The relationship of parathion concentration, exposure time, cholinesterase inhibition and symptoms of toxicity in midge larvae (chironomidae: Diptera)

Abstract

Larvae of Chironomus riparius were used to demonstrate a statistically significant relationship between four variables: parathion concentration in water (nominally 20 to 500 μg/L), duration of exposure, symptoms of toxicity, and in vivo cholinesterase (ChE) inhibition. The symptoms of toxicity were a series of swimming behaviors that were categorized and assigned numerical values according to intensity of poisoning. These values were correlated with ChE inhibition by a polynomial regression. Therefore, symptoms of poisoning could be mathematically estimated from measurements of percent ChE inhibition. A three‐dimensional relationship between ChE inhibition, the logarithm of exposure time, and the logarithm of parathion concentration was established. This permits the characterization of the range of conditions for the onset of a given toxicity symptom and also predicts the symptom for which values for at least two of these variables are provided.

Effect of Temperature and Pirimiphos Methyl on Biochemical Biomarkers in Chironomus riparius Meigen

“…The measurement of AChE activity is a fairly well established biomarker of organophosphate poisoning in C. riparius Detra and Collins, 1991;Ibrahim et al, 1998). However, if AChE is to be useful as a real tool to help detect low levels of organophosphate pollution, it should be very speci"c to pesticide poisoning but relatively insensitive to environmental variation.…”

“…Inhibition resulting from irreversible binding at the AChE active site leads to the accumulation of acetylcholine in the synapse, resulting in the disruption of normal function (Habig and DiGiulio, 1991). The measurement of AChE activity to detect inhibition resulting from pesticide binding has been used successfully in the past with various invertebrates (Karnak and Collins, 1974;Day and Scott, 1990;Crane et al, 1995;Ibrahim et al, 1998) including Chironomus riparius (Detra and Collins, 1991;Sturm and Hansen, 1999;Fisher et al, 2000;Olsen et al, 2001;Callaghan et al, 2001;Crane et al, in press).…”

Biochemical Factors Contributing to Response Variation among Resistant and Sensitive Clones of Daphnia magna Straus Exposed to Ethyl parathion

“…Unfortunately, their high biochemical speci"-city has resulted in the development of resistance in many insect and mite pests (Roush and McKenzie, 1987;Taylor and Feyereisen, 1996). Furthermore, most OPs are also toxic to nontarget organisms (Da Silva et al, 1993;Detra and Collins, 1991) and some appear to have relatively high environmental persistence (Eto, 1974). Thus, in the same manner as resistance development among target pests, populations of nontarget organisms living near areas sprayed with OPs could become adapted by developing increased resistance.…”

“…Generally, an AChE inhibition exceeding 50% is considered to constitute an acutely life-threatening situation (Ludke et al, 1975). In studies with aquatic invertebrates, AChE inhibition after exposure to lethal concentrations of OPs was usually in the range 40}100% (Detra and Collins, 1991;Abdullah et al, 1994;EscartmH n and Porte, 1996). Therefore, results obtained for in vivo AChE inhibition responses indicate that in Daphnia, AChE is the major target of toxic action of ethyl parathion.…”

Factors affecting cholinesterase activity in aquatic animals

“…In fact, after determining ChE activity in several aquatic invertebrates. Day and Scott (1990) questioned whether ChE inhibition could be used to monitor sublethal exposures; however, others (e.g., Detra & Collins, 1991;Kuhn & Streit, 1994) have had more success. The results of the present study suggest that ChE activity in caged chironomids is effective as a biomarker of OP exposure.…”