MINERAL NANOPARTICLES IN WASTE: POTENTIAL SOURCES (FRANCE 2014), OCCURRENCE IN SOME ENGINEERED NANOMATERIALS LEACHATES, IN MUNICIPAL SEWAGE SLUDGES AND IN MUNICIPAL LANDFILL SLUDGES

摘要

Environmental assessment of engineered nanoparticles (ENPs) and engineered nanomaterials (ENMs) suffer of lack of data on production, emission, transfer, behaviour, toxicity, ecotoxicity and fate in natural compartments. This paper tries to bring factual data of production, content and emission of elements in a colloidal form or in an ENP form from some products, and two waste potential sinks: municipal sewage sludge and non hazardous waste landfill sludge (part of the landfill leachate decanted and concentrated to produce a liquid or solid sludge). The study is focused on mineral ENPs, since routine analytical methods are not available for organic ENPs in complex waste leachates. The declaration of production and importation of ENPs in France in 2014 (400 000 t) include carbon black (> 100 000 t/y), organic pigments (1 250 – 12 500 t/y), miscellaneous organic substances (575 – 5 750 t/y) and mineral ENPs classified here as: 1. Group #1/Major elements: ENPs substances of Si (> 100 000 t/y), Ca, Ti (10 000 – 100 000 t/y), Al (2 000 – 20 000 t/y), Mg (1 100 – 11 000 t/y), Fe (300 – 3 000 t/y), Mn (10 – 100 t/y), P (1 – 10 t/y): ubiquitous in total content, ubiquitous as a colloid fraction in leachate of waste; 2. Group #2/Minor elements (with soluble substances not classified as ecotoxic in the CLP regulation): ENPs substances of Ba (21 – 212 t/y), Bi, Cr(III) (2 – 21 t/y), Sr (1 – 10 t/y), Zr (0.1 – 1 t/y), La (0.01 – 0.1 t/y), Pd, Mo, W, Y, Au (< 1 kg/y); 3. Group #3/Minor elements (with soluble substances classified as ecotoxic and hazard statement code H400, H410 and H411 in the CLP regulation): ENPs substances of Ce (1 000 – 10 000 t/y), Cu, Zn (10 – 100 t/y), Ni, Sb (1 – 10 t/y), Ag, Co (0.1 - 1 kg/y). The most “engineered” ENPs are not declared in high quantities: carbon nanotubes (1 t – 10 t), Fe(0) (10 kg – 100 kg), Ag(0): 0.1 kg – 1 kg, Au (quantity not declared). Colloidal form or ENPs of elements in leachates of 23 engineered nanomaterials have been found in a paint leachate (Si) and in three cosmetics leachates (Al, Si, and Zn). Two cosmetics have a colloidal or ENP Zn (Group # 3 element) fraction of 25 and 164 mg/kg. From 16 concrete samples, including two laboratory samples with nanosized TiO2, one demolition concrete released Ti in colloidal form at a concentration of 1 mg/kg. No ENP of Ag, Ce, Ti and Zn in 13 municipal sewage sludges have been found by TEM/EDS. From 10 sludges leachates from municipal landfill leachates, the colloidal fraction was very frequent for the elements of Group #3 Ni, Zn, Cu, Co and Sb (but with low mean concentration of 3.2, 2.0, 1.2, 0.6 and 0.5 mg/kg when present), and only one time on ten for Ag (with very low concentration of 0.04 mg/kg when present). Ce had 4 times on 10 a colloidal form but with a very low concentration of 0.01 mg/kg when present. From this limited research, it appears that cosmetics could be a source of ENPs, that sewage sludge could be a sink for Group #3 elements Ag and Ce since their total concentrations is significant (10 and 40 mg/kg respectively), that landfill sludges have moderate total concentration of Group #3 elements Ce, Cu, Zn, Ni, Sb, Ce, Ag and Co (46, 83, 26, 16, <10, <5 and <5 mg/kg, respectively). The concentrations of Cu, Zn and Ni are comparable to soils, composts or sediments. These concentrations could mean that the fluxes of these group #3 elements from the landfill cells (by the landfill leachate, and their build-up in landfill sludge) are low.