Friday, February 26, 2010

NEWS: Cadmium in children's and adults' jewelry

Associated Press
2 stores pull necklaces on toxic cadmium concern
By JUSTIN PRITCHARD , 02.04.10, 06:40 PM EST

LOS ANGELES -- The teen fashion chain Aeropostale and outlet stores of upscale Saks Fifth Avenue have pulled from shelves necklaces that an environmental group's tests showed have high levels of the toxic metal cadmium.

Aeropostale, Inc. (ARO - news - people ) went one step further, saying Thursday that from now on, no amount of cadmium will be acceptable in its jewelry - and that suppliers will have to prove products are clean with independent lab testing.

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The announcements are the latest fallout from an Associated Press investigation which last month reported some children's jewelry is contaminated with cadmium, a known carcinogen that also can harm bones and kidneys.

In response to that reporting, the California-based Center for Environmental Health tested adult jewelry bought at stores including Aeropostale and Saks ( SKS - news - people )' Off 5th outlets, and this week threatened to sue the retailers after lab results showed between 25 and 75 percent of the items' total weight was cadmium.

The announcement from Aeropostale was significant because it represented the first time a company has said it is effectively banning cadmium in adult jewelry. Aeropostale has more than 900 locations in the United States and Canada.

Cheap metal jewelry worn by children and typically imported from China has to date been the focus of reaction by federal regulators, lawmakers and retailers. Kids are of particular concern because they bite or suck on jewelry and thus are more likely to be exposed to any cadmium it contains.

Saturday, February 20, 2010

FIRESIDE CHAT: Hudson River PCB Dredging Phase 1 Evaluation

A two-day public meeting of the Hudson River PCB Dredging Peer Review Panel was held at the Gideon Putnam Hotel in Saratoga Springs, New York on Wednesday and Thursday 17-18 February. My oral comments to the Panel on Wednesday alluded to analysis of GE’s ‘bucket files’ (1), which are computer registers recording each closure of a dredge bucket in each delineated five-acre work area (‘Certification Unit’, or CU) in the Phase I dredging area. From my analysis of these GE files I concluded that the preponderance of sediment disturbed by dredge buckets was left in mobile form on the river bottom, not placed in waiting barges.

The GE bucket files are available for free via download from GE's dredging website, as Table G-1 in Appendix G of GE’s draft Phase I Dredging Evaluation Report. The pdf format in which the 44-page file is provided, however, precludes numerical analysis of the data without extensive manipulation. To conduct my analysis, I converted the file into a Microsoft Excel (.xls) file. As the pdf version originally provided by GE contained built-in impediments to such conversion, the Excel version that I prepared represents the product of days of labor. The Excel version, therefore, is being offered for sale (click on the Title field above to be taken to the purchase page if you are interested).

Using the bucket closure file, I analyzed the number of bucket closures in each five-acre dredging Certification Unit, and related this to separately-reported information about the volume of sediment placed in barges. This analysis is presented in the SYNTHESIS tab of the xls file that I created. Finally, I abbreviated this analysis by combining all CUs to create a BRIEF tab, or see figure below.


The figure summarizes the quantitative support for my oral statement that the preponderance of dredge-disturbed sediment is left on the river bottom, not barged. My written comments to be submitted formally to the Panel (via the facilitator) will show, further, that PCB in these sediments is more mobile than in the original buried state, which ironically is the physical state that EPA’s strategy of capping dredge prisms seeks to restore. From the river bottom, resting sediment piles produced by Phase I dredging gradually (perhaps over years) can and will erode. Some sediment will travel downstream, to be measured by GE in the EPA-mandated ‘resuspension’ monitoring program.

