Co-contamination of water with chlorinated hydrocarbons and heavy metals: challenges and current bioremediation strategies

Abstract

Chlorinated hydrocarbons can cause serious environmental and human health problems as a result of their bioaccumulation, persistence and toxicity. Improper disposal practices or accidental spills of these compounds have made them common contaminants of soil and groundwater. Bioremediation is a promising technology for remediation of sites contaminated with chlorinated hydrocarbons. However, sites co-contaminated with heavy metal pollutants can be a problem since heavy metals can adversely affect potentially important biodegradation processes of the microorganisms. These effects include extended acclimation periods, reduced biodegradation rates, and failure of target compound biodegradation. Remediation of sites co-contaminated with chlorinated organic compounds and toxic metals is challenging, as the two components often must be treated differently. Recent approaches to increasing biodegradation of organic compounds in the presence of heavy metals include the use of dual bioaugmentation; involving the utilization of heavy metal-resistant bacteria in conjunction with an organicdegrading bacterium. The use of zero-valent irons as a novel reductant, cyclodextrin as a complexing agent, renewable agricultural biosorbents as adsorbents, biosurfactants that act as chelators of the co-contaminants and phytoremediation approaches that utilize plants for the remediation of organic and inorganic compounds have also been reported. This review provides an overview of the problems associated with co-contamination of sites with chlorinated organics and heavy metals, the current strategies being employed to remediate such sites and the challenges involved.

Fungal Biosorption for Cadmium and Mercury Heavy Metal Ions Isolated from Some Polluted Localities in KSA

“…Temperature changes affect the stability of the metal ion species initially placed in solution; stability of the microorganism-metal complex depends on the biosorption sites, microbial cell wall configuration, and ionization of chemical moieties on the cell wall. An increase in the sorption capacity of lead, from 0.596 to 0.728 mg/g, was obtained when the temperature was raised from 25 to 40° (Arjoon et al, 2013).…”

Grey water characterisation and pollutant loads in an urban slum

“…In particular, sodium tripolyphosphate is an ingredient of many detergents whose use has been associated with eutrophication (Köhler 2006). Furthermore, accumulation of heavy metals and micropollutants in the environment may cause toxicity through the food chain, distort the ecological balance (Schwarzenbach et al 2006;Ternes and Joss 2006;Escher and Fenner 2011;Taghipour et al 2013) and negatively affect humans and animals after long exposure time or after bioaccumulation and biomagnification (Snyder et al 2003;Arjoon et al 2013;González-Naranjo and Boltes 2013). Also pathogenic microorganisms in grey water may cause diseases that result in either morbidity or mortality depending on the severity and duration of the exposure (Eriksson et al 2002;Ottoson and Stenström 2003;Birks and Hills 2007).…”

Electrokinetic remediation of perchloroethylene-contaminated soil

“…The contamination of soil with perchloroethylene (PCE) and trichloroethylene (TCE) is widespread (Arjoon et al 2013;Adams et al 2013). PCE is a halogenated aliphatic organic compound which, due to its unique properties and solvent effects, has been widely used in industrial degreasing agent and also used as a solvent in dry cleaning and an ingredient in paints, inks, and disinfectants.…”