What is the standard of review for environmental objections in the context of the exhaustion of administrative remedies?

been presented to the administrative agency. ... [Citation.] While "less specificity is required to preserve an issue for appeal in an administrative proceeding than in a judicial proceeding" ... generalized environmental comments at public hearings, relatively ... bland and general references to environmental matters' [citation], or isolated and unelaborated comment[s] [citation] will not suffice. The same is true for "[g]eneral objections to project approval. ..." [Citations.] [Citation.] "[T]he objections must be sufficiently specific so that the agency has the opportunity to evaluate and respond to them." '' ( Sierra Club v. City of Orange (2008) 163 Cal.App.4th 523, 535-536, 78 Cal.Rptr.3d 1.) "An appellate court employs a de novo standard of review when determining whether the exhaustion of administrative remedies doctrine applies." ( Id . at p. 536, 78 Cal.Rptr.3d 1.)