Pesticide drift

{{main|pesticide application}}

Pesticides are commonly applied by the use of mechanical sprayers. Sprayers convert a pesticide formulation, often consisting of a mixture of water, the pesticide, and other components (adjuvants, for example) into droplets, which are applied to the crop. Ideally, the pesticide droplets attach evenly to the targeted crop. Because components of the mist are highly mobile, spray drift can occur, especially for smaller droplets. Some pesticides mists are visible, appearing cloud-like, while others can be invisible and odorless.{{cite news |last1=Pollack |first1=Andrew |title=Dow Corn, Resistant to a Weed Killer, Runs Into Opposition |url=https://www.nytimes.com/2012/04/26/business/energy-environment/dow-weed-killer-runs-into-opposition.html |work=The New York Times |date=25 April 2012 }}{{cite web |title=Getting the Most from Soil-Applied Herbicides |url=http://scarab.msu.montana.edu/CropWeedSearch/Docs/GettingtheMostfromSoil-AppliedHerbicides.htm |publisher=Montana State University |accessdate=April 25, 2012 |first1=Fabian |last1=Menalled |first2=William E. |last2=Dyer |date=19 April 2005 |url-status=dead |archive-url=https://web.archive.org/web/20121221091610/http://scarab.msu.montana.edu/CropWeedSearch/Docs/GettingtheMostfromSoil-AppliedHerbicides.htm |archive-date=21 December 2012 |df=dmy-all }}

The quality of sprayer equipment affects drift problems.{{Cite web|title=Pesticide Drift – Pesticide Environmental Stewardship|url=https://pesticidestewardship.org/pesticide-drift/|access-date=2021-11-23|language=en-US}}{{cite web |last1=Peters |last2=Thostenson |last3=Nowatzki |last4=Hofman |last5=Wilson |first1=Tom |first2=Andrew |first3=John |first4=Vern |first5=James |date=July 2017 |title=Selecting Spray Nozzles to Reduce Particle Drift |url=https://www.ag.ndsu.edu/publications/crops/selecting-spray-nozzles-to-reduce-particle-drift |publisher=NDSU Extension Service |id=AE1246 }} Sprayer tanks contaminated with another herbicide are one source of drift. With placement (localised) spraying of broad spectrum pesticides, considerable efforts have been made to quantify and control spray drift from hydraulic nozzles.Hewitt, A.J., Spray drift: impact of requirements to protect the environment, Crop Protection 19 (2000) p 623-627 Conversely, wind drift is also an efficient mechanism for moving droplets of an appropriate size range to their targets over a wide area with ultra-low volume (ULV) spraying.{{cite book |doi=10.7551/mitpress/9780262015981.001.0001 |title=Pesticide Drift and the Pursuit of Environmental Justice |year=2011 |last1=Harrison |first1=Jill Lindsey |isbn=978-0-262-01598-1 }}{{pn|date=December 2022}}

"Drift retardants" are compounds added to the spray mixture to suppress pesticide drift. A typical retardant is polyacrylamide. These polymers suppress the formation of tiny droplets.{{cite book | last1=Appleby | first1=Arnold P. | last2=Müller | first2=Franz | last3=Carpy | first3=Serge | title=Ullmann's Encyclopedia of Industrial Chemistry | chapter=Weed Control | publisher=Wiley-VCH Verlag GmbH & Co. KGaA | publication-place=Weinheim, Germany | date=2001-06-15 | isbn=978-3-527-30673-2 | doi=10.1002/14356007.a28_165}}

Weather conditions and timing affect the drift problem.{{cite journal |last1=Desmarteau |first1=Dean A |last2=Ritter |first2=Amy M |last3=Hendley |first3=Paul |last4=Guevara |first4=Megan W |title=Impact of Wind Speed and Direction and Key Meteorological Parameters on Potential Pesticide Drift Mass Loadings from Sequential Aerial Applications |journal=Integrated Environmental Assessment and Management |date=March 2020 |volume=16 |issue=2 |pages=197–210 |doi=10.1002/ieam.4221 |pmid=31589364 |pmc=7064987 |bibcode=2020IEAM...16..197D }} The efficiency of the spray and reach of the spray drift can be computed.{{cite journal |last1=Hong |first1=Se-Woon |last2=Zhao |first2=Lingying |last3=Zhu |first3=Heping |title=SAAS, a computer program for estimating pesticide spray efficiency and drift of air-assisted pesticide applications |journal=Computers and Electronics in Agriculture |date=December 2018 |volume=155 |pages=58–68 |doi=10.1016/j.compag.2018.09.031 |s2cid=53791164 |doi-access=free |bibcode=2018CEAgr.155...58H }} In addition to weather, windbreaks can mitigate the effects of drift.{{cite journal |doi=10.1002/ps.341 |title=Windbreaks as a Pesticide Drift Mitigation Strategy: A Review |date=2001 |last1=Ucar |first1=Tamer |last2=Hall |first2=Franklin R. |journal=Pest Management Science |volume=57 |issue=8 |pages=663–675 |pmid=11517719 }} Other ways to mitigate spray drift is to apply the pesticide directly to the desired treatment area, as well as paying attention to where surface waters, gutters, drainage ditches, and storm drains are located. This is to make sure that the pesticide is applied in a way that prevents it from getting in to these spaces. {{Cite web |last=US EPA |first=OCSPP |date=2014-08-01 |title=Introduction to Pesticide Drift |url=https://www.epa.gov/reducing-pesticide-drift/introduction-pesticide-drift |access-date=2024-03-14 |website=www.epa.gov |language=en}}

