PRELIMINARY PUBLIC HEALTH ASSESSMENT
Appendix A - Figures
Figure 1. Alcoa (Point Comfort) Site Location
Figure 2. Alcoa (Point Comfort) Detailed Site Map
Figure 3. Lavaca Bay Land Tract Map
Criteria and Actions for Levels of Public Health Hazard from ATSDR Public Health Assessment Guidance Manual (1992)
URGENT PUBLIC HEALTH HAZARD
This category is used for sites that pose an urgent public health hazard as the result of short-termexposure to hazardous substances.
Criteria: Evidence exists that exposures have occurred, are occurring, or are likely to occur inthe future;
the estimated exposures are to a substance or substances at concentrations in the environmentthat, upon short-term exposures (less than 1 year), can cause adverse health effects to anysegment of the receptor population. The adverse health effect can be the result of eithercarcinogenic or noncarcinogenic toxicity from a chemical exposure. For a noncarcinogenic toxiceffect, the exposure exceeds an acute or intermediate minimal risk level (MRL) established in theATSDR Toxicological Profiles or other comparable value;
community-specific health outcome data indicate that the site has had an adverse impact onhuman health that requires rapid intervention;
physical hazards at the site pose an imminent risk of physical injury.
Comments Received during the Public Comment Period and Texas Department of Health Response
(Note to the reader: Page and paragraph numbers are quoted from the "Public Comment"document and may differ from the page and paragraph numbers of this document.)
Thank you for your comments on the preliminary Public Health Assessment for the ALCOA(Point Comfort)/Lavaca Bay NPL site and for providing copies of the Draft Preliminary SiteCharacterization Report for our review. We have reviewed your comments and have includedchanges in the public health assessment as appropriate. Below are listed our responses to yourcomments.
Summary Page 1, Paragraph 1:
ATSDR criteria for what constitutes an "URGENT" public health hazard is included as anappendix to the preliminary public health assessment.
Summary Page 1, Paragraph 5:
Added the sentence: "Biological monitoring results for workers in the chlor-alkali unit were usedto monitor employee exposures."
Page 3, Paragraph 2:
Changes made as needed regarding ownership of land.
Page 3, Paragraph 6:
Added "ALCOA also operated the Neumin gas plant from 1957 until 1989. In 1989 the Neumingas plant area and part of the smelter area were sold by ALCOA and are now owned by FormosaPlastics." The remainder of this paragraph was edited to include recommendations.
Page 5, Paragraph 5:
Added wording to indicate that ALCOA complied with abatement actions.
Page 6, Paragraph 1:
Deleted "mercury" from the phrase "mercury workers". The word "production" was deleted fromthe phrase "production workers". The sentence "MSHA also conducted air sampling andexamined general work practices throughout the plant, and concluded that safety standards werebeing met." Added sentence "ALCOA performed air sampling and urinalysis of workers. Theseanalyses indicated that mercury exposures above usual background were not occurring."
Page 9, Paragraph 4:
Added the sentence "ALCOA indicated that this demolition work was performed in accordancewith 29 CFR 1910.120."
Page 9, Paragraph 5:
Page 11, Paragraph 1:
Statement changed: "A well inventory is available; however, current well usage should bedetermined."
Page 13, Paragraph 3:
Deleted phrase "now owned by Formosa Plastics..." Comments on what constitutes "on-site"make it clear to the reader the definition of on-site and off-site and appear to be consistent withthe AOC.
Page 13, Paragraph 5:
No change. The PSCR was not available at the time the public health assessment was preparedbut may be reviewed when an addendum to the public health assessment is prepared.
Page 16, Paragraph 5; Page 17, Paragraphs 1, 2, and 4:
Added wording indicating that samples were not collected within the breathing zone.
Page 17, Paragraph 3:
Added "These samples were collected as part of regular inspections."
Page 18, Paragraph 3:
We opted to use the five representative food fish species, considering that an individual wouldcatch an assortment of fish of various sizes, to provide a reasonable scenario of exposure.
