Source: UNIVERSITY OF DELAWARE submitted to
PARTNERSHIP: FIELD MANAGEMENT AND POST-HARVEST METHODS TO MITIGATE TOXIC INORGANIC AND ORGANIC ARSENIC SPECIES IN RICE GRAIN
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1029775
Grant No.
2023-67017-39185
Project No.
DEL00859
Proposal No.
2022-09030
Multistate No.
(N/A)
Program Code
A1332
Project Start Date
Mar 1, 2023
Project End Date
Feb 28, 2027
Grant Year
2023
Project Director
Seyfferth, A. L.
Recipient Organization
UNIVERSITY OF DELAWARE
(N/A)
NEWARK,DE 19717
Performing Department
(N/A)
Non Technical Summary
Many people eat rice, including infants who are often fed rice as a first food. Unlike other crops, the growth conditions of rice results in its grain having higher amounts arsenic, which is a potent poison. But, not all forms of arsenic have the same toxic effects on humans. While some forms are generally regarded as nontoxic, other forms are highly toxic. Recently, a new highly toxic form of arsenic was discovered in rice, but it is unknown how prevalent this form is in US rice. It is important to understand the different forms of arsenic in rice and to find ways to keep levels of the toxic forms of arsenic in rice as close to zero as possible. In this project, we will investigate the different forms of arsenic that are found in rice - including the newly recognized form of concern. In this collaborative project, we will also test practical ways to decrease the risk of arsenic to rice consumers through project activities that range from farm management changes in irrigation strategies to food processing changes such as adjustments to the parboiling or milling techniques. The project will advance understanding of the effects of these practices on the different forms of arsenic found in rice. The net result will be a holistic perspective on ways to effectively reduce the risk of arsenic through dietary rice consumption.
Animal Health Component
0%
Research Effort Categories
Basic
50%
Applied
40%
Developmental
10%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7231530200080%
1020110310020%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships; 723 - Hazards to Human Health and Safety;

Subject Of Investigation
0110 - Soil; 1530 - Rice;

Field Of Science
2000 - Chemistry; 3100 - Management;
Goals / Objectives
The overarching objective of this work is to understand how As species in rice grain are affected by water and soil management and post-harvest mitigation strategies. Specifically, we will examine how the concentration of As species, inclusive of DMMTA, in rice grain is affected by irrigation water management, soil S amendments, and parboiling. We will use a combined lab and field approach to address these objectives. We will evaluate As species, inclusive of DMMTA, in rice grain collected from a wide range of past field studies in Arkansas where water management had been manipulated but grain DMMTA was not measured (Aim 1); conduct new field experiments where we will examine the impact of water management on concentrations of As species in rice grain inclusive of DMMTA and concurrently test a soil As availability sensor for predicting and reducing As risk across variable soils and management in Arkansas (Aim 2); investigate the impact of soil S amendments on As speciation in rice grain in a pot study (Aim 3); and use grain from Aims 1-3 to investigate the role of parboiling and milling on concentrations of As species in rice grain, inclusive of DMMTA, to relate to human health risks (Aim 4).
Project Methods
We will use a combined lab and field approach to address ourobjectives. We will evaluate As species, inclusive of DMMTA, in rice grain collected from a wide range of past field studies in Arkansas where water management had been manipulated but grain DMMTA was not measured (Aim 1); conduct new field experiments where we will examine the impact of water management on concentrations of As species in rice grain inclusive of DMMTA and concurrently test a soil As availability sensor for predicting and reducing As risk across variable soils and management in Arkansas (Aim 2); investigate the impact of soil S amendments on As speciation in rice grain in a pot study (Aim 3); and use grain from Aims 1-3 to investigate the role of parboiling and milling on concentrations of As species in rice grain, inclusive of DMMTA, to relate to human health risks (Aim 4).

Progress 03/01/23 to 02/29/24

Outputs
Target Audience:Rice farmers, USDA officials, regulatory agencies, scientists, the general public. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?We have recruited one graduate student to the Seyfferth Lab who is working on the Aim 3 pot study and will assist with field work in the summer of 2024. The Runkle lab recruited an undergraduate student and a post-masters student who worked on aspects of the project. The post-masters student led a review article on mitigation strategies for arsenic in rice that was coauthored by both PIs. How have the results been disseminated to communities of interest?Seyfferth presented some of this work at the Arkansas Soil and Water Conservation Conference in January 2024. We also submitted a review article on As mitigation techniques: Leavitt, M., Reba, M., Seyfferth, A., Runkle, B. R. Agronomic Solutions to Reduce Arsenic in Rice. Environmental Geochemistry and Health. Submitted Feb 12, 2024 What do you plan to do during the next reporting period to accomplish the goals?We will conclude the pot study on S amendments in 3 different soils and analyze data. Data to be analyzed includes porewater chemistry over the growing season, soil analyses, and plant chemistry including arsenic speciation in grain. We will plan and conduct field experiments on porewater, passive sensor, and ultimately grain sampling in a select number of fields. In part 2 (years 2 and 3), a broader sampling campaign on 12 fields (6 pairs) will receive the same field measurements as in year 1, as well as IRIS installations at heading stage and concurrent porewater sampling. The sites to be sampled will be based upon the measured As grain data collected in year 1, with the goal of sampling a wide range of grain As across different soil types. Soil and grain will be characterized as in year 1. We will present the findings at the IAFP meeting in July 2024 and at the ASA-CSSA-SSSA meeting in November 2024. Manuscripts will be promptly written as analyses and interpretations are completed.

Impacts
What was accomplished under these goals? We have tested several speciation methods for DMMTA quantification, and are in the process of making final adjustments to achieve optimal recovery of certified reference materials. In the summer of 2023, we visited several fields in Arkansas and tested four different porewater techniques as well as a passive redox sensor; these efforts helped to narrow down fields that we will plan to use in the 2024 field season. A broader survey was performed on 24 fields, comprised of 12 pairs of fields. Each pair was managed with one field using a continuous flood irrigation and the other in an aerobic system (either AWD or furrow irrigation). The paired field sizes, soil types, cultivar, planting date, and other agronomic management decisions were kept as similar as feasible given farm conditions. In each field we measured volumetric water content at two depths, water level depth, and growth staging, and collected grain and soil samples for As speciation (including DMMTA). In a subset of 6 of these fields (3 pairs), we tested IRIS and porewater sampling in the heading/grain filling stage to gain a robust initial understanding of film installation and response in these soils and field conditions. These fields included clay and silt loam soil types and at least one of each of AWD and furrow irrigated fields. At harvest, grain was collected for analysis of As species. Grain has since been dehusked, polished, ground, digested, and analyzed for As and Cd. We visited Arkansas a second time in 2024 to obtain soils to use in the pot studies, and we started the pot study with S amendments.

Publications

  • Type: Journal Articles Status: Under Review Year Published: 2024 Citation: Leavitt, M., Reba, M., Seyfferth, A., Runkle, B. R. Agronomic Solutions to Reduce Arsenic in Rice. Environmental Geochemistry and Health. Submitted Feb 12, 2024