Study of Pesticides in School Drinking Water

2012 USDA Study

On this page:

Background
Purpose of sampling project
Summary information
Conclusions
Recommendations
More information

Table 1. Summary information about pesticide and pesticide breakdown products in USDA school drinking water study (Oregon schools only)
Table 2. Summary information about the 20 pesticides detected in Oregon school drinking water
Table 3. Common uses for the chemicals detected in Oregon school drinking water
Table 4: USDA school results by school

Background

In the spring of 2012, 22 Oregon schools participated in the United States Department of Agriculture's (USDA) analysis of their drinking water. USDA's Monitoring Programs Division (Manassas, Virginia) is coordinating collection events like this in states across the country. In Oregon, all of the participating schools use groundwater wells as their source of drinking water and all are located in agricultural and rural areas. None of the 22 schools receive their drinking water from an off-site public water supply.

To assist participating Oregon schools, the Department of Environmental Quality (DEQ) Laboratory staff collected, packaged and shipped water samples from the schools, using sampling kits and instructions sent from USDA. Water samples were shipped to USDA's contract laboratory in Minnesota, where they were analyzed for 177 pesticides or pesticide breakdown products (pdf).

Purpose of sampling project

The purpose of this sampling project was to collect data on the national prevalence of pesticides and pesticide breakdown products in school well water. Participation in this project was voluntary and analytical results were provided to participating schools. The data collected in this project will be used for national research and risk assessments of these chemicals to specifically address the drinking water component for children during their developmental years. The data will be published in a nationwide summary produced by the USDA. The purpose of this summary is to describe and report on the collective test results in Oregon.

Summary information

Tables 1 and 2 below contain a basic summary of the results, which show that none of the pesticides or their breakdown products were found at levels that would cause a public health concern. The measured concentrations of pesticides or their breakdown products in the water are considered too low (parts per trillion range) to harm the health of children or school staff who drink it on a regular basis.

However, the detection of these pesticides in groundwater suggests that chemicals are getting into groundwater that is being used for drinking purposes. The Oregon Health Authority (OHA) recommends that schools consult with OHA and other experts to investigate how this is happening. State agency drinking water protection staff can assist the individual schools in developing a more detailed assessment of the sources of pesticides and develop a voluntary plan to minimize the applications and uses of these pesticides in the vicinity.

Table 3 below describes the common uses for the chemicals detected in Oregon school drinking water.

Table 4 below lists the 22 Oregon schools in the 2012 US Department of Agriculture study on pesticides in rural school drinking water. The table describes the location of each school, how many chemicals were detected in the water from each school, the names of the chemicals detected and whether or not levels of detected chemicals exceed health guidelines.

Conclusions

None of the pesticides or their breakdown products were found at levels of concern for public health (based on the comparison of health screening levels for individual pesticide concentrations).
Detection of multiple pesticides in the drinking water of some schools suggests that school drinking water in those locations may be influenced by chemicals used and applied on the surface.

Recommendations

Schools with multiple pesticides detected in their drinking water should contact OHA (Tom Pattee 541-726-2587 x24) or other experts to investigate and learn more about the connection between surface and groundwater supplying their wells.
Schools with multiple pesticides detected in their drinking water should contact the drinking water protection staff at DEQ (Sheree Stewart 503-229-5413) if they wish to initiate voluntary pesticide reduction efforts in their recharge area.

More information

Learn more about USDA's Pesticide Data Program - Drinking Water Project.
Visit Drinking Water Data Online for information about specific public drinking water systems. Use the WS Name Lookup feature to search for a specific water system by name. The site contains information about source water, latest testing results, and sampling result histories for all public drinking water systems in the state.