Page 25, Paragraph 1:
Paragraph has been reworded to specify Black Drum from Keller Bay. Other recommendedchanges for this section are not appropriate for this section but are addressed in other sections ofthe report.
Page 25, Paragraph 2:
Paragraph reworded as follows: "Anecdotal evidence and historical records suggest that workersmay have been exposed to mercury in the past; however, quarterly air sampling and biologicalmonitoring (urinalysis) data indicate that excess exposures are not presently occurring."
Page 25, Paragraph 3:
TDH has simplified this section and has added verbage to indicate that take home exposures areunlikely after 15-30 years; however, since small amounts of mercury in closed areas can result inhigh air levels, TDH continues to consider this a potential exposure pathway. ALCOA's actionsto investigate this are mentioned elsewhere in the report.
Page 28, Paragraph 1:
Added the phrase "...if appropriate health and safety measures are not followed."
Page 29, Paragraph 2:
Page 30, Paragraph 2:
John Cicmanec, EPA's IRIS contact for mercury has indicated that EPA has officially changed theRfD for mercury to 1.0 X 10-4 mg/kg/day. According to Mr. Cicmanec, the revised RfD shouldappear in IRIS April 1, 1995. Unfortunately, as with the old RfD, the revised RfD is not qualifiedwith respect to the populations to which it is applicable; therefore it must be assumed that thisRfD applies to the human population in general. Thus, although ALCOA will now have to usethe revised RfD for all populations in its baseline risk assessment for the site, TDH has flexibilityto use the best available peer reviewed science. It is our opinion that the revised RfD and theMRL should only apply to children and to women of childbearing age. We continue to believethat the science behind the derivation of the old RfD, as it applies to adults not at risk of gettingpregnant, to be valid. Thus, TDH will continue to use the old RfD of 3.0 X 10-4 mg/kg/day in theassessment for adults not at risk of getting pregnant. Since, for all practical purposes, the revisedRfD is identical to ATSDR's MRL, TDH will continue to apply the MRL to children and to thoseadults at risk of getting pregnant.
Page 30, Paragraph 3:
The current MRL has been derived from the lowest observed peak maternal hair level of totalmercury during pregnancy associated with delayed onset of walking in children of a population ofIraqi women. This hair level (14 ppm) was converted to an ingestion exposure level using a onecompartment pharmacokinetic model. An uncertainty factor of 10 was applied to adjust for theuse of a LOAEL to a NOAEL. An uncertainty factor for human variability was not used. Preliminary data from recent studies suggest that the actual NOAEL may be higher; however,these studies are still under peer review. TDH will continue to reevaluate this site as newinformation becomes available.
Page 31, Paragraph 1:
An explanation of what constitutes an "Urgent Public Health Hazard" will be included as anappendix and in the Conclusion section of this preliminary public health assessment.
Page 31, Paragraph 3:
Added the sentence "ALCOA removed employees from the chlor-alkali unit if their urine mercuryconcentrations exceeded 300 µg mercury/L urine." Since medical records were not available toTDH for review we could not comment on whether or not mercury-induced toxicity was present.
Page 32, Paragraph Community Health Concerns Evaluation #4:
TDH has not evaluated medical records of former chlor-alkali plant workers for evidence ofmercury-induced toxicity. No change to this paragraph.
Page 32-33, Paragraph Community Health Concerns Evaluation #7:
Paragraph changed as follows: "Contamination may not be strictly limited to the closure area." Fish exposed to mercury in the closure area may migrate to other areas and be caught along withfish that are not contaminated with excessive concentrations of mercury. Thus, although it maybe possible to find some fish outside the closure area with high levels of mercury, on the average,the levels of mercury in fish caught outside the closure area are low. Therefore, eating fish caughtoutside the closure area should not pose a significant health threat.
