ARTICLE pubs.acs.org/est
Ecotoxicological Effects of Activated Carbon Amendments on Macroinvertebrates in Nonpolluted and Polluted Sediments D. Kupryianchyk,*,† E. P. Reichman,† M. I. Rakowska,‡ E. T. H. M. Peeters,† J. T. C. Grotenhuis,‡ and A. A. Koelmans†,§ †
Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 47, 6700 AA Wageningen, The Netherlands ‡ Subdepartment of Environmental Technology, Department of Agrotechnology and Food Science, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands § Wageningen Imares, P.O. Box 68, 1970 AB IJmuiden, The Netherlands
bS Supporting Information ABSTRACT: Amendment of contaminated sediment with activated carbon (AC) is a remediation technique that has demonstrated its ability to reduce aqueous concentrations of hydrophobic organic compounds. The application of AC, however, requires information on possible ecological effects, especially effects on benthic species. Here, we provide data on the effects of AC addition on locomotion, ventilation, sediment avoidance, mortality, and growth of two benthic species, Gammarus pulex and Asellus aquaticus, in clean versus polycyclic aromatic hydrocarbon (PAH) contaminated sediment. Exposure to PAH was quantified using 76 μm polyoxymethylene passive samplers. In clean sediment, AC amendment caused no behavioral effects on both species after 3 5 days exposure, no effect on the survival of A. aquaticus, moderate effect on the survival of G. pulex (LC50 = 3.1% AC), and no effects on growth. In contrast, no survivors were detected in PAH contaminated sediment without AC. Addition of 1% AC, however, resulted in a substantial reduction of water exposure concentration and increased survival of G. pulex and A. aquaticus by 30 and 100% in 8 days and 5 and 50% after 28 days exposure, respectively. We conclude that AC addition leads to substantial improvement of habitat quality in contaminated sediments and outweighs ecological side effects.
’ INTRODUCTION Aquatic sediments polluted with hydrophobic organic compounds (HOCs) such as polyaromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) may become a source of secondary pollution, thus posing a risk to aquatic organisms.1,2 Traditional remediation methods include dredging of polluted sediment with subsequent deposition of dredged material in sediment storage facilities or in situ capping with clean materials. These methods focus on remediation of the total concentration of contaminants and are thus usually laborious, time-consuming, and expensive. Moreover, they may lead to complete physical deterioration of benthic habitats and benthic communities. An in situ technique based on addition of carbonaceous materials (CM), like activated carbon (AC), to contaminated sediments has recently been suggested as an alternative to dredging. Many studies have demonstrated the high effectiveness of CM application to reduce the bioavailable fractions of HOCs,3 6 the bioaccumulation of HOCs,3,6 9 and thus the toxicity of sediment-bound HOCs.10,11 Notwithstanding this advantageous effect, however, it has been shown that CM itself may have some negative effects on aquatic organisms,6,8,9,12 raising the question, to what extent can the addition of AC to sediments be considered ecologically safe? r 2011 American Chemical Society
In previous studies, many organisms exposed to sediment amended with 2 4% AC showed high survival.9,11 14 As for growth inhibition, some studies demonstrated no effects of AC addition, or only mild effects, for the clam Corbicula fluminea and the mussel Mytilus edulis.7,14 The greatest effects seem to occur in worms. Growth reductions have been reported for Neanthes arenaceodentata,9 whereas lipid content and egestion rate reductions have been observed in Lumbriculus variegatus.6,12 These studies have mainly focused on the effects of AC on sedimentdwelling benthic organisms, assuming them to be the most sensitive benthic species, since they are exposed to CM via direct contact and ingestion of CM particles. Many sediment-dwelling organisms, however, acquire their food and oxygen from the overlying water, so the effects of CM on species inhabiting the bottom sediment and overlying water should not be overlooked. Previous work on effects of AC focused on traditional end points, such as mortality or growth, but behavioral changes may occur at much lower concentrations than those inhibiting Received: April 28, 2011 Accepted: August 16, 2011 Revised: July 23, 2011 Published: August 16, 2011 8567
dx.doi.org/10.1021/es2014538 | Environ. Sci. Technol. 2011, 45, 8567–8574
Environmental Science & Technology survival and growth, and they may reveal negative impacts that would otherwise be missed.15 Therefore, the objective of this study was to assess possible effects of AC amendment on two contrasting benthic species under laboratory conditions, using a suite of behavioral and traditional end points. To our knowledge, no earlier studies addressed the effects of AC on macroinvertebrate behavioral end points such as macroinvertebrate locomotion and ventilation. Gammarus pulex and Asellus aquaticus were selected as test organisms because they (a) are common invertebrates in freshwater habitats, (b) differ in sensitivity to pollutants of various types, and (c) have different species-specific properties in terms of behavior, feeding strategies, and uptake routes, complementing those of previously studied aquatic organisms and thus providing better representation of benthic communities. Furthermore, these species are an important food source for predatory invertebrates, fish, and waterfowl and thus play an important role in the benthic pelagic coupling of the food chain transfer of HOCs. Impacts of AC amendment were tested using sediment taken from uncontaminated versus highly contaminated sites. Our whole-sediment AC toxicity tests with clean sediment used locomotion, ventilation, avoidance, growth, and mortality as end points. Because of the acute toxicity, our tests with contaminated sediment used only mortality as a toxicological end point. In the latter tests, aqueous HOC exposure was accurately determined using polyoxymethylene (POM) passive samplers. The required HOC POM-to-water partition coefficients were obtained by extrapolation from coefficients measured at a range of methanol water mixtures.
