Simultaneous removal of organics and heavy metals from industrial wastewater: A review.

Environmental pollution is increasingly becoming an issue of significant public interest in many developing countries and the international community at large. The growing socioeconomic developments as witnessed globally in recent times due to rapid urbanization and industrialization have led to the overexploitation of natural resources, while inadvertently resulted in severe environmental problems. In this chapter, we attempted to present the effect of environmental pollution to our physical environment as well as its socioeconomic impacts. Specifically, we focused more on the major types of pollution, which are widely recognized as international public health problems, namely, land/soil, water, air, noise, and plastic/microplastic pollution, enumerating their effects and how they have acted as an obstruction to the social and economic progress by placing tremendous pressure on resources and environment. Possible ways of ensuring environmental quality and sustainability leading to improved public health and well-being alongside with different kinds of intervention were proposed.

Environmental pollution and their socioeconomic impacts

Many organic chemicals are ionizable by nature. After use and release into the environment, various fate processes determine their concentrations, and hence exposure to aquatic organisms. In the absence of suitable data, such fate processes can be estimated using Quantitative Structure–Property Relationships (QSPRs). In this review we compiled available QSPRs from the open literature and assessed their applicability towards ionizable organic chemicals. Using quantitative and qualitative criteria we selected the ‘best’ QSPRs for sorption, (a)biotic degradation, and bioconcentration. The results indicate that many suitable QSPRs exist, but some critical knowledge gaps remain. Specifically, future focus should be directed towards the development of QSPR models for biodegradation in wastewater and sediment systems, direct photolysis and reaction with singlet oxygen, as well as additional reactive intermediates. Adequate QSPRs for bioconcentration in fish exist, but more accurate assessments can be achieved using pharmacologically based toxicokinetic (PBTK) models. No adequate QSPRs exist for bioconcentration in non-fish species. Due to the high variability of chemical and biological species as well as environmental conditions in QSPR datasets, accurate predictions for specific systems and inter-dataset conversions are problematic, for which standardization is needed. For all QSPR endpoints, additional data requirements involve supplementing the current chemical space covered and accurately characterizing the test systems used.

A review of quantitative structure-property relationships for the fate of ionizable organic chemicals in water matrices and identification of knowledge gaps.

The toxicity of phenol and 13 chlorinated phenols to the marine alga Dunaliella tertiolecta is presented for the first time. The newly generated marine algal toxicity data was found to correlate strongly with the widely used hydrophobicity parameter—the logarithm of the n-octanol–water partition coefficient (log KOW). Interspecies relationships using the new marine algal toxicity data of chlorophenols with the previously published data on bacterium (Vibrio fischeri), protozoan (Tetrahymena pyriformis), daphnid (Daphnia magna), freshwater alga (Pseudokirchneriella subcapitata), and fish (Pimephales promelas) revealed promising results that could be exploited in extrapolations using freshwater data to predict marine algal toxicity. Environ. Toxicol. Chem. 2012; 31: 1113–1120. © 2012 SETAC

First toxicity data of chlorophenols on marine alga Dunaliella tertiolecta: Correlation of marine algal toxicity with hydrophobicity and interspecies toxicity relationships

Releasing of toxic metals (Pb, Cd, Hg, Zn, Cr, etc.) and organic compounds (dyes, PAHs, volatile organic compounds, etc.) into the environment has become main resources of environmental pollution which affects the human being and other organism life directly or indirectly. These inorganic and organic compounds have adverse effect on living being even in trace amounts. Various materials like plant-derived biosorbents, resins, metal oxides, natural fibres, carbonaceous materials, etc., have been used for the treatment of organic and inorganic pollutants to clean the environment. From the last decade, carbonaceous materials like graphene have been extensively used for the treatment of environmental pollutants. In this book chapter, we discuss the carbonaceous materials properties, and it is used in the treatment of toxic inorganic and organic compounds removal from the environment.

Toxicology and Environmental Application of Carbon Nanocomposite

The toxicity of organic chemicals to Vibrio fischeri, river bacteria, algae, Daphnia magna and fishes were analysed. The results showed that the toxicity of chemicals to narcotics was dependent on hydrophobicity. A single model for both polar and non-polar narcotics was developed by inclusion of a polarity descriptor as well as the hydrophobic parameter. The highly hydrophobic polar narcotics could be treated as non-polar narcotics because their polar functional group(s) make(s) a relatively small contribution to polarity as compared with their hydrophobicity. In order to investigate the toxic mechanism of action for reactive compounds, the response-surface approach was used to develop models derived from easily calculated descriptors. The stepwise analysis selected the octanol/water partition coefficient and a polarity descriptor to parameterize bio-uptake and reactivity, respectively, for seven species. Benzoic acids can be easily absorbed into the unicellular bacteria, but this is not the case for multicellular D. magna and fish. Their toxicity to V. fischeri is much higher than that to D. magna and carp. Regression analysis was performed based on the model that we developed for ionizable compounds. Good correlations were observed by introducing the correction factor for ionizable compounds. The toxic mechanisms are discussed.

Toxicity of organic pollutants to seven aquatic organisms: effect of polarity and ionization.

A toxicity data set containing the toxicities of 970 hydrophobic, polar and ionizable, nitro substituted and α,β-unsaturated compounds to Tetrahymena pyriformis was classified into different groups based on the structure and substituted functional groups. Polar, ionizable and reactive compounds exhibit greater toxicity as compared with the non-polar hydrophobic compounds. Step-by-step analysis was carried out between the toxicity and descriptors representing hydrophobicity, polarity/polarizability, ionization and reactivity of compounds. Significant relationships were developed between the toxicity and these descriptors for the compounds. The models developed are simple, interpretable and transparent, using a small number of descriptors that may reflect the interactions of chemicals with the biological macromolecules at the target sites. Hydrophobic parameter log P reflects bio-uptake process compounds. Polarity/polarizability descriptor S reflects the interaction of hydrophilic residues of polar chemical...

L M Su

Papers

Toxicity of organic pollutants to seven aquatic organisms: effect of polarity and ionization.

Comparison of Tetrahymena pyriformis toxicity based on hydrophobicity, polarity, ionization and reactivity of class-based compounds