The economic downturn in Nigeria and Structural Adjustment Programme led to the flooding of Nigerian market with imported used automobiles. Most of these vehicles needed refurbishing and reworking. The present study is a human health risk assessment of metal exposure resulting from reworking of imported used vehicles in Nigeria. Scrap paint dusts from 56 Japanese made cars were collected from 8 different mechanic villages (workshops A–H] in Southeastern Nigeria. Scrap paints were homogenized, mixed, divided into fine particles and digested by standard method. The filtrates were assayed of lead, manganese and copper with atomic absorption spectrophotometry (AAS). Workshop B has the highest concentration of Pb (4.26 ± 0.93). Manganese in workshops A and F were (3.31 ± 0.85) and (3.04 ± 0.47) respectively and were higher than the levels from workshops C, B, D, G and H. Copper in workshop D (7.11 ± 0.21) was significantly greater than the other workshops. The highest hazard quotient (HQ) through ingestion, inhalation and dermal exposures in adults were 9.44E−05 (workshop B), 4.20E−01 (workshop B) and 1.08E−05 (workshop D) respectively. The highest values for HQ through ingestion, inhalation and dermal in children were 8.82E−04, 7.61E−01 and 2.86E−05 all in workshop B respectively. For children, the highest carcinogenic risk levels were 7.05E−08, 6.09E−05 and 2.29E−10 for ingestion, inhalation and dermal exposures respectively. In adults, the carcinogenic risk levels were 7.55E−09, 3.39E−05 and 8.67E−10 for ingestion, inhalation and dermal exposures respectively. Chronic exposure to scrap car paint dusts may be of significant public health importance in Nigeria as this may add to the body burden of some heavy metals.

Selective adsorption of Pb(II) and Cr(VI) by surfactant-modified and unmodified zeolites is discussed in this paper. The influences of pH, ionic strength, temperature, and adsorption time on Cr(VI) and Pb(II) adsorption are studied, The characteristics of the surface and inner structures of zeolites before and after modification are analyzed through infrared spectroscopy, scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, and zeta potential measurement. Results show that the characteristics of electric charge on the zeolite surface had changed after modification, which resulted in selective adsorption of Cr(VI) and Pb(II). Moreover, kinetic study reveals that adsorption by the different zeolites coincides with the Langmuir model and pseudo-second-order kinetic equation. The intraparticle diffusion equation proves that the Cr(VI) adsorption is mainly electrostatic, whereas Pb(II) adsorption proceeds via intrapore and electrostatic adsorption on the zeolite surface. This difference in mechanisms endows selectivity of metal ion adsorption by the modified zeolites. This study provides a reference on zeolite modification for use in various applications, such as wastewater treatment.

The aim of this work is to assess the occurrence of Polycyclic aromatic hydrocarbons (PAHs) in the Tisza River and its main Romanian tributaries (Vişeu River and Iza River) and to establish the origin (pyrogenic/petrogenic) of pollution sources. Fifteen PAHs were investigated in surface water and sediment samples collected from three selected sampling point. The target compounds were isolated from the matrices by solid phase extraction for water samples and by ultrasound-assisted extraction for the sediment samples, respectively. The quantification of the target compounds was performed by HPLC coupled with a fluorescence detector. PAH diagnostic ratios, as the abundance ratio of 2–3 ring hydrocarbons to 4–6 ring hydrocarbons (LMW/HMW), ANT/(ANT + PHE), FLT/(FLT + PYR), B[a]A/(B[a]A + CHR), and IND/(IND+ B[g,h,i]P) were used as a tool for identification and assessment of the pollution emission sources. The results of the study showed that in the studied area, the total concentrations of PAHs detected in water samples ranged from 1.22 to 260.26 ng L⁻¹, while those in sediment samples varied from 4.94 to 10.62 μg kg⁻¹. Regarding the PAH pattern, mixed sources of pollution (pyrogenic and petrogenic) occur in both water and sediment samples. Thus, leaks of petroleum products and biomass, coal, and petroleum combustion are the main sources of pollution identified into the studied area.

Geological barriers play an important role in preventing pollution of groundwater. Basalts are common geological media; however, there have not been any studies that report the effect of basalt type on the metal ion adsorption performance. In this study, we explored the metal ion (Zn²⁺ and Cd²⁺) adsorption ability of two kinds of weathering basalts, the origin weathering basalt (WB) and the eluvial deposit (ED), both of which were derived from same basaltic formation. Characteristics of the sediments were examined by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, Barrett-Joyner-Halenda (BJH) measurement, and the rapid potentiometric titration (RPT) method. Batch experiments were performed to evaluate the Zn²⁺ and Cd²⁺ adsorption performance of WB and ED and how adsorption was affected by contact time, initial metal ion concentration, pH, and ionic strength. Despite WB and ED having similar chemical compositions, WB exhibited better adsorption than ED likely due to the fact that WB was rougher and had more small-sized spherical structures and stronger electrostatic forces. The adsorption process fits the Freundlich isotherm model well. The adsorption efficiency decreased with a decrease of pH (from 4 to 2) and with increasing ionic strength. These results suggest that a geological barrier composed of WB media might be able to effectively sequester metallic contaminants to prevent them from reaching groundwater.

Myocardial infarction is the acute condition of myocardial necrosis that occurs as a result of imbalance between coronary blood supply and myocardial demand. Air pollution increases the risk of death from cardiovascular diseases (CVDs). The aim of this study was to investigate the effects of particulate matter (PM) on oxidative stress, the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) messenger RNA (mRNA) level induced by ischemia–reperfusion injury, and the protective effects of vanillic acid (VA) in the isolated rat heart. Male Wistar rats were randomly divided into eight groups (n = 10), namely control, VAc, sham, VA, PMa (0.5 mg/kg), PMb (2.5 mg/kg), PMc (5 mg/kg), and PMc + VA groups. Particles with an aerodynamic diameter <10 μm (PM₁₀) was instilled into the trachea through a fine intubation tube. Two days following the PM₁₀ instillation, the animal’s hearts were isolated and transferred to a Langendorff apparatus. The hearts were subjected to 30 min of global ischemia followed by 60 min of reperfusion. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), xanthine oxidase (XOX), and lactate dehydrogenase (LDH) were measured using special kits. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine levels of iNOS and eNOS mRNA. An increase in left ventricular end-diastolic pressure (LVEDP), S–T elevation, and oxidative stress in PM₁₀ groups was observed. Ischemia–reperfusion (I/R) induction showed a significant augment in the expression of iNOS mRNA level and a significant decrease in the expression eNOS mRNA level. This effect was more pronounced in the PM groups than in the control and sham groups. Vanillic acid caused a significant decrease in LVEDP, S–T elevation, and also a significant difference in eNOS mRNA expression level, antioxidant enzymes, iNOS mRNA expression level, and oxidative stress occurred on myocardial dysfunction after I/R in isolated rat hearts. This study showed that PM₁₀ exposure had devastating effects on the myocardial heart, oxidative stress, and eNOS and iNOS mRNA expression levels. Vanillic acid was able to improve these parameters. Vanillic acid as a potent antioxidant could also provide protection against particulate matter-induced toxicity.

Mercury contamination in water has been an issue to the environment and human health. In this article, mercury in marine and oceanic waters has been reviewed. In the aquatic environment, mercury occurs in many forms, which depend on the oxidation-reduction conditions. These forms have been briefly described in this article. Mercury concentrations in marine waters in the different parts of the world have been presented. In the relevant literature, two models describing the fate and behavior of mercury in saltwater reservoirs have been presented, a conceptual model which treats all the oceans as one ocean and the “ocean margin” model, providing that the ocean margins manifested themselves as the convergence of continents and oceans, covering such geological features, such as estuaries, inland seas, and the continental shelf. These two conceptual models have been summarized in the text. The mercury content in benthic sediments usually reflects is level in the water reservoir, particularly in reservoirs situated in contaminated areas (mines, metallurgical plants, chemically protected crops). The concentrations of mercury and its compounds determined in the sediments in surface waters in the different parts of the world have been presented. Due to the fact that the pollution caused by mercury is a serious threat for the marine environment, the short paragraph about mercury bioaccumulation in aquatic organisms has been included. The cited data demonstrated a large scatter of mercury contents both between the fish species and the water areas. Mathematical models, valuable tools which provide information about the possible responses of ecosystems, developed to simulate mercury emissions, both at a small scale, for local water reservoirs, and at a global scale, as well as to model mercury bioaccumulation in the chain web of aquatic systems have been described.

The Platanus fruit fibers (PFFs) with unique hollow tubular structures were successfully utilized in the preparation of an efficient oil sorbents for the first time by chemical modification with acetic anhydride. The structure and morphology of the pristine PFFs (p-PFFs) and acetylated PFFs (a-PFFs) were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effects of acetic anhydride to PFFs ratio, catalyst concentration, reaction temperature, and time on the weight percent gain (WPG) and oil sorption capacity were particularly investigated in detail. The results showed the hydrophobic modification of p-PFFs contributed to the enhancement of the sorption capacity of a-PFFs for various oils and organic solvents. The sorption kinetic analysis indicated the oil sorption data were fitted well with a pseudo-second-order kinetic model. And the oil-filled a-PFFs exhibited high oil retention ability with less than 30 % of the sorbed oil lost after 2-h dripping. Moreover, a-PFFs showed little loss of initial sorption capacities after eight sorbing/desorbing cycles with the recovery of sorbents by n-hexane extraction. The natural renewable a-PFFs are proved to be a promising candidate for large-scale removal of spilled oils from water.

This study tested the efficacy of Zn-Al sulphate layered double hydroxides (LDH) as sorbent to remove antimony from circum-neutral solutions. Results of experimentation showed that Sb(V) in the anionic form Sb(OH)₆ ⁻ can be efficiently removed from aqueous solutions through an exchange process with the SO₄ ²⁻ present in the interlayer; total removal can be achieved within 6–24 h for A ≥2, where A is the ratio of the maximum theoretical anion exchange capacity (AEC) to the initial Sb concentration, both expressed in milliequivalents per liter. The complex rearrangement of the LDH structure to host Sb(OH)₆ ⁻ in the interlayer is correlated to an initial fast removal of the contaminant, followed by a progressive slowing down of the exchange process. The overall speed of the process is again a direct function of A; in practice, the sorbent dose should be carefully evaluated to balance cost/efficacy/timing of the water treatment. Comparison with previous studies documenting Zn-Al sulphate LDH efficacy as arsenate and molybdate sorbent indicates a comparable affinity for As(V) and Sb(V), higher than for Mo(VI). The results of this study reinforce the possible key role of Zn-Al sulphate LDHs in water treatment for pH ranging from circum-neutral to moderately alkaline, thanks to their capability to rearrange the original structure in order to host different-sized/charged anions.

This study was carried out to comparatively evaluate the bioaccumulation potency of Zn bulk and nanoparticles in Oreochromis niloticus and to investigate the induced hematological and histological alterations. Fish were exposed to ½ LC50/96 h values of both bulk and nano Zn meal for 7, 14, and 28 days. Concerning metal bioaccumulation factor (BAF), the data displayed that zinc nanoparticles (Zn NPs) had more efficiency to penetrate the studied tissues such as the liver, kidneys, gills, skin, and muscle. Hematological parameters named red blood cells (RBC), hemoglobin (Hb), and hematocrit (Hct) values were altered in Zn NPs treated groups after 14th and 28th days while these hematological parameters recovered to some extent in bulk particles (BPs) treated groups at the end of the experimental period. The changes in hematological parameters were found to be time dependent. Blood indices such as mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) revealed the presence of normocytic normochromic anemia in the studied groups at the most exposure periods except microcytic hypochromic anemia at the 7th day of bulk particles exposed fish. Based on histological end points, several alterations in the gills, liver, and kidney tissues were observed. Severely deformations were observed at NPs treated fish groups which varied between adaptive changes to tissue damage at the end of exposure period. The deformations were recorded to be increased in NPs exposed fish compared to BPs treated fish throughout the study periods.