Monday, October 26, 2009

FIRESIDE CHAT: Hudson River PCB Dredging and Cooling Tower Air Monitoring

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The presence of cooling towers constitutes a special circumstance involving increased potential for dredging-mobilized PCB to enter the air from Hudson River water. This concern was ignored in GE’s final, EPA-approved Quality Assurance Project Plan (QAPP, GE 2009). The QAPP fails to establish an array of fixed air monitors at cooling towers or at any other key locations, except for four air monitors at the dredge spoil processing facility remote from Phase I dredging activity.

The concern about cooling towers was explicated clearly in a fully peer-reviewed article by myself and co-author Dr. Uriel Oko, published in the Cambridge University Press journal Environmental Practice in 2007. This article is available online, at no charge, at To obtain it, go to Publications, and click on 34, or just go directly to the article at,%20in%20Acrobat/34%20PCB%20Dredging,%20EP%209(2)%202007.pdf.

The basis for concern is fourfold. First, cooling towers draw cold water from the river, including dissolved, colloidal, and suspended contaminants such as PCB recently mobilized by dredging. Second, the water enters cooling towers only after first having been heated by perhaps 100° F by industrial processes that used the water to control temperature to within acceptable limits. Third, hot water in cooling towers may release PCB into the air at an accelerated rate (more than 10 times the rate of emission from cold river water) because they are open to the atmosphere at the top, allowing the water to cool before release back into the river. Fourth, cooling towers are located in the vicinity of populated areas along the river, because that’s where employees and their families live.

Concern about PCB release from cooling towers might have been ignored by GE and EPA, but not by the New York State Department of Environmental Conservations (NYS DEC). Dr. Oko and I expressed concern about this issue in connection with permitting of the Bethlehem Energy Center (BEC). We requested that the cooling tower rely on air cooling rather than water cooling. Accordingly, the permit for the facility required an expensive ‘hybrid’ cooling tower, which can operate on air or water. In the event of PCB mobilization by dredging, the cooling tower could be switched to air cooling to avoid intake of river water containing elevated levels of PCB. This requirement represents ‘voting with your feet’, that is, giving credence to the concern by doing something about it.

Now, GE and EPA should do something about the credible concern about increased PCB release to the atmosphere by industrial cooling towers that rely on water (including all or nearly all cooling towers except BEC’s). GE and EPA should place water samplers and air samplers at cooling towers. The water samplers should monitor PCB levels entering the cooling towers, and the air samplers should monitor airborne PCB emerging from the cooling towers. These monitors should remain in place until the dredging project is completed, and afterward to keep track of the impact of the project and impact mitigation over time.

As a final justification for the measures that I am suggesting, I would like to broaden my perspective. The discipline of health risk assessment evolved from being embedded as part of environmental impact assessment. Indeed, health risk assessments (HRAs), before evolving into stand-alone documents, were embedded as part of Environmental Impact Statements (EISs), which first were required under the National Environmental Policy Act (NEPA) enacted four decades ago, in 1969. Time has allowed retrospective evaluation of the results of NEPA and its State equivalents, State Environmental Quality Review Acts (SEQRAs). Possibly the greatest concern elucidated in such evaluations has been that projects have been approved one by one, resulting in cumulative impacts that no single EIS could have predicted. To overcome this concern, NEPA and SEQRA reformers have suggested undertaking studies of the accuracy of EISs (and HRAs) with respect to the impacts that they had predicted. In the case of Hudson River PCB dredging, this suggestion would include monitoring air, water, and biota along the Hudson River for an extended period beyond completion of the dredging project, to assure that impacts predicted to be within an acceptable range actually were acceptable. For these reasons, in addition to other technical reasons stated above, EPA should require adequate monitoring both during and after project implementation, but it conspicuously has required neither.

Literature Cited

GE RAM QAPP. River PCBs Site, Phase I Remedial Action Monitoring Program, Quality Assurance Project Plan; Final. Prepared for General Electric Company (GE; Albany, New York) by Hudson Liverpool, New York, Anchor QEA, LLC; in conjunction with Valley Forge, Pennsylvania, Environmental Standards, Inc.; Syracuse, New York, ARCADIS; 344 pages, i.p., May 2009.