Most herbicides are organic compounds of low volatility, unlike fumigants, which are usually gases. Several are salts and others have boiling points above 100 °C (Dicamba is a solid that melts at 114°C). Thus, drift often entails mobilization of droplets, which can be very small. The contribution from their volatility, low as they are, cannot be ignored, either.{{cite journal | last1=Bish | first1=Mandy D. | last2=Farrell | first2=Shea T. | last3=Lerch | first3=Robert N. | last4=Bradley | first4=Kevin W. | title=Dicamba Losses to Air after Applications to Soybean under Stable and Nonstable Atmospheric Conditions | journal=Journal of Environmental Quality | volume=48 | issue=6 | date=2019 | issn=0047-2425 | doi=10.2134/jeq2019.05.0197 | pages=1675–1682| doi-access=free | bibcode=2019JEnvQ..48.1675B }}

A distinction has been made between "exo-drift" (the transfer of spray out of the target area) and endo-drift, where the active ingredient (AI) in droplets falls into the target area, but does not reach the biological target. "Endo-drift" is volumetrically more significant and may therefore cause greater ecological contamination (e.g. where chemical pesticides pollute ground water).

Since drift can be problematic, alternative weed-control technologies have evolved. A topical approach is integrated pest management, which involves fewer chemicals but often greater manual work.{{cite journal | last1=Damos | first1=Petros | last2=Colomar | first2=Lucía-Adriana | last3=Ioriatti | first3=Claudio | title=Integrated Fruit Production and Pest Management in Europe: The Apple Case Study and How Far We Are From the Original Concept? | journal=Insects | volume=6 | issue=3 | date=2015-06-26 | issn=2075-4450 | pmid=26463407 | pmc=4598656 | doi=10.3390/insects6030626 | doi-access=free | pages=626–657}}

image:Dicamba.svg

Dicamba drift is a particular problem, as has been recognized since at least 1979.{{cite journal | last1=Behrens | first1=Richard | last2=Lueschen | first2=W. E. | title=Dicamba Volatility | journal=Weed Science | volume=27 | issue=5 | date=1979 | issn=0043-1745 | doi=10.1017/S0043174500044453 | pages=486–493}} The effects have been noted for many crops: grapes, tomatoes, soybeans. {{cite journal | last1=Riter | first1=Leah S. | last2=Pai | first2=Naresh | last3=Vieira | first3=Bruno C. | last4=MacInnes | first4=Alison | last5=Reiss | first5=Richard | last6=Hapeman | first6=Cathleen J. | last7=Kruger | first7=Greg R. | title=Conversations about the Future of Dicamba: The Science Behind Off-Target Movement | journal=Journal of Agricultural and Food Chemistry | volume=69 | issue=48 | date=2021-12-08 | issn=0021-8561 | doi=10.1021/acs.jafc.1c05589 | pages=14435–14444| doi-access=free | pmid=34817161 }}{{cite journal | author=Britt E. Erickson | title=EPA Finds More Risks for the Pesticide Dicamba | journal=Chemical & Engineering News | date=2022-08-28 | issn=1520-605X | doi=10.47287/cen-10030-polcon1 | pages=13}} In 2017, Dicamba-resistant soybeans and cotton were approved for use in the US. This new technology worsened the drift problem because these farmers could use Dicamba more freely.{{cite journal | last1=Egan | first1=J. Franklin | last2=Barlow | first2=Kathryn M. | last3=Mortensen | first3=David A. | title=A Meta-Analysis on the Effects of 2,4-D and Dicamba Drift on Soybean and Cotton | journal=Weed Science | volume=62 | issue=1 | date=2014 | issn=0043-1745 | doi=10.1614/WS-D-13-00025.1 | pages=193–206}}

Although already low in volatility, as discussed above, Dicamba can be made even less volatile by conversion to various salts. The approach entails treatment of Dicamba with amines, which form ammonium salts. These salts are described by their acronyms BAPMA-Dicamba and DGA-Dicamba. Although these salts are of lower volatility in laboratory tests, in the field the situation is more complicated, and drift remains a problem.

