Occurrence of alkylphenols and alkylphenol mono- and diethoxylates in natural waters of the Laurentian Great Lakes basin and the upper St. Lawrence River

Nonylphenol and its ethoxylates are on the second priority substances list (PSL2) to determine if they are ‘toxic’ as defined under the Canadian Environmental Protection Act. This study addresses the need for data on their occurrence in surface waters and sediments in Canada. Samples of surface water from 35 sites in the Laurentian Great Lakes basin and the upper St. Lawrence River were analyzed for 4-nonylphenol (4-NP), nonylphenol ethoxylate (NPE1), nonylphenol diethoxylate (NPE2) and 4-tert-octylphenol (4-t-OP). Bottom sediment samples from nine heavily industrialized sites were also analyzed for the same chemicals. Measurable quantities of 4-NP and 4-t-OP were found in 24% of all water samples. Values ranged from <0.010 μg to 0.92 μg/l and from <0.005 to 0.084 μg/l for 4-NP and 4-t-OP, respectively. Of the surface water samples, 58% were found to contain NPE1 and 32% contained NPE2. Their concentrations ranged from <0.020 to 7.8 μg/l for NPE1 and from <0.020 to 10 μg/l for NPE2. All nine sediment samples contained 4-nonylphenol, with values ranging from 0.17 to 72 μg/g (dry weight). The majority of sediment samples also contained detectable levels of the other contaminants. A total of 66% of sediments had detectable amounts of NPE1 and concentrations ranged from <0.015 to 38 μg/g (dry weight), 66% of sediments had detectable amounts of NPE2 and values ranged from <0.015 to 6.0 μg/g (dry weight) and 89% of sediment samples had detectable amounts of 4-t-OP and values ranged from <0.010 to 1.8 μg/g (dry weight). The highest concentrations of the analytes found are well below acute toxicity thresholds, but in some cases there may be cause for concern with regard to long-term effects on reproductive health of fish.