Influence of eutrophication on metal bioaccumulation and oral bioavailability in oysters, Crassostrea angulata

The interference of marine accidental and persistent petroleum hydrocarbons pollution on primary biomass and trace elements sink

More than 80 % of the primary biomass in marine environments is provided by phytoplankton. The primary mechanism in the trace element sink is the absorption of trace elements by phytoplankton. Because of their difficult degradability and bioaccumulation, petroleum hydrocarbons are one of the most significant and priority organic contaminants in the marine environment. This study chose Chlorella pyrenoidosa as the model alga to be exposed to short and medium-term petroleum hydrocarbons. The ecological risk of accidental and persistent petroleum hydrocarbon contamination was thoroughly assessed. The interaction and intergenerational transmission of phytoplankton physiological markers and trace element absorption were explored to reflect the change in primary biomass and trace element sink. C. pyrenoidosa could produce a large number of reactive oxygen species stimulated by the concentration and exposure time of pollutants, which activated their antioxidant activity (superoxide dismutase (SOD) activity, β-carotene synthesis, antioxidant trace elements uptake) and peroxides production (hydroxyl radicals and malondialdehyde). The influence of the growth phase on SOD activity, copper absorption, and manganese adsorption in both persistent and accidental pollution was significant (p < 0.05, F > Fα). Adsorption of manganese and selenium positively connected with SOD, malondialdehyde, and Chlorophyl-a (p < 0.01). These findings convincingly indicate that petroleum hydrocarbon contamination can interfere with primary biomass and trace element sinks.

Eutrophication likely prompts metal bioaccumulation in edible clams

Coastal eutrophication is an indisputable reality and becoming a worldwide concern. However, whether and how eutrophication affects metal bioaccumulation in marine bivalves have not yet been elucidated. Here, we present the potential influence of coastal eutrophication on metal bioaccumulation in the Manila clam Ruditapes philippinarum. The degree of coastal eutrophication was examined monthly over a 1-year period at three sampling sites. The bioconcentration factor (BCF), biosediment accumulation factor (BSAF) and metal pollution index (MPI) were applied to evaluate the efficiency of metal bioaccumulation in R. philippinarum. BCF and BSAF indicated that eutrophication did not significantly affect the bioaccumulation of Cr, Cu, Zn, Cd, Pb, Hg, and As in R. philippinarum. However, up to 56% of MPI variation can be related to the level of eutrophication. Therefore, further research should address the synergistic effects of eutrophication and metal pollution on coastal ecosystems.

Benefit-risk assessment of metal bioavailability in edible fungi by biomimetic whole digestive tracts with digestion, metabolism, and absorption functions

As worldwide edible fungi, Lentinula edodes and Agaricus bisporus accumulate both essential and harmful metals. Metal bioavailability is important for metal benefit-risk assessment. A full functional model of digestive tracts (including digestion, metabolism, and absorption) is established. Under the digestive tract functions, the bioaccessible and bioavailable metals are released from edible fungi and absorbed by intestinal tract, respectively. Based on bioavailable metal contents in the intestine, safe dosage and maximum consumption are 43.52 g/d and 248.7 g/d for Agaricus bisporu, 20.59/328.9 g/d (for males/ female) and 132.9 g/d for Lentinus edodes; V, Co, Ni, Cu, Zn, Se, Cr, Cd and Pb in Agaricus bisporus and Lentinula edodes are absorbed mainly in the large intestine; Fe is mainly absorbed in small intestine; edible fungi species-specificity in metal bioavailability is observed for As and Mn, which are mainly absorbed by small and large intestine for Agaricus bisporus and Lentinus edodes, respectively; and then metal toxicity on small and large intestine is disclosed. Metal benefit-risk is assessed by the content of monolayer liposome-extracted metal in the chyme from small and large intestine, which is controlled by the gastrointestinal functions, metal and edible fungi species.

