title: Haematological parameters as predictors of blood lead and indicators of lead poisoning in the black duck (Anas rubripes).
abstract: The validity of various haematological parameters as indicators of blood lead concentration and lead poisoning in the black duck (Anas rubripes) is discussed. Elevated (> 40 microg dl(-1)) blood lead (PbB) levels were recorded in 41% of the 229 wild birds examined. No correlation was found between PbB concentration and haematocrit. Zinc protoporphyrin (ZPP) was positively correlated with PbB. Haemoglobin, delta-aminolevulinic acid dehydratase (ALA-d) activity and non-activated/activated ALA-d ratios were negatively correlated with PbB. The minimum PbB levels at which these parameters were affected varied greatly. ZPP and haemoglobin were relatively insensitive to PbB concentrations; whilst ALA-d activity and ALA-d ratio were influenced by PbB concentrations of < 5 microg dl(-1). Log(10) ALA-d ratio was more strongly correlated with PbB (r = -0.953) than log(10) ALA-d activity (r = -0.914) and the predictive validity (% false -ve and +ve predictions) of the ratio method was higher. The high individual variability in ALA-d activities at low PbB levels was greatly reduced by the use of the ALA-d ratio method. The ALA-d ratio method proved the most efficient for screening black duck for lead poisoning in the field.
authors.affiliation: Edward Grey Institute, Department of Zoology, South Parks Road, Oxford, UK.
authors.forename: D J
authors.initials: DJ
authors.lastname: Pain