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PUBLIC HEALTH ASSESSMENT

BERTRAND CREEK AREA PROPERTIES
(a/k/a NORTH WHATCOM COUNTY GROUNDWATER CONTAMINATION)
LYNDEN, WHATCOM COUNTY, WASHINGTON


APPENDIX A: Figures


Figure 1. North Central Whatcom County, Washington


Figure 2. Study Area A (Meadowdale) and Study Area B (Bertrand Creek)


Figure 3. Approximate Boundaries and Well Locations of Study Area A (Meadowdale) and Study Area B (Bertrand Creek) within a 2-mile Radius


Figure 4. Boundaries of the Sumas-Blaine Aquifer


Figure 5. Direction of Groundwater Flow in the Sumas-Blaine Aquifer


Figure 6. Results of Whatcom County Well Testing for EDB from 1991-1999 (provided by WCHHS)


Figure 7. Results of Whatcom County Well Testing for 1,2-DCP from 1991-1999 (provided by WCHHS)


Figure 8. Results of Whatcom County Well Testing for Nitrate from 1991-1999 (provided by WCHHS)


APPENDIX B: Exposure Dose Calculations

This appendix provides the exposure assumptions and calculated doses used to estimate healthrisks associated with exposure to contaminants of concern in drinking water. The dose estimatesfor each of these pathways are discussed under the Pathways Analysis/Public Health Implicationssection of the document. The reader should be aware that maximum concentrations are used tocalculate these doses. This represents a worst-case scenario that may overestimate actualexposure. Non-cancer dose calculations assumed a five-year exposure of a child from birththrough 5 years of age. Cancer dose calculations assumed a 30-year exposure of a child growingto adulthood.

Maximum air concentrations reached during a 20-minute shower were estimated using a mathematical model.(c) Use of maximum concentrations will likely over estimate total shower inhalation exposure since maximum levels will not be present during the entire shower. This conservative approach was used to account for other sources of exposure such as clothes and dish washing that were not considered in the dose estimate. Dermal absorption during a 20-minute shower was estimated using EPA guidance.(d)

Ingestion

Ingestion equations and Inhalation Exposure Assumptions

Inhalation - (Shower)

Inhalation eqations and Ingestion Exposure Assumptions

Dermal Absorption and Dermal Absorption Exposure Assumptions


Table 4.

Non-cancer Dose Calculations
Receptor
Population
Media Contaminant Concentration
(ppb)
Exposure
Route
Estimated Dose

(mg/kg-day)

MRL/RfD
(mg/kg-day)
Hazard Indexa
Ingestion Inhalation Dermal
Young Child
(0-5 years)
Drinking water EDB 6.1 Ingestion
Inhalation
Dermal
3.3E-04 2.9E-04 1.1E-05 NA NA
1,2-DCP 28.4 1.5E-03 1.1E-03 1.1E-04 9.0E-02 0.03
DBCP 0.3 1.6E-05 3.5E-06 1.1E-06 2.0E-03 0.01
1,2,3-TCP 2.4 1.3E-04 5.3E-05 9.1E-06 6.0E-03 0.03
Infant Formula (drinking water) Nitrate 56 Ingestion 8.6E+00 NA NA 1.6 5
Nitrate 10 (MCL) 1.5E+00 NA NA 1.6 1

a = Hazard index is the total estimated dose divided by the RfD or MRL.


Table 5.

Cancer Dose Calculations
Receptor
Population
Media Contaminant Maximum
Concentration
(ppb)
Exposure
Route
Cancer Slope Factor
(mg/kg-day-1)
Cancer Risk EPA Cancer Class
Oral Inhalation Ingestion Inhalation Dermala
Child Adult
(30 years)
Drinking water EDB 6.1 Ingestion
Inhalation
Dermal
8.5E+01 7.6E-01 5.8E-03 5.3E-05 2.8E-04 B2
0.05 (MCL) 4.7E-05 4.4E-07 2.3E-06
1,2-DCP 28.4 Ingestion
Inhalation
Dermal
6.8E-02 6.3E-02 2.2E-05 1.7E-05 2.2E-06 NA
5 (MCL) 3.8E-06 2.9E-06 3.9E-07
DBCP 0.3 Ingestion
Inhalation
Dermal
1.4E+00 2.4E-03 4.7E-06 2.0E-09 4.8E-07 NA
0.2 (MCL) 3.1E-06 1.4E-09 3.2E-07
1,2,3-TCP 2.4 Ingestion
Inhalation
Dermal
7.0E+00 NA 1.9E-04 NA 1.9E-05 NA
40 (LTHA) 3.1E-03 NA 3.2E-04
a = Dermal cancer risk calculated using the oral cancer slope factor.


APPENDIX C: ATSDR Conclusion Categories

CATEGORY A : URGENT PUBLIC HEALTH HAZARD

This category is used for sites where short-term exposures (< 1 yr) to hazardous substances or conditions could result in adverse health effects thatrequire rapid intervention.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does notnecessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made.

Criteria:

Evaluation of available relevant information* indicates that site-specific conditions or likely exposures have had, are having, or are likely to have in the future,an adverse impact on human health that requires immediate action or intervention. Such site-specific conditions or exposures may include the presence ofserious physical or safety hazards, such as open mine shafts, poorly stored or maintained flammable/explosive substances, or medical devices which, uponrupture, could release radioactive materials.

* Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, andepidemiologic data.

ATSDR Actions:


ATSDR will expeditiously issue a health advisory that includes recommendations to mitigate the health risks posed by the site. The recommendations issued inthe health advisory and/or health assessment should be consistent with the degree of hazard and temporal concerns posed by exposures to hazardous substancesat the site.

Based on the degree of hazard posed by the site and the presence of sufficiently defined current, past, or future completed exposure pathways, one or more of the following public health actions can be recommended:

  • biologic indicators of exposure study
  • biomedical testing
  • case study
  • disease and symptom prevalence study
  • community health investigations
  • registries
  • site-specific surveillance
  • voluntary residents tracking system
  • cluster investigation
  • health statistics review
  • health professional education
  • community health education
  • substance-specific applied research

CATEGORY B: PUBLIC HEALTH HAZARD

This category is used for sites that pose a public health hazard due to the existence of long-term exposures (> 1 yr) to hazardous substance orconditions that could result in adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does notnecessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made.

