Radionuclide contents in sediment and seafood from Makoko Lagoon, Lagos State, Nigeria.

Sediment and seafood samples were collected from Makoko Lagoon, Lagos state, Nigeria. Gamma-ray spectrometry was used to determine the activity concentrations of 40K, 226Ra and 232Th in the samples. The average activity concentrations of 40K, 226Ra and 232Th in the sediment were 41.04 ± 6.41, 10.15 ± 3.19 and 4.39 ± 2.10 Bq kg-1, respectively, while the annual effective dose was 0.01 mSv/year. In seafood, the average activity concentrations of 40K, 226Ra and 232Th were 15.66 ± 8.07, 1.72 ± 1.51 and 1.93 ± 0.30 Bq kg-1, respectively. The cumulative effective ingestion dose obtained ranged from 0.016 µSv/year (giant prawn) to 1.08 µSv/year (Parrotgrunt). The mean activity concentrations and absorbed dose rate in sediment were below the worldwide average values. The cumulative dose from the ingestion of seafood was also significantly low. Sediment and seafood from the lagoon in Makoko pose no health risk from a radiological point of view to the population.

Occupational Radiation Exposure to the Extremities of Medical Staff during Hysterosalpingography and Radionuclide Bone Scan Procedures in Several Nigerian Hospitals.

OBJECTIVE: The practice of regular dose measurement helps to ascertain the level of occupational dose delivered to the staff involved in diagnostic procedures. This study was carried out to evaluate the dose exposed to the hands of radiologists and a radiologic technologist carrying out HSG and radionuclide bone scan examinations in several hospitals in Nigeria. METHODS: Radiation doses exposed to the hands of radiologists and a technician carrying out hysterosalpingography (HSG) and bone scan procedures were measured using calibrated thermo-luminescent dosimeters. Five radiologists and a radiologic technologist were included in the study for dose measurement. RESULTS: The study indicates that each radiologist carried out approximately 2 examinations per week with the mean dose ranging between 0.49-0.62 mSv per week, resulting in an annual dose of 191 mSv. Similarly, the occupational dose delivered to both the left and right hands of a radiologic technologist administering 99mTc-methylene diphosphonate (MDP) without cannula and with cannula were 10.68 (720.2) and 13.82 (556.4) mSv per week (and per annum), respectively. It was determined that the left hand of the personnel received higher doses than their right hand. CONCLUSION: The estimated annual dose during HSG is far below the annual dose limit for deterministic effects, however, it is greater than 10% of the applicable annual dose limit. Hence, routine monitoring is required to ensure adequate protection of the personnel. The total annual dose received during the bone scan exceeds the annual dose limit for both hands, and the dose to either left or right hand is greater than the dose limit of 500 mSv/yr. The radiologists monitored are not expected to incur any deterministic effects during HSG examinations, however, accumulated doses arising from the scattered radiation to the eyes, legs, and neck could be substantial and might lead to certain effects. More staff are required to administer 99mTc-MDP in Nigerian institutions to prevent excessive doses to personnel.