Appendix 2 Open Literature Review Summaries for Malathion
Description of Use in Document
Download 6.04 Mb.
|
Description of Use in Document: While there are uncertainties in this study, toxicity studies for plants evaluating mortality are limited. Therefore, this study could be used as part of the weight of evidence discussion in the effects determinations. Rationale for Use: See limitations below. Limitations of Study: Raw data were not provided so statistics could not be repeated. Field conditions for experiment III weren’t reported. Potential previous exposure to any contaminants in either the field collected or purchased plants weren’t reported. Primary Reviewer: Elizabeth Donovan, ERB6 Secondary Reviewer: Amy Blankinship, ERB6Open Literature Review Summary Chemical Name: Malathion (Malathion 500 EC, Monsanto Canada Inc. Misissauga, Ont; 50% malathion) PC Code: 057701 ECOTOX Record Number and Citation: 90644. Johnson VJ;Rosenberg AM;Lee K;Blakley BR. 2002. Increased T-Lymphocyte Dependent Antibody Production in Female SJL/J Mice Following Exposure to Commercial Grade Malathion. Toxicology 170(1-2): 119-129. Purpose of Review (DP Barcode required for Quantitative studies): Endangered Species Assessment Date of Review: March 31, 2015 Summary of Study Findings: Method Female mice (SJL/J, disease free, Jackson Laboratory, Bar Harbor, MA, 5-6 wks old, 16-20 g) were dosed via oral gavage with malathion formulation (corn oil used as vehicle) at 0.018, 7.2 and 180 mg/kg on alternate days for 28 days. A control group was added. Mice were housed 5 per cage (polycarbonate shoebox-style cages lined with woodchip bedding), and were fed rodent chow (Prolab, PMI Feeds Inc.) and water ad libitum. Temperature was maintained at 21°C with a 12:12 L:D light cycle. Body weight and water and food consumption were monitored during study. On day 25, mice were immunized with 0.2mL of 10% sheep red blood cell (SRBC) suspension via intraperitoneal injection. One mouse per treatment was immunized with sterile phosphate buffered saline (PBS) as a negative assay control animal. On day 30 (2 days after last malathion administration), mice were sacrificed, and spleen, liver, kidneys and brains removed and weighed. Brain acetylcholinesterase activity was measured. Spleens were used to determine effects of malathion on anti-SRBC humoral immune response, mitogen-induced splenic lymphocyte proliferation, and splenic cell phagocytosis. Treatment effects were analyzed using ANOVA and Dunnett’s t-test. Results According to the study authors, there was no clinical evidence of organophosphate poisoning in treatment groups, and there were no effects on brain acetylcholinesterase. There were also no effects on body weight or food and water consumption. At the high dose, 180 mg/kg, relative liver and kidney weights were significantly increased 10 and 6% compared to control; study authors noted that increase in kidney weight was not likely physiologically relevant. Splenic cellularity and viability of splenocytes were not affected. Additionally, it was reported that there were no significant differences for lymphocyte blastogenesis, and malathion exposure did not alter conA- or PHA-P-induced T-lymphocyte proliferation or LPS-induced B-lymphocyte proliferation (when expressed as CPM or SI). Malathion exposure also did not affect the phagocytic function of splenic macrophages. However, the study authors reported a significant increase in the numbers of plaques per 106 cells compared to the control (50, 48, and 33% increase in 0.018, 7.2, and 180 mg/kg groups, respectively). Additionally, the numbers of plaques per spleen were also increased 47, 48 and 43% in the 0.018, 7.2 and 180 mg/kg groups, respectively (Figure 2 in paper). 
Reviewer note: it is noted that the % increase in number of plaques (per cells and spleen relative to control) are relatively consistent (monotonic; SEMs overlap) across a 10,000 fold range in test dose (i.e., same relative level of response at 0.018, 7.2 and 180 mg/kg). Also, the reviewer assumes that the reported doses have been adjusted for % malathion (50%). Directory: pesticides -> nas -> final final -> Appendix 1-10: Summary of Diazinon Monitoring Data nas -> Description of revision final -> Appendix 2 Chlorpyrifos Species Sensitivity Distribution Analysis for Fish Download 6.04 Mb. Share with your friends:
|