Microplastics are present throughout the marine environment and ingestion of these plastic particles (<1 mm) has been demonstrated in a laboratory setting for a wide array of marine organisms. Here, we investigate the presence of microplastics in two species of commercially grown bivalves: and . Microplastics were recovered from the soft tissues of both species. At time of human consumption, contains on average 0.36 ± 0.07 particles g (wet weight), while a plastic load of 0.47 ± 0.16 particles g ww was detected in . As a result, the annual dietary exposure for European shellfish consumers can amount to 11,000 microplastics per year. The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible. Microplastics were detected in two commercially grown bivalve species ( and ), enabling us to estimate a preliminary human dietary exposure.
Cultured meat (i.e., meat produced in vitro using tissue engineering techniques) is being developed as a potentially healthier and more efficient alternative to conventional meat. Life cycle assessment (LCA) research method was used for assessing environmental impacts of large-scale cultured meat production. Cyanobacteria hydrolysate was assumed to be used as the nutrient and energy source for muscle cell growth. The results showed that production of 1000 kg cultured meat requires 26-33 GJ energy, 367-521 m(3) water, 190-230 m(2) land, and emits 1900-2240 kg CO2-eq GHG emissions. In comparison to conventionally produced European meat, cultured meat involves approximately 7-45% lower energy use (only poultry has lower energy use), 78-96% lower GHG emissions, 99% lower land use, and 82-96% lower water use depending on the product compared. Despite high uncertainty, it is concluded that the overall environmental impacts of cultured meat production are substantially lower than those of conventionally produced meat.
Benzophenone-3 (BP-3; oxybenzone) is an ingredient in sunscreen lotions and personal-care products that protects against the damaging effects of ultraviolet light. Oxybenzone is an emerging contaminant of concern in marine environments—produced by swimmers and municipal, residential, and boat/ship wastewater discharges. We examined the effects of oxybenzone on the larval form (planula) of the coral Stylophora pistillata, as well as its toxicity in vitro to coral cells from this and six other coral species. Oxybenzone is a photo-toxicant; adverse effects are exacerbated in the light. Whether in darkness or light, oxybenzone transformed planulae from a motile state to a deformed, sessile condition. Planulae exhibited an increasing rate of coral bleaching in response to increasing concentrations of oxybenzone. Oxybenzone is a genotoxicant to corals, exhibiting a positive relationship between DNA-AP lesions and increasing oxybenzone concentrations. Oxybenzone is a skeletal endocrine disruptor; it induced ossification of the planula, encasing the entire planula in its own skeleton. The LC50 of planulae exposed to oxybenzone in the light for an 8- and 24-h exposure was 3.1 mg/L and 139 µg/L, respectively. The LC50s for oxybenzone in darkness for the same time points were 16.8 mg/L and 779 µg/L. Deformity EC20 levels (24 h) of planulae exposed to oxybenzone were 6.5 µg/L in the light and 10 µg/L in darkness. Coral cell LC50s (4 h, in the light) for 7 different coral species ranges from 8 to 340 µg/L, whereas LC20s (4 h, in the light) for the same species ranges from 0.062 to 8 µg/L. Coral reef contamination of oxybenzone in the U.S. Virgin Islands ranged from 75 µg/L to 1.4 mg/L, whereas Hawaiian sites were contaminated between 0.8 and 19.2 µg/L. Oxybenzone poses a hazard to coral reef conservation and threatens the resiliency of coral reefs to climate change.
Microplastics, plastic particles <5 mm, are an emerging concern in aquatic ecosystems. Because microplastics are small, they are available to many filter-feeding organisms, which can then be consumed by higher trophic level organisms, including humans. This study documents the quantity of microplastics present in wild and cultured Manila clams (Venerupis philippinarum). Three active shellfish farms and three reference beaches (i.e., non-shellfish farm sites) in Baynes Sound, British Columbia were chosen to examine the microplastic concentrations in wild and cultured Manila clams. Microplastics were isolated using a nitric acid digestion technique and enumerated from 54 clams (27 farmed and 27 non-farmed). Qualitative attributes, such as colour and microplastic type (fiber, fragment, or film) also were recorded. There was no significant difference (F = 1.29; df = 1,4; P = 0.289) between microplastic concentrations in cultured and wild clams. Microplastic concentrations ranged from 0.07 to 5.47 particles/g (from reference beach and shellfish farm clams, respectively). Fibers were the dominant microplastic (90 %); colourless and dark gray fibers were the most common colours observed (36 and 26 %, respectively). Although this indicates that microplastics are definitely present in seafood consumed by humans, shellfish aquaculture operations do not appear to be increasing microplastic concentrations in farmed clams in this region.
