Seaweeds as bioindicators of heavy metals off a hot spot area on the Egyptian Mediterranean Coast during 2008–2010

Concentrations of Cu, Zn, Cd, Pb, Ni, Co, Fe, Mn, and Hg were measured successively in water, sediments, and six macroalgal species belonging to three algal classes during 3 years (2008–2010) from Abu Qir Bay, Alexandria, Egypt: Chlorophyceae (Enteromorpha compressa, Ulva fasciata), Phaeophyceae (Padina boryana), and Rhodophyceae (Jania rubens, Hypnea musciformis, Pterocladia capillacea). The study aimed to assess the bioaccumulation potential of the seaweeds, as well as to evaluate the extent of heavy metal contamination in the selected study site. Metals were analyzed using atomic absorption spectrophotometry coupled with MH-10 hydride system. The obtained data showed that the highest mean concentrations of Cu, Zn, Fe, and Mn were recorded in E. compressa; Cd, Ni, and Hg exhibited their highest mean concentrations in P. boryana, while Pb and Co were found in J. rubens. Abundance of the heavy metals in the algal species was as follow: Fe?>?Mn?>?Zn?>?Pb?>?Ni?>?Co?>?Cu?>?Cd?>?Hg. E. compressa showed the maximum metal pollution index (MPI) which was 11.55. Bioconcentration factor (BCF) for the metals in algae was relatively high with a maximum value for Mn. The Tomlinson pollution load index (PLI) values for the recorded algal species were low, which ranged between 1.00 in P. boryana and 2.72 in E. compressa. Enrichment factors for sediments were low fluctuating between 0.43 for Hg to 2.33 for Mn. Accordingly, the green alga E. compressa, brown alga P. boryana, and red alga J. rubens can be nominated as bioindicators. Based on MPI and PLI indices, Abu Qir Bay in the present study is considered as low-contaminated area.     

Assessment of tap water quality and corrosion scales from the selected distribution systems in northern Pakistan

Corrosion deposits formed within drinking water distribution systems deteriorate drinking water quality and resultantly cause public health consequences. In the present study, an attempt was made to investigate the concurrent conditions of corrosion scales and the drinking water quality in selected water supply schemes (WSS) in districts Chitral, Peshawar, and Abbottabad, northern Pakistan. Characterization analyses of the corrosion by-products revealed the presence of α-FeOOH, γ-FeOOH, Fe₃O₄, and SiO₂ as major constituents with different proportions. The constituents of all the representative XRD peaks of Peshawar WSS were found insignificant as compared to other WSS, and the reason could be the variation of source water quality. Well-crystallized particles in SEM images indicated the formation of dense oxide layer on corrosion by-products. A wider asymmetric vibration peak of SiO₂ appeared only in Chitral and Abbottabad WSS, which demonstrated higher siltation in the water source. One-way ANOVA analysis showed significant variations in pH, turbidity, TDS, K, Mg, PO₄, Cl, and SO₄ values, which revealed that these parameters differently contributed to the source water quality. Findings from this study suggested the implementation of proper corrosion prevention measures and the establishment of international collaboration for best corrosion practices, expertise, and developing standards.     

Population, environment and poverty in Pakistan: linkages and empirical evidence

This study explores the interlinkages among population, environment and poverty and presents empirical evidence in a developing country like Pakistan. It gives alternative views on population environment linkages. It explains poverty trap, market based harmony, and dual effect of poverty on the basis of a link between population growth and natural resource degradation. In addition, the paper also highlights social and political instability through population-poverty-environment spiral. It also presents empirical evidence on population-environment-poverty nexus in Pakistan. It also compares environmental sustainability index and human development index for selected Asian countries. The paper also gives scores for different components of environmental sustainability index for Pakistan and compares these with India. The paper concludes that the causal relationship between poverty and environment works in both directions, often through changes in GDP and population. Population stress does not have any significant direct effect on all aspects of environmental status in Pakistan.

Simplified Fabrication of Optically Transparent Composites Reinforced with Nanostructured Chitin

Optically transparent films reinforced with micro to nano scale chitin particles were successfully developed in this study. Chitin composites based on micro scale particles which are larger than the optical wavelength do not cause light scattering provided that chitin particles are composed of nano structure networks which allow monomer impregnation and polymerization. This could lead a simplified process for fabricating transparent composites. The composites reinforced by the chitin micro particles not only retained the transparency of the plastic but also helped the effectiveness of its co-efficient of thermal expansion as similar to chitin nanofibers. Furthermore, chitin nanofibers transparent films are thermally stable against temperature as high as 200 °C for a long period of time. This could lead to number of important commercial applications, and is a significant move towards the sustainable utilization of marine bio-resources.     

Genotoxicity of ferric oxide nanoparticles in Raphanus sativus: Deciphering the role of signaling factors, oxidative stress and cell death

We have studied the genotoxic and apoptotic potential of ferric oxide nanoparticles(Fe_2O_3-NPs) in Raphanus sativus(radish).Fe_2O_3-NPs retarded the root length and seed germination in radish.Ultrathin sections of treated roots showed subcellular localization of Fe_2O_3-NPs,along with the appearance of damaged mitochondria and excessive vacuolization.Flow cytometric analysis of Fe_2O_3-NPs(1.0 mg/m L) treated groups exhibited 219.5%,161%,120.4% and 161.4% increase in intracellular reactive oxygen species(ROS),mitochondrial membrane potential(ΔΨm),nitric oxide(NO) and Ca2+influx in radish protoplasts.A concentration dependent increase in the antioxidative enzymes glutathione(GSH),catalase(CAT),superoxide dismutase(SOD) and lipid peroxidation(LPO) has been recorded.Comet assay showed a concentration dependent increase in deoxyribonucleic acid(DNA) strand breaks in Fe_2O_3-NPs treated groups.Cell cycle analysis revealed 88.4% of cells in sub-G1 apoptotic phase,suggesting cell death in Fe_2O_3-NPs(2.0 mg/m L) treated group.Taking together,the genotoxicity induced by Fe_2O_3-NPs highlights the importance of environmental risk associated with improper disposal of nanoparticles(NPs) and radish can serve as a good indicator for measuring the phytotoxicity of NPs grown in NP-polluted environment.     

Validation of plant based bioassays for the toxicity testing of Indian waters

Plant-based bioassays have recently gained remarkable popularity among the toxicological/eco-toxicological assessment procedures. The reasons for their wide use are comparative simplicity, sensitivity, and cost-effectiveness as well as a good correlation with other toxicity tests. The present study describes the use of two plant bioassays, Allium cepa test and seed germination test in the evaluation of the toxicity/genotoxicity of industrial waste water and river water and standardization with the commonly occurring pollutants in Indian waters namely heavy metals and phenolics. Both tests were standardized to suit the Indian conditions, and the local varieties were used. Both bioassays responded significantly with the test range of heavy metals and phenolics. The toxicity of heavy metals was in the order of Cu > Ni > Cd in both the tests whereas 2,4-dinitrophenol was the most toxic among the phenolic compounds. Cabbage, millet, and cucumber, respectively, were found to be the most sensitive in the seed germination test for the test heavy metals and phenols. Significant amounts of chromosomal abnormalities including bridges, stickiness, and fragmentations were recorded with both the industrial waste water and the XAD concentrated river water samples by A. cepa test.     

SARS-CoV-2 variants and environmental effects of lockdowns,masks and vaccination: a review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is continuously evolving and four variants of concern have been identified so far, including Alpha, Beta, Gamma and Delta variants. Here we review the indirect effect of preventive measures such as the implementation of lockdowns, mandatory face masks, and vaccination programs, to control the spread of the different variants of this infectious virus on the environment. We found that all these measures have a considerable environmental impact, notably on waste generation and air pollution. Waste generation is increased due to the implementation of all these preventive measures. While lockdowns decrease air pollution, unsustainable management of face mask waste and temperature-controlled supply chains of vaccination potentially increases air pollution.

     

Impact of climate factors on cyanobacterial dynamics and their interactions with water quality in South Taihu Lake,China

Cyanobacterial bloom events in South Taihu Lake cause serious water quality problems and disturb aesthetic view of lake’s environment. In this study, correlations between cyanobacterial blooms and hydro-meteorological factors, including water quality, temperature and precipitation were investigated. Results demonstrated that South Taihu Lake was heavily affected by cyanobacteria and the proliferation of cyanobacteria due to variations in hydro-meteorological factors and water quality conditions. Water quality parameters, including COD, NH₃-N, TN and TP improved significantly since 2008 even at an elevated cyanobacterial bloom situation. Correlation analyses have shown that the development of cyanobacterial density and chlorophyll a concentration was sensitive to a wider temperature variation. The optimum temperature for cyanobacteria was 20°C, while extremely low and high temperatures were found to suppress their growth. Moreover, unusual rainfall patterns were measured during the study period (2003–2009), which showed an adverse impact on cyanobacterial development. Findings from this study suggested that seasonal lake’s water quality monitoring; suitable treatment of cyanobacterial blooms and strict policy implementation can solve the water quality issues in highly eutrophic lakes like Taihu.