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Nuclear contamination threatens seawaters : BEIJING - China's seawaters are at risk of being contaminated by radioactive materials coming from the Japanese nuclear power plant that was seriously damaged in the large earthquake that struck in March, China's ocean watchdog said.
The State Oceanic Administration's environmental protection department told China Daily that China will strengthen its monitoring for radioactive substances in the waters east of Fukushima, where the nuclear plant is, and in the East China Sea. By doing so, they hope to forecast what effect the radiation released by the plant will have on the marine environment and the safety of marine food.
The latest monitoring result released by the State Oceanic Administration on July 29 showed the first group of seawater samples collected from the area contained 300 times the amount of radioactive cesium that is found in nature and 100 times the amount of strontium. www.chinadaily.com.cn

www.rrjournal.org Elaine Ron, Jay H. Lubin, Roy E. Shore, Kiyohiko Mabuchi, Baruch Modan, Linda M. Pottern, Arthur B. Schneider, Margaret A. Tucker and John D. Boice, Jr. (1995) Thyroid Cancer after Exposure to External Radiation: A Pooled Analysis of Seven Studies. Radiation Research: March 1995, Vol. 141, No. 3, pp. 259-277. The thyroid gland of children is especially vulnerable to the carcinogenic action of ionizing radiation. To provide insights into various modifying influences on risk, seven major studies with organ doses to individual subjects were evaluated. Five cohort studies (atomic bomb survivors, children treated for tinea capitis, two studies of children irradiated for enlarged tonsils, and infants irradiated for an enlarged thymus gland) and two case-control studies (patients with cervical cancer and childhood cancer) were studied. The combined studies include almost 120,000 people (approximately 58,000 exposed to a wide range of doses and 61,000 nonexposed subjects), nearly 700 thyroid cancers and 3,000,000 person years of follow-up. For persons exposed to radiation before age 15 years, linearity best described the dose response, even down to 0.10 Gy. At the highest doses (>10 Gy), associated with cancer therapy, there appeared to be a decrease or leveling of risk. For childhood exposures, the pooled excess relative risk per Gy (ERR/Gy) was 7.7 (95% CI = 2.1, 28.7) and the excess absolute risk per <tex-math>$10^{4}\ {\rm PY}\ {\rm Gy}\ ({\rm EAR}/10^{4}\ {\rm PY}\ {\rm Gy})$</tex-math> was 4.4 (95% CI = 1.9, 10.1). The attributable risk percent (AR%) at 1 Gy was 88%. However, these summary estimates were affected strongly by age at exposure even within this limited age range. The ERR was greater (P = 0.07) for females than males, but the findings from the individual studies were not consistent. The EAR was higher among women, reflecting their higher rate of naturally occurring thyroid cancer. The distribution of ERR over time followed neither a simple multiplicative nor an additive pattern in relation to background occurrence. Only two cases were seen within 5 years of exposure. The ERR began to decline about 30 years after exposure but was still elevated at 40 years. Risk also decreased significantly with increasing age at exposure, with little risk apparent after age 20 years. Based on limited data, there was a suggestion that spreading dose over time (from a few days to >1 year) may lower risk, possibly due to the opportunity for cellular repair mechanisms to operate. The thyroid gland in children has one of the highest risk coefficients of any organ and is the only tissue with convincing evidence for risk at about 0.10 Gy. So, lilly, do we have a method for conversion from 0.10 Gy into units that are being more commonly used in the Tepco or GoJ "information" releases?

www3.cancer.gov this is the link for the entire pdf article from below Thyroid Cancer after Exposure to External Radiation: A Pooled Analysis of Seven Studies. Radiation Research: March 1995

0.10 Gy = 0.10 Sv = 100 mSv = 1000 uSv, for X-ray, Gamma ray or beta radiaton
0.10 Gy = 2.00 Sv, for alpha particles