SPS!IS Document ID 1052370 GEI \X';itcr ResGi.irct.-i Lnvironniental jjiel PRELIMINARY Lxtilogical Services EVALUATION OF POTENTIAL SITE-SPECIFIC ZINC AND CADMIUM STANDARDS FOR THE UPPER ARKANSAS RIVER, SEGMENTS 2B AND 2C TECHNICAL MEMORANDUM Submitted to: Resurrection Mining Company Submitted by: GEI Consultants, Inc./ Chadwick Ecological Division 5575 South Sycamore Street, Suite 101 Littleton, Colorado 80120 September 2006 Project 062510 Iff!-' PRELIMINARY EVALUATION OF POTENTIAL SITE-SPECIFIC ZINC AND CADMIUM STANDARDS FOR THE UPPER ARKANSAS RIVER, SEGMENTS 2B AND 2C TECHNICAL MEMORANDUM Submitted to: Resurrection Mining Company Submitted by: GEI Consultants, Inc./ Chadwick Ecological Division 5575 South Sycamore Street, Suite 101 Littleton, Colorado 80120 September 2006 Project 062510 Steven Canton Project Manager Table of Contents Section 1 - Background 3 Section 2 - Determination of the Appropriate Residential Fauna 4 Section 3 - Approaches to the Development of Site-Specific Standards 8 3.1 Potential Site-Specific Acute and Chronic Criteria for Zinc 8 3.2 Potential Site-Specific Acute and Chronic Standards for Cadmium 17 3.3 Proposed Site-Specific Zinc and Cadmium Standards 20 Section 4 - References 22 List of Tables Table I General macroinvertebrate groups identified from benthic samples collected spring and fall (2000-2005) from the Upper Arkansas River, Segments 2b and 2c. Table 2 New acute and chronic zinc data from the literature review included in CEC et al. Table 3 Updated acute toxicity database for zinc, with genus mean acute values (GMAV) and species mean acute values (SMAV) ranked from least sensitive to most sensitive genus (all normalized to hardness = 50 mg/L by updated slope = 0.8537). Table 4 Summary of current Colorado table value standards (TVS) and updated zinc criteria at varying hardness levels using updated toxicity database, revised pooled-hardness slope, and updated acute-chronic ratio. Table 5 Site-specific acute zinc toxicity databases for the Upper Arkansas River, Segment 2b and Segment 2c. Table 6 Recalculation of the acute and chronic site-specific zinc standard for Segment 2b of the upper Arkansas River (N = 26 genera, R = sensitivity rank in database). Table 7 Colorado chronic cadmium loxicity database ranked by genus mean chronic values (GMCV) normalized to hardness = 50 mg/L as CaCO3 , with the chronic toxicity hardness slope (0.7998). Table 8 Updated cadmium acute-chronic ratio from CEC (2004c). Only bold values were used in the final acute-chronic ratio (FACR) calculation. Table 9 Summary of existing Colorado TVS and proposed site-specific zinc and cadmium standards for Segments 2b and 2c of the upper Arkansas River at varying hardness levels. All values are u.g dissolved zinc or cadmium/L. 0625ID I l-OV-05 Preliminary I-v;iluation of PolcntiaJ Site-Spec September 2006 List of Figures Figure 1 The relationship between the species mean acute values (SMAV) and species mean acute-chronic ratios (SMACR) (log-log scale) for cadmium. List of Appendices Appendix A Benthic Macroinvertebrate Summary Appendix B Upper Arkansas River, Segments 2b and 2c 052510 I Ml'Mtt Preliminary EvaJualion of Potential Siie-Spec September 2006 Section 1 - Background At the request of Resurrection Mining Co., GEI Consultants, Inc./Chadwick Ecological Division (GEI/CED) has evaluated the potential for deriving site-specific standards, in the form of hardness based equations, for zinc and cadmium for the Upper Arkansas River. These potential site-specific standards would be for Segments 2b, and 2c of the Upper Arkansas (CDPHE 2006) representing the first two segments downstream of California Gulch. Segment 2b includes the section of the upper Arkansas River from a point immediately upstream of the confluence with California Gulch to a point immediately upstream of the confluence with the Lake Fork. Segment 2c includes the section of the upper Arkansas River from immediately upstream of the confluence with the Lake Fork to a point immediately upstream the confluence with Lake Creek. Both segments presently have temporary modifications for zinc (270 ug/L and 250 ug/L, respectively), while Segment 2b also has a temporary modification for cadmium (1.3 ug/L). Temporary modifications tor these two segments expire December 2007. While the Upper Arkansas River is classified as a cold-water, aquatic life stream, "aquatic life" is a broad designation. It is important to more appropriately characterize the aquatic life expected to be present (i.e., characterize uses that can be attained) for a specific stream segment to ensure that any proposed standards are protective of that expected "aquatic life" (Michael and Moore 1997). As such, the proposed site-specific standards derived in this effort took into consideration