Water and soil contamination by trace elements

A. FERNÁNDEZ CIRELLI

Cochabamba, Bolivia

Congreso; Congreso: Desarrollo, Medio Ambiente y Recursos Naturales: Sostenibilidad a Múltiples Niveles y Escalas; 2007

Universidad Mayor de San Simon

In contrast with most organic materials, trace elements cannot be degraded in the environment and therefore accumulate in water, soil, bottom sediments and living organisms. Water contamination with heavy metals is a very important problem in the current world. These contaminating substances normally result from two sources: anthropic activities or natural processes. Their interactions in soils determine their bioavailability and depend on the nature of metal species and the soil characteristics. These characteristics are of upmost importance in the determination of the relative capacity of attenuation of the contamination in the soils. Various natural physical processes, and chemical reactions that operate in the soil may cause the pollutant to change its chemical form which is one of the main factors determining the uptake and toxicity to plants. The potential trace element transference from the environment to the agricultural food chain, which has probed to be a mayor source to human exposure, is analyzed for high-As livestock drinking water. A biotransference factor to milk has been estimated. On the other hand, environmentally compatible low cost remediation technologies are analyzed on the basis of our own experiences. Floating macrophytes of high growth rate under varied climate conditions have been able to remove various metals simultaneously. However, the use of hytotechnologies as advanced wastewater treatment implies the disposal of high volumes of contaminated plants. The use of dead aquatic plants as biosorbent materials has advantages in its higher efficiency in detoxifying dilute effluents, minimization of the volume of chemical or biological sludge to be disposed of, no nutrient requirements, low cost, conservation, transport and handling. Their use as ion exchangers enables the recovery of heavy metals and competes favorably with commercial resins derived from oil chemistry.