Article pubs.acs.org/est
Assessment of the Direct Effects of Biogenic and Petrogenic Activated Carbon on Benthic Organisms Adam Lillicrap,* Morten Schaanning, and Ailbhe Macken Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway S Supporting Information *
ABSTRACT: Activated carbon (AC) has long been associated with the capacity to effectively remove organic substances from aquatic and sediment matrices; however, its use in remediation purposes has drawn some concern due to possible impacts on benthic communities. Within the inner Oslofjord, the use of AC has been well documented for reducing the risks associated with dioxins or dioxin-like compounds from contaminated areas. However, benthic surveys performed on areas treated with AC have revealed that the abundance of organisms inhabiting these areas can be reduced significantly in the subsequent years following treatment. The reason for the reduction in the benthic communities is currently unknown, and therefore, an integrated approach to assess the effects of 2 different forms of AC (biogenic and petrogenic) on benthic organisms has been performed. A battery of 3 different benthic organisms with different feeding and life-cycle processes has been used encompassing sediment surface feeders, sediment ingestors, and sediment reworkers. Results of the tests indicated that although AC is not acutely toxic at concentrations up to 1000 mg/L, there may be physical effects of the substance on benthic dwelling organisms at environmentally relevant concentrations of AC at remediated sites.
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INTRODUCTION Deep fjord environments have for decades acted as traps for hydrophobic, particle-bound organic contaminants discharged from anthropogenic sources. After elimination of the primary source of contaminants due to regulation of manufacture discharges and from the use of cleaner technologies, fjord sediments in the locality may become the primary source for remobilization of contaminants. In the Grenland fjord area in southeast Norway, discharges of dioxins (from its primary source) were eliminated by the closure of the main dioxinproducing factory in 2002, but levels of dioxins in several commercial seafood species are still in excess of recommended concentrations. 1 Modeling data suggests that enhanced remediation of seafood quality is best obtained by reducing contaminant availability in the sediments where contaminants enter the food web.2 Conventionally, in many cases, dredging would be used to remove contaminated sediments. However, there are significant amounts of contaminated sediments at depths that are beyond the reach of conventional dredging equipment. Due to the strong sorption of hydrophobic organic contaminants (HOCs) to carbonaceous materials, activated carbon (AC), a highly condensed and inert material, has been proposed as a remediation tool for contaminated sediment.3 The use of AC in situ overcomes the issues of disposal of dredged material as well as reducing the cost compared to conventional remediation solutions. Laboratory and field studies have shown that contaminant partitioning to pore-water and biota are © 2015 American Chemical Society
strongly reduced after addition of AC. Therefore, over the past 10 years AC amendment has been increasingly recommended for remediation of contaminated sediments.3,4 For example, mesocosm experiments and field tests with AC have confirmed the efficiency of AC in reducing dioxin bioavailability as well as other HOCs.4−7 However, in situ treatment using AC to reduce bioavailability of HOCs is still an emerging technology, and fullscale and long-term application has not yet been entirely optimized. In addition, the regulatory acceptance of the technology is not finalized, and other limitations need to be considered before being fully accepted (e.g., inorganic contaminants that may not be sorbed to AC). Although AC has been proven as an efficient way of reducing the bioavailability of HOCs, evidence has been found that carbon amendment simultaneously can, at least temporarily, cause a significant reduction of macrobenthic biomass and species diversity.7−9 The Norwegian Research Council “Coast and Sea” project described similar observations in their long-term monitoring of a pilot field survey in Trondheim Harbour in 2011. They observed that species abundance and richness was significantly reduced in all capping treatments compared to their reference site. In addition, laboratory-based ecotoxicity assessments of AC resulted in adverse effects in 20% of 82 tests Received: Revised: Accepted: Published: 3705
