DDT and its derivatives are highly toxic to aquatic organisms. Acute exposure to concentrations in water of a few micrograms per litre are sufficient to kill a large proportion of populations. In addition to its short term toxicity, DDT also has long term sublethal effects on aquatic organisms. Many physiological and behavioural parameters have been reported to be affected by DDT. This toxicity, couple with its high capacity for bioconcentration and biomagnification means that DDT presents a major hazard to aquatic organisms (WHO 1989). Acute LC50 values for Daphnia magna exposed to either DDT or its derivatives range from 0.5 to 510 µg/l (Randall et al. 1979; Berglind and Dave 1984; Mayer and Ellersieck 1986).
Acute LC50 values for other species of freshwater invertebrates range from 0.36 to 3000 µg/l, with early developmental stages more sensitive than adults (Gaufin et al. 1965; Sanders and Cope 1968; Sanders 1972; Mayer and Ellersieck 1986).
Acute LC50 values for rainbow trout (Oncorhynchus mykiss) range from 4.1 to 70 µg/l (Katz 1961; Mayer 1987). Acute LC50 values for other species of freshwater fish ranged from 1.5 to 135 µg/l (Henderson et al. 1959; Katz 1961; Mayer and Ellersieck 1986; El-Sebae 1987).
The use of DDT in the UK has been prohibited since 1986 as a result of the EU Council Directive 79/117/EEC (dated 21st December 1978) (HSE 2001). DDT compounds are highly resistant to degradation or metabolism, they are readily bioaccumulated, and they continue to persist in the environment, several decades after their use being prohibited. Although levels are lower compared to the 1960s, DDT is still released to the atmosphere, either from its use in other countries or from the volatilisation of residues resulting from its previous use. DDT has recently been identified in air sampled from hazardous waste sites (ATSDR 2000).
|Habitat/ Ecosystem Type||Critical Load/ Level||Status||Reliability||Indication of exceedance||Reference|
0.025 µg/l (DDT (all isomers), annual mean in estuary and coastal waters)
|Environmental Quality Standard||quite reliable i.e. the results of some studies are comparable||
Statutory Environmental Quality Standard (EQS). The corresponding EQS for p,p-DDT is 0.01 µg/l.