Ecological risk of Irgarol 1051 and its major metabolite in coastal California marinas and reference areas

• Published in: Marine pollution bulletin 2009-05, Vol.58 (5), p.702-710
• Main Authors: Hall, Lenwood W., Killen, William D., Anderson, Ronald D., Balcomb, Richard, Gardinali, Piero
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Antifouling paint; Applied ecology; Biological and medical sciences; California; California marinas; Ecological risk; Ecotoxicology, biological effects of pollution; Environmental Monitoring; Fresh Water; Fundamental and applied biological sciences. Psychology; Inhibitory Concentration 50; Irgarol; Lethal Dose 50; Marine; Marine and brackish environment; Pacific Ocean; Plants - drug effects; Sea water ecosystems; Seawater - chemistry; Synecology; Triazines - analysis; Triazines - chemistry; Triazines - toxicity; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2008.12.019

The objective of this study was to use a probabilistic approach to determine the ecological risk of Irgarol and its major metabolite (GS26575) in coastal California marinas and reference areas by using monitoring data collected during the summer of 2006. Distributions of environmental exposure data were compared with the distribution of plant species response data from laboratory toxicity studies and the no observed effect concentration (NOEC) from a microcosm study to quantify the likelihood and significance of ecological risk. Toxicity testing indicates plants are much more sensitive to Irgarol than animals; therefore, the conservative effects benchmark used to characterize risk was the plant 10th centile for both Irgarol (193 ng/L) and GS26575 (5622 ng/L). In addition, the microcosm NOEC of 323 ng/L was also used to characterize risk. Irgarol concentrations from 15 California marinas ranged from 1.45 to 339 ng/L while GS26575 concentrations ranged from non-detected to 74 ng/L. The probability of exceeding the Irgarol plant 10th centile of 193 ng/L for 15 marinas sampled in coastal California in 2006 was 7.3% while the probability of exceeding the microcosm NOEC of 323 ng/L was even lower (5.5%). In general, this probability of exceedence for either effects benchmark and subsequent ecological risk is considered to be low for these marinas as only one marina (Kings Harbor marina in Redondo Beach) had measured concentrations of Irgarol exceeding 193 ng/L. Irgarol exposure is concentrated within marinas and ecological risk from Irgarol exposure in adjoining reference areas was judged to be very low. Ecological risk from GS26575 exposure was also low in both marina and reference areas in California.