SEGH Articles

# Reducing human exposure to arsenic and simultaneously increasing selenium and zinc intake, by substituting non-aromatic rice with aromatic rice in the diet

01 May 2013
A team of scientists led by Dr Parvez Haris is carrying out research to identify ways of reducing human exposure to arsenic through diet

Rice is the staple food of over three billion people.  The rice plant is highly efficient at absorbing arsenic from soil and water, it is reported to be the highest arsenic-containing cereal.  For Bangladeshi’s, rice is their staple food and they consume on average half a kilogramme of rice per day.

A team of scientists led by Dr Parvez Haris from DeMontfort University, Leicester, UK is carrying out research to identify ways of reducing human exposure to arsenic through diet.

Haris and his team have already demonstrated that exposure to the more toxic inorganic arsenic species is greater in people who eat more rice.  In this latest work, published in Biomedical Spectroscopy and Imaging, the DeMontfort University team – along with Dr Michael Watts from the British Geological Survey, Keyworth, Nottingham, UK – has identified varieties that are low in arsenic but high in essential trace elements such as selenium and zinc.

Earlier studies showed high concentrations of arsenic in Bangladeshi rice, but the rice samples were mainly regions where the irrigation water contains higher levels of arsenic. The team carried out a detailed study on rice from the greater Sylhet region in the north-east of Bangladesh, which generally has a lower groundwater arsenic concentration. The team analysed 98 rice samples using a technique called Inductively Couple Plasma – Mass Spectromtetry (ICP-MS) to determine total arsenic and also arsenic species in a selected group of samples.

The results showed Sylheti rice to have a far lower arsenic concentration than similar types of rice form other regions of Bangladesh. Results also showed that the arsenic concentration in aromatic rice was 40% less than non-aromatic varieties and that it also contained higher concentrations of the essential elements selenium and zinc. This is very good news for millions of Bangladeshis who are exposed to high concentrations of arsenic through drinking water and rice and are also deficient in zinc and selenium. Several varieties of Sylheti aromatic rice even had lower arsenic than the well known Basmati aromatic rice from India and Pakistan.

For someone consuming 500 grams of non-aromatic or aromatic rice from Sylhet, the daily intake of arsenic from rice would be approximately 48% and 69% lower, respectively, compared with consuming no-aromatic rie from other parts of Bangladesh. Bangladeshis are proud of their diet and often refer to themselves as ‘mache bhathe Bangali’ which can be roughly translated as ‘fish and rice makes a Bengali’. The identification of rice with very low arsenic concentrations and higher concentrations of essential elements is good news for the Bangladeshis and other communities where rice is a staple food but it is important ot encourage a more diversified diet that is less dependent on rice.

Aromatic rice is generally cultivated during the wet (aman) season and therefore is less dependent on the use of groundwater for irrigation. It also requires less fertilizer and pesticides. Although the yield of aromatic rice is lower, the farmers will not need to spend much money on applying chemicals that could pollute the environment and harm their own health. Furthermore, energy costs (electricity or diesel) will be lower as there will be less need for them to pump groundwater for irrigation.

The impact of this finding may also have health implications for other groups of people who eat large quantities of rice daily. This type of rice could also be used in infant foods in stead of rice with higher arsenic concentrations. It could also benefit people suffering from celiac disease who consume rice-based foods on a regular basis. Therefore, it is essential that further research on aromatic rice from different parts of Bangladesh and other regions of the world are conducted.

Dr Parvez Haris, DeMontfort University

pharis@dmu.ac.uk

Reference

Shaban W. Al-Rmalli, Richard O. Jenkins, Michael J Watts, Parvez I. Haris, 2012. Reducing human exposure to arsenic and simultaneously increasing selenium and zinc intake, by substituting non-aromatic rice with aromatic rice in the diet. Watts and Parvez I. Haris. Biomedical Spectroscopy and Imaging Volume 1 / Issue 5. DOI: 1010.3233/BSI-120028.

Full text of the article has been made freely available at http://iospress.metapress.com/content/r81n381j34421481/fulltext.pdf

Keep up to date

## 34th SEGH International Conference: Geochemistry for Sustainable Development

Victoria Falls, Zambia

02 July 2018

## SubmitContent

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

## Science in theNews

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

• Fertilizer usage and cadmium in soils, crops and food 2018-06-23

### Abstract

Phosphate fertilizers were first implicated by Schroeder and Balassa (Science 140(3568):819–820, 1963) for increasing the Cd concentration in cultivated soils and crops. This suggestion has become a part of the accepted paradigm on soil toxicity. Consequently, stringent fertilizer control programs to monitor Cd have been launched. Attempts to link Cd toxicity and fertilizers to chronic diseases, sometimes with good evidence, but mostly on less certain data are frequent. A re-assessment of this “accepted” paradigm is timely, given the larger body of data available today. The data show that both the input and output of Cd per hectare from fertilizers are negligibly small compared to the total amount of Cd/hectare usually present in the soil itself. Calculations based on current agricultural practices are used to show that it will take centuries to double the ambient soil Cd level, even after neglecting leaching and other removal effects. The concern of long-term agriculture should be the depletion of available phosphate fertilizers, rather than the negligible contamination of the soil by trace metals from fertilizer inputs. This conclusion is confirmed by showing that the claimed correlations between fertilizer input and Cd accumulation in crops are not robust. Alternative scenarios that explain the data are presented. Thus, soil acidulation on fertilizer loading and the effect of Mg, Zn and F ions contained in fertilizers are considered using recent $$\hbox {Cd}^{2+}$$ , $$\hbox {Mg}^{2+}$$ and $$\hbox {F}^-$$ ion-association theories. The protective role of ions like Zn, Se, Fe is emphasized, and the question of Cd toxicity in the presence of other ions is considered. These help to clarify difficulties in the standard point of view. This analysis does not modify the accepted views on Cd contamination by airborne delivery, smoking, and industrial activity, or algal blooms caused by phosphates.

• Effects of conversion of mangroves into gei wai ponds on accumulation, speciation and risk of heavy metals in intertidal sediments 2018-06-23

### Abstract

Mangroves are often converted into gei wai ponds for aquaculture, but how such conversion affects the accumulation and behavior of heavy metals in sediments is not clear. The present study aims to quantify the concentration and speciation of heavy metals in sediments in different habitats, including gei wai pond, mangrove marsh dominated by Avicennia marina and bare mudflat, in a mangrove nature reserve in South China. The results showed that gei wai pond acidified the sediment and reduced its electronic conductivity and total organic carbon (TOC) when compared to A. marina marsh and mudflat. The concentrations of Cd, Cu, Zn and Pb at all sediment depths in gei wai pond were lower than the other habitats, indicating gei wai pond reduced the fertility and the ability to retain heavy metals in sediment. Gei wai pond sediment also had a lower heavy metal pollution problem according to multiple evaluation methods, including potential ecological risk coefficient, potential ecological risk index, geo-accumulation index, mean PEL quotients, pollution load index, mean ERM quotients and total toxic unit. Heavy metal speciation analysis showed that gei wai pond increased the transfer of the immobilized fraction of Cd and Cr to the mobilized one. According to the acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) analysis, the conversion of mangroves into gei wai pond reduced values of ([SEM] − [AVS])/f oc , and the role of TOC in alleviating heavy metal toxicity in sediment. This study demonstrated the conversion of mangrove marsh into gei wai pond not only reduced the ecological purification capacity on heavy metal contamination, but also enhanced the transfer of heavy metals from gei wai pond sediment to nearby habitats.

• Cytotoxicity induced by the mixture components of nickel and poly aromatic hydrocarbons 2018-06-22

### Abstract

Although particulate matter (PM) is composed of various chemicals, investigations regarding the toxicity that results from mixing the substances in PM are insufficient. In this study, the effects of low levels of three PAHs (benz[a]anthracene, benzo[a]pyrene, and dibenz[a,h]anthracene) on Ni toxicity were investigated to assess the combined effect of Ni–PAHs on the environment. We compared the difference in cell mortality and total glutathione (tGSH) reduction between single Ni and Ni–PAHs co-exposure using A549 (human alveolar carcinoma). In addition, we measured the change in Ni solubility in chloroform that was triggered by PAHs to confirm the existence of cation–π interactions between Ni and PAHs. In the single Ni exposure, the dose–response curve of cell mortality and tGSH reduction were very similar, indicating that cell death was mediated by the oxidative stress. However, 10 μM PAHs induced a depleted tGSH reduction compared to single Ni without a change in cell mortality. The solubility of Ni in chloroform was greatly enhanced by the addition of benz[a]anthracene, which demonstrates the cation–π interactions between Ni and PAHs. Ni–PAH complexes can change the toxicity mechanisms of Ni from oxidative stress to others due to the reduction of Ni2+ bioavailability and the accumulation of Ni–PAH complexes on cell membranes. The abundant PAHs contained in PM have strong potential to interact with metals, which can affect the toxicity of the metal. Therefore, the mixture toxicity and interactions between diverse metals and PAHs in PM should be investigated in the future.