- Email: [email protected]
Impacts of point-source Net Alkaline Mine Drainage (NAMD) on stream macroinvertebrate communities
Journal of Environmental Management 250 (2019) 109484
Contents lists available at ScienceDirect
Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman
Research article
Impacts of point-source Net Alkaline Mine Drainage (NAMD) on stream macroinvertebrate communities
T
William Griffiths Kimmel, David Gordon Argent∗ Department of Biological and Environmental Sciences, California University of Pennsylvania, 250 University Avenue, California, USA
A R T I C LE I N FO
A B S T R A C T
Keywords: Macroinvertebrates Net alkaline mine drainage Total iron Total sulfate
Over 4000 km of Pennsylvania's flowing waters and attendant ecosystems have been degraded by mine drainage to the exclusion of multiple designated uses. Both Acid Mine Drainage (AMD) and Net Alkaline Mine Drainage (NAMD) may result from coal extraction depending on the underlying geology. Acid Mine Drainage is characterized as an acidic mixture of toxic heavy metals in solution, while NAMD is circumneutral in pH with metals forming oxidized precipitates. The ecological impacts of AMD have been well documented but NAMD-impacted streams have received considerably less attention. We selected 10 low-order tributaries of the Ohio and Youghiogheny rivers in southwestern Pennsylvania impacted by point-source inputs of NAMD for assessment of water quality and benthic macroinvertebrate communities. Levels of pH, total iron (Fe), and sulfate (SO4) were significantly elevated in the impacted stream reaches when compared with upstream reference sites while total alkalinity and specific conductance were equivalent. Macroinvertebrate abundance declined by 92% in the impacted stream reaches, but community structure in terms of taxonomic composition and species richness was similar. Total iron, total sulfate, and specific conductance were significantly linked to macroinvertebrate community impairment. The presence of resident macroinvertebrate communities in the unimpacted reaches suggests that remediation would result in a rapid recolonization and establishment of viable downstream ecosystems.
1. Introduction Globally, the extraction of coal resources is a major part of energy development. Such activities frequently produce scarred landscapes, erosion, siltation, and contamination of watercourses to the exclusion of some designated uses. The issue is prevalent on just about every continent. In North America, discharges resulting from the extraction of anthracite and bituminous coal deposits are somewhat localized to Appalachia, a large north/south expanse that includes some 650,000 km2. Within this region lies Pennsylvania (USA), a state blessed to have nearly 132,000 km of streams, of which nearly 4000 km are affected by mining. Many of these streams are still emanating from long-abandoned mining operations (Pennsylvania Department of Environmental Protection (PA DEP), 1999). Such discharges are characterized as Acid Mine Drainage (AMD) or Net Alkaline Mine Drainage (NAMD) based on their chemical constituents (Scott and Hays, 1975; Rose and Cravotta, 1998). Acid Mine Drainage, resulting from the exposure of pyritic materials to air and water during and after active mining, is a highly acidic (pH < 4.5; total alkalinity/total acidity < 1) solution containing toxic metals such as iron (Fe), aluminum (Al), and
∗
manganese (Mn) which can decimate aquatic life in receiving streams. By contrast, NAMD discharges feature circumneutral pH levels, total alkalinity/total acidity > 1, and metals in suspension which can produce the familiar orange, white, or black stained substrates upon deposition. The two also differ in their effects on receiving stream ecosystems with AMD producing toxic physiological conditions often resulting in the absence of fish and macroinvertebrate communities, while the metallic precipitates of NAMD cover benthic habitats (Butler et al., 1973; Kimmel and MajumdarMiller, 1983). Both types of discharge may produce erosion and siltation during active mining and exhibit elevated sulfate (SO4) concentrations. The entrance of AMD into a receiving stream of adequate buffering capacity may create a “Recovery Zone” following neutralization of acidity and precipitation of metals mirroring NAMD conditions (Cannon and Kimmel, 1992). While significant portions of Pennsylvania's flowing waters and attendant ecosystems have been degraded by mine drainage, only AMD effects have been well studied. Little documentation exists as to the impacts of NAMD on resident macroinvertebrate communities. These assemblages consisting of stress tolerant and intolerant forms representing numerous taxa and several trophic levels are frequently
Corresponding author. E-mail addresses: [email protected] (W.G. Kimmel), [email protected] (D.G. Argent).
https://doi.org/10.1016/j.jenvman.2019.109484 Received 2 June 2019; Received in revised form 21 August 2019; Accepted 26 August 2019 0301-4797/ © 2019 Elsevier Ltd. All rights reserved.
