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The effects of municipal sewage sludge applied on topsoil and understory vegetation ( Molinia caerulea (L.) Moench) were studied in a maritime pine forest located in the South West of France (Landes of Gascogne). Understory response to sludge application is important as sludge addition to forest could increase competition with pine and affect herbivorous wildlife through incorporation of heavy metals in the food chain. The experiment was conducted in a young stand of maritime pines. The experimental design consisted of three 0.1-ha plots. One plot received composted sludge, one plot received liquid sludge, and one control plot received no sludge. Liquid sludge and composted sludge were applied on the basis of 3 tons dry matter sludge per hectare and per year. After 2 years of sludge application, we observed the following: (1) a significant increase in total concentrations of the following major and trace elements in the topsoil (layer 0-20 cm) [organic carbon (+140%), nitrogen (+140%), and lead (+80%)] and (2) no significant accumulation of trace elements in M. caerulea except nickel, which increased moderately (+40%) following application of composted sludge. These initial results need to be completed (1) by the assessment of long-term effects and dynamics of trace elements with additional applications of sludge and (2) by analyzing secondary understory species to determine if understory response to sludge application is more dependant on species than on soil parameters and sludge type. [ABSTRACT FROM AUTHOR]

A dune forest in SW France composed of maritime pines was irrigated with treated wastewater for a decade in an experiment (including irrigated plots versus control plots) to evaluate the environmental impact of applying wastewater on the water table, soil properties, and plants. The amount of treated wastewater (1921 mm yr −1 ) applied was twice the annual precipitation. Nutrient inputs were also very high, particularly nitrogen (N: 539 kg-N ha −1  yr −1 ), phosphorus (P: 102 kg-P ha −1  yr −1 ), and calcium (Ca: 577 kg-Ca ha −1  yr −1 ). Irrigation caused a rise in the water table, and increased its sodium (Na), NO 3 − , potassium (K), and calcium concentrations. Soil properties were affected by irrigation at least down to a depth of 1.2 m. After eight years of irrigation, soil pH had increased by 1.4 units, and soil available P content (P Olsen ) increased nearly 8-fold. In the short-term (i.e. 1–3 years), irrigation with treated wastewater improved growth, standing biomass, and the nutritional status of the vegetation. But tree dieback started in the fourth year of irrigation and worsened until the end of the monitoring period when almost all the irrigated trees were dead or moribund. The understory composition was drastically modified by irrigation, with an increase in α-biodiversity and in the biomass of herbaceous species, and a reduction in woody species abundance. The factor that best explained tree dieback was manganese nutrition (Mn): (i) the Mn content of the tree foliage was negatively affected by irrigation and below the deficiency values reported for pine species, and (ii) soil available Mn (CaCl 2 extraction) decreased by half in the topsoil layer. Manganese deficiency was probably the consequence of the increase in soil pH, which in turn reduced soil Mn availability. Tree dieback was not related to either to a macronutrient deficiency or to toxicity caused by a trace element. [ABSTRACT FROM AUTHOR]

RECOTOX is a cross-cutting initiative promoting an integrated research to respond to the challenges of monitoring, understanding, and mitigating environmental and health impacts of pesticides in agroecosystems. The added value of RECOTOX is to develop a common culture around spatial ecotoxicology including the whole chain of pressure-exposure-impact, while strengthening an integrated network of in natura specifically equipped sites. In particular, it promotes transversal approaches at relevant socioecological system scales, to capitalize knowledge, expertise, and ongoing research in ecotoxicology and, to a lesser extent, environmental toxicology. Thus, it will open existing research infrastructures in environmental sciences to research programs in ecotoxicology of pesticides.

In the context of biosolids utilisation in forestry, effects of sludge application on mushroom metal concentration were studied in six sites of maritime pine forests in the South-West of France. Municipal sludge were applied at a rate of 6 T dry matter per hectare. Edible mushrooms were collected two years after sludge application. As, Cd, Cu, Hg, Pb, Se and Zn concentrations were determined. Results showed a high variability for trace element concentrations in mushrooms collected from control areas. No significant correlation was found between soil parameters (pH and trace elements concentrations) and mushroom trace element concentrations. Even if the concentration of trace metals increased in the soils, sludge application did not affect As, Cu, Se and Zn concentrations in carpophores but slightly increased Cd, Pb and Hg concentrations on some sites. This effect is dependent on sludge type and sites.