AGROCHEMICAL IMPACTS ON HUMAN AND ENVIRONMENTAL HEALTH: MECHANISMS AND MITIGATION

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1025382
• Multistate No.: W-4045
• Project Start Date: Nov 30, 2020
• Project End Date: Sep 30, 2021
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF CONNECTICUT
438 WHITNEY RD EXTENSION UNIT 1133
STORRS,CT 06269

Performing Department
Natural Resources & the Environment

Non Technical Summary
Arsenic is a known carcinogen. Groundwater contamination by arsenic at levels exceeding EPA standards is widespread in New England. The source(s) of the arsenic is poorly understood. Possibilities include natural sources (leaching of arsenopyrite from rock) and historic and recent anthropogenic sources (lead arsenate as an arsenical insecticide on apple orchards and other crops; organoarsenate in chicken manure used for fertilizer for corn and other agricultural applications). Irrespective of the source, once dissolved in groundwater arsenic is transported as arsenate or arsenite and its source remains unknown. This proposal seeks to evaluate whether sources of arsenic are anthropogenic by determining if there is an association of arsenic in groundwater with bacteria communities that are commonly associated with fertilizers used on active or former farmland. Water and soil samples from select areas in Connecticut will be tested to evaluate the association. Arsenic concentrations will be determined at the CESE laboratory by ICP. Bacteria community analyses will be determined by DNA sequencing at the MARS laboratory. Data will then undergo geographic and statistical analysis to evaluate trends and associations. The resolution of this issue impacts evaluation of contamination risk to water wells, the need for filters on drinking water and water used for irrigation, and possible approaches for remediating the problem on active and past farmlands.

Animal Health Component

60%

Research Effort Categories

Basic

15%

Applied

60%

Developmental

25%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
112	0210	2050	50%
133	0320	2030	50%

Knowledge Area
133 - Pollution Prevention and Mitigation; 112 - Watershed Protection and Management;

Subject Of Investigation
0320 - Watersheds; 0210 - Water resources;

Field Of Science
2030 - Geology; 2050 - Hydrology;

Keywords

arsenic

groundwater

anthropogenic sources

food safety

water safety

Goals / Objectives
Identify, develop, and validate analytical methods, bioassays and biomarkers. Characterize abiotic and biotic processes that influence the sources, fate, transport and transformations of agrochemicals in agricultural and natural ecosystems. Quantify and mitigate human and environmental impacts of agrochemicals.

Project Methods
The Connecticut Department of Agriculture and the UConn extension Department will be contacted, and historic aerial photographs will be studied to help identify potential locations to conduct detailed soil sampling on current or former farmland. Given our past work on arsenic in Lebanon we expect to concentrate our efforts in this town. However, we will be looking at other locations. We have also identified farm property in Manchester, Connecticut owned by the Manchester Land Conservation Trust which had apple orchards for almost 100 years. During the study period, we envision working on 10 contaminated locations, along with matched control sites with similar geology but no history of farming. At each location we will collect and characterize soil cores to a depth of up to 4feet. We have several methods of drilling (by hand or using our gasoline powered mobile drill rig). Soil from at least 3 depths per soil core will be sampled and brought to the MARS laboratory for DNA gene sequencing and the UConn Center for Environmental Science and Engineering (CESE) laboratory for arsenic, organoarsenic and lead analysis. We have a previous CESE grant to cover the arsenic analyses. All soil core locations will be recorded with GPS and mapped. Water will be collected from private residential wells in proximity or on each of the properties where soil samples are collected and sent to the MARS and CESE laboratories for the same analyses as above. We will also collect water from farm ponds and springs, if available. Our research group has established private well sampling protocols and relationships with dozens of residents in the Lebanon and Bozrah, CT townships. A number of these properties are in close proximity to farmland and previously have had confirmed high levels of arsenic in their drinking water supply. As described below, correlations will be sought between bacteria associated with contaminated groundwater and bacteria at potential arsenic source locations. A drawback to the approach is the possible lack of bacteria distinction from background levels to judge correlations. In that case, we will still meet one of our objectives to define areas contaminated with arsenicrelated to agricultural practices. If this does appear to be the case, we will further stress arsenic characterization and potential for leaching based on soil profiling. We will use a standard field protocol to collect and preserve bacteria from groundwater samples on 0.22 micron Sterivex filters then buffered with a hypertonic solution. Soil samples will be transported on ice until they can be frozen at MARS. MARS will extract DNA from both the water and soil samples using commercial kits (PowerWater and PowerSoil from MoBio/Qiagen). Bacterial communities will be profiled by sequencing a conserved taxonomic marker gene (16S rRNA gene) using MARS custom library protocol. The additional water and soil samples will be collected and brought to CESE for arsenic and lead analysis with ICP MS. A YSI Multi-parameter Sonde will be used on location to analyze the following water quality parameters: temperature, ph, dissolved oxygen, and specific conductance. Water samples will be collected after stabilization of the YSI parameters.

