Bioaccumulation and translocation of field-weathered toxaphene and other persistent organic pollutants in three cultivars of amaranth (A. cruentus 'R127 México', A. cruentus 'Don León' y A. caudatus 'CAC 48 Perú') - A field study from former cotton fields

Soils polluted by persistent organic pollutants threatens habitats for plants and animals as well as basic human needs such as food security and provision of potable water. Toxaphene is a persistent organic pollutant that was heavily used as a pesticide in Central America, Brazil, Soviet Union etc. until it was banned in 1993. The objective of this study was to determine the bioaccumulation and translocation characteristics of three different cultivars of amaranth in soils contaminated with field-weathered toxaphene and other POPs in former cotton fields in Chinandega, Nicaragua to identify safety issues for human consumption and/or potential for phytoremediation. The concentration of toxaphene and other POPs in the edible parts of the amaranth (leaves and seeds) exceeded the maximum residue level for human consumption established by the European Union for most of the tested compounds. Concentrations of toxaphene congeners and other POPs were found in all vegetative organs. Many substances were accumulated to concentrations more than 10 times higher than in the soil. Of the three cultivars, A. caudatus 'CAC48 Perú' and A. cruentus 'Don Leon' presented the highest average BAF. None of the 3 cultivars can be considered a panacea hyperaccumulator for either toxaphene alone or in conjunction with other POPs but since many agricultural soils comprise a range of different contaminants, the broad-spectrum bioaccumulating capacity of amaranth can make it an interesting candidate for phytoremediation.