Much public concern has led to research into spray drift, point source pollution (e.g. pesticides entering bodies of water following spillage of concentrate or rinsate) can also cause environmental harm.{{cite journal |last1=Spanoghe |first1=P. |last2=Maes |first2=A. |last3=Steurbaut |first3=W. |title=Limitation of point source pesticide pollution: results of bioremediation system |journal=Communications in Agricultural and Applied Biological Sciences |date=2004 |volume=69 |issue=4 |pages=719–732 |pmid=15756863 }} Public concern for pesticide drift is not met with regulatory response.{{cite journal |last1=Harrison |first1=Jill Lindsey |title='Accidents' and invisibilities: Scaled discourse and the naturalization of regulatory neglect in California's pesticide drift conflict |journal=Political Geography |date=June 2006 |volume=25 |issue=5 |pages=506–529 |doi=10.1016/j.polgeo.2006.02.003 }} Farm workers and communities surrounding large farms are at a high risk of coming in contact with pesticides. People in agricultural areas are at risk for increased genotoxicity because of pesticide drift.{{cite journal |last1=Doğanlar |first1=Zeynep Banu |last2=Doğanlar |first2=Oğuzhan |last3=Tozkir |first3=Hilmi |last4=Gökalp |first4=Fulya Dilek |last5=Doğan |first5=Ayten |last6=Yamaç |first6=Ferah |last7=Aşkın |first7=Orhan Onur |last8=Aktaş |first8=Ümmühan Ersin |title=Nonoccupational Exposure of Agricultural Area Residents to Pesticides: Pesticide Accumulation and Evaluation of Genotoxicity |journal=Archives of Environmental Contamination and Toxicology |date=November 2018 |volume=75 |issue=4 |pages=530–544 |doi=10.1007/s00244-018-0545-7 |pmid=30003277 |bibcode=2018ArECT..75..530D |s2cid=51617217 }}{{cite journal |doi=10.1515/reveh-2014-0072 |title=Organophosphate pesticides exposure among farmworkers: Pathways and risk of adverse health effects |date=2015 |last1=Suratman |first1=Suratman |last2=Edwards |first2=John William |last3=Babina |first3=Kateryna |journal=Reviews on Environmental Health |volume=30 |issue=1 |pages=65–79 |pmid=25741936 |s2cid=38705916 }}

Insecticides sprayed on crop fields can also have detrimental effects on non-human lifeforms that are important to the surrounding ecosystems like bees and other insects.{{Citation|last=McEwen|first=F.L.|chapter=Pesticide Residues and Agricultural Workers—An Overview|date=1977|pages=37–49|publisher=Elsevier|isbn=9780127386508|doi=10.1016/b978-0-12-738650-8.50008-4|title=Pesticide Management and Insecticide Resistance}}

The seriousness of crop injury caused by dicamba drift is increasingly being recognized. For example, the American Soybean Association and various land-grant universities are cooperating in the race to find ways to preserve the usability of dicamba while ending drift injury.{{cite web | title=ASA Steps up Urgency in Search for Answers on Dicamba Damage | website=American Soybean Association | date=2017-09-25 | url=http://soygrowers.com/news-releases/asa-steps-urgency-search-answers-dicamba-damage/ | access-date=2021-06-13 | quote=This issue...}} Application of herbicides later in the season to protect herbicide-resistant genetically modified plants increases the risk of volatilisation as the temperature is higher and incorporation into the soil impractical.

From 1998 to 2006, Environmental Health Perspectives found nearly 3,000 cases of pesticide drift; nearly half were workers on the fields treated with pesticides and 14% of cases were children under the age of 15.{{cite journal |last1=Lee |first1=Soo-Jeong |last2=Mehler |first2=Louise |last3=Beckman |first3=John |last4=Diebolt-Brown |first4=Brienne |last5=Prado |first5=Joanne |last6=Lackovic |first6=Michelle |last7=Waltz |first7=Justin |last8=Mulay |first8=Prakash |last9=Schwartz |first9=Abby |last10=Mitchell |first10=Yvette |last11=Moraga-McHaley |first11=Stephanie |last12=Gergely |first12=Rita |last13=Calvert |first13=Geoffrey M. |title=Acute Pesticide Illnesses Associated with Off-Target Pesticide Drift from Agricultural Applications: 11 States, 1998–2006 |journal=Environmental Health Perspectives |date=August 2011 |volume=119 |issue=8 |pages=1162–1169 |doi=10.1289/ehp.1002843 |pmid=21642048 |pmc=3237344 }}

