responsiveness summary to public comments - US Environmental ...

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EPA Response: Mill Creek was initially listed by MDNR in 1998 due to impairment
from sediment. MDNR subsequently removed sediment and replaced it with habitat-loss for the
2002 list. Ultimately, Mill Creek was delisted by Missouri because no specific pollutant was
listed as the cause of impairment. No new data and/or information has been provided to EPA
that supports the removal of Mill Creek from Missouri’s 303(d) list. The basis for adding this
waterbody back to Missouri’s list is discussed in Enclosure 1 to EPA’s April 29, 2003 decision
letter to Missouri. Therefore, Mill Creek is being retained on Missouri’s 2002 303(d) list for
sediment.
Missouri River
Comment: EPA received 4 letters containing comments which opposed EPA’s listing of
two separate segments of Missouri River for mercury contamination based on fish tissue data
retrieved from EPA’s Storage & Retrieval database (STORET). The two segments are from the
mouth of the Chariton River to Kansas City, and from the mouth of the Kansas River to State
line. In general, it was commented that: (a) EPA did not consider all readily available Missouri
River fish tissue mercury information and appears to have ignored more recent sampling data
collected after 1995 showing fish tissue mercury concentrations below the 300 parts per billion
(ppb) trigger level; (b) EPA may not have consistently applied fish tissue criteria relative to
species of interest; (c) EPA did not apply appropriate analytical methodology; (d) EPA did not
apply appropriate statistical analysis of available data; (e) Missouri has not adopted a numerical
water quality standard for mercury for Human Health Protection-Fish Consumption. Therefore,
EPA’s methyl-mercury criterion should not be used as the basis for listing before Missouri adopts
it as a State water quality standard (WQS); (f) EPA did not identify the source of the alleged
mercury impairment.
EPA Response: As a result of EPA’s public comment period, more recent Regional
Ambient Fish Tissue (RAFT) monitoring data that had not been entered into STORET was
located. EPA Regional Laboratory analyses of whole fish specimens (5 fish per sample)
collected at locations on the Missouri River at St. Joseph and Kansas City since 1995, indicated
that the Missouri Department of Health & Senior Services trigger level and EPA’s
Recommended Criterion of 300 ppb mercury are not exceeded. Therefore, based on the more
recent data, presented in the table below, EPA is removing mercury as a pollutant of concern for
the two listed segments of the Missouri River.
Collection dates Results
8/9/2001 for Station #101 - Missouri River at Kansas City 38 ppb
8/21/2001 for Station #102 - Missouri River at St. Joseph 82 ppb
75 ppb (Field Duplicate)
9/10/99 for Station #6 - Missouri River at St. Joseph 26 ppb
9/13/99 for Station #7 - Missouri River at Kansas City 44 ppb
45 ppb (Field Duplicate)
10/3/97 for Station #6 - Missouri River at St. Joseph 83 ppb