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Risk assessment of the National Institute of Standards and Technology petroleum crude oil standard water accommodated fraction: Further application of a copepod‐based, full life‐cycle bioassay
Author(s) -
Bejarano Adriana C.,
Chandler G. Thomas,
He Lijian,
Cary Tawnya L.,
Ferry John L
Publication year - 2006
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/05-365r.1
Subject(s) - copepod , bioassay , biology , hatching , zoology , seawater , toxicology , fishery , ecology , crustacean
The U.S. National Institute of Standards and Technology (NIST) petroleum crude oil was used to generate NIST water‐accommodated hydrocarbon fractions (WAFs) for standardized assessment of crude oil effects on the copepod Amphiascus tenuiremis. Effects were assessed using a 96‐well microplate, full life‐cycle test. Briefly, nauplii (age, 24 h) were reared individually to adults ( n ≥ 120 nauplii/treatment) in microplate wells containing 200 μl of treatment solution (seawater control [0%] or 10, 30, 50, or 100% NIST‐WAF). Nauplii were monitored through development to adulthood, and mature virgin male:female pairs mated in wells containing original treatments (<30 d). A second bioassay using 0, 10, 30, and 50% WAFs ( n ≥ 60 nauplii/treatment) was conducted to assess the effects of ultraviolet (UV) light on naupliar endpoints (<16 d). In the first experiment, nauplius‐to‐copepodite survival in exposures to 100% WAF was 27% ± 6% lower than in controls (92% ± 1%), but copepodite‐to‐adult survival was greater than 90% across all treatments. Analysis of development curves showed that nauplii in the 10% WAF developed into copepodites 25% faster, whereas nauplii in the 50 and 100% WAFs developed 17% slower, than controls. Copepodite development into male and female copepods was significantly delayed (2 and 4 d, respectively) in the 100% WAF compared to controls. Although none of the WAF exposures had significant effects on fertilization success or total viable production ( p > 0.05), embryo hatching in the 100% WAF was significantly less (70.0% ± 21.2%) than that in controls (87.0% ± 19.4%). Results from the UV bioassay showed that relatively short exposures (<14 d) to 30 and 50% WAFs in the presence of UV light caused negative effects on copepod survival and development. Naupliar‐stage survival and developmental endpoints were the most sensitive indicators of exposure to the NIST crude oil WAF.