Identification of toxicants from a highly C10–C40‐contaminated sediment influenced by the wood industry: Petroleum hydrocarbons or biogenic organic compounds?

Sediment from a log pond located in south Finland contained 15 000 to 50 000 mg/kg dry weight of C₁₀–C₄₀ hydrocarbons. It was unclear whether they originated from the hydraulic fluid of the log hoist or the wood extractives. In the present study, methods of effect‐directed analysis were used for the identification of toxicants. A combination of fractionation, biotesting, and chemical analyses revealed that the key toxicant of log pond sediment was retene, a dialkyl‐substituted phenanthrene derived from wood resin acids. In addition, the most toxic fraction included 3 other wood‐originated diterpenic compounds. Typical wood extractives such as sesquiterpenes and odd–carbon number alkanes in the range C₂₁–C₃₃ were identified in the fraction, which showed minor genotoxic potency. The most polar fraction contained triterpenes and showed estrogenic activity. No evidence for the presence of hydraulic fluid in sediment was found. The study also indicated that in cases where the organic matter content of sediment or soil is high, using the results of standard mineral oil analysis in risk management can lead to incorrect actions because standard methods do not differentiate petroleum hydrocarbons from biogenic hydrocarbons. Environ Toxicol Chem 2019;9999:1–11. © 2019 SETAC