Some PAH are known to be potent carcinogens and this class of contaminants is therefore given high priority for environmental pollution regulation and in risk assessment of industrial discharges. Ecotoxicological issues related to PAH have been investigated in detail for many years and have been reported selleck chemicals in a high number of scientific papers and reviews. PAHs may cause e.g. DNA damage (Aas et al., 2000a) oxidative stress (Sturve et al., 2006), cardiac function defects (Incardona

et al., 2004), or embryotoxicity (Carls et al., 2008). Fish growth may be affected by aryl hydrocarbon receptor (AhR) agonists such as PAHs (Carls et al., 2005). Some PAHs may form DNA adducts and neoplasia in fish liver through metabolic intermediates (Myers et al., 1991). A recent overview of biological effects of aromatic hydrocarbons and oil hydrocarbons has been published by AMAP (2010). Alkyl phenols (AP) have created the greatest concern due to their documented

hormone-disrupting effects (e.g. Arukwe et al., 2000, Arukwe et al., 2001, Nimrod and Benson, 1996 and Soto et al., 1991). Phenol and AP are both hazardous and toxic and can cause a range of biological effects (Priatna et al., 1994). ABT-263 molecular weight In 2012 the total amount of phenol and C1–C9 AP discharged on the NCS was 206 and 316 tons respectively. Naphthenic acids, another constituent of PW, have been reported to function as xeno-estrogens (Thomas et al., 2009). In 2012 the total amount of naphtenic acids discharged was 96 tons. In 2012 concentration of phenol in PW discharged from different mafosfamide installations on the NCS varied between 0.004 and 41 mg L−1 and for C1–C9 AP between 0.1 and 23 mg L−1. C1–C3 APs dominate,

with lower levels of C4–C6 AP and very low levels of C7–C9 AP. Other publications have shown that concentrations of total AP typically vary between 0.6 and 10 mg L−1 with phenol plus C1–C3 APs constituting more than 95% (Boitsov et al., 2007, Brendehaug et al., 1992, Røe, 1998 and Utvik, 1999). Metals in PW include arsenic, cadmium, copper, chromium, lead, mercury, nickel and zinc. In the 2012 reports for all PW discharges on the NCS (http://www.norskoljeoggass.no/no/Publikasjoner/Miljorapporter/Miljorapport-2013/Feltspesifikke-utslippsrapporter-20121/) the highest levels of lead, mercury and zinc were more than a factor 1000, and arsenic and cadmium more than a factor 100 above Norwegian coastal water background levels. The highest concentration reported for arsenic, cadmium, copper, and lead was from one low volume PW source from a gas and condensate field. If these values are excluded the levels of all metals except mercury were a factor <100 above naturally levels in seawater. Barium and iron are also exceeding background concentrations in seawater (by a factor more than 1000). In 2012 the concentration range for barium was 0.0017–1100 mg L−1 and for iron 0.8–75 mg L−1. The highest values are far above the solubility of these elements in seawater.