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This study investigates the occurrence and distribution of 185 organic contaminants (regulated pollutants and contaminants of emerging concern; CECs) in surface and groundwater of the Guadalhorce River basin (southern Spain) providing the most detailed dataset regarding organic pollution presented so far in this area. Up to 63 contaminants were detected in a monitoring campaign conducted in March 2016. Most contaminants were detected more frequently in surface water where they generally present higher concentrations suggesting the prevalence of wastewater discharges into streams as the main pollutant sources. In general, hydrophobic CECs presented the highest frequencies of detection and concentrations, which can be a consequence of several factors: (1) hydrophobic compounds show a higher retardation factor, which result, along with a continuous contaminant input, in a widespread and homogeneous distribution. In contrast, hydrophilic contaminants are more easily transported by water flows towards the lower basin and potentially accumulate as driven by groundwater flow and because of low renewal rates in the detrital aquifers caused by re-pumping and irrigation return flows in agricultural lands; (2) hydrophobic CECs studied in this research are mainly personal care products and organophosphate esters flame retardants and plasticizers, which are present in many different products and are used in large amounts; Also, (3) use of biosolids (reclaimed sewer sludge) as fertilizer for crops is potentially an additional diffuse source of organic pollutants in the study area contributing to a widespread distribution, especially for hydrophobic compounds. Obtained results highlight the need to better define the potential risk of non-regulated contaminants in water resources as well as the great impact of untreated wastewater discharges., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Maltese agriculture faces great challenges due to the severe scarcity of water. Sufficient water resources, in quantity and quality, are necessary to cover the demand in the production of wine grape, one of the most important crops in Maltese agriculture. But also, economic efficiency is essential in the grape cultivation. A Cost-Benefit Analysis (CBA) is defined for Maltese vineyards in the Siġġiewi region, considering two irrigation scenarios, irrigation with groundwater or "do-nothing", compared with the "use non-conventional waters" from mixing water from a small desalination plant and groundwater. For the alternative 'mixing desalinated water with groundwater' it is possible to improve water availability and quality for vine crops, while increasing economic benefits for farmer. The results indicate a profitable project from a minimum area of 1 ha, but final benefit is highly dependent on the irrigated surface extension according to water price. Desalination, compared with other type of non-conventional water is considered the best option in this assessment with a small reverse osmosis (RO) desalination plant (120 m 3 /day) for covering the irrigation needs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This study is focused on the Guadalete River basin (SW, Spain), where extreme weather conditions have become common, with and alternation between periods of drought and extreme rainfall events. Combined sewer overflows (CSOs) occur when heavy rainfall events exceed the capacity of the wastewater treatment plants (WWTP), as well as pollution episodes in parts of the basin due to uncontrolled sewage spills and the use of reclaimed water and sludge from the local WWTP. The sampling was carried out along two seasons and three campaigns during dry (March 2007) and extreme rainfall (April and December 2010) in the Guadalete River, alluvial aquifer and Jerez de la Frontera aquifer. Results showed minimum concentrations for synthetic surfactants in groundwater (<37.4μg·L -1 ) during the first campaign (dry weather conditions), whereas groundwater contaminants increased in December 2010 as the heavy rainfall caused the river to overflow. In surface water, surfactant concentrations showed similar trends to groundwater observations. In addition to surfactants, pharmaceuticals and personal care products (PPCPs) were analyzed in the third campaign, 22 of which were detected in surface waters. Two fragrances (OTNE and galaxolide) and one analgesic/anti-inflammatory (ibuprofen) were the most abundant PPCPs (up to 6540, 2748 and 1747ng·L -1 , respectively). Regarding groundwater, most PPCPs were detected in Jerez de la Frontera aquifer, where a synthetic fragrance (OTNE) was predominant (up to 1285ng·L -1 )., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Extensive application of vinasse, a subproduct from sugar cane plantations for bioethanol production, is currently taking place as a source of nutrients that forms part of agricultural management in different agroclimatic regions. Liquid vinasse composition is characterised by high variability of organic compounds and major ions, acid pH (4.7), high TDS concentration (117,416-599,400mgL(-1)) and elevated EC (14,350-64,099μScm(-1)). A large-scale sugar cane field application is taking place in Valle del Cauca (Colombia), where monitoring of soil, unsaturated zone and the aquifer underneath has been made since 2006 to evaluate possible impacts on three experimental plots. For this assessment, monitoring wells and piezometers were installed to determine groundwater flow and water samples were collected for chemical analysis. In the unsaturated zone, tensiometers were installed at different depths to determine flow patterns, while suction lysimeters were used for water sample chemical determinations. The findings show that in the sandy loam plot (Hacienda Real), the unsaturated zone is characterised by low water retention, showing a high transport capacity, while the other two plots of silty composition presented temporal saturation due to La Niña event (2010-2011). The strong La Niña effect on aquifer recharge which would dilute the infiltrated water during the monitoring period and, on the other hand dissolution of possible precipitated salts bringing them back into solution may occur. A slight increase in the concentration of major ions was observed in groundwater (~5% of TDS), which can be attributed to a combination of factors: vinasse dilution produced by water input and hydrochemical processes along with nutrient removal produced by sugar cane uptake. This fact may make the aquifer vulnerable to contamination., (Copyright © 2015 Elsevier B.V. All rights reserved.)

This manuscript deals with the presence and degradation of the most commonly-used surfactants, including anionic (linear alkylbenzene sulfonates, LAS, and alkyl ethoxysulfates, AES) and non-ionic (alcohol polyethoxylates, AEOs, and nonylphenol polyethoxylates, NPEOs) compounds, in sediments and pore water from several aquatic environments (Southwest, Spain). Different vertical distributions were observed according to the respective sources, uses, production volumes and physicochemical properties of each surfactant. Levels of nonionics (up to 10 mg kg(-1)) were twice as high as anionics in industrial areas and harbors, whereas the opposite was found near urban wastewater discharge outlets. Sulfophenyl carboxylic acids (SPCs), LAS degradation products, were identified at anoxic depths at some sampling stations. Their presence was related to in situ anaerobic degradation of LAS in marine sediments, whereas the occurrence of these metabolites in freshwater sediments was attributed to the existence of wastewater sources nearby. No significant changes in the average length of AEO and NPEO ethoxylated chains were observed along the sediment cores, suggesting that their biodegradation was very limited in the sampling area. This may be directly related to their lower bioavailability, as their calculated sediment-pore water distribution coefficients (log K(sw)), which showed that non-ionic surfactants examined in this study had greater sorption affinity than the anionic surfactants (e.g., 2.3±0.3 for NPEOs)., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Gaining knowledge on potential climate change impacts on water resources is a complex process which depends on numerical models capable of describing these processes in quantitative terms. Under limited data or ungauged basin conditions, which constrain the modelling approach, a physically based coherent methodological approach is required. The traditional approach to assess flow regime and groundwater recharge impacts, based on coupling general atmosphere-ocean circulation models (GCM) and hydrologic models, has been investigated in the Siurana ungauged catchment (NE Spain). The future A2 (medium-high) and B1 (medium-low) greenhouse gas scenarios and time slices 2013-2037 (2025) and 2038-2062 (2050), developed by the Intergovernmental Panel on Climate Change (IPCC, 2001), have been selected. For scenario simulations, coupled GCM ECHAM5 scenarios, stochastically downscaled outputs and surface-subsurface modelling to simulate changes in water resources were applied to the catchment. Flow regime analysis was assessed by HEC-HMS, a physically based hydrologic model to assess rainfall-runoff in a catchment, while recharge was estimated with VisualBALAN, a distributed model for natural recharge estimation. Simulations show that the projected climate change at the catchment will affect the entire hydrological system with a maximum of 56% reduction of water resources. While subtle changes are observed for the 2025 time slice, the temperature and precipitation forecast for 2050 shows a maximum increase of 2.2 °C and a decreased precipitation volume of 11.3% in relation to historical values. Regarding historical values, runoff output shows a maximum 20% decrease, and 18% decrease of natural recharge with a certain delay in relation to runoff and rainfall data. According to the results, the most important parameters conditioning future water resources are changes in climatic parameters, but they are highly dependent on soil moisture conditions., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The presence of 170 pharmaceuticals, personal care products, priority substances according to the 2008/105EU Directive and four metals (Cd, Ni, Hg, Pb) have been investigated at the Llobregat delta, south of Barcelona (Spain). In the area, reclaimed water is destined to satisfy environmental uses, irrigation and the construction of a hydraulic barrier against seawater intrusion in the deep aquifer of the delta. A monitoring survey was undertaken of water samples from a tertiary wastewater treatment plant (Depurbaix), treated waste water with an additional treatment of ultrafiltration, reverse osmosis, and UV disinfection (WWATP, for the hydraulic barrier injection). Groundwater samples from the aquifer receiving recharge were also investigated. The pharmaceutical group of substances was detected in sampled waters at concentrations rarely exceeding a few microg/L, among the compounds Caffeine, Nicotine and Galaxolide (musk fragrance) were found to be present in more than 60% of the samples. Diuron was the only priority substance detected. The four metals were always present in a variable concentration. After the WWATP treatment the majority of analytes are removed from tertiary treated wastewater or their concentration is reduced below 0.1 microg/L. Monitoring revealed a widespread occurrence of analysed compounds in groundwater. Among them Codeine (analgesic), Ibuprofen (anti-inflammatory), Iopamidol, Iopromide (contrast agent) and Paraxanthine (metabolite of caffeine) have only been detected in groundwater, and are not present in water currently being injected in the deep aquifer.

The transport of Glyphosate ([N-phosphonomethyl] glycine), AMPA (aminomethylphosphonic acid, CH(6)NO(3)P), and Bromide (Br(-)) has been studied, in the Mediterranean Maresme area of Spain, north of Barcelona, where groundwater is located at a depth of 5.5m. The unsaturated zone of weathered - granite soils was characterized in adjacent irrigated and non-irrigated experimental plots where 11 and 10 boreholes were drilled, respectively. At the non irrigated plot, the first half of the period was affected by a persistent and intense rainfall. After 69 days of application residues of Glyphosate up to 73.6 microgg(-1) were detected till a depth of 0.5m under irrigated conditions, AMPA, analyzed only in the irrigated plot was detected till a depth of 0.5m. According to the retardation coefficient of Glyphosate as compared to that of Br(-) for the topsoil and subsoil (80 and 83, respectively) and the maximum observed migration depth of Br(-) (2.9 m) Glyphosate and AMPA should have been detected till a depth of 0.05 m only. Such migration could be related to the low content of organic matter and clays in the soils; recharge generated by irrigation and heavy rain, and possible preferential solute transport and/or colloidal mediated transport., (Copyright 2010 Elsevier B.V. All rights reserved.)

Starting in July 2000, treated wastewater of urban origin has been used for the "Serres de Pals" golf course irrigation (Girona, Spain). To evaluate if the soil and the aquifer underneath are affected by the utilization of this type of water, samples have been taken along a period of several months from the wastewater treatment plant, the stabilization lagoon, groundwater and soil profiles. Analyses have been performed for total coliforms and aerobic bacteria, soil water pressure and soil water content as well as chemical analyses of the irrigation water, aquifer and water of the vadose zone. Soil profiles taken at several times during the study indicate the absence of coliforms except for a short period during summer. In the vadose zone an increase of more than 1000 mg kg(-1) of NaO(2) in the top 60 cm of soil was observed while Cl(-) concentration in the aquifer reached up to 1200 mg l(-1) ten months after starting the irrigation.