Toxicity of 2,4-D ester on the embryos and adult Radix quadrasi von Moellendorf 1898

Date

2011

Degree

Bachelor of Science in Biology

Major Course

Major in Zoology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ayolani V. de Lara

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Abstract

Acute toxicity tests were conducted for both the embryos and adults of Radix quadrasi. Two-day old embryos were exposed to 0, 20, 40, 60, 80, and 100 mg/L of 2,4 D ester ® for 24, 48, 72, and 96 hours while the adults (12-14mm long) were exposed to 0, 200,400, 600, 800, and 1000 mg/L of 2,4 D ester ® for the same duration. After determining the LC50 96h, the embryos were exposed to sub-lethal doses of 21.01, 27.7, and 32.0 mg/L while the adults were exposed to 77.7, 125.5, 163.0 mg/L, both for ten days. The incubation period and percent hatching of the eggs were determined. Morphological abnormalities and growth of the embryos were likewise noted. The foot and the digestive gland of the adult survivors were dissected out and processed for light microscopy using standard methods. The LC50 for 24, 48, 72, and 96 hours of the embryos was 67.2 mg/L, 58.6 mg/L, 55.32 mg/L, 46.85 mg/L, respectively. On the other hand, the adults were found much, much less sensitive having LC50 values of 884.30 mg/L, 638.64 mg/L, 526.85 mg/L, and 411.52 mg/L, respectively. Generally, mortality was dose and time dependent. Morphological abnormalities such as enlargement of the head-foot region were observed among the treated embryos. The longest incubation period and the lowest percent hatching were recorded for the embryos exposed to the highest dose. Histological alterations in the digestive gland treated with sub-lethal doses of 77.0, 125.0, 163.0 mg/L were thinning of the tubule epithelium, widening of intertubular spaces, and occurrence of cytoplasmic materials in the tubule lumen. A slight inflammation of the subepidermal tissue and absence of secretion in the mucous glands were observed in those exposed to the highest dose. 2, 4-D ester was not only toxic but also teratogenic. It can cause histological damage to the digestive gland of a non-target organism such as the freshwater snail, R. quadrasi.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Document Type

Thesis

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