October 13, 2014 February 26, 2015 February 27, 2015 February 27, 2015 DOI: 10.1021/es506113j Environ. Sci. Technol. 2015, 49, 3705−3710
Article
Environmental Science & Technology conducted.10 The effects of multiple AC products on several freshwater and marine species have also been investigated,11 indicating that exposure to AC caused lethal effects at doses of 0.5−4 g/L for Daphnia magna and doses of 4−60 g/L for Lumbriculus variegatus and Corophium volutator. Investigations of the responses at the species level among ecological functional groups in an AC-amended area revealed that the main differences between treatments were due to the reduction of organisms that fed at or near the surface of the sediment (i.e., suspension and filter feeders and subsurface feeders), whereas functional groups that fed deeper within the sediment were less effected or even not impacted. Therefore, statements regarding the toxicity of AC to aquatic and sediment organisms must be treated with caution. There are a series of additional factors that may influence the effects of AC. For example, addition of AC to an environment may influence the physical and chemical characteristics of sediments rather than causing direct toxicological effects. It may also lead to a decrease in nutrient availability to plants and benthic organisms,11,12 cause clogging of filter feeders, or alter the chemical composition of the pore-water and pH.13,14 These factors may result in in situ organisms relocating or actively avoiding the AC-amended areas.11,15 Due to concerns over the ecological effects to the in situ community (e.g., reduction in species abundance and diversity) this paper examines whether the field results can be confirmed in tests performed in accordance with standard test procedures and test guidelines, thereby, improving the understanding of the underlying mechanisms of effects observed in sediments treated with AC. Specifically, this paper describes the effects of both biogenic (i.e., produced from life processes) and petrogenic (i.e., produced from combustion of petroleum like substances) forms of AC on species that are more likely to be impacted by remediation processes and discusses the potential confounding factors in assessing any observed effects. The species selected reflect those which may be exposed to AC in the Norwegian fjords by focusing on the marine species (Tisbe battagliai and Arenicola marina) as well as incorporating a longer term freshwater/estuarine species (Chironomus riparius) to investigate developmental effects in AC-treated sediments.
battery approach using benthic organisms from different trophic levels, varying feeding mechanisms, and from both marine and freshwater/estuarine environments was conducted. The first level of testing was the acute testing with the marine benthic harpacticoid copepod T. battagliai. T. battagliai have a wide geographic distribution, possess short life-cycles, and feed by grazing from the surface of the sediment. They are a standardized ISO (International Organization for Standardization) test species frequently employed in the assessment of sediment pore-waters and extracts18−20 and are therefore highly relevant for the assessment of the AC substances in this study. The second tier of the approach investigated the 10 day acute toxicity to the marine polychaete A. marina. A. marina burrows in marine sediments and feeds by ingesting the sediment to obtain nutrients. Therefore, exposure to the spiked test substances was through ingestion as well as dermal contact. The final tier was designed to assess the chronic effects of prolonged exposures of the AC substances to a sediment dwelling larvae of the freshwater/estuarine dipteran C. riparius. Larvae of C. riparius are highly sedentary animals that build tubes out of which they forage for food. They are deposit feeders, ingesting particles including any organic detritus within reach from the burrow. Acute Lethality Test with T. battagliai. Acute toxicity testing with the marine harpacticoid copepod T. battagliai was conducted (according to the International Standard ISO/DIS 1466921) with slight modifications to include an extended exposure period of 72 h. In brief, T. battagliai