Criteria:

Evaluation of available relevant information* suggests that, under site-specific conditions of exposure, long-term exposures to site-specific contaminants(including radionuclides) have had, are having, or are likely to have in the future, an adverse impact on human health that requires one or more public healthinterventions. Such site-specific exposures may include the presence of serious physical hazards, such as open mine shafts, poorly stored or maintainedflammable/ explosive substances, or medical devices which, upon rupture, could release radioactive materials.

*Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data.

ATSDR Actions:


ATSDR will make recommendations in the health assessment to mitigate the health risks posed by the site. The recommendations issued in the healthassessment should be consistent with the degree of hazard and temporal concerns posed by exposures to hazardous substances at the site. Actions on therecommendations may have occurred before the actual completion of the public health assessment.

Based on the degree of hazard posed by the site and the presence of sufficiently defined current, past, or future completed exposure pathways, one or more of thefollowing public health actions can be recommended:

  • biologic indicators of exposure study
  • biomedical testing
  • case study
  • disease and symptom prevalence study
  • community health investigations
  • registries
  • site-specific surveillance
  • voluntary residents tracking system
  • cluster investigation
  • health statistics review
  • health professional education
  • community health education
  • substance-specific applied research

CATEGORY C: INDETERMINATE PUBLIC HEALTH HAZARD

This category is used for sites when a professional judgement on the level of health hazard cannot be made because information critical to such a decision is lacking.

Criteria:

This category is used for sites in which "critical" data are insufficient with regard to extent of exposure and/or toxicologic properties at estimated exposure levels. The health assessor must determine, using professional judgement, the "criticality" of such data and the likelihood that the data can be obtained and will be obtained in a timely manner. Where some data are available, even limited data, the health assessor is encouraged to the extent possible to select other hazard categories and to support their decision with clear narrative that explains the limits of the data and the rationale for the decision.

ATSDR Actions:


ATSDR will make recommendations in the health assessment to identify the data or information needed to adequately assess the public health risks posed by the site.

Public health actions recommended in this category will depend on the hazard potential of the site, specifically as it relates to the potential for human exposure of public health concern. Actions on the recommendations may have occurred before the actual completion of the public health assessment.

If the potential for exposure is high, initial health actions aimed at determining the population with the greatest risk of exposure can be recommended. Such health actions include:

  • community health investigation
  • health statistics review
  • cluster investigation
  • symptom and disease prevalence study

If the population of concern can be determined through these or other actions, any of the remaining follow-up health activities listed under categories A and B may be recommended.

In addition, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring or has occurred in the past, ATSDR will reevaluate the need for any follow-up.

CATEGORY D: NO APPARENT PUBLIC HEALTH HAZARD

This category is used for sites where human exposure to contaminated media may be occurring, may have occurred in the past, and/or may occur in the future, but the exposure is not expected to cause any adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR considers sufficient to support a decision. This does not necessarily imply that the available data are complete, in some cases additional data may be required to confirm or further support the decision made.

Criteria:

Evaluation of available relevant information* indicates that, under site-specific conditions of exposure, exposures to site-specific contaminants in the past, present, or future are not likely to result in any adverse impact on human health.

*Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data; monitoring and management plans.

ATSDR Actions:


If appropriate, ATSDR will make recommendations for monitoring or other removal and/or remedial actions needed to ensure that humans are not exposed to significant concentrations of hazardous substances in the future. Actions on the recommendations may have occurred before the actual completion of the public health assessment.

The following health actions, which may be recommended in this category, are based on information indicating that no human exposure is occurring or has occurred in the past to hazardous substances at levels of public health concern. One or more of the following health actions are recommended for sites in this category:

  • community health education
  • health professional education
  • community health investigation
  • voluntary residents tracking system

However, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring, or has occurred in the past, ATSDR will reevaluate the need for any follow-up.

CATEGORY E: NO PUBLIC HEALTH HAZARD

This category is used for sites that, because of the absence of exposure, do NOT pose a public health hazard.

Criteria:

Sufficient evidence indicates that no human exposures to contaminated media have occurred, none are now occurring, and none are likely to occur in the future.

ATSDR Actions:


No public health actions are recommended at this time because no human exposure is occurring, has occurred in the past, or is likely to occur in the future that may be of public health concern.


APPENDIX D: Response to Public Comments

1. In many places in the document phrases such as "no evidence exists" are used to describe potential health threats. This may be technically correct, but we believe that it would be clearer and more accurate to say something such as "little scientific study has been conducted, and currently no evidence exists" in most of these places.

Changes have been made to address this concern. Suggested language will be used or current phrases will be qualified with an indication as to the amount of negative studies that are available.

2. When we met with representatives from ATSDR we passed along a question from a past resident of Mallard's Landing regarding any possible link between area contaminants and Idiopathic Thrombocytopenic Puppura. At the same meeting the Whatcom County Health Officer acknowledged that he knew of a number of cases of Idiopathic Thrombocytopenic Puppura, and that that number seemed suspiciously high to him. Please address this question.

This health concern was not communicated to DOH. No sampling data were located for the former well at Mallard's Landing. According to DOH public drinking water records, this water system has been inactive since August 1979. Century Water Association currently supplies drinking water to Mallard's Landing. This source is listed as being active since February 1980. Periodic testing of this water supply since 1992 has not detected any of the pesticides associated with groundwater contamination in the area. However, no data were located for this system prior to 1992. For more information on the drinking water supply that served residences at Mallard's Landing please contact the WCHHS at 360-676-6724.

The PHA evaluated exposure and the potential for adverse health effects. Evaluating the relationship between an environmental exposure and a specific health condition requires an epidemiologic investigation that examines the potential relationship between occurrence of a health effect and an exposure. Such an investigation does not appear warranted based on the lack of contamination in the well serving Mallard's Landing.

