Hazardous organic compounds in groundwater near Tehran automobile industry

Automobile service station waste assessment and promising biological treatment alternatives: a review

Unprecedented growth in the automobile sector has led to an increased number of automobile service stations across all major cities especially in the developing countries. These service stations release huge amounts of waste that contain objectionable levels of oil and grease (O&G) and heavy metals, amongst other environmentally toxic compounds. Not much literature is available on the hazardous nature, public health concerns, and sustainable treatment options of such an industrial waste. This review throws light on the nuisances caused by the automobile industry waste, the various conventional and promising physical-chemical remediation measures adopted, and the scope of bioremediation for the same. Work on the use of microbial enzymes such as lipases and microbial surface-active agents (biosurfactants) as emerging promising candidates for the bioremediation of metals and O&G contaminated automobile service centre wastewater and soil are especially highlighted in this review article. The adoption of constructed wetlands and regular scientific monitoring of service sector are the aspects that would prove to be critical in sustainable and ecological automobile service station waste management. Stricter environment regulations, along with the growing ecological and environmental awareness, call for stringent monitoring of the service station waste and its treatment in an environmentally sustainable manner. This review can effectively aid in revealing potential hazards of this industrial sectors and in policy making for effective environmental monitoring.

Evaluation of occurrence of organic, inorganic, and microbial contaminants in bottled drinking water and comparison with international guidelines: a worldwide review

The aim of this study was to evaluate the levels of inorganic and organic substances as well as microbial contaminants in bottled drinking water on a global scale. The findings were compared to WHO guidelines, EPA standards, European Union (EU) directive, and standards drafted by International Bottled Water Association (IBWA). Our review showed that 46% of studies focused on the organic contaminants, 25% on physicochemical parameters, 12% on trace elements, 7% on the microbial quality, and 10% on microplastics (MPs) and radionuclides elements. Overall, from the 54 studies focusing on organic contaminants (OCs) compounds, 11% of studies had higher OCs concentrations than the standard permissible limit. According to the obtained results from this review, several OCs, inorganic contaminants (IOCs), including CHCl3, CHBrCl2, DEHP, benzene, styrene, Ba, As, Hg, pb, Ag, F, NO3, and SO4 in bottled drinking water of some countries were higher than the international guidelines values that may cause risks for human health in a long period of time. Furthermore, some problematic contaminants with known or unknown health effects such as EDCs, DBP, AA, MPs, and some radionuclides (40K and 222Rn) lack maximum permissible values in bottled drinking water as stipulated by international guidelines. The risk index (HI) for OCs and IOCs (CHBrCl2, Ba, As, and Hg) was higher than 1 in adults and children, and the value of HI for CHCl3 in children was more than 1. Thus, further studies are required to have a better understanding of all contaminants levels in bottled drinking water.

Comparative physicochemical properties and toxicity of organic UV filters and their photocatalytic transformation products

Transformation products (TPs) of micropollutants contaminating our water resources have become an emerging issue due to the potential threats they pose to environmental and human health. This study investigated the transformation chemistry, toxicity, physicochemical properties and environmental behavior resulting from photocatalytic transformation of organic UV filters as model micropollutants. 3-Benzylidene camphor (3-BC), 4-hydroxybenzophenone (4-HB) and octocrylene (OC) were effectively degraded by UV-A/TiO₂ treatment, with TPs identified and characterized with high resolution mass spectrometry. Nitrated-TPs were observed to be formed in the presence of nitrite and nitrate for 3-BC and 4-HB, suggesting that the transformation process could be altered by components in the water matrix. Vibrio fischeri bioluminescence inhibition assay revealed an increase in toxicity of TPs derived from photocatalytic treatment, with quantitative structure-activity relationship model (ECOSAR) predicted an enhanced toxicity of individual TPs' after transformation. Assessment of physicochemical properties and environmental behavior suggested that TPs as compared to parent organic UV filters, may represent even greater hazards due to their increased water solubility, persistence and mobility - in addition to retaining the parent organic UV filter's toxicity. The results provide important information relevant to the potential risks for the selected organic UV filters, and their corresponding transformation products.

