Mapping Arsenic Accumulation in Rice

Arsenic (As) contaminated water and food affect ~150 million people worldwide, out of whom 110 m live in 10 South Asian countries. The vulnerability of these regions is mainly linked to cultivation and consumption of rice, which is an accumulator of arsenic when grown in typical (i.e. submerged soil) rice growing conditions. However, there has been a lack of systematic investigation in tracking and mapping arsenic in the food chain in order to develop field-deployable solutions for the 21st century. This project aims to understand spatial distribution and quantify arsenic (and its chemical species) in rice through synchrotron X-ray spectroscopy in collaboration with the Diamond Light Source. However, in order to develop a standard method for rapid examination of various rice types through synchrotron imaging technology, we need to overcome several methodological barriers (e.g. thickness of rice cross sections, embedding methods and imaging parameters), which we will address in this project. In parallel, we aim to produce a comprehensive baseline dataset on arsenic in rice types from Bangladesh, which is one of the worst affected countries in the world where there are no facilities nor regulations in place to monitor arsenic contents in rice and rice products, in contrast to the developed countries. This baseline data represent an essential milestone in managing arsenic in the food chain in the affected areas, and will inform the stakeholders and policymakers in developing regulations required for the health and well-being of the affected population. The outputs from this project are designed to be fed into various intervention strategies such as selection of appropriate rice cultivars which uptake less arsenic in plant parts, selection of improved soil-water management practices that translocate less arsenic to rice plants, and development of processing and cooking methods to reduce the arsenic exposure. Through this project, we shall directly address several sustainable development goals such as no poverty, no hunger, good health and well-being, clean water and sanitation, decent work and economic growth, responsible consumption and production, and life on land.

Arsenic (As) in the food chain affects the health and well-being (economically and socially) of rice producers (i.e. poor and marginal farmers of Bangladesh and elsewhere), distributors and consumers. It is known to affect 140 m people across the world from 70 countries, and Bangladesh is one of the most severely affected countries (39 m people). This project directly or indirectly addresses several sustainable development goals namely no poverty, no hunger, good health and well-being, clean water and sanitation, decent work and economic growth, responsible consumption and production, and life on land.
The adverse health impacts (arsenicosis) of arsenic can be acute (e.g. vomiting, abdominal pain and diarrhoea) and long-term exposure leads to skin conditions such as pigmentation changes and hyperkeratosis, cancers of bladder and lungs and diabetes and cardiovascular diseases, affecting on the physical and mental health of the affected population. In particular, it affects poorer sectors of society (e.g. farmers and farm workers) who have limited access to affordable health care to treat arsenicosis. Women are negatively discriminated by the society when skin conditions appear. It also places a severe economic burden on the affected people through medical treatment costs and decreased farm income (e.g. high levels of arsenic is known to decrease rice yield and health of livestock). Since the source of arsenic is natural (geogenic), selection of appropriate crop cultivars and agronomic practices (e.g. alternate wetting and drying of rice fields) are among the recommended practices by the WHO, and our strategy underpins these recommendations by helping farmers in selecting suitable rice types which are less arsenic accumulating. This will reduce the exposure of arsenic to humans and livestock (rice husk and straw are widely used as ruminant feed), and will help improve farm income.
A more comprehensive understanding of arsenic in rice types will also lead to better regulations being established such as the ones adopted by the EU and China where there are strict guidelines on arsenic content in rice and rice products. This project sets an important milestone in this regard by providing much-needed baseline data of arsenic in rice and its spatial distribution in rice grains through advanced imaging methods at the Diamond Light Source. Mapping arsenic in rice will lead to the development of novel processing and cooking methods for human consumption of rice. Rice types which accumulate lesser amounts of arsenic can safely be used as ruminant feed to improve the livestock health, which will reduce the risk of arsenic entering humans through meat and dairy products. This will have added benefit in boosting the rice export income and economic growth of Bangladesh.