@article{fdi:010062474,
  title = {({M}ethyl) {M}ercury, arsenic, and lead contamination of the world's largest wastewater irrigation system : the {M}ezquital {V}alley ({H}idalgo {S}tate-{M}exico)},
  author = {{G}u{\'e}dron, {S}t{\'e}phane and {D}uwig, {C}{\'e}line and {P}rado, {B}. {L}. and {P}oint, {D}avid and {F}lores, {M}. {G}. and {S}iebe, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the {M}ezquital valley, untreated wastewater (45 m(3) s(-1)) from {M}exico {C}ity is used for the irrigation of around 900 km(2) of agricultural soil. {H}igh concentrations of metals including methylmercury (3.8+/-2.5 ng l(-1)) and lead (0.16+/-0.05 mg l(-1)) were measured in anoxic wastewater canals. {D}ownstream, dissolved, and particulate polymetallic ({H}g, {P}b, {C}r.) concentrations decreased by factors 10 to 1,000 in the {T}ula {R}iver (which received a mix of fresh and wastewater) due to the dilution and oxidation of surface water, and to the decrease of contaminants concentration in wastewater downstream irrigated soils. {H}owever, dissolved and particulate methylmercury concentrations (0.06 to 0.33 ng l(-1) and 1.6 to 4.5 g kg(-1), respectively) remained elevated in comparison to other natural hydrosystems. {T}he monitoring of an irrigation event and the distribution of metals in a soil profile irrigated for more than 80 years showed that metals were retained in the draining tilled layer. {T}he oxic conditions and slightly acidic p{H} (similar to 6.5) in this layer were found favorable for metal adsorption and co-precipitation with redox-sensitive elements ({F}e, {M}n) and suggestively for mercury demethylation. {I}n the downstream {T}ula {R}iver and groundwater, almost all metallic concentrations remained below guideline thresholds. {O}nly, dissolved {A}s and {P}b concentrations remained two to five times above thresholds for drinking water, highlighting a potential health risk for approximately 500,000 people who use groundwater as water supply.},
  keywords = {{W}astewater irrigation ; {M}etal fractions ; {B}ioavailability ; {S}oil ; {G}roundwater ; {MEXIQUE}},
  booktitle = {},
  journal = {{W}ater {A}ir and {S}oil {P}ollution},
  volume = {225},
  numero = {8},
  pages = {art. 2045 [19 ]},
  ISSN = {0049-6979},
  year = {2014},
  DOI = {10.1007/s11270-014-2045-3},
  URL = {https://www.documentation.ird.fr/hor/fdi:010062474},
}