were exposed to a range of concentrations (10, 32, 100, 320, and 1000 mg/L AC exposure via direct addition to dilution water) of the two different forms of AC (BP2 and CP1), and their survival and behavior was assessed compared to a dilution water control after 24, 48, and 72 h exposure. Animals were 6 ± 2 days old at the start of the test with 4 replicates each containing 5 animals per concentration. Due to the nature of the test substances being insoluble (according to the definitions of Lillicrap et al.22) test concentrations were prepared in 100 mL of natural filtered (0.2 μm) seawater and stirred for 1 h under the same conditions as the test (20 ± 2 °C). While the solutions were stirring (to ensure homogeneity of the AC particles in the test solutions) they were dispensed into the 12-well exposure plates (4 mL per replicate) and allowed to settle for 1 h. Organisms were then added, and the pH and dissolved oxygen (DO) of all test concentrations were measured. Animals were exposed in a temperature-controlled room with a 16:8 h light:dark photoperiod. Values for effect concentrations were calculated with the REGTOX: macro Excel for do se−respon se (REGTO_EV7.06.xls. available at http://www.normalesup.org/ ~vindimian/en_index.html). A. marina 10 Day Survival Test. A 10 day acute toxicity test was performed on the polychaete worm A. marina in accordance with the PARCOM guideline.23 The polychaete worms were obtained from Shore Aqua Consulting, England, U.K., and each worm was between 1 and 3 g in weight. On receipt of the worms from the supplier, their health status was checked and all healthy worms were maintained in a holding tank with fresh seawater and gentle aeration. For the sediment spiking procedure, natural marine reference sediment from the outer Oslofjord was spiked with a concentration range of both BP2 and CP1 as follows, 1.25%, 2.5%, 5.0%, 10%, and 20% (wet weight sediment:dry weight AC). Three replicates of each concentration were prepared, and a negative control, with clean sediment only, was run concurrently.
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MATERIALS AND METHODS Test Substances. Aquasorb BP2 and Aquasorb CP1 were obtained from Jacobi, The Carbon Co., Sweden. BP2 (petrogenic) is a powdered coal-based AC manufactured by steam activation from selected grades of bituminous coal. This grade of AC is predominately mesopourous in nature and has an approximate surface area (BET N2) of 900 m2/g. Therefore, it is suited to the removal of medium-range organic pollutants, such as pesticides.16 Aquasorb CP1 (biogenic) is made from powdered coconut shell and considered a renewable source of material.17 It is a high-activity powdered AC that is very microporous with an approximate surface area (BET N2) of 1050 m2/g. Hence, CP1 is particularly suited to the removal of low molecular weight organics present at low concentrations. Both test substances used were in the smallest particle size available with a particle size distribution between 8 and 15 μm in diameter. Ecotoxicity Tests. Prior to performing the toxicity tests, the settling behavior and solubility of the two substances in water was assessed in order to identify the most suitable testing exposure and spiking scenarios for the proposed test species. A tiered test 3706
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oxygen and pH were measured at the start and end of the test to ensure validity. Validity parameters according to OECD 218 are that emergence of the control animals must be ≥70%, water temperature should be maintained within ±1 °C, and oxygen levels should be at least 60% of the air saturation value. At test termination, the sediment was examined for any dead or nonemerged larvae. Biological end points were subsequently assessed, and the development rate, the time to first emergence, the sex ratio, and the total number of emerged chironomids were calculated. Statistical analysis was performed to determine the no effect concentration (NOEC) and low effect concentration (LOEC) compared with the control organisms. After the assessment of equality of variance and normality, development rate was analyzed using a one-way ANOVA followed by a Dunnett’s test to identify the NOEC and LOEC. Data for total emergence and sex ratio after 28 days was analyzed using a Fisher’s Exact Test for 2 × 2 contingency tables. An overall significance level of p = 0.05 was used.
