Sex-Specific Differences in the Toxic Effects of Heavy Fuel Oil on Sea Urchin (Strongylocentrotus intermedius)

Effects of Benzo[a]pyrene on Food Metabolism and Reproductive Endocrine and Ovarian Development in Female Scallop Chlamys farreri at Different Reproductive Stages

Benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon (PAH) with the most carcinogenic effects of all the PAHs, has multiple toxic effects on marine bivalves. We investigated the interference mechanism of B[a]P on food metabolism (sugars, proteins, and sugars), and on reproductive endocrine and ovarian development in female scallops (Chlamys farreri). Scallops were exposed to different concentrations of B[a]P concentrations of 0, 0.38, 3.8, and 38 μg/L throughout gonadal development. Total cholesterol and triglyceride contents in the digestive glands were increased, and their synthesis genes were upregulated. The plasma glucose contents decreased with the inhibition of glycogen synthesis genes and the induction of glycolysis genes in the digestive gland. The results showed that B[a]P had endocrine-disrupting effects on scallops, that it negatively affected genes related to ovarian cell proliferation, sex differentiation, and egg development, and that it caused damage to ovarian tissue. Our findings supplement the information on B[a]P disruption in gonadal development of marine bivalves. Environ Toxicol Chem 2024;00:1-14. © 2023 SETAC.

Exposure of adult sea urchin Strongylocentrotus intermedius to stranded heavy fuel oil causes developmental toxicity on larval offspring

Heavy fuel oil (HFO) spills pose serious threat to coastlines and sensitive resources. Stranded HFO that occurs along the coastline could cause long-term and massive damage to the marine environment and indirectly affect the survival of parental marine invertebrates. However, our understanding of the complex associations within invertebrates is primarily limited, particularly in terms of the toxicity effects on the offspring when parents are exposed to stranded HFO. Here, we investigated the persistent effects on the early development stage of the offspring following stranded HFO exposure on the sea urchin Strongylocentrotus intermedius. After 21 d exposure, sea urchins exhibited a significant decrease in the reproductive capacity; while the reactive oxygen species level, 3-nitrotyrosine protein level, protein carbonyl level, and heat shock proteins 70 expression in the gonadal tissues and gametes significantly increased as compared to the controls, indicating that HFO exposure could cause development toxicity on offspring in most traits of larval size. These results suggested that the stranded HFO exposure could increase oxidative stress of gonadal tissues, impair reproductive functions in parental sea urchins, and subsequently impact on development of their offspring. This study provides valuable information regarding the persistent toxicity effects on the offspring following stranded HFO exposure on sea urchins.

Efficient and Fast Removal of Oils from Water Surfaces via Highly Oleophilic Polyurethane Composites

In this study we evaluated the oil adsorption capacity of an aliphatic polyurethane foam (PU 1) and two of its composites, produced through surface coating using microparticles of silica (PU-Si 2) and activated carbon (PU-ac 3). The oil adsorption capacity in diesel was improved up to 36% using the composite with silica and up to 50% using the composite with activated carbon with respect to the initial PU 1. Excellent performances were retained in gasoline and motor oil. The adsorption was complete after a few seconds. The process follows a monolayer adsorption fitted by the Langmuir isotherm, with a maximum adsorption capacity of 29.50 g/g of diesel for the composite with activated carbon (PU-ac 3). These materials were proved to be highly oleophilic for oil removal from fresh water and sea water samples. Regeneration and reuse can be repeated up to 50 times by centrifugation, without a significant loss in adsorption capacity.

Combined Effects of Elevated Temperature and Crude Oil Pollution on Oxidative Stress and Apoptosis in Sea Cucumber (Apostichopus japonicus, Selenka)

Currently, global climate change and oil pollution are two main environmental concerns for sea cucumber (Apostichopus japonicus) aquaculture. However, no study has been conducted on the combined effects of elevated temperature and oil pollution on sea cucumber. Therefore, in the present study, we treated sea cucumber with elevated temperature (26 °C) alone, water-accommodated fractions (WAF) of Oman crude oil at an optimal temperature of 16 °C, and Oman crude oil WAF at an elevated temperature of 26 °C for 24 h. Results showed that reactive oxygen species (ROS) level and total antioxidant capacity in WAF at 26 °C treatment were higher than that in WAF at 16 °C treatment, as evidenced by 6.03- and 1.31-fold-higher values, respectively. Oxidative damage assessments manifested that WAF at 26 °C treatment caused much severer oxidative damage of the biomacromolecules (including DNA, proteins, and lipids) than 26 °C or WAF at 16 °C treatments did. Moreover, compared to 26 °C or WAF at 16 °C treatments, WAF at 26 °C treatment induced a significant increase in cellular apoptosis by detecting the caspase-3 activity. Our results revealed that co-exposure to elevated temperature and crude oil could simulate higher ROS levels and subsequently cause much severer oxidative damage and cellular apoptosis than crude oil alone on sea cucumber.