Effects of Activated Carbon on PCB Bioaccumulation and Biological Responses of Chironomus riparius in Full Life Cycle Test

Abstract

The nonbiting midge Chironomus riparius was used to study the remediation potential and secondary effects of activated carbon (AC, ø 63-200 μm) in PCB contaminated sediments. AC amendments efficiently reduced PCB bioavailability determined by Chironomus riparius bioaccumulation tests and passive samplers. PCBs were shown to transfer from larvae to adults. Lower PCB concentrations were observed in adult midges emerging from AC amended compared to unamended sediments. Increased reproduction, survival, larval growth and gut wall microvilli length were observed with low AC dose (0.5% sediment dw) compared to unamended sediment, indicating an improved success of larvae in the sediment with low organic carbon content. On the other hand, higher AC doses (2.5% sediment dw) caused adverse effects on emergence and larval development. In addition, morphological changes in the gut wall microvilli layer were observed. This study showed that the secondary effects of AC amendments are dependent on the dose and the sediment characteristics. Metamorphic species, such as C. riparius, may act as a vector for organic pollutants from aquatic to terrestrial ecosystems and according to this study the AC amendments may reduce this transport.

Microplastic-mediated transport of PCBs? A depuration study with Daphnia magna

“…We explored whether exposure to microplastics (1) facilitates depuration of PCBs, similar to the sought remediation effect by adding activated carbon to contaminated sediments [24], and (2) alleviates effects of the PCB exposure on growth (somatic and reproductive) and elemental composition (carbon, %C, and nitrogen, %N) in the model filter-feeder D . magna (Straus, 1820).…”

Development of whole‐sediment toxicity identification and evaluation (TIE) techniques for two Australian freshwater species: Chironomus tepperi and Austrochiltonia subtenuis

“…This only occurred in the growth endpoint for C. tepperi in the nonpolar organics' TIE bioassay with the use of activated carbon (observed in 2 of the toxic concentrations; see 46.6 mg/g OC of permethrin [in formulation] using midge survival in Figure 1, as an example). This finding, however, is nothing new because the secondary effects of activated carbon and/or charcoal are well documented [1,10,[32][33][34]. The use of 1% activated carbon in control sediments had no acute effects or significant reduction in growth in preliminary testing; nevertheless, as shown in the results listed, it did significantly decrease growth in C. tepperi by 19% in control sediments.…”

Contaminated Sediments

“…Impacts on benthic fauna resulting from AC exposures were observed in 20% of 82 reviewed tests (primarily laboratory studies) (Janssen andBeckingham 2013, Patmont, Ghosh et al 2015). For instance, increased reproduction, survival, larval growth and gut wall microvilli length in Chironomus riparius was found at low AC dose (0.5% sediment dw), whereas at higher doses of AC, adverse effects on emergence and larval development was observed (Nybom, Abel et al 2016). Reduced growth and net loss of organism biomass of Lumbriculus variegatus were observed with a sediment concentration of AC of 0.1 and 1% respectively, whereas loss of biomass and mortality was observed when using AC in a thin layer cap (Abel et al 2017).…”

“…A study looking at bioaccumulation and secondary effects in the non-biting midge Chironomus riparius found lower PCB concentrations in adult midges from AC amended compared to unamended sediments. AC may reduce transport from aquatic to terrestrial ecosystems by reducing bioavailability and bioaccumulation in vector species like the midge (Nybom, Abel et al 2016). Reduced biouptake of PCBs was observed in Lumbriculus variegatus after remediation with AC mixed into sediment and with AC in a thin-layer cap (Abel et al 2017).…”