Table 1. Summary information about pesticide and pesticide breakdown products in USDA school drinking water study (Oregon schools only)
Schools tested	22
Schools with no pesticides detected	11
Schools with only 1 pesticide detected	5
Schools with 5 or more pesticides detected	4
Schools with at least one form of atrazine or atrazine breakdown product detected	7
Maximum number of pesticides detected in water from any one school	12
Pesticides or pesticide breakdown products tested (see full list - pdf)	177
Pesticides or pesticide breakdown products detected	20

Table 2. Summary information about the 20 pesticides detected in Oregon school drinking water
Chemical	Number of Schools with Detections	Percent of Schools with Detections (Out of 22 schools tested)	Maximum concentration measured¹ (ppt)	Health Based Screening Value (ppt)	Health Based Screening Value Source²
ppt = Parts per trillion or nanograms per liter
¹Maximum concentration found at any of the 22 schools tested. All other results for a given contaminant were lower than this level.
²Screening values were chosen according to the following order: First, the maximum contaminant level (MCL, explained below) was selected. Second, if an MCL wasn't available for a given chemical, OHA selected the lowest available health based value from the sources listed below. And third, some of the pesticide breakdown products (those marked with an *)did not have a screening value, and in these cases the MCL or screening value for the parent compound was chosen as a conservative substitute screening value.
*For these pesticide breakdown products, neither MCL nor any other screening value was available. In these cases the MCL or most health protective screening value for the parent compound was used as a substitute.
MCL = Environmental Protection Agency's Maximum Contaminant Level: This is a legally enforceable water quality standard for public drinking water systems. MCLs are usually expressed as parts per million, but because these results were measured in parts per trillion, MCLs were multiplied by 1,000,000 so that they could be directly compared with the results without using decimal points.
CA MCL = California MCL: This is a legally enforceable water quality standard in public drinking water for the state of California that is not enforced at the federal level.
USGS HBSL = United States Geological Survey's Health-Based Screening Level: This is not a legally enforceable standard. This is a human health risk-based screening value calculated using EPA's methods for developing lifetime health advisories.
EPA HHBP = EPA's Human Health Benchmarks for Pesticides in drinking water: These values are not legally enforceable but were developed by the EPA as human health-based screening values for drinking water.
EPA RSL = EPA's Regional Screening Levels for residential tap water: These values are not legally enforceable but they are human health risk-based concentrations for drinking water developed by the branch of the EPA that does clean-up at hazardous waste sites.
Herbicides
Alachlor or alachlor breakdown products
Alachlor ethanesulfonic acid (ESA)	3	14	76	2,000	MCL*
Alachlor oxanilic acid (OA)	1	5	4.8	2,000	MCL*
Atrazine or atrazine breakdown products
Atrazine	3	14	54	3,000	MCL
Desethyl atrazine	7	32	310	3,000	MCL*
Desethyl-desisopropyl atrazine	2	9	170	100,000	USGS HBSL
Desisopropyl atrazine	3	14	35	3,000	MCL*
Hydroxy atrazine	1	5	2	70,000	EPA HHBP
Metolachlor or metolachlor breakdown products
Metolachlor ethanesulfonic acid (ESA)	4	18	330	700,000	USGS HBSL*
Metolachlor oxanilic acid (OA)	2	9	28	700,000	USGS HBSL*
Norflurazon or Norflurazon breakdown products
Norflurazon	1	5	8	10,000	USGS HBSL
Norflurazon desmethyl	2	9	27	10,000	USGS HBSL*
Other herbicides
Bentazon	1	5	290	18,000	CA MCL
Bromacil	3	14	270	70,000	USGS HBSL
2,4-D	1	5	7.3	70,000	MCL
Diuron	4	18	44	2,000	USGS HBSL
Imazapyr	1	5	130	17,500,000	EPA HHBP
Prometon	2	9	0.3	190,000	EPA RSL
Propazine	3	14	9.8	100,000	USGS HBSL
Simazine	2	9	2.6	4,000	MCL
Insecticide
Imidacloprid (for sucking and some chewing insects like fleas and termites)	1	5	13	399,000	EPA HHBP