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Table 1 Summary of mean water quality parameters above and within the NAMD-impacted reaches. Parameter
Above
Below
p-value
Temperature (oC) pH Sp. Conductivity (μS/cm) Alkalinity (mg/l as CaCO3) Iron (mg/l) Sulfate (mg/l)
19.7 8.0 717.0 151.6 0.2 106.0
18.3 7.0 1078.0 136.5 12.4 335.0
0.138 0.000 0.122 0.692 0.004 0.002
inputs; however, all downstream sites exhibited total coatings of orange-colored iron deposits. Water quality parameters, temperature, pH, specific conductance, and total alkalinity did not differ significantly above and within impacted sites (Table 1). Mean pH values declined by one unit in the impacted sites well within the acceptable range for aquatic life (Environmental Protec, 2018). The reduced temperatures recorded in the impacted sites likely reflect the influence of ground water associated with the NAMD discharge. However, total iron and total sulfate concentrations in the impacted sites increased sixty-two fold and three-fold respectively over upstream sites and were statistically significant (p < 0.05, Table 1). Macroinvertebrate communities above and below the respective NAMD point-sources were similar in calculated metrics and were not significantly different. However, total mean abundance between the two locations was significantly different with a 92% decline between impacted and unimpacted reaches (Fig. 2; p < 0.05). The large error bar for the unimpacted sites reflects large differences observed among the respective community abundances (Fig. 2). For example at one location, we captured six individuals while at the other extreme we captured 479. These differences likely reflect the local geology and recent high flows. Regression analyses determined significant negative relationships among specific conductance, total iron, and total sulfate, and selected community metrics (p < 0.05; Figs. 3–5). Because taxonomic complements vary among the unimpacted reaches, no particular taxa are represented in all streams; nor is any particular taxon present completely eliminated downstream. Rather the resident upstream community is markedly reduced in total abundance below the pollutant inputs. Hence, the reclamation of such sites would result in recolonization by drift from the resident upstream community such as it exists. Therefore, the responses of impacted sites to NAMD inputs reflect the composition of the upstream community, but in a depauperate condition. Intolerant taxa scores as measured by the EPT metric did not differ significantly between unimpacted and impacted sites, nor did resident taxa, and are not presented here. Specific conductance is defined as the ability of water to conduct electricity and serves as an indicator of total dissolved solids (TDS).
Fig. 1. Map of study area indicating 10 stream locations used in this evaluation.
employed as indicators of stream health. In the bituminous coal fields of southwestern Pennsylvania, streams colored orange resulting from NAMD are a typical sight, and may support aquatic life (Kimmel and MajumdarMiller, 1983; Kimmel et al., 1981; Ventorini, 2002; Kimmel and Argent, 2006). In many cases, mine drainage discharges are diffuse throughout an impacted watershed making bioassessment involving impacted vs. control sites difficult. The purpose of this study is to characterize water quality and macroinvertebrate communities above and below point sources of NAMD emanating from abandoned sites, and assess their suitability for reclamation. 2. Methods Ten NAMD-impacted low-order tributaries of the Ohio and Youghiogheny rivers located in southwestern Pennsylvania were selected for this study (Fig. 1). In July 2018, we established two sampling stations on each selected stream – one upstream reference (above) and one downstream impacted site (below) of the NAMD point-source below the zone of complete mixing. At each sampling station, we measured temperature (oC), pH, and specific conductance (μs/cm) using a pH Testr3+ (Oakton Instruments). Two water samples were collected from each site – one returned to the laboratory at California University of Pennsylvania for analysis by standard titration of total alkalinity (mg/l as CaCO3); and the other to H&H Water Controls for determination of total iron and total sulfate. Values at the respective reference and impacted sites were pooled to generate mean values for statistical comparison using a two-sample T-test. Results were considered significant if α < 0.05. We sampled macroinvertebrate communities in riffle areas at each station using a standard 1-m2 500 μm kick-net according to protocols established by the Pennsylvania Department of Environmental Protection (PA DEP) (Chalfant, 2015; Kimmel and Argent, 2018). Three samples collected at each site were pooled to form a station composite, preserved in 70% isopropyl alcohol and returned to the laboratory at California University for processing. We identified organisms to the lowest practicable taxonomic level, enumerated them, and assigned each to appropriate community metrics – taxonomic richness, total abundance, trophic composition, intolerant taxa composition, and community diversity (H). Macroinvertebrate community metrics were compared using t-tests to determine if significant differences between reference and impacted sites existed. We used simple linear regression to relate selected water quality parameters to biological metrics. Results were considered significant if α < 0.05. 3. Results and discussion
Fig. 2. Mean and standard deviation of total macroinvertebrate abundances above and below input of NAMD.
No evidence of metal precipitates were observed upstream of NAMD 2
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Fig. 4. Relationship between iron (mg/l) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for impacted reaches. A line of best fit and its associated goodness of fit (R2) for each relationship are presented.
Fig. 3. Relationship between specific conductance (μS/cm) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for the unimpacted reference (circles, dashed line) and impacted (diamonds, straight line) reaches. A line of best fit and its associated goodness of fit (R2) are presented for each relationship. Dashed line represents unimpacted reference sites and solid line defines impacted sites.
exhibiting elevated levels of specific conductance (Kimmel and Argent, 2012, 2018), even in the absence of iron and sulfate and far above the 300 μS/cm benchmark established by the United States Environmental Protection Agency (Environmental Protec, 2011). In this study, as values of specific conductance increase, community diversity and taxonomic richness decline, but intolerant taxa persist, albeit in low numbers (Fig. 3). Total iron from mine drainages has been linked to the declines in macroinvertebrate abundance and community diversity in impacted
Therefore, it represents the totality of ions in solution in the discharges and in the receiving streams. Such a mixture may exhibit synergistic or additive properties, which could not be separately determined in this study; as a result, it is expressed as a composite measure of the streams chemical composition in solution. Previous studies have documented the presence of fish and macroinvertebrate communities in streams 3
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Weed and Rutschky, 1972). The presence of depauperate fish communities in these streams has also been reported from such streams (Cannon and Kimmel, 1992; Kimmel et al., 1981; Ventorini, 2002). Given the mobility of stream ichthyofauna, it is difficult to document these as resident or transient communities, but it strongly suggests that physiological toxicity in this environment is not a major limiting factor, and the nearby presence of colonizers to remediation. Similarly, the macroinvertebrate communities of the impacted reaches of this study mirror those of the upstream reaches suggesting drift as a source of resident or temporal assemblages and potential colonizers (Fig. 4). Sulfate concentrations in the NAMD-impacted reaches in this study are also related to significant declines in macroinvertebrate community metrics (Fig. 5). Sulfate is a typical component of coal mine drainages as a result of the oxidation and hydrolysis of pyritic materials (FeS2) often associated with coal seams. Zhao et al. (2017) report that sulfates in mine drainage exceeding 35 mg/l resulted in a significant decline in “intolerant” macroinvertebrate taxa; and the PA DEP (Shull, 2018) ranks stream sulfate concentrations - < 20 mg/l (Good); 20–200 mg/l (Fair); > 200 (Poor). In this rating system, our results for the unimpacted and impacted reaches fall into the “Fair” and “Poor” categories, respectively. Sulfate, however, can be derived from a number of sources including raw and treated sewage effluents and agriculture. The near absence of total iron in these reaches suggest such sources rather than mining, and indeed these streams drain such culturally impacted watersheds. Also, that total iron concentrations rather than sulfates are the limiting factors to macroinvertebrate communities here as suggested in the above citations. Fig. 6 illustrates the relationships between levels of total iron and total sulfate and macroinvertebrate total abundance. Below the point of entry of the NAMD at each site, total iron and total sulfate increases are accompanied by precipitous declines in macroinvertebrate abundance. Our data, in accordance with previously cited literature (Butler et al., 1973; Kimmel and MajumdarMiller, 1983), suggests that the physical coating of iron oxides in the benthic habitats of NAMD-impacted reaches is the primary driver of declines in macroinvertebrate abundance. The trophic structure of the extant reference and impacted communities is similar (Fig. 7) suggesting the latter is a reflection of upstream colonizers, which would be immediately available through drift following mitigation. In summary, the identification and mitigation of isolated point sources of NAMD in the world's coalfields continue to be a worthwhile
Fig. 5. Relationship between sulfate (mg/l) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for impacted reaches. A line of best fit and its associated goodness of fit (R2) for each relationship are presented.
stream reaches. A threshold of “Good Ecological Status” for total iron in streams has been proposed to protect aquatic life at 1.25–2.46 mg/l (Peters et al., 2011). Iron in its oxidized forms can produce turbidity when in suspension and coat stream bottoms when precipitated. The former reduces light penetration for photosynthesis and the latter can physically smother habitat niches. Other studies have linked iron oxide deposition to losses of fish and macroinvertebrate populations in NAMD – receiving streams (Cannon and Kimmel, 1992; Kimmel et al., 1981;