To prepare the test replicates, the sediment containing spiked AC was thoroughly mixed, overlying water added and allowed to settle prior to addition of the test organisms. At the start of the test, five individual worms were removed from the holding tank and added to each replicate test vessel. Observations for dead animals were made daily, and any dead organisms were removed. Any dead worms observed within the first 24 h of the test were taken out and replaced with fresh healthy worms. Theses worms were not included in the calculations of mortalities. At the end of the 10 day study, the sediment was sieved and the numbers of live and dead worms were counted in each test replicate. The animals were not fed during exposure, and the overlying water was aerated continuously throughout the study. The toxicity test was carried out in 10 L plastic test vessels in a temperature-controlled room (15 °C) in the dark. C. riparius 28 Day Emergence Test. C. riparius larvae ≤ 48 h post hatch, from continuous laboratory cultures, were used in a 28 day spiked sediment test using BP2 and CP1. All culture maintenance and testing was conducted in accordance with the OECD test guideline 218.24 The exposure duration of the test was 28 days with a sediment/AC equilibration period of 1 week prior to addition of the animals to allow the AC to equilibrate between the interstitial water and the sediment. The ratio of sediment to overlying water was approximately 1:4 in each replicate, with a sufficient gap between the water surface and the lid to allow the adult midges to emerge. Gentle aeration was provided to each vessel, and all vessels were maintained in a climate-controlled room at a temperature of 20 °C with a photoperiod of 16:8 h light:dark cycle. Four replicates per concentration and 6 control replicates were used, each containing 20 larvae. Artificial sediment formulated from sand (75% quartz sand, Sigma-Aldrich, CAS no. 14808-60-7), kaolinite (20% kaolin clay, Sigma-Aldrich, CAS no. 1332-58-7), and finely ground conditioned moss peat (5% peat, L.O.G. As, Oslo, Norway) were used for the test. Initial trials with the spiking of the test substances were conducted on a wet:dry basis to reflect the procedure in the field when applying the AC for remediation purposes. However, after the initial trials and for practical reasons, the sediment was spiked on a dry:dry basis for the definitive studies. For both substances, the following concentrations of AC were added directly to the sediment and mixed: 1.25%, 2.5%, 5.0%, 10%, and 20% dry weight AC. In addition, one concentration of BP2 at a wet:dry concentration of 20% was tested. A shared control containing no AC was also employed for the study. At the start of the equilibration period, 100 g (dry weight) of test sediment (containing the appropriate amount of AC) was weighed into the appropriate test vessel and overlying test media was added gently over the back of a spoon to avoid disturbance of the test sediment. The test vessels were left to settle without aeration until the overlying water became clear (3 days), at which point the aeration was started and the equilibration period continued for a further 4 days. On the first day of exposure (day 0) aeration was stopped and 20 larvae ≤ 48 h post hatch were randomly allocated to each test replicate. After approximately 24 h (sufficient time for the animals to reach the sediment) aeration was restarted. During the 28 day exposure, animals were fed daily (Tetra Min fish flakes). From day 12 onward, the emergence of adult midges was recorded daily. All emerged midges were sexed and removed from the test system. Observations on the animal behavior, overlying water, and sediment disturbance as well as any mortalities were recorded three times a week. Dissolved
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RESULTS T. battagliai Acute Lethality Test. Effect data for BP2 and CP1 to T. battagliai are shown in Figure 1 and the Supporting
Figure 1. T. battagliai survival data exposed to BP2 and CP1 for 72 h (asterisk (*) indicates statistically different from the control).
Information. The control mortality and physical-chemical parameters measured at the start and end of both tests were within the recommended limits (ISO, 1999). Due to the nature of the test substances it was obvious that both BP2 and CP1 physically affected the movement of T. battagliai confined within the small test wells with no way to avoid the settled material. Animals at all test concentrations were observed to have fouled appendages, and their guts appeared black due to ingestion of AC particles. Although there were statistically significant effects of both substances on T. battagliai, it was only possible to calculate an EC50 value after 72 h, at which point the most likely effect was physiological due to impairment of swimming ability leading to exhaustion. Any animals observed not to have been fouled had normal swimming ability even if there was carbon observed in the gut of the animal. A. marina 10 Day Survival Test. Due to the nature of the test substance, the activity of the worms within the sediment meant that the overlying waters became black and cloudy, and daily observation on behavior or cast formation was not possible during the test. The numbers of mortalities after day 10 results for both CP1 and BP2 are shown in the Supporting Information. There was a slight reduction in survival for BP2 and CP1 at 20%;however, there were no statistically significant effects on 3707
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and 5.0% dry weight, respectively. The EC 10 and EC 50 (concentrations at which 10% and 50% of the exposed animals were effected) were 1.3% (95% confidence interval 0.2−7.0) and 20.9% (95% confidence interval 11.6−60.1), respectively, for BP2 and 0.7% (95% confidence interval 0.07−2.18) and 9.8% (95% confidence interval 5.9−17.3), respectively, for CP1. The sex ratio (as percentage males) for the control was 51% males, supporting the assumption that the expected ratio is close to 50:50. For sex ratio there were no significant differences between any concentration and the control for BP2. For CP1 there was a significant difference at 1.25% (69% males), but this statistical difference was not observed at any of the higher concentrations and does not influence the overall results of the study. Data on time to first emergence provided information only. The mean replicate times to first emergence are shown in the Supporting Information. Visual observations made daily showed that the overlying water became turbid from day 7 onward in all test concentrations and the control indicating activity of the chironomid larvae. As the turbidity increased, the color of the overlying water turned from milky yellow in the control and lower test concentrations, developing into a gray cloudy color in the higher test concentrations (10% and 20%) for both CP1 and BP2. This gray color is indicative of the AC being remobilized into the water column from the activity of the chironomid larvae within the sediment.
