title: Chromium speciation, bioavailability, uptake, toxicity and detoxification in soil-plant system: A review.
abstract: Chromium (Cr) is a potentially toxic heavy metal which does not have any essential metabolic function in plants. Various past and recent studies highlight the biogeochemistry of Cr in the soil-plant system. This review traces a plausible link among Cr speciation, bioavailability, phytouptake, phytotoxicity and detoxification based on available data, especially published from 2010 to 2016. Chromium occurs in different chemical forms (primarily as chromite (Cr(III)) and chromate (Cr(VI)) in soil which vary markedly in term of their biogeochemical behavior. Chromium behavior in soil, its soil-plant transfer and accumulation in different plant parts vary with its chemical form, plant type and soil physico-chemical properties. Soil microbial community plays a key role in governing Cr speciation and behavior in soil. Chromium does not have any specific transporter for its uptake by plants and it primarily enters the plants through specific and non-specific channels of essential ions. Chromium accumulates predominantly in plant root tissues with very limited translocation to shoots. Inside plants, Cr provokes numerous deleterious effects to several physiological, morphological, and biochemical processes. Chromium induces phytotoxicity by interfering plant growth, nutrient uptake and photosynthesis, inducing enhanced generation of reactive oxygen species, causing lipid peroxidation and altering the antioxidant activities. Plants tolerate Cr toxicity via various defense mechanisms such as complexation by organic ligands, compartmentation into the vacuole, and scavenging ROS via antioxidative enzymes. Consumption of Cr-contaminated-food can cause human health risks by inducing severe clinical conditions. Therefore, there is a dire need to monitor biogeochemical behavior of Cr in soil-plant system.
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan. Electronic address: muhammadshahid@ciitvehari.edu.pk.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shahid
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan.
authors.forename: Saliha
authors.initials: S
authors.lastname: Shamshad
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan.
authors.forename: Marina
authors.initials: M
authors.lastname: Rafiq
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan.
authors.forename: Sana
authors.initials: S
authors.lastname: Khalid
authors.affiliation: Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; MARUM and Department of Geosciences, University of Bremen, Bremen D-28359, Germany.
authors.forename: Irshad
authors.initials: I
authors.lastname: Bibi
authors.affiliation: Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; MARUM and Department of Geosciences, University of Bremen, Bremen D-28359, Germany; Southern Cross GeoScience, Southern Cross University, Lismore 2480, NSW, Australia.
authors.forename: Nabeel Khan
authors.initials: NK
authors.lastname: Niazi
authors.affiliation: Centre d'Etude et de Recherche Travail Organisation Pouvoir (CERTOP), UMR5044, Université J. Jaurès - Toulouse II, 5 allée Antonio Machado, 31058 Toulouse Cedex 9, France.
authors.forename: Camille
authors.initials: C
authors.lastname: Dumat
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan; Center of Excellence in Environmental Studies, King Abdulaziz University, P.O Box 80216, Jeddah 21589, Saudi Arabia.
authors.forename: Muhammad Imtiaz
authors.initials: MI
authors.lastname: Rashid
mesh_terms: D001682:Biological Availability; D002857:Chromium / Q000737:chemistry / Q000493:pharmacokinetics / Q000633:toxicity*; D000075322:Heavy Metal Poisoning; D006801:Humans; D008658:Inactivation, Metabolic; D019216:Metals, Heavy / Q000737:chemistry; D010788:Photosynthesis / Q000187:drug effects; D063245:Plant Development / Q000187:drug effects; D018517:Plant Roots / Q000378:metabolism; D010944:Plants / Q000187:drug effects / Q000378:metabolism*; D011041:Poisoning; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants; D002857:Chromium
keywords: Bioavailability; Chromium; Detoxification; Toxicity; Uptake