Polychlorinated Napthalenes

[snickerd3]

Has any encountered polychlorinated napthalenes (PCNs) when trying to address PCBs?

The Army has found PCNs in an area we all thought was just PCB contamination. Just looking for info since Illinois doesn't have cleanup values for these contaminants.

 

[RIP - VTEnviro]

Damn, I used to do PCB research to make a few bucks as an undergrad.

I've never heard of PCNs before.

PCN's - Wikipedia

Oooh, a bioaccumulation factor of 10,000 and are apparently recalcitrant. Nice stuff.

 

[Guest]

Snickerd --

I have to admit that your post on PCNs was the first time I had ever heard of this class of chemicals.

I was looking over the toxicity data in the following publication http://www.unece.org/env/popsxg/docs/2000-2003/pcn.pdf and I noted that Table 5 on Page 9 provides toxicity equivalent factors (TEF) to 2,3,7,8-TCDD based on a number of congeners.

I cannot speak for Illinois, but the approach in Florida would be to apply risk-based corrective action (RBCA) principles. Our state has codified in Florida Statute 376.30701, F.S. and Florida Administrative Code 62-780, F.A.C. criteria that soil and groundwater media must be cleaned up to a carcinogenic risk level of 1E-06 or non-carcinogenic risk level of hazard index (HI) = 1.0. The carcinogenic risk level is based on the CUMULATIVE risk presented by all carcinogenic constituents identified as Chemicals of Concern (COCs).

So, as a regulator, I would be looking for a sampling plan that was inclusive of the congeners listed in Table 5, Page 9 of the linked publication above. I would apply the TEF factor to each constituent and take the summation of those constituents to see if they exceeded the 1E-06 risk level. Again, I caution that this is based on Florida's codified statute and rule - other state's may vary or only have guidance.

There is a pre-set spreadsheet for Dioxin Equivalents located at http://www.dep.state.fl.us/waste/categorie...htm#Calculators. I tried to upload the Excel sheets, but my efforts were blocked. This sheet will give you an idea of how to set up this type of analysis.

I hope this discussion provides some direction. If you have any further questions, please feel free to PM and we can discuss further by e-mail. I review workplans for risk-based corrective action

Regards,

JR

 

[snickerd3]

Thanks for the info. We are still in early discussions and trying to comply as much information as we can. We don't have the actual values yet...the lab called halfway through the running all the samples saying PNCs not PCBs were showing up.

As the decision document has already been signed sealed and delivered, this is going to cause a small hiccup.

 

[RIP - VTEnviro]

I cannot speak for Illinois, but the approach in Florida would be to apply risk-based corrective action (RBCA) principles. Our state has codified in Florida Statute 376.30701, F.S. and Florida Administrative Code 62-780, F.A.C. criteria that soil and groundwater media must be cleaned up to a carcinogenic risk level of 1E-06 or non-carcinogenic risk level of hazard index (HI) = 1.0. The carcinogenic risk level is based on the CUMULATIVE risk presented by all carcinogenic constituents identified as Chemicals of Concern (COCs).

Sounds just like the risk assessment section of the Envl PE exam...

Do you have a potency factor for PCNs?

Also, I don't know much about PCNs, but is the problem oral or inhaled? Because it doesn't seem like you'd ingest much soil.

 

[snickerd3]

The area in question is going to be included in a prairie restoration project, so there could be the potential for basically everything inhalation, ingestion, dermal (can cause chloracne).

 

[Dleg]

I've never heard of it either. All I can find on IRIS is this:

beta Chloronaphthalene

We had a really cool quick Environmental Screening Level writer developed for the CNMI by EPA region 9 just a little over a year ago. It's all risk-based stuff, using typical values for our soil types, etc., so it's not the same as a site-specific risk analysis, and it's not set up for anyplace other than the CNMI. And, it doesn't have PCNs. But it's still pretty cool - you enter your land use (e.g., residential), groundwater use, soil depth, and it will spit out your "Final Tier 1 ESLs" for the chemical of your choice.

I tried to upload it but it's too big - you can download it yourself if you're interested here Just scroll down the page to "Excel Files" and choose the (wrongly-named) "Tier 2 Direct Exposure Spreadsheet" It's pretty cool, at least for us out here in the islands.

You should ask if the state of Illinois has something like this, and then maybe you can use it to plug in the numbers from IRIS for the beta-chloronaphthalene, if that works as a representative PCN.

 

[Guest]

VTE --

RBCA is a framed on using known human health risk assessment data within a framework to arrive at 'cleanup' targets instead of trying to promote cleanup from prescribed cleanup levels. RBCA embraces the notion that cleanup is achieved when the 'risk pathways' have been reduced/abated as opposed to the chemicals remediated to a prescribed threshold.

I don't perform human health risk assessments in my job - I leave that to the toxicologists/risk assessors. However, I do take that information and within the RBCA framework see if recommended actions make sense (e.g. Institutional Controls, Engineering Controls, Leave it as is, etc.)

Dleg--

You are right on the money! US EPA Region IX Preliminary Remediation Goal (PRG) values are based on the risk-based corrective action approach to remediation.

The Region IX PRG values are based on a 1E-06 value, but EPA does promote the idea that ACCEPTALBE risk can range from between 1E-04 and 1E-06 depending on circumstances/scenarios. Some states also allow for risk as high as 1E-04, but Florida has set the risk value at 1E-06 regardless of the scenario.

The unsaid factor that is really driving how these values are applied is based on how each state has promulgated/codified this framework. Many states (and other agencies) simply have these risk-based principles established as guidance, some states have criteria, and then some states have standards (note the hierarchy of 'enforceability'). Florida was the first state to promulgate standards for applying RBCA principles to all of the waste management programs (RCRA, Brownsfield, Petroleum, etc.). I am not sure how many other states have followed suit, but I think it is fair to say that the risk-based principles are primarily taken as 'guidance' and not rules at this point in time.

snickerd --

Please let us know how things develop as your client permits.

JR