Progress 11/30/20 to 09/30/21

Outputs
Target Audience:The audiences reached this reporting period include: • Connecticut residents concerned with local issues associated with their water supply that participated in our study. • Environmental consultants with the firm, ALTA Environmental Corporation in Colchester, CT that used the methodology developed for this project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We graduated one PHD student ( Mark Higgins) who used the project as his dissertation work. We also trained one undergraduate intern on digitizing water well completion reports. How have the results been disseminated to communities of interest?Results were disseminate through presenations and peer reviewed journal articles. Following a number of interviews with reporters and publication of the results of our work on campus ( UConn Today:Arsenic in Connecticut Wells May be a Legacy of Past Pesticide Use on Orchards, December 20. 2021 )our work has been highly publized in the media and online. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Further GIS analyses took place to identify more areas throughout Connecticut that are likely to be impacted by historic uses of lead-arsenate. • Soil and water samples were collected from more Connecticut properties to undergo arsenic and bacteria community analysis. • We examined the relationship between specific bacteria which may be associated with arsenic. Ultimately these bacteria will be used as a biomarker or groundwater tracer in contaminated groundwater wells. • Conducsted a detailed statistical analysis evaluating bacteria communities and their associations with groundwater recharge and discharge areas via soils, surface water, shallow groundwater, and bedrock groundwater. • Leaching tests on arsenic contaminated soils was done to better define leachability under various conditions. We have shown there is a spatial relationship between the location of orchards and downgradient groundwater flow paths and arsenic contaminated wells We have also found that high levels of arsenic pesticide persist at historic orchard sites even after decades Our contiuning work suggests that the groundwater arsenic contamination is not geogenic by anthropogenic.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2021 Citation: Higgins, Mark A., Robbins, G.A., Metcalf, M.J. Non-point Source Arsenic Contamination of Soil and Groundwater from Legacy Pesticides. Journal of Environmental Quality, v. 51(66-77), 2021. https://doi.org/10.1002/jeq2.20304
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Use of Bacteria Community Analysis to Distinguish Groundwater Recharge Sources to Shallow Wells, with G.A. Robbins, K.R. Maas, G.K. Binkhorst, Journal of Environmental Quality, v. 49(1530-1540), 2020. https://doi.org/10.1002/jeq2.20150
• Type: Theses/Dissertations Status: Accepted Year Published: 2021 Citation: Higgins, M.A. Evaluating Sources of Arsenic, Nitrate, and Road Salt in Domestic Wells Using Bacteria Community and Spatial Analyses, Ph.D. Dissertation, University of Connecticut, May 2021.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2021 Citation: Metcalf, M., Robbins, G, and Higgins, M., (2021, December) Correlation of Lead Arsenate Use at Orchards and Drinking Water Contamination, presentation to the licensed Site Professional Association of Massachusetts. Metcalf, M., Robbins., G., and Higgins, M., (2021, December), Correlation of Lead Arsenate Use at Orchards and Drinking Water Contamination, Presentation to the USDA NRCS.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2021 Citation: Higgins, Mark A., (4 May 2021). Arsenic and Road-salt impacts to domestic wells. Two CT case studies. (Invited Oral Presentation). Connecticut DEEP Remediation Roundtable. Virtual.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2021 Citation: Kornegay, Travis, Higgins, M.A., Robbins, G.A., Metcalf, M.J., (15 March 2021). Effective Digitalization of Well Records to Create A Groundwater Resource Management Tool in the State of Connecticut. Poster Presentation. Geological Society of America Abstracts with Programs. 53(1). doi: 10.1130/abs/2021NE-361721
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2021 Citation: Metcalf, M., Robbins, G, and Higgins, M., (2021, December) Evaluation of Lead Arsenate Occurrence and Mobility at Historic Orchard Properties in Weston, CT, Presentation to the Staff of the Connecticut Dept. of Public Health.