### MEMORANDUM

TO: Bill Swietlik, EPA

FROM: Joanna Kind, ERG

DATE: April 19, 2013

SUBJECT: Literature Review – Impacts of C oal Pile Runoff and Leachate (DCN SE02153)

1.0 I NTRODUCTION
ERG is providing technical support to the U. S. Environmental Protection Agency (EPA) for development of revised effluent limitations gu idelines and standards (effluent guidelines) for the Steam Electric Power Generati ng Industry. In support of the de velopment of revised effluent guidelines, ERG conducted a literat ure review regarding the envir onmental impact of identified pollutants of concern. As part of this review, ER G examined the pollutants contained in coal pile runoff and coal pile leachate, as well as the impacts on flora, fauna, and ground water from these
waste streams.

Approximately 50 percent of facilities in the steam electric industry are coal-fired plants. At these plants, the coal is unloaded from trains , barges, and/or trucks in a designated area and conveyed to an outdoor storage area, referred to as the coal pile . Power plants generally store between 25 and 40 days worth of coal in the co al pile, which can amount to over 500,000 tons of coal being stored at the plant.

As rainwater and melting snow comes in direct contact with coal piles, constituents that are native to coal are transferred to the water. Wastewater originating fr om coal piles can reach nearby water resources in two ways: 1) seeping from coal piles and traveling along the surface of the ground prior to reaching surface waters (known as coal pile runoff); and 2) flowing through the coal pile and directly entering the groundwat er system (known as coal pile leachate). The quantity of coal pile runoff and leachate depe nds upon the amount of preci pitation, the physical location and layout of the coal pile, and the extent to which water infiltrates the ground underneath the coal pile. Coal pile runoff is usually coll ected in a runoff pond during or immediately after times of rainfall.

This memo highlights the literature ERG identified related to coal pile runoff and leachate and compares concentrations of constituents in coal pile runoff found in the studies with EPA’s National Recommended Water Qu ality Criteria (NRWQC) values 1 . This memo also

1 NRWQC values are set by EPA under Section 304(a) of the Clean Wa ter Act (CWA). EPA develope d these criter ia to protect aquatic life and human health. Organism popul ations or humans exposed to a pollutant co ncentration exceeding its criteria are a t an increased risk for health effects (U.S. EPA, 2009).Memorandum April 19, 2013 Page 2

discusses environmental impacts on groundwater from coal pile runoff and leachate. Documented environmental effect s include reductions in macroinve rtebrate and bacterial density, vegetation kills, and toxicity to fish (Brofft et al., 2002; Carlson and Carlson, 1994; Swift, 1985; Tan and Coler, 1986).

2.0 P OLLUTANTS IN C OAL P ILE R UNOFF AND L EACHATE
An important component in assessing coal pile runoff and leachate impacts on surface water and groundwater is identifying the associat ed pollutants and their concentrations. Table 2-1 lists typical pollutants and their concentration ranges in co al pile runoff based on a field study at 11 plants (U.S. EPA, 1974). Table 2-1 also includes EPA’s NRWQC for each available species to provide context for the concen trations observed in coal pile runoff.

As a general note regarding the pollutant concentrations observe d in EPA’s 1974 study, and as other investigators have pointed out (Davis and Boegly, 1981), the results have limitations but are still useful for comparative purposes. Th e magnitude of the concen tration ranges reported demonstrate that coal pile runoff has the pot ential to exceed NRWQC and pose a threat to aquatic environments.Memorandum April 19, 2013 Page 3

Table 2-1. Common Pollutants and Concentrations in Coal Pile Runoff

Pollutant Range of Concentrations

Measured in

Coal Pile Runoff (mg/L) National Recommended Water Quality Criteria Values (mg/L)

Freshwater Saltwater Human Health for the Consumption of:

Acute Chronic Acute Chronic Water + Organism Organism Only Aluminum 825–1,200 0.75 a 0.087 a
— — — — Ammonia 0.35–1.77 b b c c

— — Chloride 3.6–481 860 230 —

— — — Copper 1.6–3.4 d d 0.0048 e 0.0031 e 1.3 — Iron 0.06–93,000 — 1 — — 0.3 — Magnesium 89–174 —

— — — — — Nitrate 0.3–2.25 —

— — — 10 — Phosphorus 0.23–1.2 —

— — 0.0001 — — Sodium 160–1,260 —

— — — — — Sulfate 133–21,920 —

— — — — — Zinc 0.006–23 0.12 e 0.12 e 0.09 e 0.081 e 7.4 26 pH (standard units) 2.1–7.8 — 6.5–9

— 6.5–8.5 5–9

—

Source: U.S. EPA, 1974. Note: EPA’s 1974 study did not test for metals of most interest to the current rulemaking (e.g., arsenic, mercury, selenium). Two non-detect values were reported for ammonia. All other pollutants were detected in all samples. Blanks indicate that NRWQC values are not available, or require known water pH and temperature to be calculated. mg/L – Milligrams per liter. The study did not specify the form of each metal (total or dissolved). a – Total recoverable (pH 6.5 – 9.0). b – Freshwater criteria are pH, temp erature, and lifestage dependent. c – Saltwater criteria are pH and temperature dependent. d – Freshwater criteria calculated using the Biotic Ligand Model (BLM). e – Dissolved.