survival for either of the test substances at any concentration of AC. C. riparius 28 Day Emergence Test. The physical-chemical parameters measured during the study were all within acceptable limits (specified in OECD 218), specifically pH ranging between 6.15 and 8.61 and the DO ranging between 7.4 and 9.5 mg/L. The study satisfied the OECD test guideline minimum emergence criteria for the controls at the end of the test (OECD, 2004). Overall, the percentage emergence of the control was 72%. The cumulative daily emergences of the adult midges from each concentration for both test substances are shown in Figure 2. From these data, the time to first emergence, the mean
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DISCUSSION The application of AC has been proven as a remediation tool for contaminated marine sediment to reduce the concentrations of hydrophobic organic compounds; however, there is a need to gather information on possible ecological effects in situ. After identifying potential “at risk” functional groups, the assessment of exposure of AC to members of different taxa showed that there were effects observed in both short- and long-term assays. Backed by the data on a reduction over time in the biodiversity at treated sites,25 the question remaining is do the benefits of using AC as a remediation tool outweigh the potential ecological effects? The consensus is that AC is not acutely toxic;26 however, there is evidence that its use can reduce the abundance and diversity in treated areas.27 The sediment exposure studies described in this paper used uncontaminated reference sediment spiked with two different forms of AC. Therefore, this study looked purely at the effects of AC addition taking no account of the interaction of the AC with contaminants present in the sediment at a polluted site in the field. Other authors investigated short-term effects of clean ACtreated sediment, contaminated sediment, and AC-treated contaminated sediment.26 These authors found that ACamended sediment caused no behavioral effects, PAH-contaminated sediment caused 100% lethality, and the PAH-contaminated AC sediment showed an increase survival compared to the contaminated sediment. This is in contrast to our study where all exposures were designed to assess the effects of AC alone, and effects were observed during two of these studies (i.e., chironomid and copepod tests). Similar observations regarding the toxicity of AC in water only exposures have also been demonstrated.11 Employing freshwater and marine organisms resulted in LC50 values within the range of 0.5−4 and 4−60 g/L for D. magna and L. variegatus and C. volutator, respectively.11 The LC50 values for T. battagliai in this paper after the 72 h wateronly exposure (ca. 2.7 g/L) was similar to the D. magna data. In contrast, the authors found no significant mortalities with the two
Figure 2. Cumulative emergence of adult midges from day 13 to day 28 for (a) BP2 and (b) CP1. Initial day 0 nominal loading of 120 larvae in the control and 80 larvae in all treatments.
