Capability of Paraguaçu estuary (Todos os Santos Bay, Brazil) to form oil–SPM aggregates (OSA) and their ecotoxicological effects on pelagic and benthic organisms

Abstract

For experiments concerning the formation of oil-suspended particulate matter (SPM) aggregates (OSA), oil and sediment samples were collected from Campos Basin and six stations of Paraguaçu estuary, Todos os Santos Bay, Brazil, respectively. The sediments samples were analyzed for organic matter determined by the EMBRAPA method, nitrogen determined by the Kjeldahl method, and phosphorus determined by the method described by Aspila. The oil trapped in OSA was extracted following the method described by Moreira. The experiment showed a relationship between the amount of organic matter and OSA formation and consequently the dispersion of the studied oil. On the basis of the buoyancy of OSA and the ecotoxicological effects on pelagic and benthic community, the priority areas for application of remediation techniques are Cachoeira, Maragogipe, and Salinas da Margarida because of the large amount of oil that accumulated at the bottom of the experiment flask (5.85%, 27.95%, and 38,98%; 4.2%, 17.66%, and 32.64%; and 11.82%, 8.07%, and 10.91% respectively).

Bioaccumulation of Polycyclic Aromatic Hydrocarbons (PAHs) by the Marine Clam, Mactra veneriformis, Chronically Exposed to Oil-Suspended Particulate Matter Aggregates

“…26−28 Furthermore, by being nearly neutrally buoyant, OSAs can be easily dispersed away from the oil-contaminated sites by tides and/or currents. 29 Although characteristics of OSAs formed under various environmental conditions have been well studied, 23,30−32 there have been few studies examining bioaccumulation and/or biodegradation of oil in the form of the OSAs, by microbial communities.…”

“…This is because oil droplets originating from spills usually become coated with fine, nonsticky organic particles as oil disperses. This type of aggregation enhances biodegradation because aggregates significantly increase oil–water contact areas, which maximizes accessibility of hydrocarbon-degrading bacteria and fungi to oil. − Furthermore, by being nearly neutrally buoyant, OSAs can be easily dispersed away from the oil-contaminated sites by tides and/or currents . Although characteristics of OSAs formed under various environmental conditions have been well studied, ,− there have been few studies examining bioaccumulation and/or biodegradation of oil in the form of the OSAs, by microbial communities.…”

The Role of Bacteria in the Formation and Migration of Oil–Particle Aggregates (OPAs) after Marine Oil Spills and the Associated Mechanism

“…In experimental groups, the mass concentrations of particles, YYS crude oil, and bacteria were 1500, 500, and 1500 mg/L (mass ratio 3:1:3) or 50, 500, and 50 mg/L (mass ratio 1:10:1), respectively. The particle concentration range used was that observed in the natural nearshore environment. ,,, A high particle concentration provides more opportunities for OPA formation, facilitates the fragmentation of oil droplets, and increases the amount of captured oil. ,,, For the control group (section 2 of the SI), the mass concentrations of particles and YYS crude oil were 1500 and 500 mg/L (mass ratio 3:1) or 50 and 500 mg/L (mass ratio 1:10), respectively. Three parallel experiments were set up for each sample.…”

Formation, Fate, and Impacts of Microscopic and Macroscopic Oil‐Sediment Residues in Nearshore Marine Environments: A Critical Review

“…Therefore, it is important to understand how OPA formation may affect sensitive organisms, especially in the benthic zone. OPA formation can also present risks to nektonic and planktonic organisms in the water column, although the risk to these organisms is of lesser concern than the risk to benthic organisms (Moreira et al, ; Rios et al, ).…”