Five Black Drum (fish) taken from Keller Bay had concentrations of mercury comparable to thelevels measured inside the Lavaca Bay closure area; however, these fish were larger than the sizewhich may be legally kept. Although the fish with the elevated mercury concentrations wereabove the legal size limit it is still possible than an individual might keep an oversize fish andthereby be exposed to excessive mercury concentrations. Fish from Keller Bay which are withinthe legal size limits should be sampled and analyzed for mercury."
Page 34, Paragraph Conclusion #2:
Paragraph changed as follows: "Persons who have been exposed in the past may also include on-site workers exposed to mercury vapor. Urine samples collected from workers between 1966 to1983 showed elevated levels of mercury. Additionally, anecdotal reports of mercury in washingmachine traps suggest that former chlor-alkali workers may have brought mercury home on theirclothes. Although the likelihood is low that mercury brought to these homes continues torepresent a significant health threat, data to eliminate this as a continued source of exposure arenot available."
Page 35, Paragraph Site Characterization Activities #1:
Recommendation changed as follows: "Continue to sample fish inside the closure area formercury; analyze fish samples for PAHs and PCBs. Sample fish (of legal catch size) at Keller Baynear Rattlesnake Cove; analyze the samples for total mercury (and methylmercury) and provideresults to the Texas Department of Health/ATSDR for evaluation."
Page 35, Paragraph Site Characterization Activities #5:
The recommendation was deleted.
Page 36, Paragraph Site Characterization Activities #8:
Added the phrase: "in accordance with applicable health and safety regulations (29 CFR1910.120)."
Page 36, Paragraph Site Characterization Activities #9:
Paragraph reworded: "Determine if mercury brought into homes by former chlor-alkali workerscontinues to be a source of exposure."
Page 37, Paragraph: Public Health Action Plan #7:
Reworded as follows: "ALCOA will conduct biological monitoring studies on former chlor-alkaliplant workers to assess their current exposure to elemental mercury. The results of these testswill be used to indicate whether exposure above normal background is occurring in homes. TDHwill evaluate these data to assess whether they adequately address the issue of take homeexposure."
|Comment:||Page 1 (Summary) - paragraph 3: include results of USFWS indicating that somepiscivorous birds in the area also contain elevated levels of mercury.|
|Response:||Although the data primarily dealt with non-food waterfowl (the data for the scaup wasconsidered invalid), I added birds to the group of "media" containing elevated mercuryconcentrations in the section on off-site contamination.|
|Comment:||Page 2 (Summary) - paragraph 1: recommendations must include specific informationon estimated exposures from eating catches from the closure area, particularly with regard todose-related recommended limits of fish and crab consumption for children and women of child-bearing age. This is particularly important since the summary is the most likely section of thedocument to be read by the public and local media. The only specific discussion of recommendedconsumption limits is buried in the text on pp. 30-31 and not included in either the "Conclusions"or "Recommendations" sections at the end of the document. The public must be made aware ofthe seriousness of continuing to consume some types of seafood from the closure area.|
|Response:||Added wording in the summary, conclusions, and recommendations that fish/crabsfrom the closure area should not be eaten. In the summary, wording was added to provide thepublic with an idea of how small the portions of fish from the closure area would have to be inorder to avoid adverse health effects.|
|Comment:||Page 3 - paragraph 1: it should be made clear that the "public health significance"assessment was a "review" process of existing literature and recent studies, but did not includeany new toxicological screening of community members.|
|Response:||Inserted "has reviewed available data to evaluate...the public health significance...".|
|Comment:||Page 10 - paragraphs 2 & 5: There's a discrepancy in your estimates of populationsize of Pt. Comfort (956 vs. 1200).|
|Response:||Discrepancy noted and changed in paragraph 5.|
|Comment:||Page 10 - paragraph 5: Formosa Plastics(including downstream facilities) nowemploys 2800+ employees; there are over a thousand at the Point Comfort facility alone. Commercial and recreational fishing are very important economic factors locally; an estimate ofthe percentage of total economic value in the County would reveal just how important. Shouldinclude all seafood-related industries, etc., which might be impacted by the Superfund Site.|
