elahe zallaghi khouzestan sciences and research islamic azad university, ahvaz, ir iran gholamreza goudarzi environmental technologies research center, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of environmental health engineering, school of public health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran sahar geravandi islamic azad university, tehran medical sciences branch, tehran, ir iran mohammad javad mohammadi department of environmental health engineering, school of public health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran; department of environmental health engineering, school of public health, ahvaz jundishapur university of medical sciences, ahvaz, ir iran. tel: +98-9355439707, fax: +98-6113361544