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Text Box: On November 30, 2010 the USEPA issued its comments about an annual surface water and sediment monitoring report for Green Pond/Bear Swamp brooks. This particular report was dated August 2010 and it was the annual monitoring report for 2009.  Monitoring included chemical and toxicity testing of water samples from the respective brooks.  

The USEPA provided several general comments.  For example, the agency pointed out that the use of the term “significant” has little meaning unless backed up by statistical analysis.  The USEPA comment was as follows:  
 
‘1.  The Report concludes that concentrations of all contaminants of concern (COCs) in Regions 2, 3, and 4 are stable or decreasing.  Data trend plots presented in Appendix B are said to support that claim.  However, there is significant variability in the data, and it is difficult to determine whether the conclusion is supported.  Data for Region 2, in particular, do not appear to consistently decrease over the three year monitoring period.  It appears that, given the amount of variability displayed across sampling events, no trends can be discerned.  In addition, the document repeatedly discusses what it terms “significant” trends.  Without statistical analyses, the term “significant” has no clear meaning.’  

Since statistical analyses were not specifically requested it is unclear how the document might be revised by Picatinny Arsenal.

The second general comment also related to testing results with statistical means to determine their representativeness.  In this case, either the sample was not representative of site conditions or the results could be suspect and that therefore additional monitoring may be required.  USEPA stated the following: 

 ‘2.  The Report discounts the results of toxicity tests for Chironomous dilutus, stating that they are not representative of Site conditions.  The Report notes that the 20-day survival and growth tests did not

Surface water and sediment monitoring for green pond/bear swamp brooks

meet the minimum recommended criteria for growth and survival.  However, the long-term survival and emergence test did appear to have sufficient survival rates (77%) to meet the recommended criteria.  It may be appropriate to statistically evaluate the conclusion that the test results are not representative of conditions at the Site prior to discounting the results. Additionally, it may be useful to discuss the results with the caveat that they may be suspect and further monitoring is needed to help determine their validity. ‘

 

 

 

Finally, the USEPA pointed out a notable flaw in an argument that was used to suggest that toxicity was related to “low quality habitat” in a laboratory sample as follows:

 3.  The Report suggests that toxicity in samples with contaminant concentrations not exceeding remediation goals (RGs) was likely caused by other stressors, including low quality habitat. However, toxicity tests, in which the only known difference between the test and control samples is sediment quality, should provide evidence regarding whether contaminant concentrations in sediments at the Site are a causative factor of reduced survival or growth.  Although the habitat assessments indicated that habitat quality (as measured by factors including available cover, pool variability, sediment deposition, channel flow, channel sinuosity, bank stability, bank vegetation characteristics, and taxa richness and diversity) at the Site was marginal or sub-optimal, and those factors could certainly

 

 

Scenic Image of Body of Water

affect macroinvertebrate diversity and abundance in the field, it is not clear how those factors would impact survival in the lab. While it is possible that sediment geochemical characteristics (e.g., organic carbon content, grain size, or other factors) could be responsible for toxicity, in whole or in part, it does not seem reasonable to conclude that just because RGs were not exceeded, toxic effects are not evident.’

 

In one of the USEPA’s specific comments it appears that the conclusion of remedial actions having been effective at reducing concentrations of COCs is deemed by the agency’s analyst to be premature.  Based on a comparison of results from 2009 to those from 2008, it would seem that the concentrations decreased. But the USEPA pointedly noted that results from 2007 were actually lower than those from both 2008 and 2009.  Therefore the USEPA noted that “it is premature to conclude that the remedial actions have been effective at reducing concentrations of COCs” and also that “a significant trend has not been demonstrated in any contaminants measured.”

 

Mr. Ted Gabel (US Army Project Manager for Environmental Restoration) stated in a February 24, 2011 e-mail that the Army Team; which includes himself and such individuals as Mr. Tim Llewellyn of Arcadis and Ms. Laura Pastor of Weston, Inc.; offers the following relevant comments in reference to PICA 193 (Green Pond Brook):

 

“Additional sampling was conducted at all locations in 2010 and the Annual Report is being prepared. Sampling at these same locations is also planned for 2011. Following 2011, the 5 years of data will be comprehensively reviewed and the Army will present the findings and recommended future actions to the USEPA and NJDEP. These recommendations will be based on the agreed exit strategy that was presented in the Remedial Action Work Plan (Shaw, 2007) for this site.”

 

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