The condition called idiopathic thrombocytopenic purpurea is characterized by a reduction in blood platelets due to the presence of a substance that agglutinates platelets.(e) By definition, the cause of this condition is unknown. In general, it is important to consult a physician when dealing with a specific health condition. DOH can supply your physician with information relative to the exposure and contaminants in question. In addition, there are physicians located throughout the state who specialize in environmental health. ATSDR supports one such group of physicians, the University of Washington's Occupational and Environmental Medicine Program located at Harborview Medical Center. For more information about physicians who specialize in environmental health in your area, please contact Sandi Shaw (DOH) toll-free at 1-877-485-7316 or directly at 360-236-3179.

3. The recent EPA investigation found fairly high levels of 1,3 DCP in groundwatersamples. Our research has found that studies of 1,3 DCP show it to be a more potentcarcinogen than 1,2 DCP. Why is contamination of groundwater by 1,3 DCP not mentionedin the entire assessment?

Analysis of groundwater samples taken by EPA during August and September 1998 detected 1,3 dichloropropane in seven groundwater samples at a maximum of 2.95 ppb.(f) Two of these detections came from private drinking water wells on Birch Bay-Lynden Road while the remaining detections came from monitoring probes. Analysis of groundwater samples taken by Ecology during June, September and October 1998 detected 1,3-dichloropropane in 4 samples at a maximum of 0.14 ppb.(g) 1,3-dichloropropane is produced only for use as an intermediate in the manufacture of other chemicals. Detections of 1,3-dichloropropane in groundwater may be the result of its presence as a contaminant in pesticide mixtures containing 1,3-dichloropropene as the active ingredient. No data on cancer potency were located for 1,3-dichloropropane and no RfDs or MRLs exist for this chemical. Due to its infrequent detection at very low levels, 1,3-dichloropropane was not selected as a contaminant of concern.

The chemical 1,3-dichloropropene is currently used as a soil fumigant but was not detected inany samples during the 1998 EPA and Ecology site investigations. Its use on raspberries isrestricted to fumigation of soil prior to replanting. The California Environmental ProtectionAgency lists both 1,2-DCP and 1,3-dichloropropene in their report entitled, "Criteria forCarcinogens", released by the Standards and Criteria Work Group. This list of cancer potencyfactors shows that 1,3-dichloropropene has an oral cancer potency factor about three times higherthan 1,2-DCP while the inhalation potencies are approximately equal. U.S. EPA currently lists1,3-dichloropropene as a Group B2 probable human carcinogen but withdrew its cancer potencyfactor in October 1989 for further review.

4. In general some of the recommendations, (such as "Farm workers should observe properre-entry times for fields applied with pesticides), may be difficult to control, and puts theonus of responsibility on the farm worker or home owner. This approach seems doomed tofailure, and removes the responsibility from the pesticide applicators who are causing theproblem. A better recommendation would be "Pesticide applicators should be required toensure that farm workers observe proper re-entry times."

The role of ATSDR and DOH with respect to the public health assessment (PHA) process is anadvisory one. Neither agency has regulatory authority to enforce these recommendations as thatresponsibility lies with other agencies (e.g., Ecology, EPA, OSHA). However, DOH does haveregulatory authority to enforce drinking water regulations for public water supplies.

The recommendations contained within this PHA are designed to reduce or eliminate exposure tohazardous substances that have been determined to pose a health risk. Methods for reducingexposures of concern (risk management) are left to the regulatory agencies. DOH recognizes thatsome exposures of concern will not trigger a regulatory response. In such casesrecommendations are targeted to the exposed population in order to provide them with guidanceon how to reduce such exposure. With respect to the recommendation noted, (# 4, page 35),DOH has no information as to whether re-entry times are being observed or not. Therecommendation serves to reiterate that following these existing guidelines could help reducegeneral exposure to pesticides. As stated in the recommendation, this information should besupplied by the employer and is also contained on the pesticide label.

5. In recommendation #5 we do not understand the rationale for only including migrantfarm workers in the concern regarding combined exposure to "pesticides in soil and dust."Many of the residents in the area have nitrate contaminated wells, and are closelysurrounded by agricultural pesticide use as well as the pesticides they may be using ontheir own yards, homes, and pets. We believe this recommendation needs to be expanded toall area residents, and needs to be backed up with a health action plan item to educate arearesidents about this exposure path.

It is beyond the scope of this document to address all potential sources of exposure beyond thatassociated with nitrate and pesticides in groundwater. The PHA addresses the potential forexposure of migrant workers to pesticides in soil and indoor dust because available data indicatethat this pathway is of concern. In addition, community health concerns gathered by DOHindicated that this pathway was of concern to workers.

6. A couple of times in the report you state that "The location and boundaries ofgroundwater contamination plumes have not been established." Recent investigation bythe EPA have found level of 1,2 DCP much higher than recorded previously, and identifiednew potential plumes the boundaries of which are still unknown. We believe that arecommendation and health action plan needs to be added to actively determine the extentof the contamination to ensure public health. This also needs to be accomplished beforelegitimate analysis of potential alternative water supplies can logically move forward.

The lack of identifiable plume boundaries is indeed of concern and does present the possibility ofunidentified exposure to contaminants in groundwater. Recommendation #5 (page 36) isintended to address this issue by encouraging residents to test their wells if they live in areas ofconcern. DOH has already commented to Ecology regarding the Bertrand Creek siteinvestigation and the need to identify any other plumes that might be present in hte NorthWhatcom county area. Ecology is proposing more sampling to address this issue and this factwill be amended to the Public Health Action Plan

7. We are deeply concerned by the Departments inability to obtain pesticide applicationrecords. In answer to question #44 you state that "Pesticide applicators are required tokeep records of what they apply." Yet in three different places you state that during theyear and a half this assessment took you were unable to obtain such records. Pleaseexplain who has these records, and why state and federal health officials were unable toobtain them. We believe that a logical recommendation from this inability to obtain recordswould be to ask for an expansion of the applicators record keeping requirements. We alsobelieve that citizens should also have access to such records so they can determine what isbeing used in their areas since citizens are required to cover the costs of protecting theirhealth by testing their wells.