emergence time, and the numbers emerged after 28 days were calculated for each vessel. The time to first emergence, mean development rate, total number, and percentage of adult midges emerged after 28 days for both test substances are shown in the Supporting Information. Emerging adults in the control and all test substance concentrations occurred between days 16 and 28. For development rate, there were no significant differences between the development rate of emerged adults in the control compared to emerged adults at any concentrations for either test substance. However, it may be considered that there was a strong trend without the need for statistical analyses (on development rate) as there were considerably less emerged animals at 5.0%, 10%, and 20% for both BP2 and CP1 and at 20% wet:dry for BP2 (see Figure 2). For the total number emerged after 28 days, BP2 showed significant differences from the control at 5.0%, 10%, 20%, and 20% wet:dry weight, and for CP1 there were significant differences compared to the control at 5%, 10%, and 20%. Therefore, the NOEC and LOEC for both substances was 2.5% 3708
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Environmental Science & Technology sediment organisms in AC-containing sediment exposures.11 Here, they tested up to similar levels of AC (25%), and although there were no significant effects on mortality they observed subtle effects, like a reduction in water turbidity. The C. riparius study described in this paper showed effects on emergence at low levels (i.e., 5% dry weight), and the results indicated that C. riparius was most sensitive to BP2. AC has a low nutritional value and binds natural organic matter (especially BP2); therefore, during the test exposure the chironomids may have had a reduced source of food (binding of the AC to organic matter present in the test system) reducing their development rates and time to first emergence. Despite the significant effects shown in two of the presented studies (T. battagliai and C. riparius) these results need to be assessed in context with standard toxicity tests. For example, in the T. battagliai study the end point of mortality alone would imply an acutely toxic test substance for both of the AC forms; however, when considered in combination with the observations on behavior there are indications that these substances are not actually acutely toxic. Rather, this could be considered a physical or mechanical stressor. Observations in the T. battagliai study showed that those animals alive after 72 h were not fouled or less so than the impacted organisms and had managed to avoid the AC on the bottom of the test wells. These survivors had AC present in their guts, but this did not appear to affect them adversely. As the test substances are insoluble soot-like materials, they do not dissolve and therefore merely mix with the exposure water and settle out. The effect of the substances settling out is that they are more likely to have a physical effect on surfacefeeding benthic organisms where they have the potential to bind to foraging animals such as the copepods. Due to the method of applying AC in remediation practices, it is unlikely that the AC applied in the field will settle directly on the surface of the treated sediment, as the AC will be mixed with the contaminated sediment during application. A possible exposure route is if the AC becomes remobilized and settles out on the surface where the organisms can come into direct contact with the particles. This scenario is unlikely to occur as the levels used in remediation will never result in a concentration in the sediment as high as was employed in this testing scenario. In addition, the amount of AC generally used in field remediation is small compared to the bulk sediment in which it is mixed. On the basis of the EC values for the T. battagliai assay, it is unlikely that members of this functional group in situ would become reduced in numbers based on a lethal effect. It is more likely that the organisms that are able to avoid environments where particles bind to their appendages and hinder their swimming ability will eventually move away from the treated area. Avoidance of AC-containing sediment in laboratory-based studies has been documented with a number of species,11,28 suggesting that organisms may actively move away from treated areas, thereby reducing the abundance and diversity of species in that remediated area. Benthic community analyses at Ormefjorden and Eidangerfjorden after capping with and without AC was conducted during the period 2009−2011.7 Various methods of capping were tested at four sites in the Grenland fjord area in order to reduce transfer of dioxins from sediment to biota. Full macrofaunal investigations were performed on all test sites in 2009 and 2010. The effects in the clay-AC-treated field site showed statistically significant differences from the control field for fauna variables such as abundance, species richness, biomass, and the BQI diversity index. However, the use of the capping material did not
