Study of arsenic contents in soil , food and biomatrix by neutron activation analysis technique

Abstract

Neutron activation analysis (NAA) technique has been applied for the ~tudy of arsenic contents in soil, food (rice and vegetables) and human hair samples collected from different regions of Bangladesh. Some water and sediment samples were also anaJ)?ed. The samples were analyzed at Institute ofNuc1ear Science and Technology (INST), Sayar, Dhaka, Bangladesh and Pakistan T[l~lillLleof Nuclear Science and Technology (PINSTECH), Islamabad, Pakistan using TRIUi\ Mark-II, PARR-J and PARR-II research reactors. For the prc<;cnt work, th~ silmples were collected [rom some unaffected. moderately affected and highly affected areas of Bangladesh. Selected unaffected area~ arc again some parts of Goainghat, Companiganj and Sylhct sadar upazilas of Sylhct district and Sayar upazila, Dhaka. From unaffected areas samples of water, topsoil, sediment, rice and hrunan hair were collected and analyzed. Companiganj upazila ,vas fonnd to be a modcrately affected area. Eighteen water samples of this area were analyzed to iind the level of arsenic pollution using atomic absorption spectrometry for convenience. Soil, ricc. vegetables and brunan hair sample~ ofthcsc areas "'ere aL~oanalyzed. Kachua and faridganj npazilas under Chandpur district: Damurhuda upazila under Chuadanga district and Lohajang upazila under Munshiganj district were found to be highly arsenic affected areas. Thirteen undisturbed sediment samples ofKachua upa/ila wcre analyzed for arsenic, iron and manganese concentrations Soil, rice, vegetables and human hair of these area:. \\'ere also analyzed. The unaffected (water arsenic below 50 f-lgIL),moderately affected (water arsenic greater than 50 flglL and less than IO() jlgiL) and highly affected areas (water arsenic greater than 100 f-lg/L)have been gradcd on the basis of limits given by some NGO's (:K'GO Forum, BRAC, Grameen Bank etc.) and other groups working in Bangladcsh. Arsenic and iron were found to be positIvely correlated in all kinds of matrices, No correlation wa~ found between arsenic and manganese; belween water arsenic and hair arsenic, and also between soil arsenic and ar:.enie in rice grain. However, sometimcs negative correlation was found between arsenic and manganese in sample matrices, In the present investigation no evidence was found about arsenic pollution of rice beyond perrni~sible level. Similarly. among vegetables only arum samples contain - arsenic, which contain, both inorganic and organic arsenic. Some of organic spcdes are less harmful for human health. Most oj"the soil, of llangladesh contain les~ than 10 ppm arsenic except Lohajang ~oiI. PeopJe living in arsenic affected areas have arsenic concenrratlOn in hair as high a~ 50 ppm; whereas, hair arsenic in unaffected areas is less than J ppm.