Fig. 6. Influence of total iron and sulfate on total macroinvertebrate community abundance among sampling stations. Arrow indicates location of NAMD input. Stations are identified by numerics: 1 = Little Redstone, 2 = Laurel Run, 3 = N. Branch of Cucumber Run, 4 = Douglas Run, 5 = Guffey Run, 6 = Galley Run, 7 = McLaughlin Run, 8 = Georges Run, 9 = Coal Run, and 10 = Millers Run. 4
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
locations around the globe and to include other taxonomic groups of study (e.g., fish and amphibians). Acknowledgements We wish to thank California University of Pennsylvania's Faculty Professional Development Fund for providing financial assistance with this project. In addition, we wish to acknowledge Catie Gallmeyer and Colton Schmucker for their assistance with field collections. References Butler, R.L., Cooper, E.L., Hales, D.C., Wagner, C.C., Kimmel, W.G., Crawford, J.K., 1973. Fish and Food Organisms in Acid Mine Waters of Pennsylvania. Office of Research and Monitoring. U.S. Environmental Protection Agency, Washington, D.C EPA-R-73032. Cannon, W.E., Kimmel, W.G., 1992. A comparison of fish and macroinvertebrate communities between an unpolluted stream and the recovery zone of a stream receiving acid mine drainage. J. Pa. Acad. Sci. 66 (2), 58–62. Chalfant, B.A., 2015. An Index of Biotic Integrity for Benthic Macroinvertebrate Communities in Pennsylvania's Wadeable, Freestone, Riffle-Run Streams. Pennsylvania Department of Environmental Protection, Bureau of Clean Water, Harrisburg, Pennsylvania. U.S. Environmental Protection Agency (USEPA, 2011. A Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams. National Center for Environmental Assessment, Office of Research and Development, Cincinnati, OH EPA/600/R-10/023 F. Available at: http://cfpub.epa.gov/ncea/cfm/recordisplay. cfm?deid0233809. U.S. Environmental Protection Agency (USEPA, 2018. “National Recommended Water Quality Criteria – Aquatic Life Criteria Table. ” U.S. Environmental Protection Agency. https://www.epa.gov/wqc/national-recommended-water-quality-criteriaaquatic-life-criteria-table, Accessed date: 27 May 2018. Kimmel, W.G., Argent, D.G., 2006. Development and application of an index of biotic integrity (IBI) for fish communities of wadeable Monongahela River tributaries. J. Freshw. Ecol. 21 (2), 183–190. Kimmel, W.G., Argent, D.G., 2012. Status of fish and macroinvertebrate communities in a watershed experiencing high rates of fossil fuel extraction: tenmile Creek, a major Monongahela River tributary. Water Air Soil Pollut. 223 (7), 4647–4657. Kimmel, W.G., Argent, D.G., 2018. Scuds (Gammaridae) and darters (Percidae) dominate aquatic communities in a stream exhibiting levels of specific conductance exceeding 4,000 μS/cm. Int. J. Environ. Monit. Anal. 6 (2), 47–52. Kimmel, W.G., 1983. The impact of acid mine drainage on the stream ecosystem. In: Majumdar, S.K., Miller, E.W. (Eds.), Pennsylvania Coal: Resources, Technology and Utilization. Pennsylvania Academy of Science, Easton, Pennsylvania. Kimmel, W.G., Miller, C.A., Moon, T.C., 1981. The impact of a deep-mine drainage on the water quality and biota of a small hard-water stream. Proc. Pa. Acad. Sci. 55 (2), 137–141. Pennsylvania Department of Environmental Protection (PA DEP), 1999. The Science of Acid Mine Drainage and Passive Treatment. PA DEP Publication, Bureau of Abandoned Mine Reclamation, Harrisburg, Pennsylvania. Peters, A., Crane, M., Adams, W., 2011. Effects of iron on benthic macroinvertebrate communities in the field. Bull. Environ. Contam. Toxicol. 86 (6), 591–595. Rose, A.W., Cravotta III, C.A., 1998. Geochemistry of Coal Mine Drainage. Coal Mine Drainage Prediction and Pollution Prevention in Pennsylvania. Pennsylvania Department of Environmental Protection, Harrisburg, Pennsylvania. Scott, R.L., Hays, R.M., 1975. Inactive and Abandoned Underground Mines—Water Pollution Prevention and Control. U.S. EPA—440/9-75-007. U.S. Environmental Protection Agency; Office of Water, Washington, D.C. Shull, D., 2018. A Benthic Macroinvertebrate Multimetric Index for Large Semi-wadeable Rivers: Technical Report. The Pennsylvania Department of Environmental Protection, Harrisburg, PA. Ventorini, R., 2002. Fish Community in Warmwater Tributaries of the Youghiogheny River Impacted by Net Alkaline Deep Mine Discharges. MS Thesis. California University of Pennsylvania, California, Pennsylvania, pp. 57. Weed, C.E., Rutschky, R.W., 1972. Benthic macroinvertebrate community structure in a stream receiving acid mine drainage. Proc. Pa. Acad. Sci. 46, 41–47. Zhao, Q., Guo, F., Zhang, Y., Ma, S., Jia, X., Meng, W., 2017. How sulfate-rich mine drainage affected aquatic ecosystem degradation in northeastern China, and potential ecological risk. Sci. Total Environ. 609, 1093–1102.
