Cl. Maxon et al., SEDIMENT CONTAMINANTS AND BIOLOGICAL EFFECTS IN SOUTHERN CALIFORNIA -USE OF A MULTIVARIATE STATISTICAL APPROACH TO ASSESS BIOLOGICAL IMPACT, Environmental toxicology and chemistry, 16(4), 1997, pp. 775-784
This study attempts to predict biological toxicity and benthic communi
ty impact in sediments collected from two southern California sites. C
ontaminant concentrations and grain size were evaluated as predictors
using a two-step multivariate approach. The first step used principal
component analysis (PCA) to describe contamination type and magnitude
present at each site. Four dominant PC vectors, explaining 88% of the
total variance, each corresponded to a unique physical and/or chemical
signature. The four PC vectors, in decreasing order of importance, we
re: (1) high molecular weight polynuclear aromatic hydrocarbons (PAH),
most likely from combusted or weathered petroleum; (2) low molecular
weight alkylated PAH, primarily from weathered fuel product; (3) low m
olecular weight nonalkylated PAH, indicating a fresh petroleum-related
origin; and (4) fine-grained sediments and metals. The second step us
ed stepwise regression analysis to predict individual biological effec
ts (dependent) variables using the four PC vectors as independent vari
ables. Results showed that sediment grain size alone was the best pred
ictor of amphipod mortality. Contaminant vectors showed discrete depos
itional areas independent of grain size. Neither contaminant concentra
tions nor PCA vectors were good predictors of biological effects, most
likely due to the low concentrations in sediments.