51.   All that burning can threaten endangered species, water quality and clean air.

52.   But critics say that water quality will continue to decline, forcing the city to adopt filtration after all.

53.   But heavy demand on the delta has degraded water quality and led to a seemingly unending political struggle.

54.   But environmentalists note that the water quality in the Meadowlands has improved markedly since the garbage dumps were closed.

55.   But inside the widespread department bureaucracy, experts in water quality still sometimes do battle with engineers whose main concern is delivering water in quantity.

56.   But it succeeded in gaining attention for the problems in Grand Bois, and Foster soon ordered state agencies to begin monitoring air and water quality in the area.

57.   But it is no less threatening to water quality.

58.   But nutrients like phosphorus from such plants encourage algae growth and cloudiness, reducing water quality, said Goldstein.

59.   By implementing these recommended practices in and around their yards, these homeowners have had a positive impact upon water quality.

60.   By next spring the EPA expects to complete new guidelines for states on beach water quality.