Comparative ecotoxicity of NPAHs to larvae of the midge Chironomus riparius

• Published in: Aquatic toxicology Vol. 41; no. 1; pp. 51 - 62
• Main Authors: Bleeker, Eric A.J, van der Geest, Harm G, Kraak, Michiel H.S, de Voogt, Pim, Admiraal, Wim
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.1998; Elsevier Science
• Subjects: acridines; Animal, plant and microbial ecology; Applied ecology; azaarenes; Biological and medical sciences; Chemical descriptors; Chironomidae; Chironomus; Chironomus riparius; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on protozoa and invertebrates; Freshwater; Fundamental and applied biological sciences. Psychology; heterocyclic nitrogen compounds; larvae; LC 50; mortality; NPAH; PAH; phenanthridine; polycyclic hydrocarbons; quinoline; structure-activity relationships; toxicity; LC 50; Chemical descriptors; Chironomus riparius; NPAH; PAH; Chironomidae; Hydrocarbon; Toxicity; Insecta; Mortality; Zoobenthos; Polycyclic aromatic compound; Sediments; Freshwater environment; Pollutant; Larva; Arthropoda; Water pollution; Invertebrata; Diptera
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/S0166-445X(97)00070-2

Acute toxicity of seven azaarenes (NPAHs) has been determined using larvae of the midge Chironomus riparius. Clear dose-response relationships for mortality of first instar larvae were observed, but surviving larvae grew as equally well as the controls. LC 50 values (96 h) for a two-ringed structure (quinoline), four three-ringed structures (acridine, phenanthridine, benzo[ f]quinoline and benzo[ h]quinoline) and two four-ringed structures (benz[ a]acridine and benz[ c]acridine) were generally one order lower than the few values reported for other aquatic species in the literature. Dibenz[ a,i]acridine, a five-ringed structure, was not acutely toxic at its maximum dissolved concentration. Acute toxicity increased with increasing number of aromatic rings of the compound; accordingly, correlations between the LC 50 values and size, shape and topology-related molecular properties were strong. However, between the four benzoquinoline isomers tested also differences in toxicity were observed: acridine was significantly more toxic than the other benzoquinoline isomers tested. This is most likely caused by transformation of acridine under UV light, indicated by a HOMO–LUMO gap in the highly phototoxic region, a high correlation between isomer toxicity and heat of formation and a low recovery of acridine in the water during the experiment.