|Response:||Insert number change to "Formosa employs at least 1000..." The total percent economic value of commercial and recreational fishing were not available.|
|Comment:||Page 10-11 - paragraph 6: The city of Point Comfort will be off the Alcoa wells soonand using surface water from Lake Texana. The intake for river water for Port Lavaca is at theUnion Carbide facility in Seadrift, not Tivoli.|
|Response:||Added the phrase "In the past"... "the City of Point Comfort..." And "In February of1995 the City of Point Comfort will begin using surface water from Lake Texana (the Lavaca-Navidad River Authority)." Delete "A detailed well inventory is not available." Changedsentence: the City of Port Lavaca obtains drinking water "downstream of" the Guadalupe and ...deleted "the intake is... Tivoli, Texas."|
|Comment:||Page 11 - paragraph 1: Do you have any data to support statements about themovement of groundwater? No reference is given, is this from monitoring well data from Alcoa? This may be help explain contamination in areas outside the currently designated site.|
|Response:||Reference to the Expanded Site Inspection Report (April, 1993) added to the text.|
|Comment:||Page 11-12 - paragraph 6: For the record, since I am presumably the party identifiedas a "Sierra Club representative", I do not "represent" the Club. Club matters are determined byan Executive Committee process, so I cannot speak for the Club as a whole. Change to SierraClub member.|
|Response:||Changed "representative" to "a Sierra Club member."|
|Comment:||Page 17 - paragraph 4, et.al.: Avoid using "means" to describe mercuryconcentrations. Mobile organisms which show a wide range of mercury levels would better bedescribed in terms of ranges of contamination. It is the "worst case" or highest concentration thatmust be considered in order to determine potential human health impact. (Might be interesting tosee trends in mercury levels over the years expressed as medians also!). Do the data suggest thatseasonal variation in available mercury in the sediments might be affecting mercury levels in crabsand/or fish? What are sampling dates?|
|Response:||The purpose of this section is to present the available data. In some instances themeans are presented; in other instances the highest values are presented. Both the mean and therange of values are presented in the tables. We were not able to determine if seasonal variation ofmercury concentrations was occurring.|
|Comment:||Page 21 - paragraph 1 and Table 6: Levels of mercury in blue crabs outside theclosure area indicate some potential hazard from eating crabs from anywhere in the bay. During some years, ranges and/or means of mercury levels outside the closure area do not appearto differ significantly from levels inside.  Sample sizes are often too small to be meaningful andby compositing samples from Upper Lavaca Bay with those from the Alamo/Magnolia beaches,the data are worthless in determining the extent of contamination.  Again, what effects wouldseasonality have on these data; ie, were samples taken at the same time of year?|
|Response:|| In February and March of 1993 fish samples were collected by TDH. Out of the41 samples collected outside of the closure area, none exceeded 1.0 mg/kg. Of the 44 samplescollected inside the closure area, 18 exceeded 1.0 mg/kg mercury.  Samples from UpperLavaca Bay and Alamo/Magnolia beaches were not composited. Composite samples were madeof crabs of the same sex and collected at the same location.  Samples were collected at varioustimes of the year; however we are not able to address the effect that seasonality might have.|
|Comment:||Page 21-22 - paragraph 2,3 and Table 7:  What are the effects of seasonality? Were the fish of comparable ages? The Woodward-Clyde data suggest that older fish sequesterhigher mercury levels.  Were fish samples from different species composited?  Were thefish outside the closure area sampled by TDH from any particular part of the bay; were theycomposited by area?  What tissues were sampled? All muscle tissue, whole fish, or organmeat?  It is senseless to suggest that local fishermen can be entrusted to throw back any"oversized" fish, when we already know that people continue to fish and crab in the clearlydesignated closure area. Furthermore, it is suggested on p. 24 that subsistence fishing is likely tobe occurring.|