The PHA has been updated to reflect information on current pesticide use. The formal PHAprocess dates back to the initial acceptance by ATSDR of a community petition on November 16,1998. At this time ATSDR agreed to conduct an exposure investigation and asked DOH toprepare a health consultation and conduct community health education. On March 30, 1999,DOH held a public availability session in Lynden to gather community health concerns. One ofthe concerns raised was related to current applications of pesticides. DOH pursued thisinformation by contacting a pesticide applicator that serves berry growers in the north WhatcomCounty area. Unfortunately, no data were exchanged despite a verbal agreement to do so.

Applicators are required to keep files on pesticide application and make them accessible to theWashington State Department of Agriculture (WSDA). However, these are not public records. DOH contacted a local pesticide applicator and several state and federal agencies in order toobtain information concerning current use of pesticides on raspberry fields. Raspberry fields arethe predominant crop in the north Whatcom County area. It is clear that there are severalpesticides for a raspberry grower to choose from and not all growers will use the same pesticidesin the same amounts. In order to make their crop profitable, growers tend to use as littlepesticide as possible since the costs of such use can be significant. For example, a soil test fornematodes is often a prerequisite for determining the need for fumigation of a field. The marketalso dictates pesticide use since growers sending their harvest to juice makers will use lessfungicide than those harvesting for produce.

Discussions with WSDA indicated that summary statistics provided by the USDA provide thebest information with regard to pesticide usage on raspberry fields in the State of Washington. This information is presented in Appendix E. More complete information is available on theInternet at "http://pestdata.ncsu.edu/cropprofiles/Detail.CFM?FactSheets__RecordID=55". TheUSDA information provides an excellent overview of recent pesticide use organized by crop andstate.

House Bill 2741, which is currently before the state of Washington legislature, calls for apesticide use tracking system to be established that will make pesticide use information readilyavailable to the public. Several factors play a role in determining whether a pesticide applied ona field will be a threat to a drinking water well. Among these factors are type of pesticideapplication (i.e., soil versus foliar), chemical physical properties of the pesticide, amount applied,frequency of application, movement of groundwater, location of drinking water wells and type ofaquifer. If you are concerned about pesticides in your well and how to test for them, pleasecontact the WCHHS at 360-676-6724 or DOH toll-free at 1-877-485-7316.

8. Your recommendations do not mention the need for pollution prevention. In a shallowaquifer, such as the one in northern Whatcom County, contamination can only be avoidedif farmers, residents, and businesses all reduce the use of potential contaminants, andhandle the contaminants they do use correctly. Local government also needs to provideadequate zoning to protect this valuable drinking water source. These ideas should formthe foundation of protecting the public health and should be included in yourrecommendations.

Source reduction of pollutants entering the environment is an important aspect of public healthprotection. This comment speaks to the need for a reduction in "background" exposure as part ofa valid attempt to reduce overall health risk. An additional recommendation directed at theWCHHS will be added regarding their participation in ongoing efforts to reduce the potential forpesticide and nitrate groundwater contamination in the north Whatcom County area..

This recommendation will be made with the understanding that efforts are already underway toachieve this goal. A local ordnance was passed in 1998 restricting the use of manure withrespect to where and when it can be applied. In addition, WCHHS is working with localplanning boards to prevent the siting of new private drinking water wells in areas of knowncontamination. WCHHS will continue efforts to implement Integrated Pesticide Managementpractices as specified in the Abbotsford Sumas International Task Force Agriculture Plan. WCHHS will also be involved in future activities relating to protection of the Sumas-Blaineaquifer that could include designating this aquifer as a Groundwater Management Area.

9. Finally, many of the public health actions already taken, and those yet to come, will takea significant amount of money. Please include an action plan for paying for ongoingprograms, so these issues don't fall through the cracks like they did in the 1980s. We donot think that it is fair for taxpayers to continue to subsidize these cleanup costs sochemical companies can continue to pollute and make huge profits. We would like to see arecommendation that the State Attorney General actively seek to recoup costs ofalternative water supplies, as well as educational efforts, either cooperatively or throughthe courts, from the chemical companies that produced the pesticides of concern.

As noted previously, some recommendations are not within the scope of this document. DOHdoes not have the authority or responsibility to recoup cleanup costs from potentially liableparties. The state of Washington filed suit in 1988 against the Great Lakes Chemical Companyto recoup costs associated with investigations of EDB contamination in groundwater. A$575,000 settlement was reached in January 1992 that defined the boundaries of investigation forfour sites two of which were located in Whatcom County (Meadowdale and Bertrand Creek).

10. The summary states that "no apparent public health hazard exists for migrant farmworkers exposed to pesticides in drinking water." It also states that "no apparent publichealth hazard exists for persons exposed to mixtures of pesticides and nitrate in drinkingwater at or below respective MCLs." However, the recent University of Wisconsin studythat looked at exposure to mixtures of pesticides and nitrate does show that there areadverse effects. Results of this study should be reflected in the summary statements.

The summary is intended to provide the most important elements of each section of thedocument. Conclusion are given in the summary along with other clarifying statements. TheConclusions section (page 34) of the PHA provides more detail in support of the eachconclusion.

11. In the 'recommendations' section, the draft report states that 'migrant farm workersshould take steps to reduce exposure…to pesticides…" Farm workers have no control overthe amount and/or type of pesticides used in their work environment and therefore cannottake steps to reduce their exposure in any meaningful way. The burden should not beplaced on the farm worker. The recommendation as written is disingenuous; it shouldinstead call for action on the part of employers and regulatory agencies in order to protectfarm workers from exposure to dangerous chemicals. These action steps should includepollution prevention and the use of the precautionary principle.

Recommendation #4 emphasizes the need to observe proper re-entry times. Regulations alreadyexist regarding re-entry times and other aspects of pesticide handling by workers. DOH has noevidence that existing regulations are not being observed. The recommendation was made toreiterate the need to follow these regulations. Recommendation #4 will be modified to reflectthat the employer is in the only position to ensure that proper re-entry times are observed.

Although some exposure will invariably occur when working with pesticides or in pesticide-treated fields, workers can certainly take steps to limit their exposure. For example, farmworkers can reduce the amount of pesticide contaminated soil tracked inside the home. Thispathway of exposure is not readily apparent but is easily reduced by removing work clothes prior to entering the home.

