Investigating toxicity of urban road deposited sediments using Chinese hamster ovary cells and Chlorella Pyrenoidosa

Heavy Metals and Trajectories of Anti-Müllerian Hormone During the Menopausal Transition

BACKGROUND

Experimental and epidemiological studies have linked metals with women's reproductive aging, but the mechanisms are not well understood. Disrupted ovarian folliculogenesis and diminished ovarian reserve could be a pathway through which metals impact reproductive hormones and outcomes.

OBJECTIVE

The study aimed to evaluate the associations of heavy metals with anti-Müllerian hormone (AMH), a marker of ovarian reserve.

METHODS

The study included 549 women from the Study of Women's Health Across the Nation with 2252 repeated AMH measurements from 10 to 0 years before the final menstrual period (FMP). Serum AMH concentrations were measured using picoAMH ELISA. Urinary concentrations of arsenic, cadmium, mercury, and lead were measured using high-resolution inductively coupled plasma mass spectrometry. Multivariable linear mixed regressions modeled AMH as a function of time before the FMP interaction terms between metals and time to the FMP were also included.

RESULTS

Adjusting for confounders, compared with those in the lowest tertile, women in the highest tertile of urinary arsenic or mercury concentrations had lower AMH concentrations at the FMP (percent change: -32.1%; 95% CI, -52.9 to -2.2, P-trend = .03 for arsenic; percent change: -40.7%; 95% CI, -58.9 to -14.5, P-trend = .005 for mercury). Higher cadmium and mercury were also associated with accelerated rates of decline in AMH over time (percent change per year: -9.0%; 95% CI, -15.5 to -1.9, P-trend = .01 for cadmium; -7.3%; 95% CI, -14.0 to -0.1, P-trend = .04 for mercury).

CONCLUSION

Heavy metals including arsenic, cadmium, and mercury may act as ovarian toxicants by diminishing ovarian reserve in women approaching the FMP.

Pollution and ecological risk assessments for heavy metals in coastal, river, and road-deposited sediments from Apia City in Upolu Island, Samoa

This study was the first to investigate the pollution and ecological risks of heavy metals in coastal, river/stream and road-deposited sediments (RDS) from Apia in Samoa. Cr and Ni concentrations in sediment samples were higher than those of other metals. River sediments and RDS had relatively high EF values around the intensive commercial areas, with a moderate to significant enrichment of Cu, Zn, Cd, and Pb. The results indicate that Cr and Ni have a natural origin from volcanic parent materials, while Cu, Zn, Cd, and Pb originated from anthropogenic activities, such as traffic emissions and the discharge of municipal wastewater. The assessments of pollution and ecological risk revealed that coastal sediments adjacent to the river are anthropogenically contaminated and present a moderate ecological risk. This study demonstrates that metals that have accumulated in the urban impermeable layer and river/stream bed have flowed into the coastal environment through runoff.

Sediment and residual feed from aquaculture water bodies threaten aquatic environmental ecosystem: Interactions among algae, heavy metals, and nutrients

The effect of sediment and residual fish feed on aquaculture water bodies has gained increasing attention to alleviate the eutrophication and heavy metals enrichment induced by aquaculture. Thus, this study intended to reveal the possible interactions among nutrients, heavy metals, and Chlorella vulgaris (C. vulgaris) in aquaculture water bodies containing fish feed and sediment. The analyses showed that consistent with the composition of heavy metals in fish feed, manganese (Mn) and zinc (Zn) accounted for the highest proportions (68-78%) of heavy metals in sediment. Meanwhile, sediment in the centre of aquaculture water bodies (S2) contained more heavy metals than those in the perimeter (S1), but the released concentrations and rates (R_release) of heavy metals from S1 were higher than those from S2. Moreover, the biomass, growth rate, specific growth rate, and nitrogen and carbon fixation rate of C. vulgaris increased with adding fish feed, whereas superoxide dismutase (SOD) and malondialdehyde (MDA) decreased. In addition, with C. vulgaris, influenced by the release process from sediment and the uptake by C. vulgaris, the concentration and R_release of Mn, Pb, Cu, Mn, Cr and Cd from sediments coexisting with fish feed in water first increased and then decreased in general. The C. vulgaris biomass was significantly negatively related to Mn, Pb, Cu, Ni, Cr, and Cd and PO₄^3-P (P < 0.05), which was caused by the uptake of C. vulgaris and indicated that C. vulgaris biomass is easily affected by these factors. Accordingly, the input of residual fish feed and sediment should be controlled.

Treatment of iodine-containing water by the UV/NH2Cl process: Dissolved organic matters transformation, iodinated trihalomethane formation and toxicity variation

UV/NH₂Cl process is becoming increasingly important for water treatment, while its impact on iodine-containing water remains unknown. In this study, the structure transformation of dissolved organic matters (DOMs), generation of iodinated trihalomethanes (I-THMs), and variation of acute toxicity were evaulated during the UV/NH₂Cl treatment of iodine-containing water. The combination of exciation emission matrix-parallel factor analysis and two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy showed that fulvic-like fraction of DOM was more susceptible to UV/NH₂Cl process and particularly iodo and polysaccharide groups gave the fastest resopnses. Consequently, UV fluence lower than 60 mJ/cm² promoted the production of I-THMs, while excessive UV exhausted NH₂Cl and reactive iodine species and subsequently reduced I-THM generation. Moreover, DOM concentration and source, NH₂Cl dosage, and I^- concentration had significant impacts on I-THM formation in the UV/NH₂Cl process. Additionally, a positive correlation was found between acute toxicity variation and I-THM formation when treating iodine-containing waters with UV/NH₂Cl. These results together provide a comprehensive understanding on UV/NH₂Cl treatment of iodine-containing water.

Toxicity variability of urban road stormwater during storage processes in Shenzhen, China: Identification of primary toxicity contributors and implications for reuse safety

Urban road stormwater reuse is one of the most important ways to mitigate water resource shortage. Generally, stormwater is stored prior to reuse or further treatment. This study explored the stormwater toxicity variability during two types of storages, closed and open storages using Chinese hamster ovary cells (CHO), which are mammalian cells. The toxicity test by CHO cells can indirectly represent the risk related to human health. Both rainfall (without reaching ground surfaces) and urban road stormwater were collected to undertake laboratory-scaled storage experiments and basic water quality parameters (pH and dissolved oxygen), microorganisms (E.coli and total bacteria), total organic carbon and heavy metals (copper, Cu, zinc, Zn, nickel, Ni, chromium, Cr, cadmium, Cd and lead, Pb) were also investigated during storage processes. The outcomes showed that rainfall has a better water quality with lower toxicity than urban road stormwater (EC₅₀ values of rainfall were generally twice higher than road stormwater). Additionally, it is found that storing road stormwater for a certain period would reduce the toxicity and hence improve their reuse safety (EC₅₀ values in Day 1 were 10.30 mL and 8.46 mL for closed and open storage respectively while they were 14.3 mL and 13.0 mL in Day 7). Organic matters and Cu are important contributors of toxicity during both closed and open storages while bacteria is also essential in toxicity contribution in open storage. The research results implied that storing stormwater for a certain period has a benefit for reuse safety. This is related to cost-effectiveness in terms of treatment system design to avoid over engineering. Additionally, it is suggested that for reducing toxicity, the stormwater treatment designed before/after storage devices should focus on removal of organic matters and heavy metals (specially Cu) as well as restraining bacteria growth.

Comparison of pollutant source tracking approaches: Heavy metals deposited on urban road surfaces as a case study

A range of source tracking approaches have been developed to identify sources in the environmental pollution research field. A comparison of source tracking approaches is essential for a better understanding and practical applications of these approaches. This study compared the commonly used source tracking approaches, namely positive matrix factorization (PMF), Unmix, flag element ratio (FER), and chemical mass-balance based stochastic approach (SCMD). A case study was illustrated for tracing heavy metals (Pb, Zn, Cr, Cu, and Ni) attached to road deposited sediments, which can significantly influence urban road stormwater quality. The results indicated that the accuracy of PMF and Unmix are affected by the number of chemical species used and whether useful markers can be identified for particular sources. However, this does not have an essential influence on FER and SCMD. PMF and Unmix are easier on data preparation and calculation processes but more difficult for source identification process than FER and SCMD. This study also provided recommendations related to the selection of source tracking approach based on different study scenarios and result requirements. These study results are able to provide important guidance for undertaking effective source tracking and devising environmental pollution mitigations.

Toxicity assessment of saline extract and lectin-rich fraction from Microgramma vacciniifolia rhizome

Microgramma vacciniifolia is broadly used in folk medicine but safety information is unavailable. Therefore, we evaluated the toxicity of a saline extract and a lectin-rich fraction of M. vacciniifolia rhizome. The extract showed hemolytic activity on mice erythrocytes at 1000 μg/mL, whereas the fraction promoted hemolysis (8.57-26.15%) at all tested concentrations (10-1000 μg/mL). Acute toxicity test in mice indicated an LD₅₀ of >5000 mg/kg. Hematological alterations and increased serum alkaline phosphatase level were observed in the treated animals. Transaminases and urea levels increased in the groups treated with the extract or fraction at 5000 mg/kg. Leukocyte infiltration was observed in the liver of extract-treated animals and in the liver and lungs of mice treated with the fraction. The kidneys of animals treated with the fraction at 5000 mg/kg presented hydropic degeneration. The extract and fraction did not induce oxidative stress in the liver and did not show genotoxicity, as examined by micronucleus and comet assays. In conclusion, the preparations were not lethal to mice but caused some signs of toxicity, mainly the fraction. The results indicated the need to evaluate the toxicity of M. vacciniifolia rhizome in other models and in chronic assays.