|Response:|| We are not able to comment on seasonality.  Fish were of varying lengths;generally, however, fish of some species increased in mercury concentration with increase in sizeof fish.  Samples from different species of fish were not composited for analysis.  Fishsamples were not composited.  Muscle tissue mercury concentrations from individual fishfillets were reported in this document.  Your point "that just because a fish is larger than whatis legally allowable for catch size does not mean that some individual will not take the fish homefor food" is a good one. Wording to that effect has been included in the document.|
|Comment:||Page 21-33 - paragraphs 6 & 7:  Items 6 & 7 may not be "conservative" enough incautioning local fishermen (and crabbers, for that matter) on the safety of catches outside theclosure area. The data presented in this document do not clearly show how widespread elevatedlevels of mercury are outside the closure area.  Composited samples (as in the crab data;maybe the fish data, too?) cannot identify "hot spots", and the Keller Bay samples indicate thepossibility of a more widespread problem with older (=larger) mobile fish species.  There is adefinite need for more information before the public can be reassured that eating seafood outsidethe closure area is "safe". I would certainly suggest erring on the side of caution here.|
|Response:|| The data from 1993 indicate that with the exception of the Black Drum caught inKeller Bay few fish have mercury concentrations above 1 mg/kg.  The crab samples arecomposited in order to have an adequate sample quantity to analyze. The crabs which are to becomposited are collected in the same sampling location. At this time, from the data we have,eating fish and crabs from other parts of Lavaca Bay appears to be "safe" with regards to mercuryconcentration. In Keller Bay, the mercury concentration in Black Drum appear to be at a levelwhich would not be considered "safe" for children or pregnant women.  We arerecommending additional fish sampling in Keller Bay and periodic sampling in all parts of LavacaBay.|
|Comment:||Page 34 - paragraph 7: I would add something about the fact that contaminated crabshave also been found outside the closure area, again noting that you are not yet able to determinethe public health significance.|
|Response:||We have inserted wording to indicate that limited sampling data suggest that exposuremay have occurred from consuming crabs caught from locations outside of the designated closurearea in the past.|
|Comment:||Page 35 - paragraph 2: Add new signs where needed, especially at Point Comfort ramp and newly proposed ramp in the Olivia area, if it is constructed.|
|Response:||Added the phrase "signs should be added at the Point Comfort boat ramp and in the Olivia area".|
|Comment:||Page 35 - paragraph 5-7:  Cannot limit sampling to Keller Bay as representative ofother "outside" areas.  Fish and crab samples cannot be composited for accurate sitecharacterization; we have to know what species, sex, tissue type, size (=age) and collection site.  Seasonality must also be taken into consideration.|
|Response:|| We have included wording to recommend that Lavaca Bay be periodically sampled for mercury in fish. Keller Bay sampling was emphasized since Black Drum have been observedto have greater than 1.0 mg/kg mercury.  In the past, TDH analyzed individual fish fillets. Crab meat samples were composited to provide enough meat for analysis; these composites wereprepared from crabs taken at the same sampling point. They were of the same sex and generallyof similar size.  We were unable to comment on the seasonality of the data.|
|Comment:||Page 36 - paragraph: Alcoa has admitted that mercury is still being released to the airand the bay during the ongoing processing of the bauxite. The rate of "new releases" must bequantified and potential effects addressed.|
|Response:||Due to results of recent stack tests at ALCOA, ambient air monitors are scheduled tobe set up in the town of Point Comfort in April of 1995. Wording to this effect has been added tothe public health assessment.|
|Comment:||Pages 36-37: Public Health Action Plan needs to be modified in accordance with thecomments made above.|
|Response:||In response to your recommendations the following changes have incorporated intothe Public Health Action plan: #5 TDH will periodically collect additional crab samples from theclosure area and analyze them for mercury. TDH will use these data to re-evaluate the currentban on crabs within the closure area and determine appropriate public health actions as necessary. #8 ALCOA will conduct ambient air monitoring for mercury in the Town of Point Comfortbeginning in April of 1995. #9 TDH will recommend that fish from all parts of Lavaca Bayperiodically be analyzed for mercury.|