The use of long-chain alkylbenzenes and alkyltoluenes for fingerprinting marine oil wastes

Bacterial Diversity in Old Hydrocarbon Polluted Sediments of Ecuadorian Amazon River Basins

The Ecuadorian Amazon rainforest stands out as one of the world's most biodiverse regions, yet faces significant threats due to oil extraction activities dating back to the 1970s in the northeastern provinces. This research investigates the environmental and societal consequences of prolonged petroleum exploitation and oil spills in Ecuador's Amazon. Conducted in June 2015, the study involved a comprehensive analysis of freshwater sediment samples from 24 locations in the Rio Aguarico and Napo basins. Parameters such as water and air temperature, conductivity, soil pH, and hydrocarbon concentrations were examined. Total petroleum hydrocarbon (TPH) concentrations ranged from 9.4 to 847.4 mg kg-1, with polycyclic aromatic hydrocarbon (PAH) levels varying from 10.15 to 711.1 mg kg-1. The pristane/phytane ratio indicated historic hydrocarbon pollution in 8 of the 15 chemically analyzed sediments. Using non-culturable techniques (Illumina), bacterial analyses identified over 350 ASV, with prominent families including Comamonadaceae, Chitinophagaceae, Anaeromyxobacteraceae, Sphingomonadaceae, and Xanthobacteraceae. Bacterial diversity, assessed in eight samples, exhibited a positive correlation with PAH concentrations. The study provides insights into how microbial communities respond to varying levels of hydrocarbon pollution, shedding light on the enduring impact of oil exploitation in the Amazonian region. Its objective is to deepen our understanding of the environmental and human well-being in the affected area, underscoring the pressing need for remedial actions in the face of ongoing ecological challenges.

Marine biodegradation of crude oil in temperate and Arctic water samples

Despite increased interest in marine oil exploration in the Arctic, little is known about the fate of Arctic offshore oil pollution. Therefore, in the present study, we examine the oil degradation potential for an Arctic site (Disko Bay, Greenland) and discuss this in relation to a temperate site (North Sea, Denmark). Biodegradation was assessed following exposure to Oseberg Blend crude oil (100 mg L(-1)) in microcosms. Changes in oil hydrocarbon fingerprints of polycyclic aromatic hydrocarbons (PAHs), alkyl-substituted PAHs, dibenzothiophenes, n-alkanes and alkyltoluenes were measured by gas chromatography-mass spectrometry (GC-MS). In the Disko Bay sample, the degradation order was n-alkanes>alkyltoluenes (para->meta->ortho-isomers)>PAHs and dibenzothiophenes, whereas, the degradation order in the North Sea samples was PAHs and dibenzothiophenes>alkyltoluenes>n-alkanes. These differences in degradation patterns significantly affect the environmental risk of oil spills and emphasise the need to consider the specific environmental conditions when conducting risk assessments of Arctic oil pollution.

Characterizing shipboard bilgewater effluent before and after treatment

Operational discharges from oceangoing vessels, including discharges of bilgewater, release oil into marine ecosystems that can potentially damage marine life, terrestrial life, human health, and the environment. Bilgewater is a mix of oily fluids and other pollutants from a variety of sources onboard a vessel. If bilgewater cannot be retained onboard, it must be treated by an oily water separator before discharge for larger ocean-going vessels. We evaluated the effectiveness of bilgewater treatment systems by analyzing land-based type approval data, collecting and analyzing shipboard bilgewater effluent data, assessing bilgewater effluent concentrations compared to regulatory standards, evaluating the accuracy of shipboard oil content monitors relative to analytical results, and assessing additional pollution reduction benefits of treatment systems. Land-based type approval data were gathered for 20 treatment systems. Additionally, multiple samples of influent and effluent from operational bilgewater treatment systems onboard three vessels were collected and analyzed, and compared to the land-based type approval data. Based on type approval data, 15 treatment systems were performing below 5 ppm oil. Shipboard performance measurements verified land-based type approval data for the three systems that were sampled. However, oil content monitor readings were more variable than actual oil concentration measurements from effluent samples, resulting in false negatives and positives. The treatment systems sampled onboard for this study generally reduced the majority of other potentially harmful pollutants, which are not currently regulated, with the exception of some heavy metal analytes.