Fig. 7. Proportional representation of functional feeding groups between unimpacted reference (A) and impacted reaches (B). CG = collector/gatherer; FC = filterer/collector; PR = predator; SC = scraper; and SH = shredder.
target of remediation efforts by a variety of treatment systems usually involving precipitation of the oxidized states of heavy metals from the drainage (Pennsylvania Department of Environmental Protection (PA DEP), 1999). Future work should expand to include other geographic
5
Contents lists available at ScienceDirect
Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman
Research article
Impacts of point-source Net Alkaline Mine Drainage (NAMD) on stream macroinvertebrate communities
T
William Griffiths Kimmel, David Gordon Argent∗ Department of Biological and Environmental Sciences, California University of Pennsylvania, 250 University Avenue, California, USA
A R T I C LE I N FO
A B S T R A C T
Keywords: Macroinvertebrates Net alkaline mine drainage Total iron Total sulfate
Over 4000 km of Pennsylvania's flowing waters and attendant ecosystems have been degraded by mine drainage to the exclusion of multiple designated uses. Both Acid Mine Drainage (AMD) and Net Alkaline Mine Drainage (NAMD) may result from coal extraction depending on the underlying geology. Acid Mine Drainage is characterized as an acidic mixture of toxic heavy metals in solution, while NAMD is circumneutral in pH with metals forming oxidized precipitates. The ecological impacts of AMD have been well documented but NAMD-impacted streams have received considerably less attention. We selected 10 low-order tributaries of the Ohio and Youghiogheny rivers in southwestern Pennsylvania impacted by point-source inputs of NAMD for assessment of water quality and benthic macroinvertebrate communities. Levels of pH, total iron (Fe), and sulfate (SO4) were significantly elevated in the impacted stream reaches when compared with upstream reference sites while total alkalinity and specific conductance were equivalent. Macroinvertebrate abundance declined by 92% in the impacted stream reaches, but community structure in terms of taxonomic composition and species richness was similar. Total iron, total sulfate, and specific conductance were significantly linked to macroinvertebrate community impairment. The presence of resident macroinvertebrate communities in the unimpacted reaches suggests that remediation would result in a rapid recolonization and establishment of viable downstream ecosystems.
1. Introduction Globally, the extraction of coal resources is a major part of energy development. Such activities frequently produce scarred landscapes, erosion, siltation, and contamination of watercourses to the exclusion of some designated uses. The issue is prevalent on just about every continent. In North America, discharges resulting from the extraction of anthracite and bituminous coal deposits are somewhat localized to Appalachia, a large north/south expanse that includes some 650,000 km2. Within this region lies Pennsylvania (USA), a state blessed to have nearly 132,000 km of streams, of which nearly 4000 km are affected by mining. Many of these streams are still emanating from long-abandoned mining operations (Pennsylvania Department of Environmental Protection (PA DEP), 1999). Such discharges are characterized as Acid Mine Drainage (AMD) or Net Alkaline Mine Drainage (NAMD) based on their chemical constituents (Scott and Hays, 1975; Rose and Cravotta, 1998). Acid Mine Drainage, resulting from the exposure of pyritic materials to air and water during and after active mining, is a highly acidic (pH < 4.5; total alkalinity/total acidity < 1) solution containing toxic metals such as iron (Fe), aluminum (Al), and
∗
manganese (Mn) which can decimate aquatic life in receiving streams. By contrast, NAMD discharges feature circumneutral pH levels, total alkalinity/total acidity > 1, and metals in suspension which can produce the familiar orange, white, or black stained substrates upon deposition. The two also differ in their effects on receiving stream ecosystems with AMD producing toxic physiological conditions often resulting in the absence of fish and macroinvertebrate communities, while the metallic precipitates of NAMD cover benthic habitats (Butler et al., 1973; Kimmel and MajumdarMiller, 1983). Both types of discharge may produce erosion and siltation during active mining and exhibit elevated sulfate (SO4) concentrations. The entrance of AMD into a receiving stream of adequate buffering capacity may create a “Recovery Zone” following neutralization of acidity and precipitation of metals mirroring NAMD conditions (Cannon and Kimmel, 1992). While significant portions of Pennsylvania's flowing waters and attendant ecosystems have been degraded by mine drainage, only AMD effects have been well studied. Little documentation exists as to the impacts of NAMD on resident macroinvertebrate communities. These assemblages consisting of stress tolerant and intolerant forms representing numerous taxa and several trophic levels are frequently
Corresponding author. E-mail addresses: [email protected] (W.G. Kimmel), [email protected] (D.G. Argent).
https://doi.org/10.1016/j.jenvman.2019.109484 Received 2 June 2019; Received in revised form 21 August 2019; Accepted 26 August 2019 0301-4797/ © 2019 Elsevier Ltd. All rights reserved.