a number of factors, including: 1. Use of results of long-term field sampling of available habitat, fish, and benthic invertebrate communities to determine potential resident species in these segments, 2. Use of the zinc and cadmium toxicity databases underlying the current Colorado table value standards (TVS), 3. Use of more recent data, resulting in a further update of the Colorado zinc toxicity database, including unpublished data from the Colorado Division of Wildlife (CDOW), and 4. Use of the USEPA recalculation procedure for water quality criteria (USEPA 1994). ()f)2MO 1 MW-05 Preliminary Evaluation of Potential Site-Spec September 2006 Section 2 - Determination of the Appropriate Residential Fauna Before beginning a recalculation by deletion of non-resident taxa, one must first determine resident and potentially resident fauna for the waterbody in question. The upper Arkansas River Segments 2b and 2c provide adequate habitat for benthic macroinvertebrates and maintenance of coldwater fish communities. This has been documented with extensive biological monitoring conducted on behalf of Resurrection Mining Co., from 1994 to present (CEC 2006). These efforts have established historical resident benthic macroinvertebrate and fish species at various stations along the upper Arkansas River from the confluence of the East Fork to downstream of the confluence with Empire Gulch. The analysis in this report specifically focuses on the more recent biological data collected 2000-2005 from Segments 2b and 2c of the upper Arkansas River. Sampling sites in these segments include AR-3a and AR3b for Segment 2b and AR-4 and AR-5 (and additional fish sampling sites of the Colorado Division of Wildlife) for Segment 2c. Data collected from the sampling site immediately upstream of California Gulch (AR-2) were also taken into consideration for the determination of potentially resident species of Segments 2b and 2c that may not have been present historically due to water quality limitations. All sampling sites are described by CEC (2006). For species that were not specifically sampled for in the long-term monitoring program (e.g. zooplankton, bryozoans, ostracods), the potential for residence was determined from analyses of appropriate habitat and literature reviews. Because Segment 2 of the Upper Arkansas River is a high altitude mountain stream, several organisms included in the updated Colorado zinc toxicity database would potentially not be expected to occur. For example, warm water fish would not be expected to occur in Segments 2b or 2c of the upper Arkansas River. In addition, based on habitat preferences and known distributions, zooplankton would not be expected to inhabit these streams as "resident" populations. The potential absence (or presence) of this taxonomic group can be important, as they often represent sensitive taxa that can drive the final criteria for a particular metal. Further discussions of these groups follow. Planklonic Microinverlebrales - Despite their affinity for lentic (ponds, lakes) habitats, zooplankton, including cladocerans, are periodically observed in lotic (stream) systems. Many of these organisms are "accidentals," washed out of an upstream or off-channel lake, pond, or reservoir, with no means of sustaining a population within the stream system without the contribution of this downstream drift from the source population. 0625IO I I-O'MIS Preliminary Kvidualion of Potential Site-Spec September 2006 For example, Chandler (1937) studied the persistence of plankton drifting from three Michigan lakes into three low gradient, slow flowing rivers. He determined that plankton drifting into the rivers were rapidly eliminated, with Crustacea (which includes cladocerans) and Rotifera being the most quickly removed, having a pronounced decrease in density within a half mile and often within a few meters of the lake. These rates of removal are similar to results reported by Ward (1975), which determined that zooplankton, cladocerans in particular, are fairly rapidly removed from lotic systems below their lentic source. This pattern ofcladoceran removal from lotic habitats downstream of lentic "donor" habitats has been well documented (Novotny and Hoyt 1982, Phillips 1995). Hynes (1970) concluded that zooplankton can maintain themselves against only minimal velocities of a few millimeters/second, and that swiftly flowing systems would quickly eliminate any true zooplankton. Thorp et al. (1994) studied the zooplankton community of the Ohio River, and determined that the density of plankton in the river was negatively correlated with river velocity and was probably physically controlled. In a study of the Illinois River and its tributaries in Arkansas, Brown el al. (1989) found cladocerans comprised