Pesticides/Biocides

Exponent's team of scientists includes individuals who have considerable regulatory experience as senior scientists/directors at the US EPA and the UK Pesticides Safety Directorate. Exponent’s toxicologists have significant practice in the planning, conducting and coordinating of regulatory guideline-based safety studies to address the potential toxicity of pesticides. We are also proficient in the interpretation of study data as it relates to risk/safety assessment, endocrine disruptor screening, quantitative benchmark dose analysis, and to address questions with implications related to chemical regulation (e.g., application of the FQPA/PCPA factors and classification in Europe). Exponent’s international team of scientists offers an array of services to help navigate these issues, from interpretation and advice to directing programs and risk management proposals. Exponent is unique in that we can bring to bear powerful multi-disciplinary expertise in industrial hygiene, epidemiology, toxicology, and risk assessment on solving scientific issues in the pesticide arena.

Pesticides are substances used to help control or kill organisms that we consider pests. The types of organisms that may be controlled through the use of pesticides include insects, fungi, weeds, microbes, and nuisance animals (worms, mollusks, rodents), among others, that may be sources of disease or can destroy agricultural crops or property. Pesticides may be called by various names – for example, insecticides, fungicides, herbicides, bactericides, antimicrobials, nematicides, molluscicides or rodenticides, to name a few – depending on their use and target organisms.

Pesticides have particular value in the agricultural industry, where they are used to improve crop yields and to control invasive organisms, and their use has helped to expand agricultural practices and keep the costs of food production down worldwide. Pesticides are also important in helping to control sources of disease like mosquitos or bacteria. However, exposure to various pesticides may be associated with adverse effects on health. For example, many insecticides target metabolic or signaling pathways that are generally conserved across organisms, including those of higher taxonomic order such as humans. Off-target effects such as localized skin or eye irritation may be an issue due to substances other than the active ingredient that may be present in a pesticide formulation. Additionally, there are substantial environmental concerns related to pesticide use, including the potential for pesticide drift, water and soil pollution, effects on pollinators, and biological magnification up the food chain due to storage of the chemicals in fat tissues.

Because of their relatively widespread use and potential for effects on health, pesticides are one of the most highly regulated chemical classes. In the US, all pesticides must be registered with the US Environmental Protection Agency and meet minimal risk criteria. Similarly, many pesticides used as plant protection products in Europe are regulated by the European Commission. In both cases, pesticide registration requires significant safety testing, including study of the potential for a pesticide to cause acute or chronic toxicity, neurological effects, reproductive or developmental effects, and cancer. The possible sensitivity of children and potential for endocrine disruption also need to be addressed. Safety toxicity data, along with information on anticipated use and exposure patterns, are considered in the overall pesticide registration process.

Sample Publications:

Carmichael NG, Barton HA, Boobis AR, Cooper RL, Dellarco VL, Doerrer NG, Fenner–Crisp PA, Doe JE, Lamb JC Pastoor TP. Agricultural chemical safety assessment: a multi–sector approach to the modernization of human safety requirements. Crit Rev Toxicol 2006 36(1):1–7.

Coady KK, Kan HL, Schisler MR, Gollapudi BB, Neal B, Williams A, LeBaron MJ. Evaluation of potential endocrine activity of 2,4-dichlorophenoxyacetic acid using in vitro assays. Toxicology in Vitro 2014; 28:1018-1025.

Cooper RL, Lamb JC, Barlow SM, Bentley K, Brady AM, Doerrer NG, Eisenbrandt DL, Fenner–Crisp PA, Hines RN, Irvine LFH, Kimmel CA, Koeter H, Li AA, Makris SL, Sheets LP, Speijers GJA, Whitby KE. A tiered approach to life stages testing for Agricultural Chemical Safety Assessment. Crit Rev Toxicol 2006 36(1):69–68.

DeSesso, JM, Scialli AR, White TEK, Breckenridge CB. Atrazine multigeneration reproductive toxicity and male developmental reproduction studies in rats. Birth Def Res Part B: Develop Reprod Toxicol 2014; 101:237–253 [Epub ahead of print, 2 May].

Goodman, M, Mandel JS, DeSesso JM, Scialli AR. Atrazine and pregnancy outcomes: A systemic review of epidemiologic evidence. Birth Def Res Part B: Develop Reprod Toxicol 2014; 101:215–236 [Epub ahead of print, 2 May].

Kimmel GL, Kimmel CA, Williams AL, DeSesso JM. Evaluation of the potential developmental toxicity of glyphosate with attention to cardiovascular malformations. Critical Reviews in Toxicology 2013; 43:79-95.

Lamb JC, Neal BH, Goodman JI. Risk assessment of toxaphene and its breakdown products: time for a change? Crit Rev Toxicol 2008; 38(9):805–815. Review.

Marty MS, Neal BH, Zablotny CL, Yano BL, Andrus AK, Woolhiser MR, Boverhof DR, Saghir SA, Perala AW, Passage JK, Lawson MA, Bus JS, Lamb JC, Hammond L. An F1 –extended one –generation reproductive toxicity study in Crl:CD(SD) rats with 2,4-dichlorophenoxyacetic acid. Toxicol Sci 2013.

Juberg DR, Borghoff SJ, Becker RA, Casey W, Hartung T, Holsapple M, Marty MS, Mihaich EM, Van Der Kraak G, Wade MG, Willett CE, Andersen ME, Borgert CJ, Coady KK, Dourson ML, Fowle III JR, Gray LE, Lamb JC, Ortego LS, Schug TT, Toole CM, Zorrilla LM, Kroner OL, Patterson J, Rinckel LA, Jones BR. Lessons learned, challenges, and opportunities: The U.S. Endocrine Disruptor Screening Program. ALTEX 2014; 31:63-78.

Reiss R, Neal B, Lamb JC, Juberg DR. Acetylcholinesterase inhibition dose-response modeling for chlorpyrifos and chlorpyrifos-oxon. Regul Toxicol Pharmacol 2012; 63:124–131.

Reiss R, Johnston J, Tucker K, DeSesso J, Keen C. Estimation of cancer risks and benefits associated with potential increased consumption of fruits and vegetables. Food Chem Toxicol, 2012; 50:4421–4427. [Epub ahead of print, 5 Sept].

Scialli, AR, DeSesso JM, Breckenridge CB. Developmental toxicity with atrazine and its major metabolites in rats. Birth Def Res Part B: Develop Reprod Toxicol 2014; 101: 199–214. [Epub ahead of print, 2 May].

Williams AL, DeSesso JM. Gestational/perinatal chlorpyrifos exposure is not associated with autistic-like behaviors in animals. Critical Reviews in Toxicology 2014; 44:523-534.

Williams AL, Watson RE, DeSesso JM. Developmental and reproductive outcomes in humans and animals after glyphosate exposure: A critical analysis. Journal of Toxicology and Environmental Health, Part B 2012; 15:39–96.

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