Organochlorine pesticides in soils of the horticultural belt of Bahía Blanca (Argentina)

Abstract

The land around Bahía Blanca, Argentina, has been farmed intensively for six decades. We report the concentrations of a number of organochlorine pesticides (DDT, dieldrin, endrin, heptachlor epoxide and lindane), and of DDT metabolites (DDD + DDE) in three different layers (0–5, 5–10 and 10–20 cm) of the soils in 44 fields of eight farms that have been devoted to horticulture for periods ranging from 15 to 60 yr. In spite of the horticultural use of these substances having been banned for the past 13–35 yr, high concentrations were found – up to nearly 12 mg kg-1 for DDT + DDD + DDE, 17 mg kg-1 for dieldrin, 4 mg kg-1 for endrin, 7 mg kg-1 for heptachlor epoxide and 0.8 mg kg-1 for lindane. The highest concentrations of DDT, dieldrin, endrin and heptachlor epoxide were found on the oldest farms, the highest levels of DDD + DDE on middle-aged farms (35–40 yr), and the hi ghest levels of lindane on 15–40-year-old farms that had rather lower soil pH than the older farms. Concentrations invariably decreased slightly with increasing depth, and for DDT, dieldrin and heptachlor epoxide they exhibited significant positive correlation with soil organic matter content. Principal components analysis confirmed the distinguishability of three groups of analytes: one comprising DDT, dieldrin, endrin and heptachlor epoxide associated with higher soil organic matter and clay contents; and two singletons, DDD + DDE associated with higher pH and lindane. We conclude that these pesticides have very limited mobility in these semiarid alkaline soils. Key words: Organochlorine, semiarid soils, horticulture, depth variation.

Sorption of 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (DDT) by clays and organoclays

“…Both of them are dangerous and toxic compounds. In spite of the ban on the use of DDT for many years, DDT and its metabolites of p,p 0 -DDE (DDE) and p,p 0 -DDD (DDD) have been reported recently in different environmental media, including soils, waters, air, plants and animals (Andrade et al 2005;Binelli et al 2003;Giesy et al 2001;Kosubova et al 2005;Tao et al 2005;Shen et al 2005;Zhang et al 2005;Zhao et al 2005). It has been over 20 years since China banned the use of p,p 0 -DDT, but the ratio of DDT/DDE in soils indicates that new inputs could be present in the soils (Chen et al 2005;Gao et al 2005;Shi et al 2005).…”

Content and distribution pattern of dichlorodiphenyltrichloroethane (DDT) in soils of Moscow

“…Some scientists have reported no correlation or a weak correlation between the content of DDT and its metabolites in soils and the content of organic matter, pH, granulometric composition, and other soil characteristics [26,28,43,45,47]. Nevertheless, a significant positive correlation between soil contamination by DDT and the content of organic matter is sometimes revealed [19,36,42].…”

“…Air migration and precipitation at great distances from the site of the initial application have resulted in the global pollution of the biosphere by these ecotoxicants [7,10,11,18]. In published works, the soil of agroecosystems is conventionally considered the main object of contamination by DDT and its metabolites [3,6,12,19,26,29,30,32,35,38,42,44]. Undeservedly little attention has been paid to DDT and other stable organochlorine pesticides among the most dangerous pollutants of the soil cover in cities.…”

Assessment of Soil Contamination of a Cattle Market around River Ogun Basin, Isheri, Nigeria

“…Because of the dangers they pose to non-target organisms, DDT and a number of other organochlorine pesticides were banned in most countries in the 1970s and 1980s, at least for agricultural use. However, because of their resistance to degradation processes and immobility, many are still found in high concentrations in soils to which they were formerly applied, where they constitute a reservoir and secondary source of ongoing contamination of waters, wildlife, and crops [21,22,23].…”