BOSTON (AP) — Health officials in Massachusetts are reporting that no radiation has been discovered in a dozen reservoirs, ponds and rivers that serve as sources of drinking water across the state.

The surface water was tested after officials detected very low concentrations of radioiodine-131 in a single sample of rainwater.

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That radiation was likely from the Japanese power plant severely damaged by the earthquake and tsunami. Officials said it did not pose a health risk.

Officials said the latest testing was conducted as a precaution.

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The surface water testing was completed in addition to analyses of raw drinking water samples from the Quabbin and Wachusett reservoirs, which also showed no detectable levels of I-131.

The state is continuing to collect and analyze weekly samples of raw drinking water from the two reservoirs.

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