Bioconcentration of Organotin Cations during Molting Inhibits Heterocypris incongruens Growth

Abstract

The densely populated North Sea region encompasses catchments of rivers such as Scheldt and Meuse. Herein, agricultural, industrial, and household chemicals are emitted, transported by water, and deposited in sediments, posing ecological risks. Though sediment monitoring is often costly and time-intensive, modeling its toxicity to biota has received little attention. Due to high complexity of interacting variables that induce overall toxicity, monitoring data only sporadically validates current models. Via a range of concepts, we related bio-physicochemical constituents of sediment in Flanders to results from toxicity bioassays performed on the ostracod Heterocypris incongruens . Depending on the water body, we explain up to 90% of the variance in H. incongruens growth. Though variable across Flanders’ main water bodies, organotin cations and ammonia dominate the observed toxicity according to toxic unit (TU) assessments. Approximately 10% relates to testing conditions/setups, species variabilities, incoherently documented pollutant concentrations, and/or bio-physicochemical sediment properties. We elucidated the influence of organotin cations and ammonia relative to other metal(oxides) and biocides. Surprisingly, the tributylin cation appeared ∼1000 times more toxic to H. incongruens as compared to “single-substance” bioassays for similar species. We inferred indirect mixture effects between organotin, ammonia, and phosphate. Via chemical speciation calculations, we observed strong physicochemical and biological interactions between phosphate and organotin cations. These interactions enhance bioconcentration and explain the elevated toxicity of organotin cations. Our study aids water managers and policy makers to interpret monitoring data on a mechanistic basis. As sampled sediments differ, future modeling requires more emphasis on characterizing and parametrizing the interactions between bioassay constituents. We envision that this will aid in bridging the gap between testing in the laboratory and field observations.

Nanoparticles in bodily tissues: predicting their equilibrium distributions

“…Detecting bioactive substances enhances local internal concentrations. 162–164 BAFs along (cell signaling 94,165 ) pathways may be ∼100 times higher than BCF for the same substance. 166 Bioaccumulation K BAF may be described as K BCF ·K BCF · K BCF … etc.…”

“…Environmental Science: Nano Communication concentrations. [162][163][164] BAFs along (cell signaling 94,165 ) pathways may be ∼100 times higher than BCF for the same substance. 166 Bioaccumulation K BAF may be described as…”

“…Bioaccumulation (in organisms), rather, involves multiple uptake steps by different signaling pathways. Detecting bioactive substances enhances local internal concentrations [162][163][164]. BAFs along (cell signaling [94,165]) pathways may be ~100 times higher than BCF for the same substance [166].…”

Contaminant curiosity and pollutant puzzles: Conceptual insights in ecotoxicity and practical implementation of higher-tiered risk assessment.

“…Of the effects in toxicity assays, 60-100% + and 20%-90% could be attributed to the identified chemicals for Daphnia magna and Hyaella azteca, respectively. Moreover, the fraction explained for Hyaella azteca and Heterocypris incongruens increased from 20% to 90% after accounting for chromium, tin, ammonia and phosphate availability (Nolte et al 2020(Nolte et al , 2021). Yet, contributions of other substances not covered in monitoring programs could have contributed, as was demonstrated for organophosphate pesticides in Spanish sediments (De Castro-Català et al, 2016).…”