Role of filtration in managing the risk from Cryptosporidium in commercial swimming pools - a review.

Most commercial swimming pools use pressurised filters, typically containing sand media, to remove suspended solids as part of the water treatment process designed to keep water attractive, clean and safe. The accidental release of faecal material by bathers presents a poorly quantified risk to the safety of swimmers using the pool. The water treatment process usually includes a combination of maintaining a residual concentration of an appropriate biocide in the pool together with filtration to physically remove particles, including microbial pathogens, from the water.

Transpiration and water relations of poplar trees growing close to the water table.

Sap flow was measured on five branches of two poplar (Populus trichocarpa Torr. & A. Gray x P.