ENVIRONMENTAL AUDIT OF THE SITES IMPACTED BY THE PROBO KOALA TOXIC WASTE DUMPING IN ABIDJAN, CÔTE D IVOIRE

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1 ENVIRONMENTAL AUDIT OF THE SITES IMPACTED BY THE PROBO KOALA TOXIC WASTE DUMPING IN ABIDJAN, CÔTE D IVOIRE This series of fct sheets ws prepred s prt of UN Environment s environmentl udit of the sites impcted by the Probo Kol toxic wste dumping in Abidjn, Côte d Ivoire. The fct sheets provide complete nlysis results, observtions nd the recommendtions for ech of the smpling sites. They should be red in conjunction with the full ssessment report, vilble t: 1

2 Site Description Site nme: Plteu Dokoui 2 UN Environment site reference no: 17 This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 2

3 Spill History This site, which is djcent to the Adjmé-Abobo express wy, consists of n opertionl rodside sewge disposl tnk. Wstes from the Probo Kol re reported to hve been dischrged into the concrete structure, which ws emptied nd clened s prt of clen-up opertions conducted by Trédi in During the clening process, smll quntities of sewge reportedly overflowed nd rn down the djcent steep slope towrds culvert dischrging into the nerby rinwter holding bsin (Site 16). The contminted soil ws then excvted nd removed for off-site tretment. At the time of smpling, smllscle, informl industril nd griculturl ctivities were observed between the rodside nd the culvert. Approch Two sets of surfce soil (0-20 cm) nd 1 m-depth soil smples (4 smples in totl) were tken: The first t the top of the slope next to the sewge storge tnk; nd The second downwrds of the slope. In ddition, one ir smple nd one smple of comestible vegettion (sweet potto) were collected t the site. Assessment Criteri Bsed on the different nlyses of the chemicl composition of the smples tken onbord the Probo Kol in 2006, s well s those undertken on smples collected on the dumping sites, UN Environment considered the following groups s the key contminnts of interest for the udit: Petroleum hydrocrbons; Sulfur compounds; nd Hevy metls. The specition of contminnts to be nlyzed within the bove three groups ws primrily determined by wht ws present in the Probo Kol wste s well s the environmentl stndrds set by the Government of Côte d Ivoire for clen-up. In ddition, the impct of high levels of sodium hydroxide ws mesured through the ph vlue of the soil. The results obtined from the nlyses of soil smples were screened ccording to the following process: 1. Findings were first compred with relevnt ntionl stndrds. In this cse, results for soil from ll the sites where Probo Kol wstes were dumped nd which hd undergone remedition were compred with the environmentl stndrds set by the Government of Côte d Ivoire for clen-up opertions conducted by Biogénie t Alépé. If the vlues obtined were lower thn the stndrds set by the Government, UN Environment considered tht no dditionl clen-up intervention ws necessry on the site. This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 3

4 2. If lbortory results for given prmeter showed vlues exceeding the clen-up stndrds set by the Government or contrctor, results were then compred with the interntionlly recognized Dutch soil remedition stndrds (intervention vlues) to see if further immedite ction ws needed from n environmentl point of view. Dutch stndrds hve been in existence for over 30 yers nd re used s bsis for contminted site ssessment nd clen-up in mny prts of the world, when locl stndrds re not vilble. For most prmeters of nlysis, however, the Government s clenup stndrd ws more stringent thn the Dutch vlues. 3. Results were lso compred with the control sites to see if the observed pollution ws lso present in the bckground. For ir qulity nlysis, for which no ntionl stndrds exist in Côte d Ivoire, the pproch tken ws to compre ir qulity results from the ffected sites with Control Site 21. Fruit nd vegetble smples were tested using similr protocols s those used for nlysis of soil nd wter smples. In the bsence of ntionl food qulity stndrds, the Europen Commission s mximum levels of certin contminnts in food stuffs (EC regultion 1881/2006) re used for comprison. It should be noted tht s it ws found tht there were interferences from nturlly occurring substnces with the hydrocrbon nlyses, the nlyticl results relting to hydrocrbons were discrded. Lbortory Anlysis Findings Soil Prmeters (mg/kg) Site 17 Plteu Dokoui cm 1 m 0-20 cm 1 m Government stndrd (mg/kg) Totl Hy C5-C ,000 Benzene < < < < Ethylbenzene < < < < Toluene < < Xylene < < < < Totl sulfur (%) Pb Cd < 0.1 < As Cr Ni Co Hg Cu Zn ,000 ph This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 4

