Microplastics pollution is a global paradigm that raises concern in relation to environmental and human health. This study investigated toxic effects of microplastics and mercury in the European seabass (Dicentrarchus labrax), a marine fish widely used as food for humans. A short-term (96 h) laboratory bioassay was done by exposing juvenile fish to microplastics (0.26 and 0.69 mg/L), mercury (0.010 and 0.016 mg/L) and binary mixtures of the two substances using the same concentrations, through test media. Microplastics alone and mercury alone caused neurotoxicity through acetylcholinesterase (AChE) inhibition, increased lipid oxidation (LPO) in brain and muscle, and changed the activities of the energy-related enzymes lactate dehydrogenase (LDH) and isocitrate dehydrogenase (IDH). All the mixtures caused significant inhibition of brain AChE activity (64–76%), and significant increase of LPO levels in brain (2.9–3.4 fold) and muscle (2.2–2.9 fold) but not in a concentration-dependent manner; mixtures containing low and high concentrations of microplastics caused different effects on IDH and LDH activity. Mercury was found to accumulate in the brain and muscle, with bioaccumulation factors of 4–7 and 25–40, respectively. Moreover, in the analysis of mercury concentrations in both tissues, a significant interaction between mercury and microplastics was found. The decay of mercury in the water increased with microplastics concentration, and was higher in the presence of fish than in their absence. Overall, these results indicate that: microplastics influence the bioaccumulation of mercury by D. labrax juveniles; microplastics, mercury and their mixtures (ppb range concentrations) cause neurotoxicity, oxidative stress and damage, and changes in the activities of energy-related enzymes in juveniles of this species; mixtures with the lowest and highest concentrations of their components induced different effects on some biomarkers. These findings and other published in the literature raise concern regarding high level predators and humans consuming fish being exposed to microplastics and heavy metals, and highlight the need of more research on the topic.
Pollution and Marine Debris
The topic of Micro(nanoplastics) in the marine environment is attracting attention because of their potential impact in sea organisms and humans. There are several sources of Micro (nanoplastics) such as micro and nanoparticle production or fragmentation off bigger plastics. Nanoplastics can have a bigger capacity to concentrate toxic compounds either associated with its production or sorbed from the environment has not been extensively evaluated. Indications suggest that nanoplastics carry more toxics than microplatics (more than million times than seawater). These nanoplastics can also carry microorganisms. There is no harmonization of methodologies for sampling and analysis of micro(nanoplastics) and there are limits in the accuracy of sizes of these particles that can be detected. Calculation of their possible concentrations in the environment is biased by the analytical instrumentation. This paper summarizes the knowledge gaps in the analysis and repercussions of micro(nanoplastics) in the environment and organisms.
Marine pollution due to littering from anthropogenic activities is a serious global environmental problem—the main reason accumulation of debris in the environment, including in the ocean. There is a significant hazard coming from plastic debris. Besides entanglement and ingestion, marine plastics debris has more complex problems and can release additional and by-product chemical substances. If we keep producing and not doing anything, a recent study said by 2050 there would be three times more plastic than fish in the ocean. We only have a limited understanding of marine plastic debris distribution, implication, fate, and behavior. Science is the key to getting the right alternative for processing debris. To prevent marine pollution successfully requires education and outreach programs, strong laws and policies, and law enforcement for government and private institutions. This chapter explores marine plastic debris.
Çandarlı Bay is a marine environment at risk of heavy pollution because of industrial facilities including the only ship recycling zone of Turkey, and intense marine traffic related to the raw materials needs of a dense industrial zone. These risk factors make the development of practical environmental management strategies increasingly necessary. Oil spills from the heavy ship traffic, one of the major risks, can be detected by satellite remote sensing technologies. In this study, it is aimed to show spatial characteristics of oil spills as well as its dynamics in the time domain of the bay. Results from a three year period of the study show that as a main environmental problem, oil pollution has a relatively high percentage of spatial distribution in the bay. It is therefore concluded that regular monitoring of the intense oil pollution in the bay is required with an agile and low-cost method of satellite monitoring to intervene in good time and to minimize its impacts. The study provided an extensive understanding of spatio-temporal dynamics of oil pollution in the bay. The approach used will also provide a baseline for decision-makers to develop environmental management plans for other coastal zones with similar sensitivities.