High concentrations of airborne particles have been associated with increased pulmonary and cardiovascular mortality, with indications of a specific toxicologic role for ultrafine particles (UFPs; particles < 0.1 μm). Within hours after the respiratory system is exposed to UFPs, the UFPs may appear in many compartments of the body, including the liver, heart, and nervous system. To date, the mechanisms by which UFPs penetrate boundary membranes and the distribution of UFPs within tissue compartments of their primary and secondary target organs are largely unknown. We combined different experimental approaches to study the distribution of UFPs in lungs and their uptake by cells. In the in vivo experiments, rats inhaled an ultrafine titanium dioxide aerosol of 22 nm count median diameter. The intrapulmonary distribution of particles was analyzed 1 hr or 24 hr after the end of exposure, using energy-filtering transmission electron microscopy for elemental microanalysis of individual particles. In an in vitro study, we exposed pulmonary macrophages and red blood cells to fluorescent polystyrene microspheres (1, 0.2, and 0.078 μm) and assessed particle uptake by confocal laser scanning microscopy. Inhaled ultrafine titanium dioxide particles were found on the luminal side of airways and alveoli, in all major lung tissue compartments and cells, and within capillaries. Particle uptake in vitro into cells did not occur by any of the expected endocytic processes, but rather by diffusion or adhesive interactions. Particles within cells are not membrane bound and hence have direct access to intracellular proteins, organelles, and DNA, which may greatly enhance their toxic potential.
There is growing evidence that exposure to persistent organic pollutants (POPs) is statistically associated with incidence of cardiovascular disease (CVD) or its risk factors. Decarbromodiphenyl ether (BDE-209) is a new POP which exists extensively in human tissues, but its potential effects on CVD have so far received less focus. The adhesion of circulating monocytes to endothelial cells is one of the critical underlying steps in the initiation and development of CVD. In the present study, we investigated the effect of BDE-209 on the adhesion of THP-1 monocytes to human aortic endothelial cells (HAECs) and identified the molecular mechanisms involved. Our results showed that 6.25, 12.5 and 25 µM of BDE-209 exposures caused significant increases in monocyte–endothelial cell adhesion, in a dose-dependent manner. Mechanistically, BDE-209 exposure increased the expression of intercellular adhesion molecule-1 (ICAM-1). Moreover, the up-regulation of ICAM-1 was accompanied by a decrease in the expression of microRNA-141 (miR-141). Furthermore, the up-regulation of ICAM-1 and the increased adhesion induced by BDE-209 could be reversed by miR-141 supplement. Taken together, our results show that BDE-209 potentiates monocyte–endothelial cell interaction via miR-141/ICAM-1 pathway in HAECs.
Microplastics are an emerging concern in the marine environment due to their small size; they can be ingested by aquatic organisms, especially filter-feeding organisms, such as oysters. The presence of microplastics in seafood may pose a threat to food safety, and there is an urgent need to evaluate the potential risks of microplastics to human health. This study quantified the microplastics in oysters from 17 sites along the coastline of China. Qualitative attributes, such as shape and size, were also determined under a microscope. Additionally, the polymer types were identified using Fourier-Transform Infrared Micro-Spectroscopy (μ-FT-IR). The results showed that the average abundance of microplastics in oyster was 0.62 items/g (wet weight) or 2.93 items/individual. Additionally, 84% of the sampled oysters had inhaled microplastics, indicating the high prevalence of microplastic pollution in different coastal areas of China. Fibers were the most common shape (60.67%), and the most common size was <1500 μm, accounting for 81.89% of the total microplastics. The μ-FT-IR analysis identified eight different polymers, and the main polymeric types of microplastics were cellophane (CP), polyethylene (PE) and polyethylene terephthalate (PET). Our results suggest the widespread prevalence of microplastics in cultured oysters from different coastal areas of China with similar or lower abundances than other countries. In addition, our results exhibited regional characteristics of high microplastics abundance in southern coastal area of China and low microplastics abundance in northern China. Further investigations are warranted to examine microplastics contamination in other seafood species from different geographical sites in coastal area of China.