The preponderance of PCB, however, may not go downstream. EPA’s criterion of ‘benefit’ of the dredging project therefore is illogical. The ‘benefit criterion’ allows no increase in downstream transport of resuspended sediment during the planned six-year duration of the project. Instead, under the benefit criterion, downstream transport may be increased by dredging in the short term only in amounts that will be offset by future decreases over the longer term, meaning the project duration. This benefit criterion is illogical because it assumes incorrectly that potential dredging impacts consist of nothing more than downstream transport of resuspended sediment, whereas this appears to constitute a relatively minor contributor to total potential dredging impacts.

Specifically, EPA’s benefit criterion fails to consider demonstrated increases in the amount of PCB released to other ecosystem compartments. The amount of such release may greatly outweigh the amount resuspended and addressed by EPA’s “benefit” criterion. Much if not most dredge-moblized PCB-tainted sediment will enter ecosystems, including migrating species of fish and birds, and much will enter the air. For example, whereas resuspension has approximately doubled in downstream areas, PCB concentration in fish tissue (filets) already has increased approximately fivefold, and organs such as the liver might have increased even more; the liver represents the filter for toxins consumed by the fish.

A major concern relates to risks potentially posed to human health. Apart from participation of people as ecosystem components at the top of the food chain, I am concerned about airborne PCB, which is derived from PCB released to the water and largely unmeasured. In that regard, I will urge the Panel to demand delivery of the results of personal monitoring samples taken on dredge platforms (minus employee identifying information). These samples generated the only data of which I am aware that reflects airborne PCB levels produced by dredging, at the location of dredge platforms. These samplers all operated with sensitivity to the occupational airborne PCB limit of 1,000 ug/M3, which is over 9,000 times EPA’s residential limit of 11 ug/M3… so these samples all had better be negative, but nobody I spoke with has been willing to say that they were indeed consistently negative. Rather, EPA told me that the data belong to GE, and GE told me that the data belong to its contractors. Information of possibly critical concern to the public clearly has been ‘compartmentalized’ out of public view… and members of the pubic and the Peer Review Panel have an opportunity to demand an end to such compartmentalization.

EPA asserts that portable air monitors placed on each shoreline adjacent to each dredge platform should do the air monitoring job. This is not the case. These monitors do not receive aerosols that fall back to the river before reaching shore. They do receive air, but the air they receive comes from all directions, 360 degrees, and only rarely from the direction of their adjacent dredge platform. The 24-hour samples recorded, therefore, all are massively diluted, not reflective of airborne PCB levels over the river. Finally, these monitors routinely are withdrawn downstream with their adjacent dredge platforms and, at the end of Phase I, they are withdrawn from service altogether… all very likely long before PCB release from the river surface to the air reaches a maximum or a steady state.

In short, the monitors are withdrawn before they can characterize the evolution of PCB release to the air over the six-year planned life of the project and beyond. Indeed, as the acreage of dredged river increases, the number of monitors per acre declines, but the fraction of river surface contributing to air levels over the river and on shore increases… never to be measured because the monitors that could have measured these evolving levels were withdrawn from service. I call this ‘hit-and-run dredging’. My formal comments to the Panel, therefore, will assert the need for a permanent array of air monitors to capture the evolution of PCB release levels as the fraction of river bottom dredged increases, and as PCB-tainted sediments are restratified and processed by physical, chemical, and biological processes of degradation, mobilization, and eventual release to ecosystems and the atmosphere.

Given the Phase I experience of massive sediment mobilization by clamshell dredging, I have raised the issue of whether dredging should continue with Phase II. This issue is specifically precluded from Peer Review Panel consideration, but it should be added to the purview of the Panel. If Phase II is to be implemented, alternative technologies should be considered, such as use of dredging enclosures (one technology of this sort is termed ELB, for Environmental Lunch Box) and/or hydraulic dredging (also termed vacuum or suction dredging).

