In most cases, when the remaining population is removed, most of the main threat [from contaminated water] should decrease, ... are much more persistent and may leave a residue of problems after the water recedes, especially in some areas.
"Robert Pitt" was a Kingdom of Great Britain/British politician who sat as Member of Parliament for Old Sarum (UK Parliament constituency)/Old Sarum from 1705, a pocket borough controlled by his family. He was the eldest son of Governor Thomas 'Diamond' Pitt, a businessman who had made a fortune while in India. Governor Pitt built the family's wealth on his acquisition of the Regent Diamond/Pitt Diamond which he then sold on for a large profit. The diamond was brought into Britain in the heel of Robert Pitt's boot. Unlike the rest of his family, who were Whigs, Robert Pitt became a Tory possibly partly in resistance to his domineering Whig father.
Pitt married Harriet Villiers, the daughter of Edward Villiers-FitzGerald and the Kingdom of Ireland/Irish Beneficiary/heiress Katherine FitzGerald, Viscountess Grandison/Katherine FitzGerald.
Robert Pitt is best known for being the father of William Pitt the Elder, a British statesmen who led the country three times between 1756–57, 1757–62 and 1766–68. Another son Thomas Pitt of Boconnoc/Thomas Pitt was also an MP who sat for Okehampton (UK Parliament constituency)/Okehampton. He was also brother-in-law to General James Stanhope, through his sister Lucy Pitt. His grandson William Pitt the Younger became Prime Minister in 1783.More Robert Pitt on Wikipedia.