Tissue-Specific Accumulation and Antioxidant Defenses in Flounder (Paralichthys olivaceus) Juveniles Experimentally Exposed to Methylmercury

Methylmercury (MeHg) is the most toxic form of mercury and can accumulate in the cells of marine organisms, such as fish, causing adverse effects on various physiological functions. This study examined MeHg accumulation and its toxicological role in antioxidant defenses in tissues, including the liver, gills, and muscle of flounder (Paralichthys olivaceus) juveniles. After 30 d of MeHg exposure (0, 0.1, 1.0, 10.0, and 20.0 µg L^-1), the accumulation of MeHg in the three tissues correlated positively with the concentration of MeHg and exhibited tissue specificity in the order of liver > gills > muscle. Among the antioxidant markers, the activities of SOD (superoxide dismutase) and GST (glutathione S-transferase) as well as the content of glutathione (GSH) in the liver and gills were induced at 0.1-10.0 µg L^-1 but repressed at 20.0 µg L^-1. The activities of SOD and GST and the content of GSH in the muscle significantly increased with increasing MeHg concentration. Catalase (CAT) activity in the liver was induced at 0.1-1.0 µg L^-1 but inhibited at 10.0-20.0 µg L^-1, whereas exposure to MeHg did not remarkably affect CAT activity in the gills and muscle. The levels of lipid peroxidation (LPO) increased dose dependently, showing tissue specificity with the highest level in the liver, then the gills, followed by muscles. Overall, higher sensitivity to oxidative stress induced by MeHg was detected in the liver than the gills and muscle. These findings improve our understanding of the tissue-specific accumulation of heavy metals and their roles in antioxidant responses in marine fish subjected to MeHg exposure.

Pollution characteristics and underlying ecological risks of primary semi-volatile organic compounds (SVOCs) in urban watersheds of Shanghai, China

We investigated the pollution characteristics of ninety semi-volatile organic compounds (SVOCs) in the rivers and lakes of Shanghai. Total concentrations of Σ₉₀SVOCs in water and sediment samples from 30 sites ranged from 1.47 to 19.5 μg/L and 2.38 to 9.48 mg/kg, respectively. PAEs and PAHs were the major contaminant compounds found in all samples. OCPs accounted for less than 3% of the total concentrations of Σ₉₀SVOCs and other SVOCs were either not detected or only detected in trace amounts. Our results indicated that domestic swage, industrial wastewater, petroleum products, and other human activities were the pollutant sources to the water and sediment. It is noteworthy that products that contain the banned chemicals HCH and DDT are still under use within the studied areas. Ecological and health risk assessment results showed that dieldrin and BBP have the potential to cause adverse effects on the environment, while B(a)p and DBP have high carcinogenic risks to humans.

Anthropogenic Effects on Hydrogeochemical Characterization of the Shallow Groundwater in an Arid Irrigated Plain in Northwestern China

Many irrigated plains in arid and semi-arid regions have groundwater quality issues due to both intensive human activity and natural processes. Comprehensive studies are urgently needed to explore hydrogeochemical evolutions, investigate possible pollution sources, and understand the controls on groundwater compositions in such regions. Here, we combine geostatistical techniques and hydrogeochemical assessments to characterize groundwater quality over time in the Yinchuan Plain (a typical irrigated plain in China), using 12 physicochemical variables derived from sampling in 600 and 602 wells in 2004 and 2014, respectively. Our results show that groundwater-rock interactions and evaporation are the key natural factors controlling groundwater compositions. Hydrogeochemical water types in both 2004 and 2014 were Ca-HCO3, Na-Cl, and mixed Ca·Mg-Cl. Along with the hydrogeochemical compositions, we used ionic ratios and the saturation index to delineate mineral solution reactions and weathering processes. Dissolution of gypsum, halite, fluorite, and mirabilite, along with silicate weathering and cation exchange, were identified in the study area. Our results indicated rising ion concentrations in groundwater, which could be the result of anthropogenic influences. Increasing total hardness and nitrates over the study period were most likely caused by agricultural activity and the discharge of waste water from human residential areas.

Phthalate acid esters (PAEs) accumulation in coastal sediments from regions with different land use configuration along the Persian Gulf

Phthalate acid esters (PAEs) are widely used as plasticizers in various plastic products and have aroused considerable concern over their ubiquitous presence and potentially hazardous effects on the environment. This research provides the first data on PAEs distribution in the sediments of northern part of the Persian Gulf. To determine the concentration of 16 PAEs, 26 samples of sediments were collected from industrial stations (IS), urban stations (US), agricultural stations (AGS), and natural field stations (NS) from Asalouyeh Harbor coasts from Nov 2016 to Jan 2017. The mean values of Ʃ16PAEs in the samples taken from IS, AGS, US, and NS were 78.08, 11.69, 46.56, and 5.180 µg/g, respectively. The results indicated that the mean concentrations of Ʃ16PAEs in the samples taken from IS and AGS areas were significantly higher (p < 0.05) than the ones taken from US and NS areas. The order of PAEs concentrations in sediment samples were as di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DnBP), butylbenzyl phthalate (BBP), and di-n-octyl phthalate (DnOP), respectively. DEHP was detected in all collected samples and the mean ± SD of its concentration in the IS, US, AGS, and NS regions were as 28.15 ± 4.9, 4.040 ± 0.53, 11.58 ± 1.2, and 1.780 ± 0.78 µg/g, respectively. The major sources of PAEs in the sediments collected from the study region were associated with the industrial and agricultural activities. The findings of this study indicated that the sediments of the Asalouyeh coasts are heavily contaminated with PAEs. They have shown potential ecotoxicological effects on the aquatic organisms and benthic. Therefore, more attention should be paid to prediction of the marine ecosystem in this region by the authorities.

