Stability of dissolved and soluble Fe(II) in shelf sediment pore waters and release to an oxic water column

Shelf sediments underlying temperate and oxic waters of the Celtic Sea (NW European Shelf) were found to have shallow oxygen penetrations depths from late spring to late summer (2.2–5.8 mm below seafloor) with the shallowest during/after the spring-bloom (mid-April to mid-May) when the organic carbon content was highest. Sediment porewater dissolved iron (dFe, 85%) consisted of Fe(II) and gradually increased from 0.4 to 15 μM at the sediment surface to ~100–170 µM at about 6 cm depth. During the late spring this Fe(II) was found to be mainly present as soluble Fe(II) (>85% sFe, 7 h. Iron(II) oxidation experiments in core top and bottom waters also showed removal from solution but at rates up to 5-times slower than predicted from theoretical reaction kinetics. These data imply the presence of ligands capable of complexing Fe(II) and supressing oxidation. The lower oxidation rate allows more time for the diffusion of Fe(II) from the sediments into the overlying water column. Modelling indicates significant diffusive fluxes of Fe(II) (on the order of 23–31 µmol m−2 day−1) are possible during late spring when oxygen penetration depths are shallow, and pore water Fe(II) concentrations are highest. In the water column this stabilised Fe(II) will gradually be oxidised and become part of the dFe(III) pool. Thus oxic continental shelves can supply dFe to the water column, which is enhanced during a small period of the year after phytoplankton bloom events when organic matter is transferred to the seafloor. This input is based on conservative assumptions for solute exchange (diffusion-reaction), whereas (bio)physical advection and resuspension events are likely to accelerate these solute exchanges in shelf-seas

In Vitro Cytogenetic Assays: Chromosomal Aberrations and Micronucleus Tests

Chromosome damage is a very important indicator of genetic damage relevant to environmental and clinical studies. Detailed descriptions of the protocols used for detection of chromosomal aberrations induced by genotoxic agents in vitro both in the presence or absence of rat liver-derived metabolizing systems are given in this chapter. Structural chromosomal aberrations that can be observed and quantified at metaphases are described here. For the detection of chromosomal damage (fragments or whole chromosome) in interphase, the micronucleus test can be used, and a description of this test is also presented. Criteria for determining a positive result using appropriate statistical methods are described

Effect of socioeconomic status on the healthcare-seeking behavior of migrant workers in China

In recent years, China has made great efforts to resolve the health inequality caused by household registration restrictions, and the unequal allotment of health services faced by migrant workers has been effectively alleviated. However, inequality in health services may exist not only between migrant workers and local citizens but also among migrant workers. Thus, the unbalanced utilization of health services among migrant workers deserves attention. Using data from the 2017 China Migrants Dynamic Survey (CMDS), we examined the relationship between socioeconomic status (SES) and healthcare-seeking behavior through multivariate regression analysis. Then, from the perspective of SES, this study divided migrant workers into different groups to explore the characteristics of healthcare-seeking behavior in different groups. The results showed that SES had a significant relationship with healthcare-seeking behavior. Those with high SES were more likely to use high-quality health services. By subdividing the category of migrant workers, we found that the utilization of health services among migrant workers was unbalanced. Education and income had significant gradients in multiple measures of healthcare-seeking behavior, while occupation had no significant difference in the behavior. Migrant workers with higher income and education were more likely to use high-quality health services. Especially for migrant workers who had high incomes (above 15,000 CNY) or whose educational backgrounds were graduate level or above, their utilization of health resources was significantly higher than that of other groups. When designing particular policies to improve the healthcare-seeking behavior of different SES migrant workers, we should pay attention to the low-education groups and low-income groups. Policymakers can reduce the current health inequality of migrant workers by strengthening health education and increasing medical subsidies to achieve health equality among migrant workers and between migrant workers and local citizens