Copyright © 2009 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation

Sunday, October 25, 2009

FIRESIDE CHAT: Hudson River PCB Dredging and Air Monitoring

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Phase I of GE’s EPA-mandated PCB dredging project focusing on selected hotspots in the most PCB-contaminated sector of the Hudson River ended in mid-October for this year, and probably for next year. This year’s effort failed to complete its PCB removal target, leaving square miles of dredged river surface to release recently-mobilized PCB to the air. An essential public and environmental health measure is to maintain a fixed array of air monitors to quantify airborne PCB levels and variations over the coming months and years. Such information is essential for determining the wisdom and possibly the manner of completing Phase I and entering Phase II of the dredging project. However, GE’s final, EPA-approved Quality Assurance Project Plan (QAPP, GE 2009) fails to establish such a fixed array of monitors:

“Air monitoring for PCBs will be conducted employing samplers operating for 24-hour periods continuously during dredging activities and operation of the sediment unloading and processing facility to verify assessment and demonstration of achievement of the air quality standards for PCBs. Such monitoring will be conducted at locations along the dredging corridor (using two portable locations at each general dredging area) and around the sediment unloading/processing facility (four permanent locations). In addition, monitoring will be conducted throughout the remediation program at a permanent background station situated away from the river upwind of the Phase 1 dredge areas and the unloading/processing facility. Further, a meteorological station will be established at the processing facility to provide meteorological data for use in this air monitoring program” [pages 183-4, emphasis added].

As stated in the QAPP (above), monitoring airborne PCB along the dredging corridor will occur only during dredging activities. That constitutes a two-fold deficiency. First, it fails to put in place a fixed array of air monitors, relying instead on just a single portable air monitor on each shore of the river opposite each dredging unit. Second, as the dredging units progress downstream, they are followed by the air monitors, which therefore cease to monitor the air upstream, where PCB just was mobilized. Yet, as long as PCB-bearing sediments remain on the river bottom (probably decades), PCB transfer from water to air will be a long-term process, and may not reach peak or typical transfer rates immediately. Air monitors must remain for months if not years to quantify airborne PCB levels and variations, characterize the transfer process, and ultimately protect the health of the public and the environment.

The reality is that monitoring for airborne PCB was entirely inadequate during Phase I of the Hudson River dredging project. Its inadequacy increased with each increment in the dredged area of the river, as the portable monitors withdrew downstream with the dredges, and as the river surface area releasing PCBs to the air increased. The inadequacy of airborne PCB monitoring ultimately will progress to complete failure if portable monitors are withdrawn from service at the end of the active dredging season, leaving only four fixed monitors arrayed at the sediment processing facility. EPA should require GE to put in place a fixed array of samplers to overcome the deficiencies documented above.

Literature Cited

GE RAM QAPP. River PCBs Site, Phase I Remedial Action Monitoring Program, Quality Assurance Project Plan; Final. Prepared for General Electric Company (GE; Albany, New York) by Hudson Liverpool, New York, Anchor QEA, LLC; in conjunction with Valley Forge, Pennsylvania, Environmental Standards, Inc.; Syracuse, New York, ARCADIS; 344 pages, i.p., May 2009.

Copyright © 2009 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation

Saturday, October 3, 2009

FIRESIDE CHAT: Hudson River PCB Dredging and Personnel Monitoring

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Numerous General Electric Company (GE) personnel are engaged in EPA-mandated dredging of PCBs from selected ‘hotspots’ in the Hudson River. They may be exposed to PCBs occupationally if assigned, most notably, to either of two general locations: --1. on the water, including any of 12 dredging platforms or numerous supporting barges and tugboats deployed in the dredging corridor, or --2. on the land, primarily including a large dredge spoils ‘processing facility’. These two groups include at least 100 people potentially exposed occupationally, and probably closer to 200. Yet as of 17 September, after 114 days into the project, according to EPA spokesperson Kristin Skopeck, only 243 work-day personal monitoring samples for possible exposure to airborne PCB had been collected for these personnel working at the processing facility and in the dredging corridor combined.

