The quality of the water from Lake Bosomtwe was assessed to aid in the conservation decision on the lake. Twenty-six parameters of physico-chemical, bacteriological, and organic effects and major and trace ions were evaluated using the principal component analysis. The levels of these parameters were also compared with surface water benchmarks of Ghana EPA, WHO, EU, US EPA and CCEM. As prescribed by the benchmarks of these regulatory bodies, the mean levels of temperature, pH, dissolved oxygen, total suspended solids, total dissolved solids, nitrates, phosphate, biochemical oxygen demand, chemical oxygen demand, total hardness, conductivity, alkalinity, turbidity and fluorine did not signal any lake pollution, but sulphate, total and faecal coliforms, chlorophyll-a, cadmium and mercury showed pollution tendencies. Temperature, pH, dissolved oxygen, total suspended solids, total dissolved solids, nitrates, phosphate, sulphate and total coliform bacteria were found to be the main parameters that drive 71.2% of the limnological characteristics of the lake water and deserve careful consideration in designing conservation strategies for the lake.

In order to evaluate the impact on water quality of the abandoned Sidi Kamber mine in Skikda, NE Algeria, Pb, Zn, Cd, Fe, Cu, Mn and Ni metals were collected at surface water and groundwater, from twenty eight sites located near the mine. Conventional hydrochemical methods, heavy metal pollution index (HPI) and multivariate statistical analysis techniques: correlation matrix (CM), principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used. Surface water results show that El-Souk River has a high level of pollution, but Guenitra dam water is less contaminated. Regarding the groundwater results, the wells and springs are not suitable for drinking. The overall quality estimated by HPI values of surface and groundwater are poor; they may pose a potential health risk to the local population. The PCA and HCA suggest that surface water and groundwater are contaminated by two sources: anthropogenic and natural. According to the obtained results, surface water and groundwater pollution state of this area raises serious concerns about health and environment.

Mercury pollution is an issue of global concern. In Colombia, the use of contaminated water for food crop irrigation and artisanal mining contributes to mercury pollution in soil, affecting food production and restoration of disturbed areas. Mycorrhizal fungi are symbionts that provide benefits to plants including resistance to heavy metals, but fungal effects on germination remain to be fully described. This study tested the effect of mercury and mycorrhizal fungi on Lactuca sativa seed germination. A 2x5 completely randomized factorial experiment was developed to assess the effect of five HgCl2 polluted treatments, two mycorrhizal treatments (i.e., with inoculum, without inoculum), and the interaction of both factors on seed germination, seedling root colonization, pH, and final water content. In samples with no mercury pollution, mycorrhizal fungi had an inhibitory effect on seed germination. Likewise, the effect of mercury on seed germination is significantly inhibitory. However, pots inoculated with arbuscular mycorrhizal fungi showed constant germination probabilities, independently of mercury concentration. According to the best model determined for the data, a key step in the mitigation of mercury toxicity in seed germination is to prevent substrate pH changes. The environmental conditions of the experiment contributed to densely activate populated biomass of inoculum, which promoted root invasion from various points. Overall, the presence of mycorrhizal fungi in seedbeds could lead to a reduced number of plant individuals. However, the use of fungal inoculum in polluted environments, highly contributes to plant establishment, which is relevant in further vegetable cultivations growing in soil polluted areas.

Plastic pollution is a threat to the environment because of its slow degradation rate and high usage. The aim of this study is to isolate plastic degrading microorganisms from soils. The soil samples used for this study were collected from dumpsites filled with plastic and plastic materials and the effectiveness of the degradation of plastic materials was studied over a period of six (6) weeks in broth and agar culture under laboratory conditions by weight determination method. Physicochemical and microbiological analysis was carried out on the various soil samples using standard protocols. The biodegradation of polyvinylchloride (PVC) was done in-vitro using the microorganisms isolated from the soil. Microorganisms that were able to degrade a higher percentage of the plastic materials were; Staphylococcus aureus, Streptococcus sp, Bacillus sp, Escherichia coli Aspergillus niger, Aspergillus flavus and Trichoderma viridae. The total viable count for bacteria and fungi were within the range of 11.8x105 CFU/g to 2.0x1010 CFU/g and 3.3x105 CFU/g to 0.1x1011 CFU/g respectively. Staphylococcus aureus, Streptococcus sp, Bacillus sp, Micrococcus sp, Aspergillus niger, Aspergillus flavus, and Trichoderma viridae, degraded plastic up to 25%, 31.2%, 25% 31.2%, 12%, 10% and 10% respectively. These isolates may be used to actively degrade plastics, thereby reducing the rate of plastic pollution in our ecosystem.

Worldwide there is an immense demand for plastic material that results in “white pollution”. Petrochemical-based plastic is used all over the world which leads to adverse impacts on every sphere of the earth. However, many steps have been taken to control this plastic pollution globally, such as chemical treatments, plastic waste incineration, sanitary landfilling, and 7 R programs. Still, plastic pollution is one of the major international problems. Non-biodegradable plastic would not eradicate from our environment until we have an economically feasible and more biodegradable substitute. In recent years algae, especially microalgae, have got attention worldwide, owing to their various applications. Microalgae is one of the sustainable ways of bioplastic synthesis as during cultivation it also purifies wastewater. This review paper has summarized various species of microalgae used for the synthesis of bioplastic, their cultivation system, and methods for bioplastic production by using microalgae biomass, followed by multiple challenges, solutions, and future prospects.

