Bioaccumulation of ivermectin from natural and artificial sediments in the benthic organism Lumbriculus variegatus

Abstract

Purpose Although ivermectin is a widely used lipophilic parasiticide, data on its potential bioaccumulation in aquatic invertebrates are scarce. In this study, bioaccumulation patterns of radiolabeled 3 H-ivermectin from sediments into tissues of the sediment-dwelling worm Lumbriculus variegatus were investigated and assessed. Materials and methods Two independent studies are described. In the first study, bioaccumulation kinetics of ivermectin in L. variegatus were investigated by following uptake, elimination, and biotransformation of the compound in worms exposed in artificial sediment. In the second study, possible effects of sediment characteristics on bioavailability of ivermectin were evaluated by comparing accumulation in worms exposed in three different natural sediments and one artificial sediment (organic carbon content 2% to 21%). Results and discussion During 28 days of exposure, ivermectin accumulated in worms exposed in all sediments with calculated bioaccumulation factors ranging from 0.2 to 11.0. Bioaccumulation factors correlated with total increase in biomass of worms during the exposure period and with organic carbon content of the sediments. Calculated biotasediment accumulation factors ranged from 2.1 to 16.6, indicating that other variables, like quality of organic carbon and feeding behavior of the worms, may have influenced the bioavailability of ivermectin. Biotransformation products of ivermectin were only found in water, but not in sediment and worms. Conclusions Results show that ivermectin has potential to bioaccumulate in L. variegatus, which could indicate a risk for biomagnification of the compound in the food chain.

Proposal for a Monitoring Concept for Veterinary Medicinal Products with PBT Properties, Using Parasiticides as a Case Study

“…This is related to its log Kow of 3.2, which is lower than the value of ≥4 triggering a bioconcentration study for a parasiticide [ 7 ]. However, bioaccumulation of ivermectin was studied in the oligochaete worm Lumbriculus variegatus in artificial and natural sediments [ 55 ]. Depending on the sediment characteristics (mainly the content of organic matter), the biota/sediment accumulation factor (BSAF28 d) varied between 1.9 and 5.5, indicating a potential for bioaccumulation.…”

Isolation and determination of ivermectin in post-mortem and in vivo tissues of dung beetles using a continuous solid phase extraction method followed by LC-ESI+-MS/MS

“…Furthermore, the ivermectin concentration in hemolymph was approximately 10-50-fold higher than in the respective excreta extract. This interesting result could suggest the potential bioaccumulation of ivermectin in dung beetles as occurs in other invertebrate species such as Lumbriculus variegatus [ 37 ]. The pharmacokinetic properties of ivermectin affect the function of each species in which the compound is studied [ 38 ].…”

Biomagnification and body distribution of ivermectin in dung beetles

“…In the case of ivermectin, only a few studies addressed its bioaccumulation in aquatic invertebrates, such as the sediment-dwelling worm Lumbriculus variegatus Müller (Oligochaeta) 23 , the zooplanktonic microcrustacean 24 . The present study is thus the first to analyse the bioaccumulation of an organic chemical, such as ivermectin, in dung beetles.…”