12. Further, the Recommendations section states that 'residents using drinking water withnitrate at or above the MCL and detectable levels of pesticides should consider steps toreduce exposure." However, there is no mention of the migrant farm worker camps, manyof which had high nitrate levels above the MCL, as well as detections of 1,2-DCP. Dept. ofHealth should take action to ensure that workers and their families have a safe watersupply - levels of nitrate in the range found in migrant camp wells of 16 - 25 ppm are NOTacceptable. All camps except 1 had nitrate levels at or above the MCL.

The issue of nitrate and pesticide exposure of migrant camp workers is addressed inRecommendation #4. However, Recommendation #3 will be modified to include migrant campworkers. There is currently only one migrant camp well that has detectable levels of pesticides(1,2-DCP). Continued sampling of this well for 1,2-DCP is recommended along with nitratesampling in accordance with current regulations.

13. There is no mention of current pesticide use or 1,3-DCP. Though not as persistent ingroundwater, information from California shows that 1,3-DCP has 10 times thecarcinogenic potential of 1,2-DCP. Potential health effects from current pesticideapplications should be explored in this document.

Please see response to Comment #3.

14. The recommendations on testing for pesticides in migrant camp wells should specifythat testing should be done yearly.

The Division of Drinking Water within DOH recently completed an evaluation of 150 water systems supplying 189 temporary farm worker facilities. This effort was directed by the Governor and conducted in the summer and fall of 1999. This effort covered the entire state and included all active water systems serving temporary farm worker facilities except 16 to which DOH was denied access. Analysis of drinking water samples included volatile organic compounds (VOC), synthetic organic compounds (SOC), inorganic, nitrate ans bacteria. These systems are currently required to test regularly for only nitrate and bacteria. Only two systems (1%) contained organic chemicals (EDB) above drinking water standards. Approximately 20% of these system were in violation of the nitrate standard. Based on this finding DOH concluded that current testing requirements for these wells are sufficient. Recommendation #4 was modified in light of this report which is available on the Internet at "http://www.doh.wa.gov/water/final_report.htm" or by calling DOH at (360) 236-3110.

15. Why was the EPA data, which shows concentrations of 1,2-DCP as high as 52 ppb, not mentioned in this draft report? The fact that these high levels were detected, and that the boundaries of the contamination have never been defined and thus we do not by any means have a clear idea of the total population potentially affected, should be made clear in this report.

A level of 51.4 ppb 1,2-DCP was detected in a push-probe sample taken by EPA during their 1998 site investigation and will be noted Table 1. Most of the EPA groundwater samples taken during this investigation were extracted from push-probes as opposed to drinking water wells. Push-probes serve as temporary, single-sample monitoring wells. The data summarized in Table 1, (page 7) represents groundwater samples collected from drinking water wells between 1984 and 1999. The vast amount sampling data available for drinking water wells provided a good basis for estimating actual exposure.

As discussed in the Background section of the PHA (Part C. Nature and Extent of Contamination, page 6), it is likely that several groundwater contaminant plumes exist in north Whatcom County. Extensive sampling has been conducted by several state and federal agencies as well as private well owners that have helped to delineate the areas with the highest levels of pesticides in groundwater. Ecology has proposed to re-sample pesticide contaminated wells that do not currently qualify for an alternate water source (i.e., detections below one-half the MCL). Wells located near these areas of known contamination that have not yet been sampled will also be included in the plan.

16. Page 14. "There is little evidence, however, of such synergistic effects between chemicals…" I found statements of this type to be a problem throughout the document, in light of the fact that virtually NO testing of ANY nature has been done on the synergistic effects of chemicals. This type of statement is misleading, as it implies that testing HAS been done and no adverse effects have been found, when in fact we haven't done the testing and don't have any idea what the long-term synergistic effects are.

The issue of synergy between chemicals and the toxicity of chemical mixtures in general has received considerable attention in recent years. While the database for evaluating chemical mixtures is small, relevant studies are discussed in the Public Health Implications section of the PHA (Part D. Multiple Chemical Exposure, page 17). One such study exposed rats and mice to a mixture of contaminants in drinking water that included EDB, DBCP, 1,2-DCP and nitrate at levels much higher than those encountered in north Whatcom County groundwater. No adverse reproductive or developmental effects were noted. Reproductive toxicity has been identified as an endpoint of concern in animals given high doses of EDB and DBCP. In addition, developmental toxicity is often the most sensitive endpoint of chemical exposure. Therefore, this study provides good evidence that synergistic effects between the contaminants of concern in north Whatcom County groundwater are unlikely.

17. Page 16, "..cancer risk associated with pesticides at levels of health concern is likely overestimated. There is no evidence that this level of pesticide exposure can cause cancer in humans." What data is the first statement based on, that the risk is 'likely overestimated?" In the second sentence, here again it is implied that tests of low levels of pesticide exposure have been done and have shown no increase in cancer risk. Do we have conclusive evidence that low levels do NOT cause cancer? The Department of Health should endorse the precautionary approach.

The approach used in the PHA to estimate cancer risk relies on exposure assumptions that are used to calculate a dose. Since levels of contamination vary between wells, a "worst-case" evaluation was made assuming a 30-year exposure to the maximum detected levels of each pesticide (see Appendix B). This approach ensures that exposure will not be underestimated. However, no individual is or has been exposed at this level since the maximum pesticide levels are not found in the same well. In addition, a 30-year exposure will likely be incurred in only a small percent of the exposed population. Uncertainty accompanies both the exposure and toxicity assessment components of the process. This uncertainty has made the "precautionary approach" inherent in the process of analyzing health risks associated with exposure to hazardous chemicals in the environment.

As noted in the response to Comment #1, statements noting the lack of evidence that a contaminant causes cancer in humans will be qualified.

18. Page 18. "..there is little evidence demonstrating this …." Again, is there evidence proving the contrary?

Please see response to Comment #16.

19. Page 18, last paragraph begins by discussing toxic effects from interactions between chemicals. The bulk of the paragraph then tends to discount this finding, then the last sentence suggests that there may in fact be a reason for concern. The intervening statements between the first and last sentence should be removed, as they cloud the main point that there are interactions between chemicals and there is some evidence that adverse health effects result. Also, it is not relevant when talking about chemical mixtures that the chemicals were not those detected in Whatcom County - the point is about the effects of mixtures of chemicals.

Health risk assessment is fraught with uncertainty especially with respect to chemical mixtures. This paragraph provides an overview of the preceding discussion and how the available science relates to the exposures occurring in north Whatcom County. Addressing the uncertainties involved in risk assessment is vital in making an informed recommendation.

We respectfully disagree with the final statement "it is not relevant when talking about chemical mixtures that the chemicals were not those detected in Whatcom County". The recent study from the University of Wisconsin that found mild immunological effects in mice exposed to nitrate, atrazine and aldicarb is relevant. However, these pesticides differ from those found in north Whatcom County groundwater. Even small differences in chemical structure can significantly change the metabolism and toxicity of a chemical. Further, no reproductive or developmental effects were found in rats and mice exposed to chemical mixtures that included EDB, 1,2-DCP, DBCP and nitrate. Taken as a whole, this evidence does not indicate that nitrate and those pesticides found in north Whatcom County groundwater interact to produce a toxic effect.

However, the Wisconsin study is cause for concern since the exposure levels were not the traditional high dose variety but closer to what might actually be encountered in the environment. This fact generated Recommendation #6 that advises residents to consider reducing exposure when nitrate is present above the MCL along with detectable levels of pesticides. Infants and pregnant women should not drink any water with nitrate above the MCL.

20. Page 19. "Interactions between the pesticides found in north Whatcom County groundwater and nitrate are not of concern for reproductive or developmental endpoints. " What data exists to support this statement?

Please see response to Comments 16 and 19. This issue is also discussed in the Public Health Implications of the PHA (Part D. Multiple Chemical Exposure, page 17)

21. Page 20, first line. "…no evidence exists that chronic, low doses can impact humans." Again, is there data that shows that low doses do not impact humans?

This statement relates only to liver and kidney effects seen in animals at high doses and will be revised for clarity. As noted in the text, reproductive effects have been observed in workers exposed to EDB. However, these studies have limitations with respect to statistical power, exposure assessment and appropriate control groups. Please see response to Comment #1.

22. Page 25. Risks from current pesticide applications. The Department of Health should conduct a public health assessment from current pesticide applications. 1,2-DCP has been replaced by 1,3-DCP in most cases. Although not as persistent in groundwater, 1,3-DCP is more highly carcinogenic. This fact should be noted in the public health assessment, and a follow-up study should be done.

Please see response to Comment #3. Detections of 1,3-dichloropropane were infrequent and at low levels while 1,3-dichloropropene was not detected in either of the 1998 site investigations conducted by EPA and Ecology. The data do not warrant a follow-up study.

23. Page 33, number 43. "Natural degradation will slowly remove the pesticides…" It should be noted that this process may take decades to occur.

Responses to Community Health Concerns # 42 and 43 (page 33) will be modified accordingly.

24. Page 33, number 44. Why are attempts to get information on current products and quantities (of pesticide applications) "not yet successful"? This statement is very alarming. Pesticide application information should be readily available to the public and agencies. Relevant government agencies should take steps immediately to determine why this data is not immediately available. The Dept. of Health should perform a follow-up study regarding current pesticide/fertilizer applications after obtaining this data.

Please see response to Comment #7 for information on current pesticide use. Regarding a follow-up health study on fertilizer/pesticides exposure, Recommendation #7 (page 36) suggests that the issue of concurrent exposure to nitrate and pesticides be further examined. A health study examining the relationship between adverse health effects and exposure to nitrate and pesticides will require a much more detailed exposure assessment than mere application rates for a particular field. It is likely that any such exposed population will have to be studied on a state or regional basis in order to obtain an adequate study population. It is important to note that the University of Wisconsin study is but one piece of information suggesting a further look into this type of exposure. In addition, this study looked at different pesticides, in conjunction with nitrate, than were found in north Whatcom County groundwater. It may be more appropriate for ATSDR to look at Midwest populations exposed to nitrate and those same pesticides.

25. Page 34. "…additional exposure of migrant farm workers to pesticides in soil and indoor dust is also cause for concern." There is a serious lack of data on this point. Dept. of Health should conduct a study of health risks to migrant workers and their families from exposure to pesticides and nitrate via multiple pathways.

Researchers at the University of Washington (UW) and other institutions have made significant contributions towards the understanding of worker exposure to pesticides including the indoor dust pathway. A current project by the UW is underway to determine the overall exposure of farm workers and their families to pesticides. This project will help to identify the pathways of greatest significance with respect to farm worker exposure (e.g., spray drift, soil contact, indoor dust). Recommendation #4 indicates the steps that farm workers can take to reduce their exposure to pesticides.

26. Page 35. "Farm workers should observe proper re-entry times for fields applied with pesticides." This places the burden on farm workers. It is not the decision of the farm workers as to when to re-enter a field.

Please see response to Comment #11.

27. Page 35. Dept. of Health should undertake a study of health risks to farm workers and their families from chronic exposure to pesticides and nitrate through multiple exposure pathways.

The University of Washington (UW) and the Fred Hutchinson Cancer Research Center are currently evaluating exposure of workers and their families to pesticides. This project is part of a larger effort by the UW to evaluate various environmental health issues under a grant from the EPA and the National Institute of Environmental Health Sciences. DOH currently evaluates discrete incidences of pesticide exposure to workers as part of the Pesticide Incidence Reporting and Tracking Review Panel.

The UW study will be helpful in discerning the major exposure pathways for farm workers. Concerning the evaluation of health effects as a result of nitrate exposure in combination with these multiple pesticide exposure, Recommendation #7 encourages such an effort. DOH has asked ATSDR's Division of Health Studies to consider whether such an effort is feasible and warranted.

28. Page 35. All wells in migrant farm worker camps should be tested yearly for pesticides and nitrate.

Please see response to Comment #14.