By comparison, if 100 people instead worked in a radiation area, each person would be required to wear a radiation badge all day, every day. Personal exposure would have been monitored daily for each person on all 114 days, producing 11,400 samples. The dredging project, judged by this personal monitoring regimen, generated only two percent of the number of samples that might be expected (calculation: 100 x 243/11,400 = 2.1 percent). Further, EPA has been unable to provide a breakdown of the 243 samples to report what percent were taken in the processing facility vs. the dredging corridor, claiming that such personnel monitoring data are GE property. Thus, at this stage, available information fails to assure that any personal monitoring of dredging corridor personnel has been undertaken at all.

Even if all 243 samples were taken in the dredging corridor, monitoring two percent of workers, workdays, and work locations combined can hardly be deemed to constitute a reliable program, either for personnel protection or for air monitoring at dredge platform locations over the dredged area and project period covered. Available data could represent, at the extremes, inclusion of 100 employees on two percent of 114 days, or one employee on all 114 days. If the number of employees is closer to 200, then the personal monitoring commitment falls from just two percent to even less, closer to one percent.

The argument that personnel monitoring data, as GE property, need not be disclosed by EPA ignores an important public interest in having this information. Specifically, water sampling routinely has occurred approximately five to 6.5 miles downriver from active dredging locations. Levels of airborne PCB arise from PCB in the water: higher waterborne concentrations generate higher airborne concentrations. PCB concentrations in Hudson River water, however, have not been measured anywhere near the dredge platform locations, where concentrations must be most elevated, so PCB concentrations in air at those presumably most-contaminated locations can be known only from direct air monitoring. The public therefore, has a legitimate interest in knowing where and when airborne PCB was measured onboard dredging platforms, and whether air sampling within the dredging corridor has been adequate to characterize PCB levels in air each day and at each dredging location. Moreover, employees on the dredging platforms have a personal health interest in being protected adequately from exposure to airborne PCB, and in knowing whether or not exposure levels were excessive (and to what degree) at any time(s) during their period of duty.

EPA indicated to me that, according to GE, all personal monitors so far have reported non-detect for airborne PCB. The detection levels, however, were reported to correspond to the relatively high occupational exposure limit of 1000 ppm as a time-weighted average over an eight-hour exposure period. Thus, even if air sampling had occurred every day at every dredging location, levels might have exceeded the commercial-zone airborne PCB limit of 21 ppm and the residential-zone limit of 11 ppm as a 24-hour time-weighted average. Exceedances of these benchmark airborne PCB concentrations would be undetected unless they also exceed the occupational standard. Whether they have exceeded the occupational standard can be known only if monitoring has been adequate. The small number of personal monitors, however, strongly suggests that monitoring has not been adequate, and that airborne PCB levels at dredging platform locations are completely or nearly completely unknown.

This lack of information seems potentially serious, because EPA data relating PCB in water to PCB in air suggest that air levels must be excessive at dredging platform locations. Specifically, EPA quantified the relationship between PCB concentrations in water from a cold river and in air a meter above the river surface. For each ug/L (that is, for each 1000 ppt) of PCB in river water, PCB concentrations in air (in ug/M3) were reported to be: a minimum of 0.02, a median of 0.09, a mean of 0.15, and a maximum of 0.40 ug/M3. These values are explained and cited in a fully peer-reviewed article by myself and co-author Dr. Uriel Oko, published in 2007 in the Cambridge University Press journal Environmental Practice. This article is available for download in its entirety, for free, at

The bottom line is that, when waterborne PCB reaches EPA’s 500-ppt stop-dredging benchmark, airborne PCB a meter above the river would be expected to be at about the mean observed value, 0.08 ug/M3. Significantly, that concentration also is EPA’s airborne PCB Level of Concern (LOC). This seems technical and maybe esoteric, until one considers that measurements of waterborne PCB have been taken five to 6.5 miles downstream of dredging locations. Waterborne PCB concentrations at locations of dredge platforms may be thousands of times higher than at locations miles away (ppm rather than ppt), or even millions of times higher (parts per thousand rather than ppt) where liquid PCB oils have been encountered (five locations, I am told by EPA). These massively higher waterborne concentrations imply massively higher airborne concentrations at dredge platform locations… nothing too esoteric about that.