kill 10 out of 25 species of organisms. These species were not observed at the treated sites or were present in reduced numbers compared to the control site. However, recolonization by these organisms may simply be delayed. The use of AC for remediation purposes is still a relatively new technology, and therefore, the long-term effects and potential site recovery after treatment are still not well known. In the case of Ormefjorden and Eidangerfjorden, monitoring the recovery of biodiversity at the clay-AC fields will provide further information about future recolonization of treated sites. The use of AC in sediment remediation should be considered as an amendment technique in the early stages of development. Although there have been several pilot field studies in recent years, the long-term effects of remediation with AC and the effects on benthic communities over time (e.g., recolonization) are still largely unknown. What is known is that there have been confirmed effects on local communities in treated sites, but the potential for recovery has not been fully investigated. Although laboratory-based toxicity tests have shown effects on benthic organisms in sediment and water treated with AC, these results should be treated with caution. The effects observed in this paper are more likely to be physical effects of the AC and could be attributed to things such as particles size and binding of organic matter leading to a reduction in food availability within the test systems. These effects may not be so prominent in the field, where organisms can avoid a specific area during times of low food availability and colonize more favorable sites. For example, in the natural environment, organic matter content and particle size distribution are interacting factors which determine the abundance of chironomid larvae, and so these organisms are unlikely to colonize areas treated with AC. It should also be noted that organisms similarly avoid polluted sites, and as a consequence, there is often a lower diversity and abundance of species in polluted sediments compared to cleaner areas.29 In conclusion, sediments containing HOCs pose health risks to aquatic organisms and indirectly to humans. In contaminated sites that are difficult to reach with conventional methods of remediation (e.g., dredging), the choice of AC management strategies may be appropriate. Literature data suggests that addition of 4% AC to sediments is sufficient to reduce aqueous concentrations of HOCs, but effects on some species have been reported at these levels.11 However, in this study, no or minimal effects were observed at these levels (e.g., NOEC/LOEC of 2.5/ 5% AC for the C. riparius sediment test). Therefore, from the studies described in this paper, there appears to be limited risk in applying BP2 and CP1 in the remediation of HOCs in fjord sediments. In addition, the proven benefits of AC application as a tool for reducing the bioavailability of HOCs suggest that potential aversive effects at treated sites may not be a sufficient reason to deter the use of AC for future remediation purposes. Furthermore, beyond the potential impact on the benthic community, the addition of AC to sediments for remedial purposes may also have a positive effect on reducing bioaccumulation, trophic transfer, and biomagnification of pollutants at higher trophic levels. Finally, it could be considered that the use of AC with a larger particle size than that tested in these investigations may have less detrimental effects on benthic organisms while retaining the adsorptive capacity to remove HOCs in contaminated areas. 3709