Table 3. Common uses for the chemicals detected in Oregon school drinking water
Chemical	Potential Contaminant Sources, Land Uses, Applications and Other Notes	Primary Uses In Oregon and Crop Types
Herbicides
2,4-D	Agriculture, residential, recreation, utilities, forestry	Lawns, turf, orchards, vegetables, wheat, grasses, canals, ditches, fence lines
Alachlor	Agriculture, forestry	Corn, sorghum, beans, trees
Atrazine	Agriculture, residential, recreation, forestry (controls weeds, broadleaf, grasses)	Grassland, corn, recreation areas, sorghum, home lawns
Bentazon	Agriculture, residential, recreation (controls broadleaf, sedge weeds)	Soybeans, corn, sorghum, peanuts, lawns
Bromacil	Agriculture, utilities (controls weeds, brush)	Non-crop areas, fence lines, right-of-ways
Diuron	Agriculture, utilities, recreation (controls weeds, mosses, grasses)	Citrus, grass seed, berry crops, vines, wheat, flowers, apple, mint, right-of-ways, pools
Imazapyr	Agriculture, residential, utilities, forestry (controls weeds, grasses)	Corn, right-of-ways, home lawns, non-crop areas, tree crops, nurseries, pasture
Metolachlor	Agriculture (controls grasses, broadleaf)	Corn, sorghum
Norflurazon	Agriculture, utilities	Cranberry, filberts, fruits, nuts, berry crops, fence lines, ditches
Prometon	Agriculture, utilities (non-selective herbicide)	Non-crop areas, right-of-ways
Propazine	Agriculture (controls annual grasses, broadleafs)	Ornamentals, sorghum, garden vegetables
Simazine	Agriculture, residential, recreation	Corn, turf, nuts, apple, home lawns, berry crops, tree nurseries, golf courses, cherry, seed crops, plum, peach, ponds
Insecticide
Imidacloprid	Agriculture, residential, recreation	Cereals, fruits, turf, leafy vegetables, pet flea control, nuts, beans, berry crops, potato, ornamentals, flowers, corn, tomato

Table 4: USDA school results by school
School Name	City	Sample Date	Total Detections	Chemical(s) Detected	Levels of Chemicals Above Health Guidelines?
Pinehurst School	Ashland	4/11/2012	0	None	No
North Marion SD #15 High School	Aurora	2/21/2012	0	None	No
North Marion SD #15 Intermediate School	Aurora	2/21/2012	0	None	No
Bridges Academy	Bend	4/16/2012	1	Desethyl atrazine	No
Triangle Lake School	Blachly	4/9/2012	1	Imazpyr	No
Brookings Head Start	Brookings	4/11/2012	0	None	No
Dixie Elementary	Corvallis	4/9/2012	12	Atrazine, Bromacil, Desethyl atrazine, Desethyl-desisopropyl atrazine, Desisopropyl atrazine, Diuron, Imidacloprid, Metolachlor ethanesulfonic acid (ESA), Norflurazon, Norflurazon desmethyl, Propazine, Simazine	No
Fairplay Elementary	Corvallis	4/9/2012	12	Alachlor ethanesulfonic acid (ESA), Atrazine, Desethyl atrazine, Desethyl-desisopropyl atrazine, Desisopropyl atrazine, Diuron, Hydroxy atrazine, Metolachlor ethanesulfonic acid (ESA), Norflurazon desmethyl, Prometon, Propazine, Simazine	No
Mt View Elementary	Corvallis	4/9/2012	0	None	No
Eddyville Charter School	Eddyville	4/9/2012	0	None	No
Applegate Elementary	Eugene	4/9/2012	7	Atrazine, Bromacil, Desethyl atrazine, Desisopropyl atrazine, Diuron, Prometon, Propazine	No
Crow High School	Eugene	4/9/2012	0	None	No
Rogue Community College	Grants Pass	4/11/2012	1	Desethyl atrazine	No
Country Christian School	Molalla	4/16/2012	0	None	No
Rural Dell School	Molalla	4/16/2012	0	None	No
Clarkes School	Mulino	4/16/2012	1	Bromacil	No
Ewing Elementary School	Newberg	4/16/2012	1	2,4-D	No
Cairo Elementary	Ontario	4/24/2012	4	Alachlor ethanesulfonic acid (ESA), Alachlor oxanilic acid (OA), Metolachlor ethanesulfonic acid (ESA), Metolachlor oxanilic acid (OA)	No
Pioneer Elementary SD8C	Ontario	4/24/2012	5	Alachlor ethanesulfonic acid (ESA), Bentazon, Desethyl atrazine, Metolachlor ethanesulfonic acid (ESA), Metolachlor oxanilic acid (OA)	No
Pleasant Valley Elementary School SD 28J	Portland	4/16/2012	0	None	No
Jewell School District #8	Seaside	4/17/2012	0	None	No
Sweet Home Charter School	Sweet Home	4/9/2012	2	Desethyl atrazine, Diuron	No