Lead concentrations in long-lived Corallium species of known age, from the Mediterranean Sea, Atlantic and Pacific Oceans, were determined by laser ablation, inductively coupled plasma mass spectrometer (LA-ICPMS). Lead concentrations in a 2000-year-old sub-fossil Mediterranean C. rubrum are ca 0.09 ± 0.03 μg/g. For the period 1894–1955, lead concentrations in C. rubrum skeletons from the Mediterranean are stable within the range 0.2–0.4 μg/g; concentrations increase to about 1–1.2 μg/g during the period 1960–1978, then decrease progressively to stabilize and reach values in the range 0.2–0.4 μg/g in present-day corals. These variations can be related to the lead gasoline pollution event that (1) started in the early 1950s with the increase of the numbers of cars in the world, and (2) was mitigated by the implementation of new regulations starting in 1975, leading to a return to pre-1950 levels in 2000. In the Pacific, lead concentrations in C. japonicum and C. konojoi are lower than in the Mediterranean C. rubrum, with values close to 0.17 ± 0.03 μg/g. The lowest lead concentrations in present-day samples (0.11 μg/g) are found in C. johnsoni and C. niobe from the Azores islands in the Atlantic, and in a Mediterranean C. rubrum from Montecristo Island, one of the least accessible and most protected areas in the Mediterranean Sea. Using lead concentrations in C. rubrum and in the Mediterranean seawaters, a partition coefficient Kd = [Pb/Ca]calcite / [Pb/Ca]seawater of 13 ±3 is estimated; it allows calculating past and present lead contents in seawater in which corals grew. Application to Coralliumspecies indicates that values endangering human health or threatening the preservation of aquatic ecosystem on long terms were nearly reached or exceeded in Mediterranean seawaters at the maximum of the lead gasoline pollution event in the 1980s. Measurements in C. rubrum from different places in the Mediterranean indicate that present-day seawater concentrations vary between 40 and 200 pmol/kg. As expected, the lowest concentrations come from protected areas insulated from human activities, while the highest come from places close to lead mining or processing sites.
Contaminants in the marine environment are widespread, but ship-based sampling routines are much narrower. We evaluated the utility of seabirds, highly-mobile marine predators, as broad samplers of contaminants throughout three tropical ocean regions. Our aim was to fill a knowledge gap in the distributions of, and processes that contribute to, tropical marine contaminants; and explore how species-specific foraging ecologies could inform or bias our understanding of contaminant distributions. Mercury and persistent organic pollutant (POPs) concentrations were measured in adults of five seabird species from four colonies in the central Pacific (Laysan and Tern Islands, Hawaii; Palmyra Atoll) and the eastern Caribbean (Barbuda). Blood-based total mercury (THg) and 89 POPs were measured in two seabird families: surface-foraging frigatebirds (Fregataspp.) and plunge-diving boobies (Sula spp.). Overall, largescale contaminant differences between colonies were more informative of contaminant distributions than inter-specific foraging ecology. Model selection results indicated that proximity to human populations was the best predictor of THg and POPs. Regional differences in contaminants were distinct: Barbudan Magnificent Frigatebirds had more compounds (n = 52/89 POP detected) and higher concentrations (geometric mean THg = 0.97 μg g−1; mean ΣPOP53 = 26.6 ng mL−1) than the remote colonies (34–42/89 POP detected; range of THg geometric means = 0.33–0.93 μg g−1; range of mean ΣPOP53:7.3–17.0 ng mL−1) and had the most recently-synthesized POPs. Moderate differences in foraging ecologies were somewhat informative of inter-specific differences in contaminant types and concentrations between nearshore and offshore foragers. Across species, contaminant concentrations were higher in frigatebirds (THg = 0.87 μg g−1; ΣPOP53 = 17.5 ng mL−1) compared to boobies (THg = 0.48 μg g−1; ΣPOP53 = 9.8). Ocean currents and contaminants' physiochemical properties provided additional insight into the scales of spatial and temporal contaminant exposure. Seabirds are excellent, broad samplers with which we can understand contaminant distributions in the marine environment. This is especially important for tropical remote regions that are under-sampled.