’ MATERIALS AND METHODS Chemicals and Materials. Virgin powdered coal-based activated carbon (Norit SAE Super) was obtained from Norit Activated Carbon (Amersfoort, The Netherlands). To mimic the long-term condition of AC in field applications, AC was washed prior to experiments, as described previously by Jonker et al.12 Briefly, demineralized water with AC was heated to 100 °C for 30 min while stirring. After AC had been allowed to settle, the overlying water was decanted, and the procedure was repeated twice. Finally, AC was dried at 105 °C overnight. Polyoxymethylene (POM) film (76 μm thickness) was purchased from CS Hyde Co., Lake Villa, IL. Following previously published procedures, POM passive samplers were prepared by cutting the film into strips (70 mg each) and cold-extracting them with hexane (30 min) and methanol (3 30 min), after which they were air-dried.16 Acenaphthene (ACE), acenaphthylene (ACY), anthracene (ANT), benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), benzo[b]fluoranthene (BbF), benzo[e]pyrene (BeP), benzo[ghi]perylene (BghiP), benzo[k]fluoranthene (BkF), chrysene (CHR), dibenzo[a,h]anthracene (DBA), fluoranthene (FLU), indeno[1,2,3-cd]pyrene (InP), naphthalene (NAP), phenanthrene (PHE), and pyrene (PYR) were obtained from Sigma-Aldrich or Acros Organics, The Netherlands, all with a purity of >98%. Internal standard 2-methylchrysene (99.2% pure) was supplied by the Community Bureau of Reference (BCR), Geel, Belgium. Other chemicals used were hexane and acetone (Promochem; picograde), methanol (Mallinckrodt Baker, Deventer, The Netherlands; HPLC gradient grade), ethanol (Merck, Darmstadt, Germany; p.a.), acetonitrile (Lab-Scan, Dublin, Ireland; HPLC grade), calcium chloride (Merck; p.a), sodium azide (Aldrich; 99%),
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aluminum oxide-Super I (ICN Biomedicals, Eschwege, Germany), and silica gel 60 (Merck; 70 230 mesh). Prior to use, silica gel was activated at 180 °C for 16 h, and aluminum oxide was deactivated with 10% (w/w) Nanopure water (Barnstead). To prevent photodegradation of PAH, brown or aluminum foil covered glassware was used. Organisms. G. pulex were collected in the spring and summer of 2009 from a noncontaminated brook (Heelsumse Beek, Heelsum, The Netherlands). A. aquaticus were collected from a noncontaminated pond (Duno pond, Doorwerth, The Netherlands). Organisms were transferred to the laboratory and kept in white buckets filled with aerated copper-free water in a climatecontrolled room at 18 °C and 12:12 light:dark cycle. Organisms were fed dry poplar leaves that were collected in the field. Prior to the experiments, organisms were acclimatized for a month and sorted to obtain a group of organisms with a narrow body size range (4 7 mm). Sediments. Uncontaminated freshwater sediment was sampled at Station Veenkampen, Wageningen, The Netherlands, using a sampling bucket. The natively contaminated sediment was taken from a previously stored batch, which had originally been dredged from Petroleum Harbor (PH), Amsterdam, The Netherlands. An overview of the concentrations of PAHs, PCBs, and metals is provided as Supporting Information (Tables S1 and S2). The sediments were passed over 2 mm sieves, homogenized, and amended with AC to obtain AC concentrations of 0, 1, 3, 6, 15, and 30% (dry weight, dw). Subsequently, sediments were homogenized on a roller bank for 48 h and stored at 4 °C in the dark for 2 months until use. Toxicity Tests. Motility Patterns Measured with Multispecies Freshwater Biomonitor (MFB). Movements were measured using a multispecies freshwater biomonitor (MFB), following previously published procedures.15,17 The MFB measures different types of behavior (e.g., locomotion, ventilation, feeding) of aquatic species by recording changes in a high frequency alternating current caused by the movements of organisms in the MFB chambers. Locomotion and ventilation generate currents of different frequencies, viz.,