29. Page 37/38 - Action Plan. Dept. of Health should commit to studying synergistic effects of exposure to multiple chemicals, including farm workers and their families through multiple pathways.

Please see response to Comment #27.

30. Page 37/38 - Action Plan. Dept. of Health should undertake steps to conclusively determine the extent of the groundwater contamination in north Whatcom County.

Ecology is currently implementing another sampling plan (Phase III) to better determine the extent of groundwater contamination and the need for an alternate water source.


APPENDIX E: Current Pesticide Use on Raspberry Fields in Washington State

The information presented below in Tables A1 and A2 was obtained from the USDA Office of Pest Management Policy and the Pesticide Impact Assessment Program and is provided in response to questions raised about the current use of pesticides in north Whatcom County. This information is specific to raspberries as they are the major crop in north Whatcom County. More complete information regarding pesticide use on raspberries can be accessed on the Internet at "http://pestdata.ncsu.edu/cropprofiles/Detail.CFM?FactSheets__RecordID=55".

The reader should be aware that application rates will vary between growers. Table A2 provides a typical application profile for a grower targeting high-end markets such as produce. Growers selling to lower-end markets such as juice are expected to use about half of the fungicide estimated in Table A2. In addition, not all pesticides are applied annually. The soil fumigant 1,3-dichloropropene (Telone II) is not listed in Table A2 because it is used only prior to planting and not on existing fields.


Table A1.

Estimate of Usage of the Most Common Pesticides* in Raspberries in Washington State During the 1997 crop year
Pesticide % Area treated # Applications
per year
Lb. AI/acre
per application
Lb. AI/treated acre per season
Insecticides
»»Bifenthrin**

81

1.0

0.10 0.10
Bt

46

2.1

»»Diazinon

77

1.4

1.10 1.54
Esfenvalerate

36

1.0

0.06 0.06
»»Malathion

44

1.0

1.07 1.07
Fungicides
»»Benomyl

76

1.7

0.49 0.83
»»Captan

94

5.0

1.17 5.85
Ferbam

61

1.3

1.23 1.60
Iprodione

71

1.3

0.60 0.78
»»Lime Sulfur

70

1.0

9.16 9.16
»»Metalaxyl

49

1.2

0.49 0.59
Vinclozolin

58

2.6

0.54 1.40
Herbicides ***
»»Diuron

31

1.0

0.97 0.97
Norflurazon

4

1.0

1.20 1.20
»»Oryzalin

62

1.0

1.20 1.20
»»Oxyfluorfen

74

1.0

0.10 0.10
»»Paraquat

85

1.1

0.32 0.35
Sethoxydim

5

1.0

0.19 0.19
»»Simazine

56

1.1

0.62 0.68

Source: Adapted from the National Agriculture Statistics Service, USDA Pesticide Data Program, Fruit summary for the 1997 Crop Year. URL: http://www.usda.gov/nass/pubs/estindx1.htm#agchem

* Limited to pesticides used to control insects, diseases, and weeds only.

** Materials shown in red or marked with this symbol (»») are heavily relied upon and have few or no currently registered and effective substitutes.

*** Discrepancies in rates between this table and text in the weed control section are due to different methods of reporting. The text shows labeled rates per acre. Because these materials are typically applied in 3-4 ft. wide bands in the row, actual use per acre is 30-40% of the labeled/broadcast rate as shown here.


Table A2.

Typical Pesticide Spray Program for the Year On an Average Farm
Date Pesticide Lbs ai/acre Method Target Pest* Crop Stage
March Diazinon

2.0

Banded Crown borer Dormant
Diuron

1.6-2.4

Banded Weeds Dormant
Metalaxyl

0.5

Banded Root rot Dormant
Late March Lime Sulfur

9

Foliar Cane diseases Delayed dorm.
Early April Oxyfluorfen

0.1

Directed base Cane burn Pre-bloom
Early May Captan

2.0

Foliar SB Pre-bloom
Mid May Captan

2.0

Foliar SB Early Bloom
Iprodione

0.5

Foliar Botrytis, SB Early Bloom
Diazinon

1.0

Foliar Fruitworm Early Bloom
Late May Captan

2.0

Foliar Botrytis, SB Bloom
Early June Captan

2.0

Foliar Botrytis, SB Bloom
Vinclozolin

0.5

Foliar Botrytis Bloom
Mid June Captan

2.0

Foliar Botrytis, SB Bloom
Late June Captan

2.0

Foliar Botrytis, SB Pre-Harvest
Iprodione

0.5

Foliar Botrytis, SB Pre-Harvest
Bifenthrin

0.1

Foliar Insects Pre-Harvest
August Benomyl

0.375

Foliar Cane blight Post-Harvest
Fenbut. Oxide

1.0

Foliar Spider Mites Post-Harvest
October/Nov Fenamiphos

6.0

Banded Nematodes Post-Harvest

Source: WSU Vancouver, Lynden Satellite Station IPM Project (1998) and personal communication with raspberry growers

*Target pest codes where abbreviated:

· Crown borer: Raspberry Crown Borer, Pennisetia marginata

· Root rot: primary target is Phytophthora fragariae var rubi

· Cane burn: Primocane suppression

· SB: Spur Blight, Didymella applanata

· Botrytis: Gray mold fruit rot; Botrytis cinerea

· Insects: Adult root weevils and miscellaneous harvest- contaminating insects and spiders

· Nematodes: Root Lesion Nematodes, Pratylenchus spp.


GLOSSARY

Acute:
Occurring over a short time, usually a few minutes or hours. An acute exposure can result in short-term or long-termhealth effects. An acute effect happens a short time (up to 1 year) after exposure.


Aquifer:
Water-bearing rock or rock formation located beneath the ground surface.


Carcinogen:
Any substance that may produce cancer.


Chronic:
Occurring over a long period of time (more than 1 year).


Concentration:
The amount of one substance dissolved or contained in a given amount of another. For example, sea water contains a higher concentration of salt than fresh water.


Contaminant:
Any substance or material that enters a system (e.g., the environment, human body, food, etc.) where it is not normally found.


Dermal contact:
Contact with the skin. Refers to absorption through the skin as a route of exposure.


