If Ricin is mixed with a large amount of water, is it still harmful?

Yes, it isn't hard to get a lethal dose as some might think.The U.S. Centers for Disease Control (CDC) gives a possible minimum figure of 500 micrograms (about half a grain of sand) for the lethal dose of ricin in humans if exposure is from injection or inhalation. Ricin is poisonous if inhaled, injected, or ingested, acting as a toxin by the inhibition of protein synthesis. It is resistant, but not impervious, to digestion by peptidases. By ingestion, the pathology of ricin is largely restricted to the gastrointestinal tract where it may cause mucosal injuries; with appropriate treatment, most patients will make a full recovery.[2] Because the symptoms are caused by failure to make protein, they emerge only after a variable delay from a few hours to a full day after exposure. An antidote[3] and a vaccine[4] have been manufactured by military organizations. Symptomatic and supportive treatment is available. Long term organ damage is likely in survivors. Ricin causes severe diarrhea and victims can die of shock. It only takes a little and the symptoms can be easily misdiagnosed, and if the poisoning is minuscule then you could slowly be dying and not even know it. Hope I helped.