When director Cullen Hoback began work on his latest documentary, "What Lies Upstream," he hoped to find out why it took months for local officials in West Virginia to investigate chemically contaminated tap water.   But his initial investigation into chemically polluted drinking water in West Virginia soon expanded into a far-reaching analysis of local regulators’ inability, and in some cases unwillingness, to safeguard the people and resources they were entrusted to protect.