3.0 I MPACTS OF C OAL P ILE R UNOFF ON F LORA AND F AUNA

Two studies at the Savannah River Site, a Department of Energy (DOE) site, in South Carolina, which received discha rges from the D-Area power pl ant, described the observed impacts of coal pile runoff on flora. A 1994 study de scribed a coal reject pile (i.e., coal that cannot be crushed by the mill and therefore cannot be burned in the boiler) that was covered by a layer of soil and repeatedly became exposed during heavy rainfall events, causing coal pile runoff. In a wide band surrounding th e direction of the coal pile runoff flow, trees and understory vegetation either died or exhibi ted severe sublethal stress. A se parate band of vegetative stress observed at the site did not align with the flow of coal pile runoff, but instead followed the flow of groundwater. In a study conducted at the site, analysis of the wa ter available to root systems determined that the water was highly acidic and sa line, and contained elevat ed concentrations of aluminum and manganese, both found in coal (C arlson and Carlson, 1994). In a similar study conducted at the Savannah River Site in 2002, bacter ia samples taken from sediments at varyingMemorandum April 19, 2013 Page 4

depths and in different proximities to coal pile runoff flows indicated that exposure to coal pile runoff greatly reduced the diversity of b acteria species (Brofft et al., 2002).

Documented sources have also shown that coal pile runoff can create surface water conditions that are toxic to fish and macroinvertebrates. Taylor Brook in western Massachusetts receives coal pile runoff directly from a 50,000-ton coal pile. Minnows in the brook exhibited disrupted metabolisms and juveni le mortality. Based on a profile of the coal pile runoff water chemistry, the authors determined that aluminum , iron, and manganese were the pollutants most likely contributing to the adverse effects to fi sh. The authors conducted laboratory tests that replicated stream conditions, from which they concluded that the poor health of fish was primarily a function of the elevat ed aluminum concentrations (Tan and Coler, 1986). The effect of coal pile runoff on macroi nvertebrates was studied at Ge orges Creek in Maryland. At sampling sites immediately downstream of the co al pile runoff discharg e, macroinvertebrate densities were very low relative to sample sites upstream of the discharge. Adversely affected areas of Georges Creek were found to be acidic and had elevated concentrations of manganese, aluminum, zinc, iron, and sulfate (Swift, 1985).

4.0 I MPACTS OF C OAL P ILE R UNOFF AND L EACHATE ON G ROUNDWATER

Groundwater is stored in aquifers, which ar e underground rock formations composed of materials such as sand, soil, or gravel that supply groundwater to wells and springs which, in turn, are often used as a direct source of drinking water. Groundwater and drinking water supplies can be degraded by the pollutants present in coal pile runoff and leachate (Cross, 1981). The extent to which pollutants from coal pi les reach underground aquifers depends on the location of the aquifer relative to the coal pile, the nature of in tervening geologic formations, and the porosity of the soil (Cross, 1981). Coal pile leachate can crea te groundwater conditions that make the water unsafe for humans to drink (C ook and Fritz, 2002). St udies of groundwater contaminated by coal pile runoff or coal pile le achate have found lead in concentrations that exceed state maximum contaminant levels (MCLs), as well as elevated sulfate, iron, aluminum, chromium, and nickel concentr ations (Anderson, 1990; Cook and Fritz, 2002; Washburn, 1998). Cook and Fritz (2002) measured the lead concentration of a contam inated groundwater site to be 62 μg/L, which exceeded the state of Indiana MCL of 15 μg/L. Washburn (1998) reported the following trace metal concentrations in th e groundwater at a contaminated site:

 Aluminum: 301 mg/L;

 Chromium: 0.182 mg/L;

 Iron: 216 mg/L;

 Nickel: 1.66 mg/L; and

 Sulfate: 8,430 mg/L.Memorandum April 19, 2013 Page 5

5.0 R EFERENCES

Anderson, M.A., 1990. A Hydrogeochemical Investiga tion of Metalliferous Coal Pile Runoff and its Interaction with Soil a nd Groundwater. Dissertation.

Brofft, J.E., J.V. McArthur, and L.J. Shimke ts, 2002. Recovery of Novel Bacterial Diversity from a Forested Wetland Impacted by Reject Coal. Environmental Microbiology, 4 (11): 764- 769.

Carlson, C.L. and C.A. Carlson, 1994. Impacts of Coal Pile Leachate on a Forested Wetland in South Carolina. Water, Air, and Soil Pollution. 72: 89-109.

Cook, A.M., and S.J. Fritz, 2002. Environmental Impacts of Acid Leachate Derived from CoalStorage Piles upon Groundwater. Water, Ai r, & Soil Pollution, 135 (1-4): 371-388.

Cross, F.L., 1981.Coal Pile Environmental Impa ct Problems. Pollution Engineering. 13(7): 35- 37. DCN SE01881.

Davis, E.C. and W.J. Boegly, Jr ., 1981. A Review of Water Quality Issues Associated with Coal Storage. Journal of Environmental Quality, 10:127-133.

Swift, M.C., 1985. Effects of Coal Pile Runo ff on Stream Quality and Macroinvertebrate Communities. Journal of the American Wate r Resources Association, 21 (3): 449-457.

Tan, B. and R.A. Coler, 1986. Effects of Coal Pile Leachate on Taylor Brook in Western Massachusetts. Environmental Toxi cology and Chemistry. 5: 897-903.

U.S. EPA, 1974. Development Document for Effl uent Limitations Guidelines and New Source Performance Standards for the Steam Electri c Power Generating Point Source Category. Washington, D.C. (October).

U.S. EPA. 2009. National Recommended Wate r Quality Criteria. Washington, DC. DCN SE01908.

Washburn, F.A., 1998. D-Area Coal Pile R unoff Basin Groundwater Treatability Study Preliminary Report. September.