As a final issue I introduce the movie version of Isaac Asimov’s wonderful Sci-Fi novel “I Robot.” The holographic image of the deceased robot inventor advises that “My responses are limited… You must ask the right question.” In evaluating Phase I of the Hudson River PCB dredging project, some of the wrong questions have been asked; and wrong, irrelevant, or only partially relevant answers therefore obtained. I give several examples of how the wrong questions can be and should be converted to the right questions:

--1. SHEENS
WRONG: What is the composition of PCB sheens found during dredging?
RIGHT: Where is the source of the sheens, and what is their composition, volume, and potential for mobilization with further (clamshell) dredging?

--2. DREDGE PASSES
WRONG: What is the optimum number of dredge passes needed to complete and close a five-acre dredging Certification Unit?
RIGHT: What is the minimum number of dredge bites (or ‘cuts’), and therefore the minimum degree of mobilization of PCB-tainted sediments, associated with completing and closing a five-acre dredging Certification Unit?

--3. RESUSPENSION
WRONG: What strategies can be employed to keep resuspension and downstream transport of PCB-tainted sediments within acceptable limits defined by EPA’s benefit criterion?
RIGHT: What strategies can be employed to keep dredging impacts, including resuspension and downstream transport, within acceptable limits?

--4. AIRBORNE PCB
WRONG: What concentrations of airborne PCB are measured by mobile detectors on opposite shores adjacent to dredge platforms?
RIGHT: What are the anticipated maximum, steady state, and evolving air impacts of PCB dredging at Hudson River communities during active dredging, between dredging Phase I and Phase II, and following dredging completion as modeled for a perod of years, and as confirmed by a permanent array of air monitors if further dredging goes forward?

Issues raised above are amplified and technically supported in earlier posts on this blog.

LITERATURE CITED

1. GE. Phase I Evaluation Report: Hudson River PCBs Superfund Site. Draft report prepared for General Electric Company (Albany, New York) by: Anchor QEA (Glens Falls, New York) and Arcadis (Syracuse, New York); 191 pages plus tables, figures, and appendices; Appendix G, Table G-1, 44 pages; January 2010.

Saturday, February 6, 2010

FIRESIDE CHAT: Hudson River PCB Dredging: The Case of the Shifting Sediment Mobilization Definition



In my 4-February post, I called attention to a major discrepancy between sediment mobilized in Phase I of GE’s EPA-mandated Hudson River PCB dredging project vs. the much smaller amount of sediment mobilization measured and reported by GE and EPA. Sediment mobilization as reported refers to the amount that is ‘resuspended’ by dredging, and monitored miles downstream of the Phase I dredging area, almost all of which is near Roger’s Island. As EPA also has reported, however, most dredged sediment falls back to the river bottom in the trench or near the spot from which it was dredged initially. Thus, the preponderance of mobilized sediment remains on the river bottom, still mobile, but unrecorded in GE or EPA sediment mobilization data... hence the ‘sediment mobilization discrepancy’.

The sediment mobilization discrepancy is more than merely a difference between a measured and an actual parameter value. Rather, it is a fundamental inconsistency in EPA’s past justification of the need to dredge vs. the Agency’s current characterization of the performance of the dredging project now that it is underway. The need for dredging was justified by the mobility of sediments in PCB ‘hotspots’ requiring, according to EPA, their removal by dredging. Indeed, a small but persistent trickle of buried PCB moving downstream was documented from some 27 PCB hotpsots.

In contrast, in the new context of actual dredging, EPA dramatically altered its concept of mobility. Mobility in the dredging project now is quantified by the lightest-weight fractions of PCB-tainted sediments measured in the water at the Thompson Island Dam about five miles downstream of Phase I dredging, and further downstream at Lock 5 and still further downstream at Waterford (see EPA’s figure, below).



Don’t be confused by EPA’s altered terminology, referring to mobilized sediment as ‘resuspension’ estimates. These estimates reflect near-term mobilization, and ignore the fact that all of the sediment that falls back to the riverbed also is ‘mobilized’, in the original sense of that term as used by EPA to justify dredging. That is, it is mobilized because it can re-enter the water column whenever turbulent conditions arise, and it can enter riverine ecosystems. It can be transported by migrating organisms, such as fish and birds, and it can enter the air in communities directly from the water, or from heated sources of water (cooling towers) used to cool industrial processes, such as in factories and power plants.

