Wastewater toxicity of tannin- versus chromium-based leather tanneries in Marrakesh, Morocco.
The toxicity of leather tanning wastewater from a traditional tannery (TT), which is based on vegetable tannin (VT), was compared with wastewater from a tannery combining the use of chromium-based tanning (CT) with VT-based tanning operations. Wastewater samples from a TT and a CT plant as well as from five sewer sampling points were collected in Marrakesh, Morocco, and the concentrations of VT and some selected inorganics were measured. A set of bioassays were used to test wastewater toxicity in sea urchin (Paracentrotus lividus) embryos and sperm, in Daphnia magna, and in marine microalgae (Dunaliella tertiolecta). Toxicity end points included: (1) developmental defects, embryonic mortality, sperm fertilization success, and offspring damage in sea urchins; (2) D. magna immobilization; and (3) algal growth rate inhibition. Toxicity tests on TT and CT effluents (TTE and CTE) were run at dilutions ranging from 0.1% to 2% (sea urchins and algae) or up to 12% in D. magna. Parallel bioassays were run on VT extract (VTE) at nominal tannin concentrations ranging from 0.1 to 10 mg l(-1). The results showed higher toxicity of CTE compared with TTE. CTE toxicity in sea urchins and algae showed concentration-related trends, whereas TTE exerted hormetic effects at levels of 0.1% to 0.2% and toxic effects at levels >or=1%. The same trends were observed for VTE, suggesting a prevailing role of tannin in TTE-associated effects. The moderate wastewater toxicity of VT-based tanneries might prompt interest in the VT tanning process.
De Nicola
E
E
G. Pascale Foundation, Italian National Cancer Institute, I-80131, Naples, Italy.
Meriç
S
S
Della Rocca
C
C
Gallo
M
M
Iaccarino
M
M
Manini
P
P
Petruzzelli
D
D
Belgiorno
V
V
Cheggour
M
M
Di Gennaro
A
A
Moukrim
A
A
Tünay
O
O
Pagano
G
G
D000818:Animals; D001681:Biological Assay; D002857:Chromium / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000187:drug effects; D056890:Eukaryota / Q000187:drug effects / Q000254:growth & development; D005260:Female; D008297:Male; D012617:Sea Urchins / Q000196:embryology; D013633:Tanning; D013634:Tannins / Q000633:toxicity*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D013634:Tannins; D014874:Water Pollutants, Chemical; D002857:Chromium