevent mobile coal tar from discharging to the river. This wall will collect coal tar that reaches it for off-site disposal [6]. Plans are also being developed to remove coal tar waste from a subsurface container on the site [7,10]. Therefore, the objective of the Remedial Action Plan is to remove mobile coal tar from the site to the extent that it is feasible, not to contain it in place.

  • "Will some or all of the clean up be taking place during the annual lake draw down? If so, does that mean that the length of draw down will be longer? When?"

Response: Remedial actions began in the fall of 1999 and are scheduled for completion at the end of 2000 [6]. At this time, there are no plans to alter the draw down schedule to facilitate remedial actions.

  • "What things could we as residents do to help clean up the chemicals?"

Response: DES is supervising the implementation of the remedial actions on the site. If the plans are completely and successfully implemented, DHHS believes that the public health hazards present on the site will be removed. If you would like more detailed information on the cleanup, please contact Bob Minicucci of the Department of Environmental Services at (603) 271-3503.

On January 14, 2000, DHHS released the Draft Public Health Assessment for the Messer Street MGP Site for public comment. In addition to mailing the report to nearly 100 local residents, government officials, and interested parties, the availability of the document was announced through local media and posted on the internet. The public comment period lasted for one month (January 14, 2000 to February 18, 2000). On February 3, 2000, the midpoint of the public comment period, DHHS mailed a brief note to everyone who had received a copy of the document to remind them to send in comments.

Appendix F contains all the written comments that DHHS received within the public comment period. In this appendix, DHHS responds to each comment (or set of related comments).



Next Section     Table of Contents

  
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #