The aim of the current research was to systematically review and summarize the studies that evaluated the concentration of lead (Pb) and cadmium (Cd) in cow milk in different regions of Iran and to perform a meta-analysis of the findings. Moreover, the non-carcinogenic and carcinogenic risks of Pb and Cd through milk consumption in adult and child consumers were assessed. As a result of a systematic search in the international and national databases between January 2008 and October 2018, 17 reports involving 1874 samples were incorporated in our study for meta-analysis. The pooled concentrations of Pb and Cd were estimated to be 13.95 μg mL⁻¹ (95% CI 9.72–18.11 μg mL⁻¹) and 3.55 μg mL⁻¹ (95% CI − 2.38–9.48 μg mL⁻¹), respectively, which were lower than the WHO/FAO and national standard limits. The estimated weekly intake (EWI) of Pb and Cd through consuming milk was 16.65 and 7 μg day⁻¹ for adults of 70 kg and 45 and 34 μg day⁻¹ for children of 26 kg, respectively, which was well below the risk values set by Joint FAO/WHO Expert Committee on Food Additives (JECFA). The maximum target hazard quotient values (THQs) of Pb and Cd were 5.55E−5 and 5.55E−5 for adults and 5.55E−5 and 5.55E−5 for children, respectively, which were lower than 1 value, suggesting that Iranian consumers are not exposed to non-carcinogenic risk through consuming milk. Moreover, the incremental lifetime cancer risk (ILCR) of Pb estimated to be 2.96E−04 in adults and 1.0E−03 in children, indicating that consumers in Iran are at threshold carcinogenic risk of Pb through consuming milk (ILCR > 10⁻⁴). Therefore, planning and policy making for the sustainable reduction of these toxic metals in milk, particularly in industrial regions of Iran, are crucial.

The cleaning of metallic artworks is a crucial step for their preservation. Cleaning operations generally aim at removing deposits and corrosion layers, and all the non-stable and potentially reactive phases formed as a consequence of the interaction of the metal with the environment. Thus, all secondary-formed compounds and layers that can undermine the overall preservation of the artwork, both from the esthetic and the corrosion point of view, should be removed. On the other hand, superficial stable patinas contributing to the artistic and historic value of the objects and that may provide protection to the metallic surface should be preserved. The optimal cleaning procedure should be able to promote a long-term improvement of the corrosion resistance of the surfaces. Therefore, the long-term monitoring of the corrosion behavior of the cleaned surfaces with electrochemical techniques could provide valuable information for the selection of the optimal methodology. In this work, five cleaning procedures have been applied to five bronze sculptures. The cleaned surfaces have been characterized following a multi-analytical and non-invasive approach, and the long-term evolution of their corrosion behavior has been monitored by means of on-site non-invasive linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS) measurements for more than 2 years.

In order to make hydropower station’s development and operation harmonious with ecological protection, the optimal operation of hydropower stations to meet the needs of ecological protection is studied. Firstly, the ecological protection function of river course is defined according to the minimum ecological runoff and suitable ecological runoff. Then, a multi-objective optimal running model of reservoir which can maximize the capacity of ecological protection and generation is proposed. Finally, an improved multi-objective particle swarm optimization algorithm (MOPSO), which can construct a neighborhood for each particle and choose the neighborhood optimal solution by adopting self-organizing mapping (SOM) method, is proposed to solve the model. The model is applied to the Shui-Kou Hydropower Station in Minjiang, China. The results show that the model can get the optimal schedule with balanced consideration of ecological benefits and power generation benefits, which has not a great impact on the economic benefits of reservoirs while achieving the goal of ecological environment. The research results can provide theoretical basis and concrete scheme reference for reservoir operation.

This study aimed to investigate the effect of honeybee pollen as an antioxidant source in a maturation medium of sheep oocytes on the in vitro maturation rate, glutathione concentration, and gene expression. To our knowledge, this study might be the first of its kind in this field. Sheep oocytes were cultured in vitro with honeybee pollen at four different concentrations (0.0, 1.0, 10.0, and 50.0 μg/ml). The results indicated that the ratio of oocytes that reached metaphase II stage was higher in the honeybee pollen-treated groups than in the control group (p ≤ 0.05). The reduced glutathione (GSH) mean content of matured oocytes was 9.85 nmol/25 oocytes, when honeybee pollen was added to the in vitro maturation (IVM) medium at a concentration of 1.0 μg/ml, compared with 5.84 and 4.44 nmol when using 10.0 and 50.0 μg/ml honeybee pollen, respectively. On the other hand, there was no significant difference in glutathione concentration between the control and 1.0 μg/ml honeybee pollen groups. Expression of candidate genes (GDF-9, BAX, Cyclin B, C-MOS, and IGF1) was upregulated in oocytes cultured with honeybee pollen when compared with oocytes cultured without honeybee pollen. In conclusion, the addition of honeybee pollen at a concentration of 1.0 μg/ml to IVM medium improved the in vitro maturation rate of sheep oocytes, increased the glutathione concentration, and improved gene expression.

Heavy metal contamination of river water has become a major issue affecting environmental and human health worldwide. This study makes an effort to observe the heavy metal incidence of River Brahmaputra, India, and its river restoration assessment for 2 years, 2017–2018 and 2018–2019. River Brahmaputra is the second longest and a major transboundary river of the South Asian region, which transcends the political boundaries of China, India and Bangladesh. The Pearson correlation analysis was used to analyse the interrelationships between physico-chemical parameters (which was also analysed during our study) and heavy metals. Heavy metal pollution index and multivariate analyses such as hierarchical cluster analysis and principal component analysis were used to establish our scientific observations. An assessment involving people’s willingness to pay for river restoration was also done. Arsenic (As), lead (Pb), antimony (Sb), nickel (Ni), chromium (Cr), mercury (Hg) and cadmium (Cd) were monitored in three stations, namely, Dibrugarh Town (Tinkunia Ghat), Guwahati City (Bharalumukh) and Dhubri Town (Jahajghat), for the periods 2017–2018 and 2018–2019. The overall mean concentration was in the order Hg > Ni > Cr > Pb > Cd > As > Sb. Heavy metal pollution index was found in the order station 2 (344) > station 3 (320) > station 1 (317). Results clearly indicate the presence of heavy metal pollution in the Brahmaputra river, with very high levels in Guwahati City. Concentrations of Ni, Cr, Hg and Cd were found to be very high while As presence was marginally high. Concentration of Pb and Sb were nearly the prescribed World Health Organization and Bureau of Indian Standards limits. Multivariate analyses suggest that the heavy metal pollution is linked to similar sources in all the sampled sites. Further, the river restoration assessment revealed that citizens are willing to pay an average of INR 22.6 (USD 0.30) for restoring the water quality. Therefore, given the high levels of heavy metal contamination witnessed in the Brahmaputra river and citizens willingness to contribute towards restoring its water quality, the need for an appropriate river restoration strategy and water policy is strongly felt as an outcome of this study.

The anthracite granules were coated with iron oxide by a solution combustion synthesis method in a muffle furnace oven. As for iron precursor, an iron-containing precipitate of water treatment plants was used. The influence of four different reducing reagents on surface phase composition and properties of the modified materials was investigated. Obtained samples were investigated using different diffraction and spectroscopic methods. Using the solution combustion synthesis method, anthracite granules formed fine dispersed and crystalline structures of iron oxides on their surface with the iron content up to 40.7 wt%. This had a positive effect on the catalytic capacity of the material for deironing of underground water as well as for the increase in specific surface area. The catalytic properties of the obtained samples and the effectiveness of deferrization of groundwater were investigated. The use of tested materials makes it possible to reduce of catalytic layer height of the filter media from 50 to 20 cm for the filtration rate 12 m/h and enhance the treatment efficiency during the first start-up of filters after regeneration up to 3 times.

Dissolved silicate (DSi) and particulate silica (PSi) concentrations were measured at Arakawa River and at sewage treatment plants (STP) during October 2018 to October 2019. These included flooding observations after super Typhoon Hagibis. At ordinary water levels, the STP effluents were found to be the largest source of DSi in the river. Although DSi concentrations during the flooding events (165 μmol L⁻¹) decreased by about 25% compared to that of ordinary water level (221 μmol L⁻¹), PSi was more than sixteen times higher value (301 μmol L⁻¹) compared to that of ordinary water level (18 μmol L⁻¹). Loading amounts of DSi and PSi (± 1 standard error) were 1.5 × 10⁸ (± 0.1 × 10⁸) and 0.15 × 10⁸ (± 0.02 × 10⁸) mol year⁻¹, respectively, excluding the data of Typhoon Hagibis. Loading amounts during flooding events of DSi and PSi were 1.2 × 10⁸ (± 0.1 × 10⁸) and 2.4 × 10⁸ (± 0.4 × 10⁸) mol 15 days⁻¹, respectively. Although the silica loading at ordinary water level was mainly derived from DSi, the silica loading during flooding events was extremely large due to both high level of DSi and PSi; moreover, it was higher than the annual loading amount.

The availability of clean water from the already scarce sources is threatened by continuous addition of contaminated industrial and of abattoir waste into watercourses globally. The aim of the current study was to reduce the amount of waste produced, to decrease pollution derived from discharge of effluent meat wastewater, and also to minimise environmental health risk. This was all achieved by successfully synthesising a natural biopolymer chitin chitin-chitosan derivative derived from crab shell waste. Characterisation of the chitin polymer using physicochemical properties like yield, ash content, degree of acetylation, solubility, intrinsic viscosity, and molecular weight indicated that crab shell waste was a good source of chitin. This polymer was later deacetylated to form chitosan and then cross-linked with s-methylbutylamine to form chitin-chitosan adsorbent. The effectiveness of the above-modified product in purifying meat wastewater was conducted by means of comparative testing using hydride gas atomic absorption spectroscopy. The results of the qualitative and quantitative analysis showed that chitosan cross-linked s-methylbutylamine was efficient in removing the following metal ions: Cu (II), Zn (II), Cr (II), Pb (II), and Cr (II). The highest removal percentage was Cr (IV) and Pb (II) (95.45 and 92.66%), while Zn (II) and Fe (II) were 87.32 and 67.48%. The lowest percentage recovery of 38.55% was observed for the metal Cr. From the current study, it was evident that the cross-linked can significantly reduce the metal concentration in meat wastewater before it is released in the aquatic environment. Therefore, properly permitted international waste disposal methods should be employed to reduce adverse effects on the receiving environment.

Despite the benefits of shellfish consumption, the bioaccumulation of heavy metals in shellfish can endanger consumer’s health. The consumption of seafood in Shenzhen (a fast-developing metropolis in China) has received more and more attention. Arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), and lead (Pb) in ten common shellfish species and associated health risks were analyzed for Shenzhen’s consumers by evaluating estimated weekly intake (EWI), non-carcinogenic and carcinogenic health risks to children, adolescents, and adults. In this study, 50 shellfish samples were collected in total. The results showed that the levels of inorganic arsenic (iAs) in Babylonia areolata exceeded the maximum permissible limit set by the food safety guidelines (0.5 mg/kg), while other elements were below the limit in the present guidelines (Ministry of Health of the People’s Republic of China, GB 2762-2012). EWI values of children, adolescents, and adults were all lower than provisional tolerable weekly intakes (PTWIs) of all shellfish species. The analysis of total target hazard quotients (TTHQ) showed that the ingested B. areolata in children, adolescents, and adults were all at non-carcinogenic risks; the consumption of Argopecten irradians and Chlamys farreri would pose non-carcinogenic risks for children only. In all age groups, the consumption of A. irradians, B. areolata, C. farreri, and Crassostrea ariakensis would lead to lifetime cancer risk due to Cd bioaccumulation, with toxicity of Pb and iAs to be acceptable and negligible.

Although hospital wastewaters (HWWs) are usually discharged in urban sewage systems, their separate treatment has several benefits, such as the specific treatment of potential toxics as well as avoidance of further dilutions. In this work, an integrated industrial pilot plant (2200 L) corresponding to the technology SeMPAC® is proposed and validated for such purpose. The process consists of a sequential batch reactor (SBR) connected to an external submerged microfiltration membrane, in which powdered activated carbon (PAC) is directly added into the biological reactor to enhance the removal of the organic micropollutants (OMPs). The combination of different redox conditions in the SBR, as well as the operation at long sludge retention times (SRTs) and high biomass concentrations favored OMP biotransformation in the SBR, being their final removal efficiencies enhanced clearly after PAC addition, especially for the recalcitrant compounds. A periodical renewal of the adsorbent is necessary to overcome its gradual saturation. The main operational conditions were influenced by (i) the recalcitrant OMP carbamazepine, which defines the PAC dosage; (ii) the easily degradable OMP ibuprofen, which can be used to optimize the duration of the aerobic cycle; and (iii) the denitrification efficiency, which defines the correct time length of the anoxic period.