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Table 1 Summary of mean water quality parameters above and within the NAMD-impacted reaches. Parameter
Above
Below
p-value
Temperature (oC) pH Sp. Conductivity (μS/cm) Alkalinity (mg/l as CaCO3) Iron (mg/l) Sulfate (mg/l)
19.7 8.0 717.0 151.6 0.2 106.0
18.3 7.0 1078.0 136.5 12.4 335.0
0.138 0.000 0.122 0.692 0.004 0.002
inputs; however, all downstream sites exhibited total coatings of orange-colored iron deposits. Water quality parameters, temperature, pH, specific conductance, and total alkalinity did not differ significantly above and within impacted sites (Table 1). Mean pH values declined by one unit in the impacted sites well within the acceptable range for aquatic life (Environmental Protec, 2018). The reduced temperatures recorded in the impacted sites likely reflect the influence of ground water associated with the NAMD discharge. However, total iron and total sulfate concentrations in the impacted sites increased sixty-two fold and three-fold respectively over upstream sites and were statistically significant (p < 0.05, Table 1). Macroinvertebrate communities above and below the respective NAMD point-sources were similar in calculated metrics and were not significantly different. However, total mean abundance between the two locations was significantly different with a 92% decline between impacted and unimpacted reaches (Fig. 2; p < 0.05). The large error bar for the unimpacted sites reflects large differences observed among the respective community abundances (Fig. 2). For example at one location, we captured six individuals while at the other extreme we captured 479. These differences likely reflect the local geology and recent high flows. Regression analyses determined significant negative relationships among specific conductance, total iron, and total sulfate, and selected community metrics (p < 0.05; Figs. 3–5). Because taxonomic complements vary among the unimpacted reaches, no particular taxa are represented in all streams; nor is any particular taxon present completely eliminated downstream. Rather the resident upstream community is markedly reduced in total abundance below the pollutant inputs. Hence, the reclamation of such sites would result in recolonization by drift from the resident upstream community such as it exists. Therefore, the responses of impacted sites to NAMD inputs reflect the composition of the upstream community, but in a depauperate condition. Intolerant taxa scores as measured by the EPT metric did not differ significantly between unimpacted and impacted sites, nor did resident taxa, and are not presented here. Specific conductance is defined as the ability of water to conduct electricity and serves as an indicator of total dissolved solids (TDS).
Fig. 1. Map of study area indicating 10 stream locations used in this evaluation.
employed as indicators of stream health. In the bituminous coal fields of southwestern Pennsylvania, streams colored orange resulting from NAMD are a typical sight, and may support aquatic life (Kimmel and MajumdarMiller, 1983; Kimmel et al., 1981; Ventorini, 2002; Kimmel and Argent, 2006). In many cases, mine drainage discharges are diffuse throughout an impacted watershed making bioassessment involving impacted vs. control sites difficult. The purpose of this study is to characterize water quality and macroinvertebrate communities above and below point sources of NAMD emanating from abandoned sites, and assess their suitability for reclamation. 2. Methods Ten NAMD-impacted low-order tributaries of the Ohio and Youghiogheny rivers located in southwestern Pennsylvania were selected for this study (Fig. 1). In July 2018, we established two sampling stations on each selected stream – one upstream reference (above) and one downstream impacted site (below) of the NAMD point-source below the zone of complete mixing. At each sampling station, we measured temperature (oC), pH, and specific conductance (μs/cm) using a pH Testr3+ (Oakton Instruments). Two water samples were collected from each site – one returned to the laboratory at California University of Pennsylvania for analysis by standard titration of total alkalinity (mg/l as CaCO3); and the other to H&H Water Controls for determination of total iron and total sulfate. Values at the respective reference and impacted sites were pooled to generate mean values for statistical comparison using a two-sample T-test. Results were considered significant if α < 0.05. We sampled macroinvertebrate communities in riffle areas at each station using a standard 1-m2 500 μm kick-net according to protocols established by the Pennsylvania Department of Environmental Protection (PA DEP) (Chalfant, 2015; Kimmel and Argent, 2018). Three samples collected at each site were pooled to form a station composite, preserved in 70% isopropyl alcohol and returned to the laboratory at California University for processing. We identified organisms to the lowest practicable taxonomic level, enumerated them, and assigned each to appropriate community metrics – taxonomic richness, total abundance, trophic composition, intolerant taxa composition, and community diversity (H). Macroinvertebrate community metrics were compared using t-tests to determine if significant differences between reference and impacted sites existed. We used simple linear regression to relate selected water quality parameters to biological metrics. Results were considered significant if α < 0.05. 3. Results and discussion
Fig. 2. Mean and standard deviation of total macroinvertebrate abundances above and below input of NAMD.
No evidence of metal precipitates were observed upstream of NAMD 2
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Fig. 4. Relationship between iron (mg/l) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for impacted reaches. A line of best fit and its associated goodness of fit (R2) for each relationship are presented.