5 Air Site 17 Prmeters/units Plteu Dokoui 2 Control site 21 Agboville Dimethyl sulfide ppm v/v < 0.1 < 0.1 Ethyl mercptn ppm v/v < 0.1 < 0.1 Methyl ethyl sulfide ppm v/v < 0.1 < 0.1 Crbonyl sulfide ppm v/v < 0.1 < 0.1 Tertiry butyl mercptn ppm v/v < 0.1 < 0.1 Hydrogen sulfide ppm v/v < 0.1 < 0.1 Methyl tert-butyl ether µg/m3 ND ND Benzene µg/m3 ND ND Toluene µg/m3 4 ND Ethylbenzene µg/m3 ND ND Xylene µg/m3 ND ND Nphthlene µg/m3 ND ND TPH (C4-C6) µg/m3 ND 10 TPH (C6-C8) µg/m TPH (C8-C10) µg/m TPH (C10-C12) µg/m TPH (C4-C12) µg/m3 ND 120 Aliphtic (C4-C6) µg/m3 100 ND Aliphtic (C6-C8) µg/m Aliphtic (C8-C10) µg/m Aliphtic (C10-C12) µg/m Aromtic (EC5-EC7) µg/m3 ND ND Aromtic (EC7-EC8) µg/m3 ND ND Aromtic (EC8-EC10) µg/m3 4 ND Aromtic (EC10-EC12) µg/m3 ND ND This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 5

6 Fruit nd vegetble Site 17 Control site 21 Plteu Dokoui 2 Agboville Prmeters (mg/kg) Sweet potto Pomegrnte Totl sulfur (%) < PAH < < EC regultion (mg/kg) Pb < 0.7 < Cd < 0.02 < As < 0.6 < 0.6 Cr < Ni < Co < Hg < 0.14 < 0.14 Cu Zn Conclusions nd Recommendtions The lbortory results show tht the current concentrtions of the contminnts of concern in soil re ll below the stndrds set by the Government of Côte d Ivoire for clen-up. Likewise, hydrocrbon levels in the smple nlysed re well below Dutch intervention vlues. Furthermore, the ph vlues re not in the custic rnge (9 or bove), demonstrting tht the impct of the disposl of custic substnces cn no longer be detected. No further ction is therefore needed on this site to remedite the soil impcts of the 2006 toxic wste dumping from the Probo Kol. The results of the ir qulity nlysis cn be summrized s follows: Mercptns, hydrogen sulfide nd relted components cnnot be detected in this site, nor the control site. This is significnt considering tht the key odornts in the Probo Kol wstes were most likely hydrogen sulfide nd mercptns. Concentrtions of the vrious nlytes t the ffected site re comprble to the concentrtions found t the control site. Finlly, bsed on the fruit nd vegetble results, the following observtions cn be mde: All smples, including the pomegrnte smple from Control Site 21 t Agboville, show the presence of vrious nlytes nd hevy metls. Fruits nd vegetbles nturlly ccumulte hevy metls from the soil. As most of the hevy metls re essentil to humn helth in smll quntities, their uptke through fruits nd vegetbles is not considered to be risk. The EC stndrd for led is below the detection limit of the lbortory nlyses. However, considering tht ll smples, including control smples, show comprble hevy metl vlues, these results re not considered to wrrnt further follow up. This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 6

7 Site Photos Source: UN Environment Source: UN Environment This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 7

8 Source : UN Environment Source: UN Environment This fct sheet should be red in conjunction with the min ssessment report vilble t: unep.org/cotedivoire 8