Occurrence of the marine antifouling agent irgarol 1051 within the Plymouth Sound locality: Implications for the green macroalga Enteromorpha intestinalis

Abstract

Water samples taken from the Plymouth Sound locality were analysed for the presence of the s-triazine herbicide Irgarol 1051, which is an ingredient of antifouling paints used on pleasure boats and ships. Irgarol 1051 was detected at all sampling sites within the Sound; the highest levels were found in close proximity to areas of high boat density, especially where water flow was restricted within marinas. Concentrations within the semi-enclosed Sutton Harbour were less than values predicted from leach rate data. The highest detected concentration of over 120 ng dm −3 significantly inhibited the growth of Enteromorpha intestinalis spores under laboratory conditions; the no effect concentration was 22 ng dm −3. Photosynthetic efficiency in the adult frond of E. intestinalis from Sutton Harbour marina was inhibited by Irgarol 1051 in the laboratory with an EC 50 (72 h) of 2.5 |Gmg dm −3. A small adverse impact on E. intestinalis reproduction within the harbour is therefore likely. More polluted sites identified elsewhere in Europe will suffer proportionally greater impact.