Characteristics, distribution and sources of polychlorinated biphenyls (PCBs) in coastal sediments from the heavily industrialized area of Asalouyeh, Iran

In this research, the levels of polychlorinated biphenyls (PCBs) were investigated in the marine sediments of Asaluyeh harbor, in the Persian Gulf. The samples were taken from industrial, semi-industrial and urban regions. The mean concentration levels of total (Σ) 18 detected PCBs were 514.32, 144.67 and 31.6 pg/g dw for the industrial, semi-industrial and urban sampling stations, respectively. Based on a multivariate statistical analysis, it was found that high contamination levels of PCBs in sediments collected along the Persian Gulf were associated with releases from local industries. Total organic carbon (TOC) content was significantly and positively correlated with the concentrations of PCB congeners. World Health Organization toxic equivalents (TEQs) for PCBs ranged from 0.04 to 2.66 pg TEQ/g dry weight (dw) in the coastal sediments. The TEQ values in this study were higher than many reported worldwide in the literature for sediments. This suggests that there are high levels of contamination in the area due to industrial and other human activities.

Application of ascorbic acid to enhance trichloroethene degradation by Fe(III)-activated calcium peroxide

The enhancement effect of an environmentally friendly reducing agent, ascorbic acid (AA), on trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) was evaluated. The addition of AA accelerated the transformation of Fe(III) to Fe(II), and the complexation of Fe(III)/Fe(II) with AA and its products alleviated the precipitation of dissolved iron. These impacts enhanced the generation of reactive oxygen species (ROSs). Investigation of ROSs using chemical probe tests, electron paramagnetic resonance (EPR) tests, and radical scavenger tests strongly confirm large production of hydroxyl radicals (HO•) that is responsible for TCE degradation. The generation of Cl- from the degraded TCE was complete in the enhanced CP/Fe(III)/AA system. The investigation of solution matrix effects showed that the TCE degradation rate decreases with the increase in solution pH, while Cl-, SO42- and NO3- anions have minor impact. Conversely, HCO3- significantly inhibited TCE degradation due to pH elevation and HO• scavenging. The results of experiments performed using actual groundwater indicated that an increase in reagent doses are required for effective TCE removal. In summary, the potential effectiveness of the CP/Fe(III)/AA oxidation system for remediation of TCE contaminated groundwater has been demonstrated. Additional research is needed to develop the system for practical implementation.

A new bioindicator, shell of Trachycardium lacunosum, and sediment samples to monitors metals (Al, Zn, Fe, Mn, Ni, V, Co, Cr and Cu) in marine environment: The Persian Gulf as a case

BACKGROUND

The present work was designed to detect heavy metal contents of Al, Zn, Fe, Mn, Ni, V, Co, Cr and Cu in sediments and shells of the Trachycardium lacunosum collected in polluted and unpolluted areas along the Persian Gulf.

METHODS

The samples were taken from surface sediments (0-10 cm) and shells of Trachycardium lacunosum in two separated areas (polluted and unpolluted) in northern part of the Persian Gulf, Asaluyeh Bay, during summer 2013. The prepared samples were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES).

RESULTS

Based on the results, all measured metals including Al, Zn, Fe, Mn, Ni, V, Co, Cr and Cu were meaningfully higher in the sediment samples of polluted area compared to unpolluted area and the order of metal concentrations in the sediment samples were Cr > Co > V > Ni > Zn > Cu > Fe > Al > Mn in polluted area. In the case of shell samples of Trachycardium lacunosum, polluted area contained significantly higher contents of Al, Zn, Fe, Mn, Ni, Co, Cr and Cu compared to unpolluted area and the order of metal concentrations in the shell samples were Fe > Zn > Al > Mn > Cu > Cr > Ni > Co in the polluted area.

CONCLUSION

It was concluded that shells of the Trachycardium lacunosum can be used as a suitable bioindicator for heavy metals in the aquatic environment. Results confirmed that due to the possible contaminations by oil and gas activities near the polluted area perennial monitoring and mitigation measures is extremely necessary.

Application of calcium peroxide activated with Fe(II)-EDDS complex in trichloroethylene degradation

This study was conducted to assess the application of calcium peroxide (CP) activated with Fe(II) chelated by (S,S)-ethylenediamine-N,N'-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O2(-) promoted HO generation. Cl(-), HCO3(-) and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed.

Polycyclic aromatic hydrocarbons (PAHs) in coastal sediments from urban and industrial areas of Asaluyeh Harbor, Iran: distribution, potential source and ecological risk assessment

The distribution and toxicity levels of 16 EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) in the sediments of Asaluyeh shore, Iran were investigated. The total concentrations of the PAHs in surface sediments ranged from 1,054 to 17,448 ng/g dry weights with a mean concentration of 8,067 ng/g. The spatial distribution of PAHs showed that PAH levels are much higher in the industrial areas in comparison with urban areas. Based on diagnostic ratios, pyrogenic activities were dominant sources of PAHs pollution in sediments comparing petroleum sources. The toxic equivalent concentrations (TEQ Carc) of PAHs ranged from 172 to 2,235 ng TEQ/g with mean value of 997.9. Toxicity levels were evaluated using sediment quality guidelines (SQGs) and toxic equivalent factors. Samples were collected from industrial and urban stations in Asaluyeh shores. According to SQGs, ΣPAHs concentrations in sediments of urban areas were below the ERL (effects range low), but the industrial samples had ΣPAHs concentrations between ERL and ERM (effects range median). Furthermore, ΣHPAHs (heavy PAHs) and some individual PAHs in some industrial stations exceeded ERM, indicating adverse ecological risk effects frequently occur. Findings demonstrate that the surface sediment from Asaluyeh shore is highly to very highly contaminated with PAHs.

Transformation efficiency and formation of transformation products during photochemical degradation of TCE and PCE at micromolar concentrations

BACKGROUND

Trichloroethene and tetrachloroethene are the most common pollutants in groundwater and two of the priority pollutants listed by the U.S. Environmental Protection Agency. In previous studies on TCE and PCE photolysis and photochemical degradation, concentration ranges exceeding environmental levels by far with millimolar concentrations of TCE and PCE have been used, and it is not clear if the obtained results can be used to explain the degradation of these contaminants at more realistic environmental concentration levels.

METHODS

Experiments with micromolar concentrations of TCE and PCE in aqueous solution using direct photolysis and UV/H2O2 have been conducted and product formation as well as transformation efficiency have been investigated. SPME/GC/MS, HPLC/UV and ion chromatography with conductivity detection have been used to determine intermediates of degradation.

RESULTS

The results showed that chloride was a major end product in both TCE and PCE photodegradation. Several intermediates such as formic acid, dichloroacetic acid, dichloroacetaldehyede, chloroform, formaldehyde and glyoxylic acid were formed during both, UV and UV/H2O2 treatment of TCE. However chloroacetaldehyde and chloroacetic acid were only detected during direct UV photolysis of TCE and oxalic acid was only formed during the UV/H2O2 process. For PCE photodegradation, formic acid, di- and trichloroacetic acids were detected in both UV and UV/H2O2 systems, but formaldehyde and glyoxylic acid were only detected during direct UV photolysis.

CONCLUSIONS

For water treatment UV/H2O2 seems to be favorable over direct UV photolysis because of its higher degradation efficiency and lower risk for the formation of harmful intermediates.

Polycyclic Aromatic Hydrocarbons in drinking water of Tehran, Iran

Distribution and seasonal variation of sixteen priority polycyclic aromatic hydrocarbons (PAHs) were investigated in the drinking water of Tehran, the capital of Iran. Detected single and total PAHs concentrations were in the range of 2.01-38.96 and 32.45-733.10 ng/L, respectively, which were quite high compared to the values recorded in other areas of the world. The average occurrence of PAHs with high molecular weights was 79.55%; for example, chrysene occurred in 60.6% of the samples, with a maximum concentration of 438.96 ng/L. In addition, mean carcinogen to non-carcinogen PAHs ratio was 63.84. Although the concentration of benzo[a]pyrene, as an indicator of water pollution to PAHs, was lower than the guideline value proposed by World Health Organization (WHO) as well as that of Iranian National Drinking Water Standards for all of the samples, the obtained results indicated that carcinogen PAHs present in the drinking water of Tehran can cause threats to human health.

Survey of hazardous organic compounds in the groundwater, air and wastewater effluents near the Tehran automobile industry

Potential of wastewater treatment in car industry and groundwater contamination by volatile organic compounds include perchloroethylene (PCE), trichloroethylene (TCE) and dichloromethane (DCM) near car industry was conducted in this study. Samples were collected in September through December 2011 from automobile industry. Head-space Gas chromatography with FID detector is used for analysis. Mean PCE levels in groundwater ranged from 0 to 63.56 μg L(-1) with maximum level of 89.1 μg L(-1). Mean TCE from 0 to 76.63 μg L(-1) with maximum level of 112 μg L(-1). Due to the data obtained from pre treatment of car staining site and conventional wastewater treatment in car factory, the most of TCE, PCE and DCM removed by pre aeration. Therefor this materials entry from liquid phase to air phase and by precipitation leak out to the groundwater. As a consequence these pollutants have a many negative health effect on the workers by air and groundwater.