Arsenic in Latin America: A forgotten Continent?
Chair: Professors Marta Litter1) and Jochen Bundschuh2)
1) Comisión Nacional de Energía Atómica, and Universidad de Gral. San Martín, 1650 San Martín, Argentina
litter@cnea.gov
2)Professor, University of Applied Sciences, Institute of Applied Research,
Moltkestrasse 30, 76133 Karlsruhe, Germany
In Latin America, more than 14 million people are at risk of serious illnesses coming from drinking water containing high levels of As, mainly present naturally in groundwater. Although the arsenic problem has been known since one century; the problem has not received enough attention by national authorities or international cooperation agencies to mitigate the problem. Furthermore, the rural people are often dependent on arsenic-contaminated water as their only drinking water resource. Thus, although suitable remediation methods were developed (e.g., solar oxidation methods, phytoremediation, use of natural materials as adsorbents for arsenic removal) they were mostly tested only on laboratory scale, and only few pilot studies on field scale exist even today.
The geochemistry and microbiology of arsenic and humic substances in aquifers of the Blackfoot Disease Area, South-western Taiwan
Chairs: Prof. Dr. Bart E. van Dongen1) and Thomas Kulp2)
1)School of Earth, Atmospheric and environmental Sciences, The University of Manchester, Manchester, United Kingdom
2) U.S. Geological Survey, Water Resources Division, Menlo Park, CA, USA
bart.vandongen@manchester.ac.uk
The Chianan Plain of southwestern Taiwan is historically associated with endemic cases of Blackfoot Disease (BFD), a peripheral vascular disease that has been linked to long-term consumption of As-rich groundwater from regional wells. While the exact etiology of BFD is still a subject of debate, it is suggested that high dissolved geogenic As in combination with high concentrations of fluorescent humic compounds in the area’s groundwater are primary causative factors. Despite considerable interest in this problem over the past several decades, relatively little is currently known about the geologic sources and geochemical forms of As and humic/organic matter in this aquifer. Furthermore, very few studies have been conducted to identify microbiological processes that may influence the speciation and mobility of As, including the role of the organic matter present, in this system. The Chianan Plain thus represents a unique area for research into the geochemical and biogeochemical processes that control/influence As speciation and mobility. This session will be open to anybody who wants to present new results on sources and sinks of As, speciation and mobilization of the element, and relevant microbiological processes in aquifers of this region. We are particularly interested in submissions concerning the (initial) results of analyses of sediments obtained from wells recently drilled within and adjacent to the BFD endemic area of Budai Township and Yichu Township, Chiayi County.
Arsenic in Rice – Advances and Challenges to Minimizing Hazard
Chairs: Prof. Richard Loeppert
Texas A&M University
e-mail : r-loeppert@tamu.edu
Description:
Background:
Arsenic, which is toxic to plants and animals, is especially problematic in rice since it is more soluble and more bioavailable under the conditions of flooded rice culture. Rice is the staple grain and major caloric source for more than half of the world’s population. Two major problems have emerged with arsenic in rice. Firstly, with the relatively high bioavailability of arsenic under flooded rice culture, arsenic species are more readily transported to the grain and represent a major source (often the major source) of total ingested arsenic by humans. In regions of the world already impacted by high arsenic concentrations in drinking water, the additional high arsenic concentrations in rice even further exacerbate an already critical problem. Arsenic in rice impacts food quality, food security and public perception of the quality of the agricultural product. The second and perhaps most devastating problem is arsenic toxicity to rice. The problem is exacerbated by the extravagant use of arsenic-contaminated water for irrigation, with a resulting continual increase in soil arsenic concentration. In separate studies throughout the globe, but especially in South Asia, there is increasing evidence of catastrophic arsenic-induced rice-yield reductions. The most effected areas are regions of the globe that are already impacted by the devastating effects increasing population, decreasing land availability for agriculture, increasing food prices and decreasing availability of food. The sustainability of rice production is threatened by arsenic in regions of south, southeast, east and central Asia, as well as major rice-producing regions in the Western Hemisphere. This emerging problem impacts international food security, nutrition, health and poverty worldwide. The critical need to address issues of arsenic in rice has garnered international scientific attention to this interdisciplinary challenge. Over the past few years there have been significant advances in the understanding of arsenic reactions, including those involving rice rhizosphere biogeochemistry; rice physiology and genetics; water and crop management approaches to minimizing arsenic hazard; and rice grain biochemistry and implications to processing. Through disciplinary and interdisciplinary approaches, new opportunities are emerging to minimize arsenic hazard in rice.
Overall Objective --- An interdisciplinary forum to address the advances and challenges in minimizing the hazard of arsenic in rice
Scope of Presentations
- Overview and implications of arsenic in agricultural systems
- Geochemistry of arsenic in the rice rhizosphere
- Physiology of arsenic in rice
- Arsenic acquisition
- Biochemical transformations and transport of arsenic
- Rice genetics
- Genetic variability of tolerance to arsenic
- Genetic variability in concentration and speciation of arsenic in grain
- The South Asian situation
- Water and Crop Management to minimize arsenic hazard
- Seed physiology, grain processing and implications to minimizing arsenic hazard