Fig. 3. Relationship between specific conductance (μS/cm) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for the unimpacted reference (circles, dashed line) and impacted (diamonds, straight line) reaches. A line of best fit and its associated goodness of fit (R2) are presented for each relationship. Dashed line represents unimpacted reference sites and solid line defines impacted sites.
exhibiting elevated levels of specific conductance (Kimmel and Argent, 2012, 2018), even in the absence of iron and sulfate and far above the 300 μS/cm benchmark established by the United States Environmental Protection Agency (Environmental Protec, 2011). In this study, as values of specific conductance increase, community diversity and taxonomic richness decline, but intolerant taxa persist, albeit in low numbers (Fig. 3). Total iron from mine drainages has been linked to the declines in macroinvertebrate abundance and community diversity in impacted
Therefore, it represents the totality of ions in solution in the discharges and in the receiving streams. Such a mixture may exhibit synergistic or additive properties, which could not be separately determined in this study; as a result, it is expressed as a composite measure of the streams chemical composition in solution. Previous studies have documented the presence of fish and macroinvertebrate communities in streams 3
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
Weed and Rutschky, 1972). The presence of depauperate fish communities in these streams has also been reported from such streams (Cannon and Kimmel, 1992; Kimmel et al., 1981; Ventorini, 2002). Given the mobility of stream ichthyofauna, it is difficult to document these as resident or transient communities, but it strongly suggests that physiological toxicity in this environment is not a major limiting factor, and the nearby presence of colonizers to remediation. Similarly, the macroinvertebrate communities of the impacted reaches of this study mirror those of the upstream reaches suggesting drift as a source of resident or temporal assemblages and potential colonizers (Fig. 4). Sulfate concentrations in the NAMD-impacted reaches in this study are also related to significant declines in macroinvertebrate community metrics (Fig. 5). Sulfate is a typical component of coal mine drainages as a result of the oxidation and hydrolysis of pyritic materials (FeS2) often associated with coal seams. Zhao et al. (2017) report that sulfates in mine drainage exceeding 35 mg/l resulted in a significant decline in “intolerant” macroinvertebrate taxa; and the PA DEP (Shull, 2018) ranks stream sulfate concentrations - < 20 mg/l (Good); 20–200 mg/l (Fair); > 200 (Poor). In this rating system, our results for the unimpacted and impacted reaches fall into the “Fair” and “Poor” categories, respectively. Sulfate, however, can be derived from a number of sources including raw and treated sewage effluents and agriculture. The near absence of total iron in these reaches suggest such sources rather than mining, and indeed these streams drain such culturally impacted watersheds. Also, that total iron concentrations rather than sulfates are the limiting factors to macroinvertebrate communities here as suggested in the above citations. Fig. 6 illustrates the relationships between levels of total iron and total sulfate and macroinvertebrate total abundance. Below the point of entry of the NAMD at each site, total iron and total sulfate increases are accompanied by precipitous declines in macroinvertebrate abundance. Our data, in accordance with previously cited literature (Butler et al., 1973; Kimmel and MajumdarMiller, 1983), suggests that the physical coating of iron oxides in the benthic habitats of NAMD-impacted reaches is the primary driver of declines in macroinvertebrate abundance. The trophic structure of the extant reference and impacted communities is similar (Fig. 7) suggesting the latter is a reflection of upstream colonizers, which would be immediately available through drift following mitigation. In summary, the identification and mitigation of isolated point sources of NAMD in the world's coalfields continue to be a worthwhile
Fig. 5. Relationship between sulfate (mg/l) and selected biological metrics (intolerant taxa richness, taxa richness, and diversity) for impacted reaches. A line of best fit and its associated goodness of fit (R2) for each relationship are presented.
stream reaches. A threshold of “Good Ecological Status” for total iron in streams has been proposed to protect aquatic life at 1.25–2.46 mg/l (Peters et al., 2011). Iron in its oxidized forms can produce turbidity when in suspension and coat stream bottoms when precipitated. The former reduces light penetration for photosynthesis and the latter can physically smother habitat niches. Other studies have linked iron oxide deposition to losses of fish and macroinvertebrate populations in NAMD – receiving streams (Cannon and Kimmel, 1992; Kimmel et al., 1981;
Fig. 6. Influence of total iron and sulfate on total macroinvertebrate community abundance among sampling stations. Arrow indicates location of NAMD input. Stations are identified by numerics: 1 = Little Redstone, 2 = Laurel Run, 3 = N. Branch of Cucumber Run, 4 = Douglas Run, 5 = Guffey Run, 6 = Galley Run, 7 = McLaughlin Run, 8 = Georges Run, 9 = Coal Run, and 10 = Millers Run. 4
