Presentation on theme: "INAPPROPRIATELY STORAGED DDT AS A POTENTIAL RISK FOR HUMAN HEALTH AND ENVIRONMENT 6th ALPS-ADRIA SCIENTIFIC WORKSHOP 30 April - 5 May, 2007 Obervellach,"— Presentation transcript:
INAPPROPRIATELY STORAGED DDT AS A POTENTIAL RISK FOR HUMAN HEALTH AND ENVIRONMENT 6th ALPS-ADRIA SCIENTIFIC WORKSHOP 30 April - 5 May, 2007 Obervellach, Austria by Sanja Miloš Croatian Food Agency
DDT (dichlorodiphenyltrichloroethane) and its metabolites: very significant for environment and public health worldwide normally regulated trough maximum residue levels (MRLs) - permitted in food on sale MRLs are not strictly “safety limits”
DDT now banned in most countries: was used mainly to control mosquito-borne malaria civilian populations to control typhus and malaria vectors extensively used as an agricultural insecticide after 1945 During seventieths of the last century DDT was proscribed mainly because of the environmental effects (persistency, bioaccumulation, negative impact wildlife), but not because of eventually toxics effect on humans.
Prohibited use of DDT in Croatia: during seventieths of the last century by taking the model from other countries Stocholm Convention about Persistent Organic Pollutants (held in 2001, with appliance from 2004) National Plan for Implementation of Stockholm Convention Principals in December, 2004.
... after the ban implementation: remaining quantities of DDT entombed all around the agricultural properties and forestry sectors several decades later, during old storehouse disintegration, the unknown quantities of DDT were split around
... possibility of well water pollution becomes quite realistic in these situations consumption of water at the area of Osijek-Baranya County is mostly provided by exploitation of ground waters 20 % of populations drink water from shallow wells independently of public water supply availability
In this very case the story started… suspicious pesticide intoxication of a woman hospitalized in Osijek clinical hospital epidemiological investigation identified origin of exposure uncontrolled effusion of buried DDT stocks during old storehouse disintegration ALARM
Sampling in a disputable area Soil sample was sampled from 30 and 60 cm depth Water well was sampled in concentric distance of 200 m concentration of DDT was 2 g/kg dry matter (MRL is 0,5 mg/kg) 30 (60) m distance had 3.85 (2.31) µg/l 100 m distancehad (n=3) 0.012 – 0.057 µg/l
The results of measuring concentration of DDT (µg/l) in water from wells Location Distance from source of pollution (m) Elapsed Time from pollution (weeks) 02410 1.303.85*1.093*0.12*0.0152 2.602.31*0.0250.0100.049 3.1000.080.0570.01- 4.1500.0260.0120.008- 5.2000.00220.0380.003-
DDT was detected by gas chromatography (Aglient 6890 ECD) and confirmed by GC MS (Thermo – Finnigen) in the well water samples, sampled several days after the incident and heavy rain, the measurements have shown higher concentrations on two locations 30-60 m apart from the origin of pollution sampling two and four weeks after the incident was performed in the period without rainfalls and high temperatures, concentration of DDT has been reduced upon the standard referred in the literature
Dynamics of DDT remission in one of the tested wells
Exposure assessment as part of Chemical Risk Assessment performed: Considering known values it was estimated that the EDI* (estimated daily intake) was 0,005775 mg/l EDI=average daily consumption of water × maximal measured concentration of DDT in water It is expected that water for human consumption should be out for use throw several weeks.
Whats that mean ? For a grown - up man of 70 kg body weight it was less than ADI* and RfD**, but in the percentage zone of ADI (30%). But under various scenarios such elevated concentration and water consumption (increased consumption lead to breakthrough of ADI) The consequence may be far reaching * ADI – acceptable daily intake, 0.02 mg/kg/day for DDT **RfD – reference dose, 0.0005 mg/kg/day
Contexts of food safety Stocks of expired and banned pesticides are still “hot” issues in high number, especially developing countries Risk assessments may play a significant role in the evaluation of risks posed by pesticides if concentration exceedes above MRL estimation of (EDI) indicates that there is possible acute health risk These findings indicate the necessity of environmental monitoring on the sites of known or suspected chemical storage, whether obsolete or currently in usage