TY - JOUR

T1 - Suspended particles only marginally reduce pyrethroid toxicity to the freshwater invertebrate Gammarus pulex (L.) during pulse exposure

AU - Rasmussen, Jes

AU - Cedergreen, Nina

AU - Kronvang, Brian

AU - Bjergager, Maj-Britt Andersen

AU - Nørum, Ulrik

AU - Kretschmann, Andreas Christopher

AU - Strobel, Bjarne W.

AU - Hansen, Hans Chr. Bruun

PY - 2016

Y1 - 2016

N2 - Current ecotoxicological research on particle associated pyrethroids in freshwater systems focuses almost exclusively on sediment-exposure scenarios and sediment-dwelling macroinvertebrates. We studied how suspended particles influence acute effects of lambda-cyhalothrin and bifenthrin on the epibenthic freshwater amphipod Gammarus pulex (L.) using brief pulse exposures followed by a 144 h post exposure recovery phase. Humic acid (HA) and the clay mineral montmorillonite (MM) were used as model sorbents in environmentally realistic concentrations (5, 25 and 125 mg L-1). Mortality of G. pulex was recorded during the post exposure recovery phase and locomotor behavior was measured during exposure to lambda-cyhalothrin. We found that HA in concentrations ≥25 mg L-1 adsorbed the majority of pyrethroids but only reduced mortality of G. pulex up to a factor of four compared to pyrethroid-only treatments. MM suspensions adsorbed a variable fraction of pyrethroids (10% for bifenthrin and 70% for lambda-cyhalothrin) but did not significantly change the concentration–response relationship compared to pure pyrethroid treatments. Behavioral responses and immobilisation rate of G. pulex were reduced in the presence of HA, whereas behavioral responses and immobilisation rate were increased in the presence of MM. This indicates that G. pulex was capable of sensing the bioavailable fraction of lambda-cyhalothrin. Our results imply that suspended particles reduce to only a limited extent the toxicity of pyrethroids to G. pulex and that passive uptake of pyrethroids can be significant even when pyrethroids are adsorbed to suspended particles.

AB - Current ecotoxicological research on particle associated pyrethroids in freshwater systems focuses almost exclusively on sediment-exposure scenarios and sediment-dwelling macroinvertebrates. We studied how suspended particles influence acute effects of lambda-cyhalothrin and bifenthrin on the epibenthic freshwater amphipod Gammarus pulex (L.) using brief pulse exposures followed by a 144 h post exposure recovery phase. Humic acid (HA) and the clay mineral montmorillonite (MM) were used as model sorbents in environmentally realistic concentrations (5, 25 and 125 mg L-1). Mortality of G. pulex was recorded during the post exposure recovery phase and locomotor behavior was measured during exposure to lambda-cyhalothrin. We found that HA in concentrations ≥25 mg L-1 adsorbed the majority of pyrethroids but only reduced mortality of G. pulex up to a factor of four compared to pyrethroid-only treatments. MM suspensions adsorbed a variable fraction of pyrethroids (10% for bifenthrin and 70% for lambda-cyhalothrin) but did not significantly change the concentration–response relationship compared to pure pyrethroid treatments. Behavioral responses and immobilisation rate of G. pulex were reduced in the presence of HA, whereas behavioral responses and immobilisation rate were increased in the presence of MM. This indicates that G. pulex was capable of sensing the bioavailable fraction of lambda-cyhalothrin. Our results imply that suspended particles reduce to only a limited extent the toxicity of pyrethroids to G. pulex and that passive uptake of pyrethroids can be significant even when pyrethroids are adsorbed to suspended particles.

U2 - 10.1007/s10646-016-1609-y

DO - 10.1007/s10646-016-1609-y

M3 - Journal article

C2 - 26831865

VL - 25

SP - 510

EP - 520

JO - Ecotoxicology

JF - Ecotoxicology

SN - 0963-9292

IS - 3

ER -