This study aimed at quantifying the heavy metal levels in soils and vegetables sampled from five suburban regions of Nairobi, Kenya. Using inductively coupled plasma- mass spectrometry (ICP-MS) the metals were quantified from the samples. The assayed heavy metals including Cd, Cr, Co. Cu, Fe, Hg, Mn, Ni, Pb, Zn and the metalloid arsenic were elevated beyond the reference values in both soils and vegetables. High pollutant levels in soils were affiliated to use of industrial and domestic wastewater for irrigation, application of heavy metal containing agrochemicals and geogenic sources of the pollutants. In collard leaves, the uptake of contaminated water via the roots and subsequent accumulation in the leaves was attributable to the observed results. The total hazard quotient (THQ) and hazard index (HI) as a result of arsenic and Hg was >1 in all sampled sites and >10, respectively for both indices and heavy metals. Similarly, the cancer risk (CR) and target cancer risk (TCR) from consumption of collard was greater than the recommended levels of 10-6 and 10-4, respectively with exception of Pb. The indices were indicative of negative non-carcinogenic and carcinogenic effects of consuming the vegetables to the community of the study area. The results of the study, though preliminary, suggest the need to safeguard the health of communities in the study area to ensure that they do not consume heavy metal contaminated vegetables due to the established health effects of such pollutants.

peer reviewed | This study investigated for the first time the oxidative biomarkers responses in all larval stages of sea urchin. The contamination effects were reproduced by using contaminated seawater to concentrations measured in the area adjacent to an old asbestos mine at factors of 5 and 10. The results suggested that the concentrations were not sufficiently high to induce a major oxidative stress. The biometric differences make this method a more sensitive approach for assessing the effects on sea urchin larvae. Measurements of specific activities of antioxidant enzymes at each stage suggested a high capacity of the larvae to respond to oxidative stress. This normal activity of the organism must be considered in future research. This work also highlighted the importance of spawners provenance in ecotoxicological studies. These data are essential to better understand the stress responses of sea urchin larvae and provide baseline information for later environmental assessment research.

International audience | Metal pollution in rivers should not be overlooked before their entry into the sea. However, there are few studies for estimating such contamination in rivers entering the Algerian coastal waters. Semimonthly quantification of dissolved and particulate metals, near the mouths of two industrial-tainted rivers, El Harrach and Mazafran rivers, was carried out during a period of one year. All the trace metals analyzed are originating from anthropogenic sources (EF > 1.5), with higher contamination of dissolved Pb, Cd, Zn and Ni and a slight degree of contamination of particulate Cu and Zn (0 < I geo < 1). Particulate metals show a stable complex with the particulate phase (e.g. 2 < LogK d < 6). The risk assessment results indicate that particulate Pb and Zn have a 33% likelihood of toxicity for adverse biological effects. A significant toxicity effect (ΣTUi >4) of the combined particulate metals (Pb, Cd, Cu, Zn, Cr, Ni and As) was primarily due to the higher particulate Cd, Zn, and Cr availability.

In the global COVID-19 epidemic, humans are faced with a new challenge. The concept of quarantine as a preventive measure has changed human activities in all aspects of life. This challenge has led to changes in the environment as well. The air quality index is one of the immediate concrete parameters. In this study, the actual potential of quarantine effects on the air quality index and related variables in Tehran, the capital of Iran, is assessed, where, first, the data on the pollutant reference concentration for all measuring stations in Tehran, from February 19 to April 19, from 2017 to 2020, are monitored and evaluated. This study investigated the hourly concentrations of six particulate matters (PM), including PM2.5, PM10, and air contaminants such as nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO). Changes in pollution rate during the study period can be due to reduced urban traffic, small industrial activities, and dust mites of urban and industrial origins. Although pollution has declined in most regions during the COVID-19 quarantine period, the PM2.5 rate has not decreased significantly, which might be of natural origins such as dust. Next, the air quality index for the stations is calculated, and then, the interpolation is made by evaluating the root mean square (RMS) of different models. The local and global Moran index indicates that the changes and the air quality index in the study area are clustered and have a high spatial autocorrelation. The results indicate that although the bad air quality is reduced due to quarantine, major changes are needed in urban management to provide favorable conditions. Contaminants can play a role in transmitting COVID-19 as a carrier of the virus. It is suggested that due to the rise in COVID-19 and temperature in Iran, in future studies, the effect of increased temperature on COVID-19 can be assessed. | peer reviewed

Microplastics (MPs) pollution in Tangxun Lake, the largest urban lake in China, was investigated. The average MPs pollution in sediment (1.81 ± 1.75 × 10⁴ items kg⁻¹) is at a high level, while the MPs in lakeshore water (917.77 ± 742.17 items m⁻³) is in the middle to low level compared with existing studies, which is related to the government's protection. Fragments and fibers are the most common shapes in sediment and water, respectively. MPs size <1 mm dominates in the sediment, while the MPs in water has a larger size. The distribution of MPs in the inner lake shows that pellets tend to “hidden” in sediments. Suspected MPs are randomly selected for polymer detection by Micro-Raman microscopy. Polypropylene (PP), polyethylene (PE) and polyethylene terephthalate (PET) are the most common polymer types in water, sediment and atmospheric deposition MPs samples. The input of wastewater, fishery and surrounding human activities are the main sources of MPs in sediment. Atmospheric deposition has a great impact on the distribution of MPs, while the contribution of surface runoff to lake MPs is not remarkable. In addition, MPs in sediments have exceeded the environmental carrying capacity. More attention should be focused on the sediment, where huge amounts of MPs are “hidden”.