Armel, Greg

Breeden, Greg

Brosnan, James T.

Thomas, Joseph

English

University of Tennessee, Knoxville: Trace

University of Tennessee, KnoxvilleTrace: Tennessee Research and CreativeExchangeCommercial Horticulture UT Extension Publications5-5-2011W270 Safety of Herbicides Compared to OtherCommonly Used Chemicals Pub Number W270Greg BreedenJames T. BrosnanGreg ArmelJoseph ThomasFollow this and additional works at: http://trace.tennessee.edu/utk_agexcomhortPart of the Agricultural Science CommonsThe publications in this collection represent the historical publishing record of the UT Agricultural Experiment Station and do not necessarily reflectcurrent scientific knowledge or recommendations. Current information about UT Ag Research can be found at the UT Ag Research website.This Turf is brought to you for free and open access by the UT Extension Publications at Trace: Tennessee Research and Creative Exchange. It has beenaccepted for inclusion in Commercial Horticulture by an authorized administrator of Trace: Tennessee Research and Creative Exchange. For moreinformation, please contact trace@utk.edu.Recommended Citation"W270 Safety of Herbicides Compared to Other Commonly Used Chemicals Pub Number W270," Greg Breeden, James T. Brosnan,Greg Armel, and Joseph Thomas,W270, http://trace.tennessee.edu/utk_agexcomhort/43W270Safety of Herbicides  Compared to Other Commonly Used ChemicalsIntroduction Herbicides are products that are used to control weeds. Concern over herbicide safety has led to increases in some natural weed control methods, such as salt and vinegar applications. In some parts of the United States and Canada, the use of herbicides to control turfgrass weeds has been banned entirely. However, materials used for natural weed control, such as salt and vinegar, also have toxicological properties similar to herbicides. This publication was developed to provide practitioners with a reference to which they can refer individuals concerned about the safety of herbicides and other commonly used chemicals.What are MSDS sheets? 1,4MSDS sheets are used for product stewardship and safety. These sheets contain data describing the properties of a particular substance and are intended to inform workers and other personnel about the risks associated with coming in contact with these substances. MSDS sheets provide pertinent information on how to properly handle, store and dispose of a substance, as well as any environmental or health risks associated with the material. MSDS sheets will state whether or not the substance is a carcinogen or teratogen and will provide information about acute toxicity often represented in the form of an LD50 value. Greg Breeden, Assistant Specialist I – Turfgrass Weed ScienceJames T. Brosnan, Ph.D., Assistant Professor – Turfgrass Weed ScienceGreg Armel, Ph.D., Assistant Professor- Extension Weed SpecialistJoseph Thomas, Graduate Research AssistantWhat are LD50 values? 2,4In toxicology, an LD50 value represents the dose of a chemical required to kill half  of a tested population (usually mice or rats) after a specified duration. These values are frequently used as a general indicator of a substance’s acute toxicity. Acute toxicity describes the adverse effects resulting from a single exposure to a chemical (i.e., accidental ingestion of a product). LD50 values are expressed in units of milligrams (mg) of substance per kilogram (kg) of body weight. Toxicity increases as LD50 values decrease. For example, a chemical with a LD50 of 10 mg/kg is 10 times more toxic than one with a LD50 of 100 mg/kg.Considering that LD50 studies are conducted on all chemicals sold in the United States, they can be used as a means to compare the toxicity of one chemical to another. Table 1 presents LD50 values for many herbicides, as well as many chemicals commonly found in household products. MSDS sheets for most herbicides can easily be accessed for free from websites such as http://www.cdms.net.MSDS sheets for household products can be accessed directly from company websites. Often, a single product may be sold by different companies. For example, several different brands of sodium hypochlorite  W270   5/11   11-0180 Programs in agriculture and natural resources, 4-H youth development, family and consumer sciences, and resource development.University of Tennessee Institute of Agriculture, U.S. Department of Agriculture and county governments cooperating.UT Extension provides equal opportunities in programs and employment.(i.e., bleach) can be found in most grocery stores. As a result, each product will have its own MSDS sheet with LD50 values that may vary slightly. The values in Table 1 are simply examples presented as a guide for comparing the relative toxicity of one compound to another. Any discrepancy in this publication with a MSDS sheet is unintentional. If  such a discrepancy exists within this publication, and in all cases, use the MSDS sheet as the authority to guide you in the legal use of the product.What is a carcinogen? 4A carcinogen is a substance that causes cancer. Carcinogens can increase cancer development by changing cellular metabolism or damaging cellular DNA. Once this happens, biological processes are disrupted and uncontrolled, leading to malignant cell division. Examples of commonly known carcinogens include asbestos and tobacco.What is a teratogen? 