Occurrence, toxicity and ecological risk of larvicidal oil in the coastal marine ecosystem of Hong Kong

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Original languageEnglish
Article number111178
Journal / PublicationMarine Pollution Bulletin
Online published12 May 2020
Publication statusPublished - Jul 2020


Application of larvicidal oil (LO) is the most common practice in Hong Kong to control mosquitos, and hence prevent mosquito-borne diseases and protect human health. Globally, this study represented the first comprehensive assessment of toxicity and risk posed by LO to marine organisms. We found concentrations of LO ranged from 0.08 to 0.66 mg/L in coastal seawaters of Hong Kong. Waterborne exposure to water-accommodated fractions of LO resulted in growth inhibition to two microalgal species (72–h EC50: 1.92–2.90 mg/L) and acute mortality to three marine animals (96-h LC50: 3.41–8.10 mg/L). From these toxicity results, a concentration that considered to be hazardous to 5% of species (HC5) was predicted at 1.45 mg/L, while the predicted no-effect concentration was determined to be 0.29 mg/L. The hazard quotient of LO exceeded 1 at 9 out of 15 sites, indicating moderate-to-high ecological risk to exposure of LO in the marine environment of Hong Kong.

Research Area(s)

  • Larvicidal oil, Mosquitos, Risk assessment, Species sensitivity distribution, Toxicity