Direct and Indirect Exogenous Contamination by Pesticides of Rice-Farming Soils in a Mediterranean Wetland

Abstract

It is known that the sources of soil contamination can be endogenous or exogenous and that exogenous contamination may be direct or indirect. In this work, an environmental pesticide fate study was conducted in soil profiles collected from 23 rice field sites in an important Mediterranean wetland (Albufera Natural Park, Valencia, Spain) from April 1996 to November 1997. Temporal and spatial distribution of 44 pesticide residues in an alluvial Mediterranean soil (gleyic-calcaric Fluvisol, Fluvaquent) were monitored. During this period, the levels of pesticide residues in different soil horizons (Ap1 0-12 cm, Ap2 12-30 cm, ApCg 30-50 cm, C1gr 50-76 cm, and C2r 76-100 cm) were investigated. In addition, information was collected on agricultural pesticide application practices and soil characteristics. Distribution throughout the soil profile showed that pesticide concentrations were always higher in the topsoil (Ap1 horizon), in the autumn season, and in the border with citrus-vegetable orchard soils (calcaric Fluvisol, Xerofluvent). Chlorpyrifos (organophosphorus), endosulfan (organochlorine), and pyridaphenthion (organophosphorus) insecticides were, respectively, the most detected of all the pesticides investigated. These results were associated with processes, such as nonleaching, transport by movement into surface waters, retention, volatilization, and chemical and biological degradation in the topsoil, as well as with direct and indirect exogenous contamination sources.

Isolation and Identification of Bacteria from Chlorpyrifos Polluted Soil

“…Approximately 90% of agricultural pesticide application never reaches its target organisms but is, instead, dispersed through the air, soil, and water (Moses et al 1993). In addition, many soil-applied pesticides are also intentionally introduced into the soil environment for the control of soil borne pests and pathogens, which results in the accumulation of their residues and metabolites in soil at unacceptably high levels (Redondo et al 1997;Gamo´ n et al 2003).…”

In vitro study of mycoremediation of cypermethrin-contaminated soils in different regions of Punjab

“…Most of the applied pesticide gets dispersed through the air, soil and ground water in spite of reaching to its target organism. This results in to the accumulation of their residues and metabolites in soil at toxic levels (Gamon et al 2003;Shalaby and Abdou 2010). Because of this, cypermethrin has been reported in nearly all sediment samples tested from urban creeks (Riederer et al 2010;Weston et al 2009Weston et al , 2011.…”

Biodegradation of the Synthetic Pyrethroid, Fenvalerate by <i>Pseudomonas </i><i>v</i><i>iridiflav</i><i>a</i>

“…Many soil-applied pesticides are also intentionally introduced into the soil environment for the control of soil borne pests and pathogens, which results in the accumulation of their residues and metabolites in soil at unacceptably high levels [4]. Pesticides are washed into aquatic ecosystems by water runoff and soil erosion.…”