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(11) Jonker, M. T. O.; Suijkerbuijk, M. P. W.; Schmitt, H.; Sinnige, T. L. Ecotoxicological effects of activated carbon addition to sediments. Environ. Sci. Technol. 2009, 43, 5959−5966. (12) Hilber, I.; Bucheli, T. D.; Wyss, G. S.; Schulin, R. Assessing the phytoavailability of dieldrin residues in charcoal-amended soil using Tenax extraction. J. Agric. Food Chem. 2009, 57, 4293−4298. (13) Berglund, L. M.; DeLuca, T. H.; Zackrisson, O. Activated carbon amendments to soil alters nitrification rates in Scots pine forests. Soil Biol. Biochem. 2004, 36, 2067−2073. (14) Strijakova, E. R.; Vasilyeva, G. K. Influence of activated carbon on soil fertility and quality of crops grown in contaminated soil, “-omics approaches and agricultural management: driving forces to improve food quality and safety?”; COST 859: St. Étienne, France, 2006. (15) Millward, R. N.; Bridges, T. S.; Ghosh, U.; Zimmerman, J. R.; Luthy, R. G. Addition of activated carbon to sediments to reduce PCB bioaccumulation by a polychaete (Neanthes arenaceodentata) and an amphipod (Leptocheirus plumulosus). Environ. Sci. Technol. 2005, 39, 2880−2887. (16) Jacobi Technical Datasheet. AquaSorb BP2 Powdered coal based activated carbon; Jacobi The Carbon Co.: Sweden, 2012a. (17) Jacobi Technical Datasheet. AquaSorb CP1; Jacobi The Carbon Co.: Sweden, 2012b. (18) Macken, A.; Giltrap, M.; Foley, B.; McGovern, E.; McHugh, B.; Davoren, M. An integrated approach to the toxicity assessment of Irish marine sediments: Validation of established marine bioassays for the monitoring of Irish marine sediments. Environ. Int. 2008, 34 (7), 1023− 1032. (19) Macken, A.; Giltrap, M.; Foley, B.; McGovern, E.; McHugh, B.; Davoren, M. An integrated approach to the toxicity assessment of Irish marine sediments: Application of porewater Toxicity Identification Evaluation (TIE) to Irish marine sediments. Environ. Int. 2009, 35 (1), 98−106. (20) Thomas, K. V.; Barnard, N.; Collins, K.; Eggleton, J. Toxicity characterization of sediment porewaters collected from UK estuaries using a Tisbe battagliai bioassay. Chemosphere 2003, 53 (9), 1105−1111. (21) ISO/DIS 14669. Water quality−determination of acute lethal toxicity to marine copepod (Copepoda, Crustacea); International Organisation for Standardisation, Geneva, Switzerland, 1999. (22) Lillicrap, A.; Allan, I.; Freid, B.; Garmo, Ø.; Macken, A. Is the Transformation/ Dissolution protocol suitable for ecotoxicity assessments of inorganic substances such as Silica fume. Sci. Tot. Environ. 2014, 468−469, 358−367. (23) Thain, J. E. M., Bifield, S. A sediment bioassay using the polychaete Arenicola marina. Test guideline for PARCOM sediment reworker ring-test; MAFF Fisheries Laboratory: Burnham-on-Crouch, Essex, U.K., 1993. (24) OECD Guideline for testing of chemicals 218: Sediment-water chironomid toxicity using spiked sediment. Adopted Nov 23, 2004. (25) Thin layer capping of fjord sediments in Grenland. Chemical and biological monitoring 2009−2013. NIVA report number 6724-2014, 2014; ISBN 978-82-577-6459-3. (26) Kupryianchyk, D.; Reichman, E. P.; Rakowska, M. I.; Peeters, E. T.; Grotenhuis, J. T.; Koelmans, A. A. Ecotoxicological effects of activated carbon amendments on macroinvertebrates in nonpolluted and polluted sites. Environ. Sci. Technol. 2011, 45 (19), 8567−74. (27) Norwegian Research Council. Sediment remediation through activated carbon amendment. Long-term monitoring of a field pilot in Trondheim Harbour. Norwegian research Council “Coast and Sea” Project 185032. Final report Apr 2011. (28) Hellou, J.; Cheeseman, K.; Jouvenelle, M. L.; Robsertson, S. Behavioural response of Corophium volutator relative to experimental conditions, physical and chemical disturbances. Environ. Toxicol. Chem. 2005, 24, 3061−3068. (29) Janssen, E. M. L.; Thompson, J. K.; Luoma, S. N.; Luthy, R. G. PCB-induced changes of a benthic community and expected ecosystem recovery following in situ sorbent amendment. Environ. Toxicol. Chem. 2011, 30, 1819−1826.
ASSOCIATED CONTENT
S Supporting Information *
The supporting information contains the effect data from the 3 different studies, plus the developmental rates and emergence data for the C. riparius test. This material is available free of charge via the Internet at http://pubs.acs.org.
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AUTHOR INFORMATION
Corresponding Author
*Phone:+4798215407. Fax: +4722185200. E-mail
[email protected]. Author Contributions
The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes
The authors declare no competing financial interest.
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ACKNOWLEDGMENTS We acknowledge Steve Ragan of Jacobi Carbons AB and Bernt Malme of Norsk Hydro for financing this project and Geir Markussen of Sparks AS for information regarding the test substances and constructive input during the studies.
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REFERENCES
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DOI: 10.1021/es506113j Environ. Sci. Technol. 2015, 49, 3705−3710
