title: Observations on the effects of barite on the gill tissues of the suspension feeder Cerastoderma edule (Linné) and the deposit feeder Macoma balthica (Linné).
abstract: Barite, an important component of offshore drilling muds, is shown to adversely affect the ctenidia of the suspension feeding bivalve, Cerastoderma edule and the deposit feeder, Macoma balthica. SEM observations showed that exposure to barite caused cilia to shorten and coagulate, and, in some extreme cases, cause the disintegration of the gill structure itself. Using a simple ciliary condition index (CCI) the impact of the barite was quantified and damage rates expressed. The bivalves were treated with daily doses of 1, 2, and 3-mm depth equivalents of barite. In all treatments significant damage to the gills was recorded although, in the case of the 1-mm dose rate, this did not occur for 4 days. In the other two treatments, damage was apparent within a day of exposure with 100% mortality occurring within 12 days. Macoma balthica appeared slightly more tolerant of exposure to barite than C. edule.
authors.affiliation: Department of Biological Sciences, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Barlow
authors.forename: P F
authors.initials: PF
authors.lastname: Kingston
mesh_terms: D000818:Animals; D001466:Barium Sulfate / Q000009:adverse effects*; D002923:Cilia / Q000473:pathology; D003287:Contrast Media / Q000009:adverse effects*; D004305:Dose-Response Relationship, Drug; D005880:Gills / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D007221:Industry; D008855:Microscopy, Electron, Scanning; D008974:Mollusca / Q000502:physiology*; D010578:Petroleum; D014873:Water Pollutants / Q000009:adverse effects*
chemical_list: D003287:Contrast Media; D010578:Petroleum; D014873:Water Pollutants; D001466:Barium Sulfate