In past posts I estimated that 80 percent of sediment disrupted by dredging was mobilized rather than transferred successfully to barges. In my 4-February post I used GE’s ‘bucket files’ (1), recording dredge bucket hauls on onboard computers on each dredge platform, to better quantify this estimate. The best number that I came up with is 74 percent for the five-cubic-yard capacity bucket typically used, but that excludes sediment that is disrupted by dredge buckets when they crash to the bottom but fail to close due to obstructions such as boulders or construction debris. The 80-percent estimate therefore looks pretty good, though I can quantify only a 74-percent estimate, and only approximately as explained in my 4-February post.

The mobilized fraction of sediment, therefore, amounts to about 211,000 cubic yards of sediment, which is about 100 million kilograms, assuming a dredged sediment density of about 0.6 compared with water. Yet, EPA’s figure reports 388 kg at Thompson Island, 226 kg at Lock 5, and 122 kg at Waterford. Ignoring the obvious double-counting, EPA reports 736 kg of mobilized ‘resuspended’ sediment, which most would agree is less than 100 million kg. Thus, EPA’s figures exclude nearly all mobilized sediment… EPA simply ignores it in evaluating the performance of the dredging project, notwithstanding that the mobility of sediment was a central rationale for dredging in the first place.

Literature Cited

1. GE. Phase I Evaluation Report: Hudson River PCBs Superfund Site. Draft report prepared for General Electric Company (Albany, New York) by: Anchor QEA (Glens Falls, New York) and Arcadis (Syracuse, New York); 191 pages plus tables, figures, and appendices; Appendix G, Table G-1, 44 pages; January 2010.

Copyright © 2010 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation

Thursday, February 4, 2010

FIRESIDE CHAT: Hudson River PCB Dredging: The Case of the Sediment Mobilization Discrepancy



Sediment mobilization in Phase I of GE’s EPA-mandated Hudson River PCB dredging project is monitored miles downstream of the Phase I dredging area, almost all of which is near Roger’s Island. Available data, therefore, reflects mobilization of PCB-tainted sediment that enters the water column and remains waterborne over miles of downstream river flow. As EPA has reported, however, most of the dredged sediment falls back to the river bottom in the trench or near the spot from which it was dredged initially. Thus, the preponderance of mobilized sediment remains on the river bottom, still mobile, but unrecorded in GE or EPA sediment mobilization data... hence the discrepancy between mobilized sediment vs. sediment mobilization measured and reported by GE and EPA.

Sediment that rests on the river bottom is termed ‘mobile’ because it can enter the riverine ecosystem and food chain, from which it can disperse further, such as in migrating fish and birds. These previously buried sediments, now mobile, also can re-enter the river flow in turbulent conditions, such as in storms. From the water, PCBs also may enter the air, and may be inhaled by people in affected communities. These outcomes constitute compelling reasons to monitor mobilization of dredged sediment, not just to learn about the near-term flow of the lightest-weight PCB fractions over the Thompson Island Dam and Troy Dam miles downstream, but also to learn about the long-term transport of all mobilized PCBs into ecosystems and the air, and their possible bioconcentration in organisms.

Design of the dredging project conspicuously omits holistic quantification of sediment mobilization that is needed. The evolution of technology, however, seems to have introduced a kind of ‘back-door’ way of quantifying sediment mobilization, at least approximately. Specifically, dredges used in the project are computer-controlled to keep them operating within defined dredging ‘prisms’ corresponding to PCB ‘hotspots’ slated for removal. Each time a dredge bucket descends to the river bottom, it can do either of two things: close, or remain opened. If the bucket remains opened, it still has massively disrupted and mobilized a significant amount of sediment, as these buckets weigh tons, and they are large. The five-cubic-yard capacity bucket typically used has two sets of jaws that are nearly 15 feet in length. These massive jaws crash to the river bottom violently, thereby mobilizing much sediment and removing none of it. Obstructions in the river bottom, such as boulders or construction debris, sometimes prevent closure. In those cases the dredge bucket may be crashed to the river bottom repeatedly before withdrawal unclosed. My guess is that closure fails to occur between one and 10 percent of the times that a bucket descends to the river bottom. These sediment mobilization events, unfortunately, are not recorded.


