Appendix 2 Open Literature Review Summaries for Malathion

EPA Primary Reviewer: Amy Blankinship Date: ___5/15__________

EPA Secondary Reviewer: Date: _____________

Data Evaluation Record

ECOTOX Code: E158899
STUDY TYPE: Non-Guideline
DP BARCODE: NA
PC CODES: 057701; 109704
CAS NOs.: 121-75-5; 52315-07-8
MRID NO.: NA
TEST MATERIAL (% purity): Malathion (50% ai) and Cypermethrin (25% ai)
CITATION: Nataraj, M.B. and Krishnamurthy, S.V. (2012). Effects of Combinations of Malathion and Cypermethrin on Survivability and Time of Metamorphosis of Tadpoles of Indian Cricket Frog (Fejervarya limnocharis). Journal of Environmental Science and Health. 47:67-73.
SPONSOR: NA
EXECUTIVE SUMMARY: The study examined the influence of malathion and cypermethrin on the survivability and time of metamorphosis of tadpoles of the common paddy field frog, Fejervarya limnocharis. The test concentrations were environmentally realistic for use in rice paddy fields. The test was conducted under laboratory conditions that simulated the natural habitat of F. limnocharis.
Methods: The test animals, F. limnocharis, were collected from paddy fields as several egg masses (>25 spawns) from different individual frogs, and the eggs were about to hatch. The paddy fields were located in Belandur village, Sringeri Taluk, Karnataka State, India (13°25’43” to 13°25’46” N, 75°14’26” to 75°14’30” E; altitude: 648 m asl). The egg masses were transported to laboratory in polythene containers, and then incubated in aged tap water at 20-23°C until hatch. The tadpoles were maintained in same tub until they reached Stage 25 and later for use in testing. Tadpoles from different egg masses were pooled randomly for use in the test. The fully 3x3 factorial tests were conducted with 0, 25, and 50 µg/L concentrations of cypermethrin and 0, 250, and 500 µg/L concentrations of malathion. The test solutions were renewed once every 6 days during the test. Based on 20 randomly selected tadpoles at test start, the mean total length was 13.8 ± 1.36 mm, and the mean body weight was 0.028 ± 0.006 g. Each treatment group used two simultaneous replicates each that contained 20 tadpoles. The inert circular polythene test containers (18 cm height, 24 cm radius) were filled with 10 L of water. For each 10 L of aged tap water, 250 mL of plankton concentration from 20 L of habitat water was inoculated as food and provided every 6 days during the study. The test was conducted at 12 hours light:12 hours dark photoperiod. Commercial grade malathion AI 50% from Insecticides Limited (Rajasthan, India) and cypermethrin AI 25% from Pioneer Pesticide Private Limited, J&K (India) were used for testing.
Mortality was recorded daily until the hind limbs appeared in surviving tadpoles. The time required for the emergence of surviving tadpoles as metamorph was recorded until Day 145.
Statistical analyses were performed on replicate means with significance determined at p<0.05. Data were examined for conformity with the assumption of parametric tests prior to analyses. Analyses of variance (ANOVA) was used to analyze the differences among treatment groups for survivorship and time of emergence data. The median emergence periods for the froglets in each treatment group are presented using box plots. All statistical analyses were conducted using SPSS version 16 software.

Results (EDSP List 1 Chemicals): The 56-day survivability for tadpoles treated with malathion and cypermethrin are presented in Fig 1 and Fig 2 (copied without alteration from Nataraj et al. 2012). For malathion, the differences in average survivability over the 56 days were marginally significant (p = 0.076) for the two treatment groups (95.94-96.25%) compared to the control (98.75%) [however, it does not appears that a pair-wise comparison between control and each treatment to determine which, if any, specific test treatment was statistically different was conducted (same for cypermethrin)].
For cypermethrin, average survivability was 69.38 and 53.44% in the 25 and 50 µg/L groups, respectively. The average survivability reductions for both cypermethrin treatment groups were highly significant (p < 0.001) compared to the control.

Download 6.04 Mb.

Share with your friends: