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Pharmaceuticals reach terrestrial environments through the application of treated wastewaters and biosolids to agricultural soils. We have investigated the toxicity of 15 common pharmaceuticals, classified as nonsteroidal anti-inflammatory drugs (NSAIDs), blood lipid-lowering agents, β-blockers and antibiotics, in two photosynthetic organisms. Twelve pharmaceuticals caused inhibitory effects on the radicle and hypocotyl elongation of Lactuca sativa seeds. The EC values obtained were in the range of 170-5656 mg L in the case of the radicle and 188-4558 mg L for the hypocotyl. Propranolol was the most toxic drug for both root and hypocotyl elongation, followed by the NSAIDs, then gemfibrozil and tetracycline. Other effects, such as root necrosis, inhibition of root growth and curly hairs, were detected. However, even at the highest concentrations tested (3000 mg L), seed germination was not affected. NSAIDs decreased the photosynthetic yield of Chlamydomonas reinhardtii, but only salicylic acid showed EC values below 1000 mg L. The first effects detected at low concentrations, together with the concentrations found in environmental samples, indicate that the use of biosolids and wastewaters containing pharmaceuticals should be regulated and their compositions assessed in order to prevent medium- and long-term impacts on agricultural soils and crops.

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18Many dryland areas are being converted into intensively managed irrigation crops, what 19 can disrupt the hydrological regime, degrade soil and water quality, enhance siltation, 20 erosion and bank instability, and affect biological communities. Still, the impacts of 21 irrigation schemes on the functioning of terrestrial and aquatic ecosystems are poorly 22 understood. Here we assess the effects of irrigation agriculture on breakdown of coarse 23 organic matter in soil and water. We measured breakdown rates of alder and holm oak 24 leaves, and of poplar sticks in terrestrial and aquatic sites following a gradient of 25 increasing irrigation agriculture in a semi-arid Mediterranean basin transformed into 26 irrigation agriculture in 50% of its surface. Spatial patterns of stick breakdown 27