Eutrophication alters biological and physical characteristics of aquatic freshwater ecosystems, and different macrophytes exhibit variable capacities to tolerate the subsequent stress factors. is one of the most eutrophication tolerant submerged macrophyte species. . from Fuxian (oligotrophic) and Xingyun (eutrophic) lakes, in South West China, were cultured in water conditions corresponding to their origin and the alternative trophic state (4 treatments) for a year. Each treatment was exposed to NH –N (0, 5, 10, 50, 100, and 200 mg/L) for five days (24 treatments) to investigate the effect of the sources and acute NH –N enrichment on photosynthetic performance. Both sources and NH –N affected photosynthetic performance, and eutrophic source plants in high nutrients and oligotrophic source plants in low nutrients exhibited higher NH –N tolerance. High nutrient cultured individuals had higher leaf number, branching, and heights. There were trade-offs between NH –N tolerance in turbid high nutrient conditions and photosynthetic performance in low nutrient conditions with high irradiance. Oligotrophic source plants in low nutrients had the highest chlorophyll levels at ≤10 mg/L, which dropped markedly afterwards. Soluble carbohydrates and starch decreased at ≥50 mg/L and ≥5 mg/L, respectively. Individuals growing in eutrophic conditions could be prone to higher damage in the field owing to potentially weaker stem and leaf biomechanical properties, because of carbohydrate and energy intensive NH –N detoxification in higher NH –N conditions.
Anthropogenic eutrophication of freshwater bodies increases the occurrence of toxic cyanobacterial blooms. The cyanobacterial toxin cylindrospermopsin (CYN) is detected in the environment with increasing frequency, driving the scientific effort to assess emerging health risks from CYN-producing blooms. Oral exposure to CYN results primarily in hepatotoxicity. Nevertheless, extrahepatic manifestations of CYN toxicity have been reported. Furthermore, cyanotoxins have been detected in aerosols and dust particles, suggesting potential toxic effects in the respiratory tract. To assess the susceptibility of airway epithelia towards cyanotoxins, monolayers of immortalized human bronchial epithelial cells HBE1 and 16HBE14o- were exposed to a concentration range of 0.1–10 μM CYN. Cytotoxic endpoints were assessed as morphologic alterations, resazurin reduction capacity, esterase activity, neutral red uptake, and by impedimetric real-time cell analysis. Depending on the endpoint assessed, EC values ranged between 0.7 and 1.8 μM (HBE1) and 1.6–4.8 μM (16HBE14o-). To evaluate alterations of other cellular events by subcytotoxic concentration of CYN (1 μM), phosphorylation of mitogen-activated protein kinases ERK and p38 was determined. Only a slight increase in p38 phosphorylation was induced by CYN in HBE1 cell line after 48 h, while activities of both ERK1/2 and p38 gradually and significantly increased in 16HBE14o- cells during 8–48 h exposure. This study suggests possible hazards of inhalation CYN exposures, which may severely impact the integrity of airway epithelia and epithelial cell signaling. Further research of CYN-induced toxicity and underlying mechanisms is needed, as well as more data on environmental concentrations of cyanotoxins in aerosols for exposure assessment.
The responses of cultured phototrophic biofilms to diverse phosphorus (P) regimes were assessed using a semi-continuous flow incubator. Three biofilms were grown over 18 days under three different P regimes: replete inorganic P, organic P-only and limited inorganic P. Assessing the response of the biofilms took into account the rate of phosphomonoesterase and phosphodiesterase activities, biofilm nutrient contents and biomass accrual across the growth period. Phosphorus limitation was indicated by slower biomass accumulation and higher phosphatase activities of the organic P-only and P-limited biofilms compared to the P-replete biofilms. The cyanobacterium sp. dominated the later stages in all the treatments forming a dense layer at the biofilm–medium interface. This layer possibly led to a reduction of light and nutrient diffusion to sub-surface cells and may account for the production of phosphatases under P replete conditions. In addition, the -layer possibly produced a top-heavy P (and N) distribution and could explain the large reductions in areal nutrient concentrations. End-product repression and de-repression of phosphatase activity was suggested to be a main controlling factor of phosphatase activity. Consequently, it is proposed that for efficient nutrient removal from wastewaters that biofilms should be regularly removed to continually maintain biofilms at the initial stages (3–7 days). ► Boifilms produce phosphatases in response to phosphorus limitation. ► Two phosphatases were measured indicating the potential use of many substrate types. ► Younger biofilms had higher enzyme activities and phosphorus contents. ► Simple frequent harvesting could maintain higher water treatment potential of biofilms.