Thermal discharge influences the bioaccumulation and bioavailability of metals in oysters: Implications of ocean warming

Human-induced temperature changes influence coastal regions, both via thermal pollution and ocean warming, which exerts profound effects on the chemistry of metals and the physiology of organisms. However, it remains unknown whether the increased temperature of discharged water or ocean warming, as a result of climate change, lead to an increase of human health risks associated with the consumption of sea foods. In this study, the influence of temperature on metal accumulation by oysters was studied in individuals collected from a coastal area affected by the thermal water discharge of the Houshi Power Plant, China. The bioaccumulation factor (BAF) and oral bioavailability (OBA) of metals in oysters was determined. Elevated temperatures led to an increase in BAF for Cu, Zn, Hg, and Cd (p < 0.05), but no change was observed for As and Pb (p > 0.05). The OBA for Cd, As, and Pb correlated positively to elevated temperatures (p < 0.05). However, for Cu and Zn, OBA was negatively correlated with increasing temperature (p < 0.05). As, Pb, and Cd in the trophically available metal (defined as a sum of heat-stable proteins, heat-denaturable proteins, and organelles) was significantly elevated at the highest temperature seawater site (site A) compared to the lowest seawater site (site B). Thus, the irregular variation of OBA for each metal may be the result of variations in the subcellular distribution of metals and the protein quality influenced by the increased temperature. Moreover, the increased temperature and increased the hazard quotient values of As and Cd (p < 0.05 for As, n = 6, p < 0.05 for Cd, n = 6), which provided an indication of the potential risks of the consumption of oysters or other seafood to future warming under climate change scenarios.

Colorimetric Detection of Norovirus in Oyster Samples through DNAzyme as a Signaling Probe

Worldwide, norovirus is one of the most associated causes of acute gastroenteritis, which leads to nearly 50 000 child deaths every year in developing countries. Therefore, there is great demand to develop a rapid, low-cost, and accurate detection assay for the foodborne norovirus infection to reduce mortality caused by norovirus. Considering the importance of norovirus, we have demonstrated a highly sensitive and specific colorimetric detection method for analysis of human norovirus genogroups I and II (HuNoV GI and GII) in oyster samples. This is the first report to employ colorimetric HRPzyme-integrated polymerase chain reaction (PCR) for direct norovirus detection from the real shellfish samples. We found that the HRPzyme-integrated PCR method is more sensitive than the gel electrophoresis approach and could detect the HuNoV GI and GII genome up to 1 copy/mL. The specificity of the proposed method was successfully demonstrated for HuNoV GI and GII. Further, we performed testing HuNoVs in the spiked oyster samples, and the HRPzyme-integrated PCR method proved to be an ultrasensitive and selective method for detecting HuNoVs in the real samples. By integration of the proposed method with the portable PCR machine, it would be more reliable to improve food safety by detecting HuNoVs in the different types of shellfish, such as oyster and mussel, at the production field.

The study of lead content distribution in Chinese seafood and its oral bioavailability in mice

Using inductively coupled plasma mass spectrometry (ICP-MS), the lead concentrations and isotope ratios of 32 kinds of seafood collected from local markets of China were measured. Among these seafoods, the highest concentrations of lead were found in Patinopecten yessoensis and Mugil cephalus, which were 2.94 ± 0.40 and 2.02 ± 0.26 μg g(-1) of dry weight, respectively. Pb concentration was found to be higher in benthic fish than in other fish. The result indicated that lead concentrations in some seafood exceeded the maximum levels of Pb in foods proposed by European Commission (EC). Nine species of cooked seafood were chosen to feed mice (35-38 g). The result showed that Pb oral bioavailability of cooked seafood in vivo was below 10%. Furthermore, oral bioavailability of the same lead-containing seafood increased greatly in pregnant mice compared with non-pregnant mice.

Unique lead adsorption behavior of ions sieves in pellet-like reduced graphene oxide

A pellet-like reduced graphene oxide has been presented for lead ions removal like behavior of ions sieves in aqueous solution.