Lanthanum from a Modified Clay Used in Eutrophication Control Is Bioavailable to the Marbled Crayfish (Procambarus fallax f. virginalis)

Abstract

To mitigate eutrophication in fresh standing waters the focus is on phosphorus (P) control, i.e. on P inflows to a lake as well as a lake's sediment as internal P source. The in-lake application of the lanthanum (La) modified clays – i.e. La modified bentonite (Phoslock) or La modified kaolinite, aim at dephosphatising the water column and at reducing the release of P from a lake's sediment. Application of these clays raises the question whether La from these clays can become bioavailable to biota. We investigated the bioavailability of La from Phoslock in a controlled parallel groups experiment in which we measured the La in carapace, gills, ovaries, hepatopancreas and abdominal muscle after 0, 14 and 28 days of exposure to Phoslock. Expressing the treatment effect as the difference of the median concentration between the two treatment groups (Phoslock minus control group) yield the following effects, the plus sign (+) indicating an increase, concentrations in µg g−1 dry weight: Day 14: carapace +10.5 µg g−1, gills +112 µg g−1, ovaries +2.6 µg g−1, hepatopancreas +32.9 µg g−1 and abodminal muscle +3.2 µg g−1. Day 28: carapace +17.9 µg g−1; gills +182 µg g−1; ovaries +2.2 µg g−1; hepatopancreas +41.9 µg g−1 and abodminal muscle +7.6 µg g−1, all effects were statistically significant. As La from Phoslock is bio-available to and taken up by the marbled crayfishes (Procambarus fallax f. virginalis), we advocate that the application of in-lake chemical water treatments to mitigate eutrophication should be accompanied by a thorough study on potential side effects.

A critical review on control methods for harmful algal blooms

“…Additionally, it has been experimentally shown that the lanthanum included in the Phoslock ® formulation is bioaccumulated in organisms such as shrimp ( Procarmabarus ), in proportional concentrations while being exposed to this modified clay (Van Oosterhout et al . ). Herrmann et al .…”

Potential Hazard of Lanthanides and Lanthanide-Based Nanoparticles to Aquatic Ecosystems: Data Gaps, Challenges and Future Research Needs Derived from Bibliometric Analysis

“…Altogether, there were seven studies that followed all of the major REACH recommendations, e.g., included long-term bioaccumulation studies with benthic organisms. These studies exposed bivalves [33,[53][54][55][56], crayfish [57], chironomids [50], and rooted aquatic plants [50] to Ln ions or their complexes. Only one study concerned Ln-based NPs (CeO 2 ) [58] examining accumulation in a food web that included bivalves, snails, and benthic shrimps.…”

“…The highest reported bioconcentration and bioaccumulation factor values for bivalves were between 23 and 357 [34,[54][55][56], which are well below 2000-the threshold to classify substances as bioaccumulative by REACH legislation (Annex VIII) [45]. Freshwater crayfish accumulated La from La modified bentonite, mainly in gills resulting in 122-fold increase when compared to the control (182 µg/g) and in the carapace (18 µg/g), indicating La uptake by gills [57]. Similarly, La content in rooted plant Elodea nuttallii increased up to 127-fold when compared to the control plants during the first growing season after application of La-modified bentonite.…”

Synergistic effects of polyaluminum chloride and Phoslock on phosphate and cyanobacteria removal in eutrophic lake water

“…Limited studies on Phoslock seem to suggest that the solubilization of La ions and the toxicity risks associated with Phoslock can be minimized under normal lake water conditions and controlled Phoslock application (Lurling & Tolman, ). However, one study showed that La from Phoslock is bioavailable to and taken up by the marbled crayfish (Van Oosterhout, Goitom, Roessink, & Lurling, ). Further evaluations are needed to determine potential side effects of Phoslock.…”