Dose:
The amount of substance to which a person is exposed. Dose often takes body weight into account.


Downgradient:
Refers to a location toward which groundwater will flow.


Exposure:
Contact with a chemical by swallowing, breathing, or direct contact (such as through the skin or eyes). Exposure may be short term (acute) or long term (chronic).


Exposure Pathway:
An exposure pathway is the process by which an individual is exposed to contaminants that originate from some source of contamination. It consists of five elements: 1) Source of Contamination, 2) Environmental Media/Transport, 3) Point of Exposure, 4) Route of Exposure and 5) Receptor Population.


Groundwater:
Water contained in the spaces between soil and rock below the water table. This water can be in shallow (overburden) aquifers or bedrock aquifers.


Ingestion:
Swallowing (such as eating or drinking). Chemicals can get into or on food, drink, utensils, cigarettes, or hands where they can then be ingested. After ingestion, chemicals can be absorbed into the blood and distributed throughout the body.


Inhalation:
Part of the breathing process. Exposure can occur by inhaling contaminants which can then be deposited in the lungs, taken into the blood, or both.


Lowest Observed Adverse Effect Level (LOAEL):
The LOAEL is the lowest dose at which an adverse health effect is seen in a particular study. The LOAEL is often used to derive MRLs and RfDs.


Maximum Contaminant Level (MCL):
The MCL is a regulatory limit set by the Environmental Protection Agency (EPA) for contaminants in drinking water. If an MCL is exceeded, regulatory action is required under the Safe Drinking Water Act. MCLs are not always strictly health based but can consider technological or economic feasibility.


Media:
Soil, water, air, plants, animals, or any other parts of the environment that can contain contaminants.


Minimal Risk Level (MRL):
Minimal Risk Levels (MRLs) are levels of chemical exposure below which non-cancer effects are not expected. MRLs are derived by the Agency for Toxic Substances and Disease Registry. An MRL is derived by dividing a LOAEL or NOAEL by "safety factors" to account for uncertainty and provide added health protection.


National Toxicology Program (NTP):
NTP conducts toxicological testing on those substances most frequently found at sites on the National Priorities List of the EPA, and which also have the greatest potential for human exposure.


No Apparent Public Health Hazard:
A conclusion category used when human exposure to contaminated media is occurring or has occurred in the past, but the exposure is below a level of health hazard.


No Observed Adverse Effect Level (NOAEL):
The NOAEL is the highest dose from a study that did not find any adverse health effects. The NOAEL is often used to derive MRLs and RfDs.


No Public Health Hazard:
A conclusion category used when data indicate that no current, past or potential for future exposure exists and, therefore, no health hazard exists.


Oral Reference Dose (RfD):
Oral Reference Doses (RfDs) are levels of chemical exposure, derived by the Environmental Protection Agency, below which non-cancer effects are not expected. An RfD is derived by dividing a LOAEL or NOAEL by "safety factors" to account for uncertainty and provide added health protection.


Plume:
An area of chemicals in a particular medium, such as air or groundwater, moving away from its source in a long band or column. A plume can be a column of smoke from a chimney or chemicals moving with groundwater.


Potential/Indeterminate Public Health Hazard:
A conclusion category used when no conclusions about public health hazard can be made because environmental and/or toxicological data are lacking.


Public Availability Session:
An informal, drop-by meeting at which community members can meet one-on-one with state health department and ATSDR staff members to discuss health and site-related concerns.


Public Health Assessment:
The evaluation of data and information on the release of hazardous substances into the environment in order to assess any current or future impact on public health, develop health advisories or other recommendations, and identify studies or actions needed to evaluate and mitigate or prevent human health effects; also, the document resulting from that evaluation.


Public Health Hazard:
Sites that pose a public health hazard as the result of long-term exposures to hazardous substances.


Receptor Population:
Persons who are exposed or potentially exposed to the contaminants of concern at a point of exposure.


Risk:
In risk assessment, the probability that something will cause injury, combined with the potential severity of that injury.


Route of Exposure:
The way in which a person may contact a chemical substance. For example, drinking (ingestion) and bathing (skin contact) are two different routes of exposure to contaminants that may be found in water.


Shallow aquifer:
Sub-surface water-bearing area that lies between the water table and bedrock characterized by loose soil, sand, gravel, etc. Also known as the overburden.


Source:
Origin of a contaminant release into the environment, or, if the source is unknown, the environmental media through which contaminants are presented at a point of exposure.


Volatile Organic Compounds (VOCs):
Substances that easily become vapors or gases and contain carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen. Many VOCs are commonly used as solvents (paint thinners, lacquer thinner, degreasers, and dry cleaning fluids).

CERTIFICATION

This Whatcom County Groundwater Public Health Assessment was prepared by the WashingtonState Department of Health under a cooperative agreement with the Agency for Toxic Substancesand Disease Registry (ATSDR). It is in accordance with approved methodology and proceduresexisting at the time the health consultation was begun.

Debra Gable
Technical Project Officer, SPS, SSAB, DHAC
ATSDR

The Division of Health Assessment and Consultation, ATSDR, has reviewed this public healthconsultation and occurs with the findings.

Richard Gillig
Chief, SPS, SSAB, DHAC
ATSDR


c Foster SA, and Chrostowski PC. Inhalation exposures to volatile organic contaminants in the shower. Presentation at the 80th Annual Meeting of the Association Dedicated to Air Pollution Control and Hazardous Waste Management (ALCA). New York, NY. June 1987.

d U.S. Environmental Protection Agency. Dermal Exposure Assessment: Principles and Applications. Interim Report. January 1992. EPA/600/8-91/011B.

e Thomas CL. Taber's Cyclopedic Medical Dictionary. 1985. 15th Edition. Philadelphia: F.A. Davis Company:

f Roy F. Weston, Inc. Bertrand Creek Properties: Site Investigation Report, Lynden, Washington. Prepared for the U.S. Environmental Protection Agency, Region 10. March 1999.

g Washington State Department of Ecology. 1998 Site Investigation Bertrand Creek & Meadowdale Areas, Whatcom County, Washington. October 1999. Publication No. 99-601.




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