International audience | The current challenge in sustainable agriculture is to introduce new cropping systems to reduce pesticides use in order to reduce ground and surface water contamination. However, it is difficult to carry out in situ experiments to assess the environmental impacts of pesticide use for all possible combinations of climate, crop, and soils; therefore, in silico tools are necessary. The objective of this work was to assess pesticides leaching in cropping systems coupling the performances of a crop model (STICS) and of a pesticide fate model (MACRO). STICS-MACRO has the advantage of being able to simulate pesticides fate in complex cropping systems and to consider some agricultural practices such as fertilization, mulch, or crop residues management, which cannot be accounted for with MACRO. The performance of STICS-MACRO was tested, without calibration, from measurements done in two French experimental sites with contrasted soil and climate properties. The prediction of water percolation and pesticides concentrations with STICS-MACRO was satisfactory, but it varied with the pedoclimatic context. The performance of STICS-MACRO was shown to be similar or better than that of MACRO. The improvement of the simulation of crop growth allowed better estimate of crop transpiration therefore of water balance. It also allowed better estimate of pesticide interception by the crop which was found to be crucial for the prediction of pesticides concentrations in water. STICS-MACRO is a new promising tool to improve the assessment of the environmental risks of pesticides used in cropping systems.

Sea level rise induced-salinization is lowering coastal soils productivity. In order to assess the effects that increased salinity may provoke in terrestrial plants, using as model species: Trifolium pratense, Lolium perenne, Festuca arundinacea and Vicia sativa, two specific objectives were targeted: i) to determine the sensitivity of the selected plant species to increased salinity (induced by seawater-SW or by NaCl, proposed as a surrogate of SW) and, ii) to assess the influence of salinization in total biomass under different agricultural practices (mono- or polycultures).The four plant species exhibited a higher sensitivity to NaCl than to SW. Festuca arundinacea was the most tolerant species to NaCl (EC₅₀,ₛₑₑd gₑᵣₘᵢₙₐₜᵢₒₙ and EC₅₀,gᵣₒwₜₕ of 18.6 and 10.5 mScm⁻¹, respectively). The other three species presented effective conductivities in the same order of magnitude and, in general, with 95% confidence limits overlapping. Soil moistened with SW caused no significant adverse effects on seed germination and growth of L. perenne. Similar to NaCl, the other three species, in general, presented a similar sensitivity to SW exposure with EC₅₀,ₛₑₑd gₑᵣₘᵢₙₐₜᵢₒₙ and EC₅₀,gᵣₒwₜₕ within the same order of magnitude and with confidence limits overlapping.The agricultural practice (mono-vs polyculture) showed some influence on the biomass of each plant species. When considering total productivity, for aerial and root biomass, it was higher in control comparatively to salinization conditions. Under salinization stress, the practice of polyculture was associated with a higher aerial and root total biomass than monocultures (for instance with combinations with T. pratense and F. arundinacea).Results suggest that the effects of salinity stress on total productivity may be minimized under agricultural practices of polyculture. Thus, this type of cultures should be encouraged in low-lying coastal ecosystems that are predicted to suffer from salinization caused by seawater intrusions.

Perchlorate is an endocrine-disrupting chemical (EDC) that contaminate various foodstuffs. Exposure to perchlorate may cause severe health problems, mainly thyroid dysfunction. However, information on perchlorate contamination of consumer foods in Taiwan is limited. This study investigated perchlorate levels in 310 food samples belonging to 12 food groups collected from Taiwanese markets. A probabilistic risk assessment was conducted to assess the related exposure to Taiwanese people. Perchlorate was detected in 65% of the samples and high levels were identified in certain plant-origin, fruit, and processed food samples. A probabilistic approach was used to estimate daily dietary dose (Monte Carlo–estimated 95th percentile dietary exposure [MCS 95]) by using the Taiwan National Food Consumption database for 14 sex/age groups. The highest and lowest average daily doses (ADDs) were in the age groups of >65 years (MCS 95 = 3.60/3.90 [male/female] μg/kg bw/day) and 16–18 years (MCS 95 = 1.70/1.47 [M/F] μg/kg bw/day), respectively. The 95th percentile of the hazard index of exposure to perchlorate of all sex/age groups far exceeded the tolerable daily intake (0.3 μg/kg bw/day) and reference dose (0.7 μg/kg bw/day) set by the European Food Safety Authority and US EPA, respectively, but it was lower than the provisional maximum tolerable daily intake (10 μg/kg bw/day) suggested by the Joint FAO/WHO Expert Committee on Food Additives. The intake quantity and concentrations of perchlorate from vegetables, fruits, and whole grains are the critical contributors for the ADDs and integrated risk of dietary exposure to perchlorate. Long-term exposure through diets should be considered, instead of focusing on individual EDC during dietary risk assessment in specific populations. Furthermore, cumulative risks for exposure to multiple contaminants, particularly those causing thyroid adverse effects, may be higher than that from perchlorate exposure alone.

Agriculture is critical to the economies of developing countries. It is the basic source of food supply and a major contributor to economic development. But there is a cost. Today, agricultural water pollution undermines economic growth and threatens the environmental and physical health of millions of people around the world. The annual social and economic costs of agricultural water pollution could reach trillions of dollars. Yet the issue receives scant attention in global research and debate.