This study investigated the role of a municipal wastewater treatment plant (WWTP) effluent and an abandoned coastal landfill as pathways for microplastics (MPs) input into the marine environment. MPs were first analyzed in raw sewage influent, sludge and effluent samples, and their fate was studied along a distance gradient from the WWTP in three matrices: surface water, sediments and wild mussels. All suspected MPs were characterized according to their polymer nature using micro-Raman spectroscopy. The investigated WWTP had an estimated daily discharge of 227 million MPs. MPs were found in all matrices with a decreasing abundance from the effluent. Strong MPs abundances (higher than those found near the WWTP effluent) were observed in the vicinity of the coastal landfill suggesting its importance as a MPs entry route into the marine coastal environment. Our study supports the idea that blue mussels are a promising sentinel species for MPs (<200 μm).
Phosphate mining activities on Christmas Island began in the late 1800's providing a unique, long-term case study in which to assess the impacts of mining on coral reef development. Watershed modelling was used to identify potential “hotspots” of mining runoff on to adjacent reefs. Pollution hotspots were also confirmed by analysis of reef sediment. Phosphate rich mining runoff flowed from local watersheds onto nearshore coral reefs with levels of up to 54,000 mg/kg of total phosphate recorded in reef sediment at the Dryers reef site adjacent to the main phosphate storage facility. Using this combination of watershed modelling and in-situ sediment contamination data we identified six coral reef sites along an environmental impact gradient. In-situ benthic transects were paired with a new rubble-encruster method enabling the analysis to combine large scale transect information alongside fine-scale data on epibenthic and encruster assemblages. Results demonstrate that phosphate rich sediment loading negatively impacted coral reef building communities, in particular, branching corals and calcareous encrusting organisms, critical to the future survival of coral reef ecosystems. These findings highlight the importance of curtailing runoff and pollution from catchment based mining activities and protecting reefs for the future.
Marine plastic pollution is heavily driven by escaped plastic waste from land. Effectively reducing flows of plastic pollution into the oceans requires incentivizing efficient disposal decisions, discouraging production and consumption of products with low recyclability and reuse potential, and encouraging lower-impact, easily recyclable product and packaging designs. We examine the economic literature on waste management and integrated environmental policy to assess how particular policies target these individual pathways and can efficiently reduce flows of plastics into waterways. These policies include production/retail bans and standards, extended producer responsibility, price-based policies such as advance disposal fees and two-part instruments, and interventions grounded in behavioral economics and psychology. We also consider the applicability of these policies in coastal developing nations that often rely upon the informal sector for waste management services. We conclude by identifying important issues for future research.
The Deepwater Horizon (DWH) oil spill may be indicative of future large, deep spills that may occur in the coming decades. Given that future deepwater spills are possible, critical considerations include (1) establishing baselines for oceanic marine mammal and populations in at-risk areas, (2) understanding the implications of response choices for oceanic marine mammals, (3) designing studies with adequate coverage for post-spill monitoring, and (4) identifying effective strategies for oceanic marine mammal restoration. In this chapter, we consider these four stages in the context of a series of hypothetical oil spill scenarios, identifying ways that lessons learned from the DWH oil spill and prior events can be applied to future disasters.