Tender: Water and Sediment Sampling and Laboratory Analysis for Hinkley Point C – Bridgwater Bay

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Cefas (BEEMS programme funded by NNB Generation Company (HPC) Limited) is seeking a supplier to deliver vessel-based marine water and sediment sampling, CTD and water-column profiling, and all required laboratory analyses for baseline monitoring adjacent to Hinkley Point C in Bridgwater Bay. The contract starts as soon as possible following award with an initial 12-month period and the option to extend by up to four further 12-month periods; the first survey is planned for summer 2026 with potential annual repeats. The supplier must acquire water samples at six stations (three near the cooling water outfall and three near the fish recovery and return outfall) with surface and near-bottom sampling across a full tidal cycle using niskin bottles and a multi-parameter sonde, conduct nominal hourly sampling over a 12-hour period (two vessel days for water sampling), and collect sediment using a Day grab from 20 stations in one day with A and B replicate sets. Hydrazine samples will be analysed by Cefas (Cefas will provide sampling equipment and SOPs and hazardous reagents for fixing), while the supplier must perform onboard Total Residual Oxidant (TRO) measurements using a CamLab CW1000 or equivalent with a detection limit of at least 0.02 mg/L and three replicates per sample. All laboratory analysis must meet the determinand list and minimum reporting requirements (Table 4) and be completed by an MMO-certified laboratory; the supplier will provide RAMS at least one month before the survey detailing sample acquisition, storage, shipping and laboratory requirements for agreement with Cefas.