Sevenhills Wholefoods Spirulina powder is sourced from an island in the South China Sea, in an environmentally pristine area, far from industrial activity. Our spirulina is harvested in freshwater cultivation ponds, under strict conditions of purity, with our supplier taking great care in the manufacturing of this micro-algae. Every batch undergoes a heavy metal test at the production facility and the UK port health authorities check for radiation for any products they deem at risk or have potential for exposure as well.