4A teratogen is a substance that causes abnormalities in physical development and/or birth defects. Birth defects occur in about 3 to 5 percent of newborns and are the leading cause of infant mortality. Many chemicals and environmental factors are suspected to cause teratogenic effects in humans and animals. Some examples of teratogens include caffeine, tobacco and radiation.Discussion 2,3,4Using LD50 values as an indicator, many herbicides are less toxic than common chemicals such as caffeine (found in coffee, tea and many soft drinks) and nicotine (found in tobacco products). Pendimethalin, a commonly used herbicide in Tennesee, has an oral LD50 value of greater than 5000 mg/kg, which is similar to ethanol, the active ingredient in Dawn Ultra™ dishwashing liquid.This is not the case with all herbicides though. Paraquat, a restricted-use pesticide that can only be used by licensed pesticide applicators, has an LD50 value of approximately 300 mg/kg; however, it is less toxic than bleach. When used according to label instructions, Paraquat is a highly effective herbicide; however, end-users must take special precautions when applying the material (e.g., wear correct personal protective equipment, etc).ConclusionWhen used according to label instructions, herbicides are safe and effective. Many of the problems that have been associated with herbicides are the result of improper use. Similarly, many health problems have been linked to improper (e.g., excessive) use of substances like alcohol. Before applying any herbicide, always refer to the product label for specific information on proper product use; tank-mix compatibility; and turfgrass, vegetable, fruit or ornamental tolerances. For more information on weed control, visit the University of Tennessee’s turfgrass weed science website,  http://tennesseeturfgrassweeds.org or the University of Tennessee horticultural weed control site at  http://hortweeds.tennessee.edu/.References  Fishel, F., J. Ferrell, G. MacDonald, and B. Sellers. Herbicides: How Toxic Are They? University of Florida Cooperative Extension PI-133. University of Florida, Gainesville, FL. Anonymous. 2011. Lethal Dosage (LD50) Values. Online. Available at: www.epa.gov/oecaagct/ag101/pestlethal.html. Accessed 20 January 2011MayoClinic staff. 2011. Caffeine content of coffee, tea, soft drinks and more. Online. Available at: http://www.mayoclinic.com/health/caffeine/AN01211. Accessed 20 January 2011  Hodgson, E. 2010. A Textbook of Modern Toxicology. John Wiley and Sons, Inc. Hoboken, NJ.Table	  1	  LD50	  Values*Herbicides Chemical	  Structure Oral Dermal Carcinogen Teratogen2,4-­‐D370 1500 No UnlikelyDiquat	  (Reward)886 >5000 No PotentialGlyphosate	  (Roundup	  Pro)5108 >5000 No NoneGlufosinate	  (Finale)3570 >2000 No NoneImazaquin	  (Image)>5000 >2000 No NoneLD50	  (mg/kg)2Isoxaben	  (Gallery)>5000 >5000 Potential YesMSMA700 2500 Unknown UnknownMCPP+2,4-­‐D+Dicamba	  (Trimec	  Classic)>1550 >2240 Unknown UnknownParaquat	  (Gramoxone	  Inteon)310 >2000 No NonePendimethalin	  (Pendulum	  Aquacap)>5000 >5000 No NoneProdiamine	  (Barricade)>5000 >2000 Potential YesTriclopyr	  (Turflon	  Ester)1338 >2000 Potential NoneTrifluralin	  (Trifluralin	  10G/Preen)>5050 >2020 No UnknownCommon	  Chemicals Chemical	  Structure Oral Dermal Carcinogen TeratogenAcetic	  acid	  (Vinegar)3310 >5000 No UnknownSodium	  hypochlorite	  (Bleach)192 NA Unknown UnknownCaffeine127 NA Potential UnknownClove	  oil1370 1200 Unknown UnknownEthanol	  +	  surfactant	  (Ultra	  Dawn)6300 NA No UnknownEthyl	  alcohol	  (grain	  alcohol)7060 NA Unknown PotentialIsopropyl	  alcohol	  (Windex)>5000 >2000 Unknown UnknownNicotine3.4 50 Yes PotentialSaccharin	  (Sweet-­‐n-­‐low)14200 NA Yes UnknownSalicylic	  acid	  (Aspirin)200 NA No PotentialCrystaline	  silica	  (Silica	  sand) NA NA Yes UnknownSodium	  chloride	  (Table	  Salt) NaCl 3000 10	  g/kg Unknown UnknownSucrose	  (Sugar)29700 NA No Unknown*MSDS	  sheets	  for	  most	  herbicides	  can	  easily	  be	  accessed	  for	  free	  from	  websites	  such	  as	  http://www.cdms.net.	  MSDS	  sheets	  for	  household	  products	  can	  be	  accessed	  directly	  from	  company	  websites.	  Often,	  a	  single	  product	  can	  be	  sold	  by	  different	  companies.	  For	  example,	  several	  different	  brands	  of	  sodium	  hypochlorite	  (i.e.,	  bleach)	  can	  be	  found	  in	  most	  grocery	  stores.	  As	  a	  result,	  each	  product	  will	  have	  its	  own	  MSDS	  sheet	  with	  LD50	  values	  that	  may	  vary	  slightly.	  The	  values	  in	  this	  table	  are	  simply	  examples	  presented	  as	  a	  guide	  for	  comparing	  the	  relative	  toxicity	  of	  one	  compound	  to	  another.	  Any	  discrepancy	  in	  this	  publication	  with	  a	  MSDS	  sheet	  is	  unintentional.	  If	  such	  a	  discrepancy	  exists	  within	  this	  publication,	  and	  in	  all	  cases,	  use	  the	  MSDS	  sheet	  as	  the	  authority	  to	  guide	  you	  in	  the	  legal	  use	  of	  the	  product.

W270 Safety of Herbicides Compared to Other Commonly Used Chemicals Pub Number W270

https://trace.tennessee.edu/cgi/viewcontent.cgi?article=1042&amp;context=utk_agexcomhort

W270 Safety of Herbicides Compared to Other Commonly Used Chemicals Pub Number W270

Abstract

Similar works

Full text

Available Versions

University of Tennessee, Knoxville: Trace