The Sylheti rice also contained higher levels of the essential nutrients selenium and zinc, according to a study published in the journal Biomedical Spectroscopy and Imaging.
Rice is the main staple in Bangladesh, where a study published in The Lancet in 2010 found that as many as 77 million people out of a population of some 160 million may have been exposed to toxic levels of arsenic in contaminated ground water.
The UN's World Health Organisation has called the country's arsenic crisis "the largest mass poisoning of a population in history".
Under a 1970's campaign to provide villagers with clean, germ-free water, millions of wells were dug -- unfortunately many of them into soil heavily laced with naturally occurring arsenic.
Chronic exposure to arsenic is linked to cancers of the liver, kidney, bladder and skin, as well as heart disease.
Rice is highly efficient at absorbing arsenic from soil and water, and is reported to be the highest arsenic-containing cereal, said the latest report.
Compared to several other regions of Bangladesh already tested, rice from the greater Sylhet region had lower arsenic levels. The arsenic content dropped even lower in aromatic strains of the grain such as Basmati or Jasmine, than in non-aromatic types.
The region includes areas around the settlements of Sylhet, Moulvibazar and Habiganj and has lower arsenic concentrations in its groundwater, wrote the team from Britain and Libya.
"For someone consuming 500g (1.1 pounds) of non-aromatic or aromatic rice from Sylhet, the daily intake of As (the chemical symbol for arsenic) from consumption of rice would be reduced by approximately 48 percent and 69 percent, respectively, compared to non-aromatic rice from other parts of Bangladesh thus far investigated," the scientists said.
Half-a-kilogramme is the average daily consumption per person.
"Also the daily intake of As from consumption of aromatic rice is 40 percent lower compared to non-aromatic rice sourced from the Sylhet region," said the team.
This may be due to a genetic difference, but further research is needed.
Study co-author Parvez Haris from the De Montfort University in Leicester, England, said the study offers good news.
"Consumption of certain types of aromatic rice will not only reduce human exposure to arsenic, but will also increase their intake of zinc and selenium," he said.
Bangladeshis generally are deficient in zinc and selenium.
Sylhet is one of Bangladesh's top rice-producing regions, Haris told AFP.
"Unfortunately, there is no labelling requirement for arsenic content in rice. That is an issue that needs to be addressed."