Vol. 32 – 2006 - Ecologia Mediterranea
Vol. 32 – 2006 - Ecologia Mediterranea
Vol. 32 – 2006 - Ecologia Mediterranea
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
concentration. The pH has been measured<br />
also in soils and tailings.<br />
Soil and plant samples were air-dried. Samples<br />
of soil have been sieved at 2 mm mesh<br />
and have been grounded carefully. Plant samples<br />
have been grounded and transferred into<br />
small bottles and oven dried at 60 oC until a<br />
constant weight has been reached. Samples<br />
(c.a. 2 g) were then calcinated in an oven at<br />
460 oC after stepwise increase of temperature<br />
(120, 240, 350, and 460 oC). Soil and plant<br />
tissues were digested by concentrated acid<br />
solutions (1 ml nitric acid 70% + 10 ml fluorhydric<br />
acid) at about 120 oC. After drying,<br />
perchloric acid was added (5 ml for plant tissues<br />
and 10 ml for soil) and evaporated at 160<br />
oC. After drying, minerals were dissolved in<br />
nitric acid 70% (1 ml) and hydrochloric acid<br />
38% (3 ml). Solutions were filtered and volume<br />
was completed with deionised water<br />
(H2O MQ). Quantification was performed<br />
using ICP-AES (Inductive Coupled Plasma-<br />
Atomic Emission Spectroscopy). Each sample<br />
was analyzed in triplicates.<br />
ecologia mediterranea <strong>–</strong> <strong>Vol</strong>. <strong>32</strong> <strong>–</strong> <strong>2006</strong><br />
Heavy Metals in Tailings,Soils and Vegetation of an Abandoned Lead Mine Land in Morocco<br />
Figure 2 <strong>–</strong> Zaida mine tailings (a: tailings, b: nearby the barrens, c: 50 m, d: 200 m and e: 1000 m away from the tailings).<br />
b<br />
Acidity in soil and tailings samples was measured<br />
using an electrode pH meter (soil to<br />
water ratio was of 1/2.5) according to standard<br />
procedure (Lean 1982).<br />
Results<br />
a c<br />
d e<br />
Mean, maximum, and minimum concentrations<br />
of heavy metals in soils, tailings and<br />
plant species as well as pH, are summarized<br />
in Table 1. These data showed higher concentrations<br />
of heavy metals nearby the piles<br />
of tailings and by their surroundings.<br />
High concentration of lead was found in the<br />
tailing while the concentration of this pollutant<br />
remained lower at the place where the<br />
plants were collected. For both plant species,<br />
concentration remained higher in the root than<br />
in the shoots. As far as aerial parts of the<br />
plants were concerned, lead concentration<br />
was slightly higher in Artemisia herba-alba<br />
than in Stipa tenacissima.<br />
87