In most cases, presumably, the dredge bucket does close, at least partially, and those cases are recorded by onboard computers on each dredge platform. Also in those cases, even more sediment is disrupted and mobilized. Sediments within closing dredge bucket jaws are forced upward, with much material billowing out of the open tops of dredge buckets and into the downstream river flow (see photo above). The slurry of sediment and water that remains within the bucket, which typically leaks from the bottom, is released gradually to the water column and, upon emerging, drops back to the river surface (see photo below). As sediment is concentrated at the bottom of each dredge bucket, much if not most of the material that leaks back into the river is sediment (not just water).


GE’s dredge platform on-board computer records may be used to quantify the number of bucket closures. Indeed, GE published its ‘bucket files’ in its recent draft report (1) as Table G-1 in Appendix G. This information can be combined with GE’s separate records of the volume of material that was retained by the buckets, even after all these losses, and placed into barges. A summary of my analysis of this information is presented in the table below.


As the table indicates, the preponderance of dredged material was not barged, but mobilized. The exact fraction mobilized depends upon the capacity of the dredge buckets that were used. The dredge bucket capacity in turn depends upon the maximum capacity of each bucket and the depth of its bite into the sediment, both of which were variable because three bucket sizes were used, and sometimes they did not penetrate to their full design depth, for example if they struck a boulder or construction debris. The standard bucket capacity was five cubic yards with a design penetration depth of 18 inches. My understanding is that the five-cubic-yard bucket was used routinely, except in sensitive spots, say near shore, when a one-cubic-yard capacity bucket sometimes was used. The project also had one two-cubic-yard bucket. I further assume that the design penetration depth was typically the target depth, so the overall average bucket capacity probably was close to five cubic yards.

As the above table shows, Phase I dredging pulled out 286,006 cubic yards of sediment (actually a slurry of sediment and river water), which went into barges (topped by a layer of water). The dredge buckets closed 221,521 times, producing an average load of 1.29 cubic yards per bucketload that was transferred to the waiting barges (including the water). The amount of sediment that will be shipped by train to Texas will be less, because sediments must be dried before loading. Even using the larger figure as the estimate of barged ‘sediment’, however, the amount barged still is only 26 percent of an assumed five-cubic-yard average bucket capacity, or 32 percent of a four-cubic-yard capacity, or 43 percent of a three-cubic-yard capacity.

That means that the amount of sediment that was mobilized was 74 percent if the average bucket capacity is assumed to be five cubic yards, 68 percent if the average bucket capacity is assumed to be four cubic yards, and 57 percent if the average bucket capacity is assumed to be three cubic yards. Whatever assumption you choose, the preponderance of material was mobilized, not barged. Whatever assumption you choose, still more was mobilized when the dredge buckets descended but failed to close. Some of the mobilized sediment, however, might be dredged again, and a fraction removed from the river, if the sediment falls back to the river bottom within a ‘prism’ slated for future dredging.

Literature Cited

1. GE. Phase I Evaluation Report: Hudson River PCBs Superfund Site. Draft report prepared for General Electric Company (Albany, New York) by: Anchor QEA (Glens Falls, New York) and Arcadis (Syracuse, New York); 191 pages plus tables, figures, and appendices; Appendix G, Table G-1, 44 pages; January 2010.
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Copyright © 2010 by The Center for Health Risk Assessment and Management, a Division of RAM TRAC Corporation