Journal of Environmental Management 250 (2019) 109484
W.G. Kimmel and D.G. Argent
locations around the globe and to include other taxonomic groups of study (e.g., fish and amphibians). Acknowledgements We wish to thank California University of Pennsylvania's Faculty Professional Development Fund for providing financial assistance with this project. In addition, we wish to acknowledge Catie Gallmeyer and Colton Schmucker for their assistance with field collections. References Butler, R.L., Cooper, E.L., Hales, D.C., Wagner, C.C., Kimmel, W.G., Crawford, J.K., 1973. Fish and Food Organisms in Acid Mine Waters of Pennsylvania. Office of Research and Monitoring. U.S. Environmental Protection Agency, Washington, D.C EPA-R-73032. Cannon, W.E., Kimmel, W.G., 1992. A comparison of fish and macroinvertebrate communities between an unpolluted stream and the recovery zone of a stream receiving acid mine drainage. J. Pa. Acad. Sci. 66 (2), 58–62. Chalfant, B.A., 2015. An Index of Biotic Integrity for Benthic Macroinvertebrate Communities in Pennsylvania's Wadeable, Freestone, Riffle-Run Streams. Pennsylvania Department of Environmental Protection, Bureau of Clean Water, Harrisburg, Pennsylvania. U.S. Environmental Protection Agency (USEPA, 2011. A Field-Based Aquatic Life Benchmark for Conductivity in Central Appalachian Streams. National Center for Environmental Assessment, Office of Research and Development, Cincinnati, OH EPA/600/R-10/023 F. Available at: http://cfpub.epa.gov/ncea/cfm/recordisplay. cfm?deid0233809. U.S. Environmental Protection Agency (USEPA, 2018. “National Recommended Water Quality Criteria – Aquatic Life Criteria Table. ” U.S. Environmental Protection Agency. https://www.epa.gov/wqc/national-recommended-water-quality-criteriaaquatic-life-criteria-table, Accessed date: 27 May 2018. Kimmel, W.G., Argent, D.G., 2006. Development and application of an index of biotic integrity (IBI) for fish communities of wadeable Monongahela River tributaries. J. Freshw. Ecol. 21 (2), 183–190. Kimmel, W.G., Argent, D.G., 2012. Status of fish and macroinvertebrate communities in a watershed experiencing high rates of fossil fuel extraction: tenmile Creek, a major Monongahela River tributary. Water Air Soil Pollut. 223 (7), 4647–4657. Kimmel, W.G., Argent, D.G., 2018. Scuds (Gammaridae) and darters (Percidae) dominate aquatic communities in a stream exhibiting levels of specific conductance exceeding 4,000 μS/cm. Int. J. Environ. Monit. Anal. 6 (2), 47–52. Kimmel, W.G., 1983. The impact of acid mine drainage on the stream ecosystem. In: Majumdar, S.K., Miller, E.W. (Eds.), Pennsylvania Coal: Resources, Technology and Utilization. Pennsylvania Academy of Science, Easton, Pennsylvania. Kimmel, W.G., Miller, C.A., Moon, T.C., 1981. The impact of a deep-mine drainage on the water quality and biota of a small hard-water stream. Proc. Pa. Acad. Sci. 55 (2), 137–141. Pennsylvania Department of Environmental Protection (PA DEP), 1999. The Science of Acid Mine Drainage and Passive Treatment. PA DEP Publication, Bureau of Abandoned Mine Reclamation, Harrisburg, Pennsylvania. Peters, A., Crane, M., Adams, W., 2011. Effects of iron on benthic macroinvertebrate communities in the field. Bull. Environ. Contam. Toxicol. 86 (6), 591–595. Rose, A.W., Cravotta III, C.A., 1998. Geochemistry of Coal Mine Drainage. Coal Mine Drainage Prediction and Pollution Prevention in Pennsylvania. Pennsylvania Department of Environmental Protection, Harrisburg, Pennsylvania. Scott, R.L., Hays, R.M., 1975. Inactive and Abandoned Underground Mines—Water Pollution Prevention and Control. U.S. EPA—440/9-75-007. U.S. Environmental Protection Agency; Office of Water, Washington, D.C. Shull, D., 2018. A Benthic Macroinvertebrate Multimetric Index for Large Semi-wadeable Rivers: Technical Report. The Pennsylvania Department of Environmental Protection, Harrisburg, PA. Ventorini, R., 2002. Fish Community in Warmwater Tributaries of the Youghiogheny River Impacted by Net Alkaline Deep Mine Discharges. MS Thesis. California University of Pennsylvania, California, Pennsylvania, pp. 57. Weed, C.E., Rutschky, R.W., 1972. Benthic macroinvertebrate community structure in a stream receiving acid mine drainage. Proc. Pa. Acad. Sci. 46, 41–47. Zhao, Q., Guo, F., Zhang, Y., Ma, S., Jia, X., Meng, W., 2017. How sulfate-rich mine drainage affected aquatic ecosystem degradation in northeastern China, and potential ecological risk. Sci. Total Environ. 609, 1093–1102.
Fig. 7. Proportional representation of functional feeding groups between unimpacted reference (A) and impacted reaches (B). CG = collector/gatherer; FC = filterer/collector; PR = predator; SC = scraper; and SH = shredder.
target of remediation efforts by a variety of treatment systems usually involving precipitation of the oxidized states of heavy metals from the drainage (Pennsylvania Department of Environmental Protection (PA DEP), 1999). Future work should expand to include other geographic
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