Potential occupational exposure at dredging platform locations may be significantly greater than that implied by EPA’s published relationship of waterborne PCB to airborne PCB. This is because the original EPA data relating airborne levels of PCB over a cold river to the source PCB levels in the river water do not account for dredge buckets in the Hudson River billowing sediments to the river surface as they close, and then lifting sediments and water above the surface, where leakage drops sediments and water violently onto the river surface. These processes must produce abundant droplets (aerosols) of various sizes, all containing PCBs, whereas air samples above river water in EPA’s original data did not include this source of airborne PCB. So, for occupationally exposed individuals, the relationship of PCB levels in water to levels in air must be much worse, exposing them to inhalable PCBs that are volatilized as well as to PCBs that are aerosolized. That unhealthy process happens yet again when the dredges swing their retained load over the barges, and drop them again, this time in their entirety, producing yet another burst of PCB entry into the air in the form of vapors and aerosols near dredge platform personnel.

Though airborne PCB concentrations in the dredging corridor would seem to be higher than EPA’s stop-dredging standards as explained above, the nearest measurements are taken onshore rather than on location. EPA established a stop-dredging standard of 0.11 ug/M3 for airborne PCB in residential zones, and of 0.26 ug/M3 for airborne PCB in commercial zones. EPA also orders GE to stop dredging when the waterborne level is 500 ppt, and presumably the air level is about 0.08 ug/M3, and that has happened on multiple occasions… but the stop-dredging conditions presumptively would exist often if not perpetually at active dredging locations based upon the relationship between PCB concentrations in water vs. air above the water as elucidated by EPA and explained above.

The obvious question is: why are such troubling airborne PCB levels not captured in EPA air samples to either side of the river at dredge sites? The answer is either that I am wrong, which I don’t believe, or that EPA’s sampling process is flawed in a way that causes it to miss the preponderance of PCB entering the air. Indeed, air monitors are moved to follow dredging platforms as they move downstream, so they are relatively close to ongoing dredging. As the recently-dredged area of Hudson River surface expands, however, each onshore monitor becomes less capable of characterizing airborne PCB concentrations area-wide, as they are positioned only to capture airborne PCB from active dredges. As the recently-dredged area increases, the number of onshore monitors must increase commensurately to quantify PCB entry into air from the increasing area of affected river surface.

Onshore airborne PCB monitors also are unlikely to capture the preponderance of PCB entering the air even at the nearest active dredging platform. A major problem with EPA’s airborne PCB sampling procedure is that samples are taken at significant distance from the dredge platform, whereas employees are right there, at virtually zero distance away. Onshore sampling is inadequately protective for dredging personnel. By the time air reaches sampling units on shore, much of the PCB already has dropped out, because aerosols are heavier than vapors, and do not carry as far in air currents (wind). So, EPA samplers are capturing only a fraction of PCBs that dredge employees’ respiratory systems must be capturing. Further, wind speed and wind direction are variable. Only a fraction of PCBs entering the air at the location of dredge platforms (and of people working on them) will reach the sampling units. Dilution in air will have occurred even when the air blows directly toward the samplers. Air samples are 24-hour averages, however, virtually assuring that wind direction will shift, steering airborne PCBs away from sampling units.

I draw four qualitative conclusions from the above observations. The first is that airborne PCB levels to which dredgers and possibly some residents at the riverfront are exposed via inhalation appear to exceed EPA acceptability limits significantly. The second is that the Hudson River PCB dredging project is being conducted in a manner that fails to reliably capture and record such exceedances, if they are occurring. The third is that the burden of proof now rests with EPA to show that its pre-project predictions of no unacceptable health risks associated with PCB dredging are correct, in view of evidence clearly suggesting that they are incorrect. Finally, the fourth conclusion is that the public has an interest in having all of GE’s airborne PCB personal monitoring data made public, especially data taken in the dredging corridor.

Copyright © 2009 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation