Just a month after human remains were turned up during renovations of Holden Chapel, testing has revealed that the site is contaminated by arsenic, environmental experts said this week.

The results of tests confirming presence of the substance--which were completed last Friday--caused concern and discontent among college officials.

"Even though I was one of the people who suggested they test for arsenic, and knew there could be arsenic, I am so very disappointed that they did indeed find arsenic," said Associate Professor of Anthropology Carole A.S. Mandryk, who gathered a team to excavate the artifacts.

Mandryk recommended the tests after she discovered that the basement was used by the Medical School in the early 1800's as a dissecting lecture hall.

Before beginning the excavation yesterday, the archaeologists underwent medical evaluations.

Extensive training in health precautions and suited up in full hazardous materials suits and respiratory masks while digging.

"Basically we're not supposed to breath the air or let anything touch our skin," said Rachel E. Sexton '00, an anthropology student who was overseeing the renovations.

Sexton was asked to oversee the site in case anything interesting turned up. When workers found the bones, they immediately called her to identify them.

She said despite the uncomfortable environment and the safety procedures, the dig has been progressing nicely.

"It went well, considering the conditions," she added.

"We've all been through an amazing amount of medical evaluation and training," Mandryk said.

The dig is the latest in a series of excavations in and around the Yard. Some of the others, including the most recent, a dig behind Wadsworth House completed in June, have also turned up artifacts of student life.

But according to Mandryk--who estimated that excavations will be finished today--the Holden Chapel site could give archaeologists the first clear look at academic life at Harvard in the early 19th century.

The discoveries are also expected to delay the building's reopening.

Renovations of the chapel basement were due to be complete before classes started in September, but Michael N. Lichten, director of the Office of Physical Resources in the Faculty of Arts and Sciences, said the dig, could set the renovations back at least three weeks.