ORIGINAL ARTICLE Removal of selected metals from drinking water using modified powdered block carbon V. Campos Æ I. J. Sayeg Æ P. M. Buchler Received: 13 February 2007 / Accepted: 18 September 2007 / Published online: 13 October 2007 Ó Springer-Verlag 2007 Abstract This paper presents the possible alternative removal options for the development of safe drinking water supply in the trace elements affected areas. Arsenic and chromium are two of the most toxic pollutants, introduced into natural waters from a variety of sources and causes various adverse effects on living bodies. Performance of three filter bed method was evaluated in the laboratory. Experiments have been conducted to investigate the sorp- tion of arsenic and chromium on carbon steel and removal of trace elements from drinking water with a household filtration process. The affinity of the arsenic and chromium species for Fe/Fe 3 C (iron/iron carbide) sites is the key factor controlling the removal of the elements. The method is based on the use of powdered block carbon (PBC), powder carbon steel and ball ceramic in the ion-sorption columns as a cleaning process. The PBC modified is a satisfactory and practical sorbent for trace elements (arse- nite and chromate) dissolved in water. Keywords Arsenite  Chromate  Activated carbon block  Modified  Drinking water Introduction As soils are increasingly used in the society for purposes other than agriculture, the frequency and extent of soil contamination by toxic trace elements also increases. Arsenic (As) is a metalloid element that has achieved great notoriety because of the toxic properties of a number of its compounds. Arsenic levels in soils (1–40 mg As kg –1 ) may be elevated due to mineralization, contamination from industrial activity, and the use of As-based pesticides and synthetic fertilizers (Sadiq 1997). According to Campos (2002), a study area showed that at a certain depth the arsenic has a gradual mobility down to the aquifer, but disappears below the water level, indicating specific removal from soil with groundwater contamination. Arsenic exposure is a potential health risk to local populations around gold mining areas in southeastern Brazil, where 20% of the total sample population showed elevated As con- centrations (2.2–106 lgl –1 ; Matschullat et al 2000). In the Iron Quadrangle region, the public water supply comes mainly from local watersheds. However, in some places the population uses spring water or groundwater from areas close to mines, for human consumption. The main natural sources of arsenic in the Iron Quadrangle come from rocks that contain lode gold deposits. The anthropic sources of As are contaminated refuse piles, soil, and sediments. It was found that total As concentration was 2,980 lgl –1 and As 3+ was 86 lgl –1 in water samples collected in underground gold mines, artesian wells, and springs in Ouro Preto and Mariana counties (Borba et al 2001). Speciation is important since mobility and toxicity of As(III) is supposed to be much higher than that of As(V). Chadha (2000) showed that As(III) is more prevalent in groundwater than As(V). The toxicity of such com- pounds decreases in the order: arsine [ arsenite [ arsenate [ alkyl arsenic acids [ arsenium compounds and metallic arsenic. Chromium is a naturally occurring element typically found in the US soils from 1 to 2,000 mg kg –1 , apart from V. Campos (&)  P. M. Buchler University of Sa ˜o Paulo, EPUSP, Rua Marie Nader Calfat, 351 apto 71 Evoluti, Morumbi, 05713-520 Sa ˜o Paulo, SP, Brazil e-mail: vcampos@usp.br I. J. Sayeg Institute of Geosciences, University of Sa ˜o Paulo, Sa ˜o Paulo, SP, Brazil 123 Environ Geol (2008) 55:1023–1028 DOI 10.1007/s00254-007-1051-9