Bystander exposure describes the event when individuals unintentionally come in contact with airborne pesticides. Bystanders include workers working in an area separate to the pesticide application area, individuals living in the surrounding areas of an application area, or individuals passing by fields as they are being treated with a pesticide.{{cite book |last1=Matthews |first1=Graham |title=Pesticides: Health, Safety and the Environment |date=2016 |publisher=John Wiley & Sons |isbn=978-1-118-97602-9 }}{{pn|date=December 2022}}

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Different pesticides can affect different body systems, inflicting different symptoms.{{Cite web |date=March 30, 2018 |title=Pesticide Drift Exposure and Your Health |url=https://www.health.state.mn.us/communities/environment/hazardous/docs/pdriftpatient.pdf |access-date=March 2, 2023 |website=Minnesota Poison Control System}} Pesticides can have long-term negative health impacts, including cancer, lung diseases, fertility and reproductive problems, and neurodevelopmental issues in children, when exposure levels are high enough.{{Cite web |date=March 20, 2018 |title=Pesticide Drift Exposure and Your Health |url=https://www.health.state.mn.us/communities/environment/hazardous/docs/pdriftpatient.pdf |access-date=March 14, 2024 |website=Minnesota Poison Control System}}

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In 2001, the United States Environmental Protection Agency published a guidance to "manufacturers, formulators, and registrants of pesticide products" (EPA 2001){{cite web |title=PRN 2001-X Draft: Spray and Dust Drift Label Statements for Pesticide Products |url=https://www.epa.gov/pesticide-registration/prn-2001-x-draft-spray-and-dust-drift-label-statements-pesticide-products |publisher=U.S. Environmental Protection Agency |date=4 September 2014 }} that stated the EPA's stance against pesticide drift as well as suggested product labelling practices.

To try and reduce pesticide drift, the EPA is a part of several initiatives. The EPA has routine pesticide risk assessments to check potential drift impact on farmworkers living near or on fields where crops are grown, farmworkers, water sources, and the environment.{{cite web |title=What EPA is Doing to Reduce Pesticide Drift |url=https://www.epa.gov/reducing-pesticide-drift/what-epa-doing-reduce-pesticide-drift |publisher=U.S. Environmental Protection Agency |date=1 August 2014 }} The USDA and EPA are working together to examine new studies and how to improve scientific models to estimate the exposure, risk, and drift of pesticides. The EPA is also working with pesticide manufacturers to ensure labels are easy to read, contain the correct application process and DRT for that specific pesticide.{{cite web |title=About the Drift Reduction Technology Program |url=https://19january2017snapshot.epa.gov/reducing-pesticide-drift/about-drift-reduction-technology-program_.html |publisher=U.S. Environmental Protection Agency }}{{cite web |title=Improving Labels to Reduce Pesticide Drift |url=https://www.epa.gov/reducing-pesticide-drift/improving-labels-reduce-pesticide-drift |publisher=U.S. Environmental Protection Agency |date=1 August 2014 }}

• Aerial application
• Agricultural runoff
• Environmental impact of agriculture
• Environmental protection
• Nonpoint source pollution

{{reflist|2|refs=

{{cite web|title=Community Guide to Recognizing and Reporting Pesticide Problems|url=http://www.cdpr.ca.gov/docs/dept/comguide/index.htm|publisher=CA Dept. of Pesticide Regulation|accessdate=25 March 2011}}

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• {{cite web |title=For Your Information: Spray Drift of Pesticides |publisher=U.S. Environmental Protection Agency |date=1999 |id=735F99024 |url=https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=200002PC.txt }}

• {{cite book |last1=Himel |first1=C.M. |year=1974 |chapter=Analytical methodology in ULV |title=Pesticide application by ULV methods |series=British Crop Protection Council Monograph No. 11 |pages=112–119 |oclc=16299124 }}
• Matthews G.A. (2006) Pesticides: Health, Safety and the Environment Blackwell, Oxford

• [http://earthjustice.org/blog/2010-march/npr-pesticide-drift-plaguing-rural-communities EarthJustice] - health impacts of pesticide drift in rural farming community
• [http://www.panna.org/ Pesticide Action Network North America (PANNA)]- "Advancing alternatives to pesticides worldwide"
• [http://www.dropdata.org International Pesticide Application Research Centre (IPARC)]

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