The shift from rural lifestyles to urban living has dramatically altered the way humans interact and live across the globe. With over 50% of the world’s populations living within cities, and significant increases expected over the next 50 years, it is critical that changes to social, economic and environmental sustainability of cities globally be implicit. Protecting and enhancing aquatic ecosystems, which provide important ecosystem services, is challenging. A number of factors influence pollutants in urban waterways including changes in land-use, impervious area and stormwater discharges, with sediment-bound pollution a major issue worldwide. This work aimed to investigate the spatial and temporal distribution of trace metals in freshwater sediments from six urbanised catchment over a 30-year period. It provides an estimate of pollution using a geoaccumulation index and examines possible toxicity using a probable effect concentration quotient (mPECq). Results showed significant temporal changes in metal concentrations over time, with lead generally decreasing in all but one of the sites, attributed to significant changes in environmental policies and the active elimination of lead products. Temporal changes in other metals were variable and likely dependent on site-specific factors. While it is likely that diffuse pollution is driving changes in zinc, for metals such as lead, chromium and copper, it is likely that watershed landuse and/or point sources are more important. The results clearly indicated that changes to watershed landuse, environmental policy and pollution abatement programs are all driving changes in sediment quality, highlighting the utility of long-term sediment monitoring for assessment of urban watershed condition. While this study has demonstrated the utility of detecting long-term changes in metal concentrations, this approach could easily be adapted to detect and assess future trends in other hydrophobic contaminants and emerging chemicals of concern, such as synthetic pyrethroids, providing essential information for the protection of catchment.

In Mexico, the mangrove is distributed in 764,486 ha, comprising the Atlantic coast from the Laguna Madre in Tamaulipas to Chetumal Bay in the Caribbean and in the Pacific from Ensenada, Baja California to Chiapas. On the coast of Oaxaca, coexist four species: red mangrove (Rhizophora mangle), white mangrove (Laguncularia racemosa) button mangrove (Conocarpus erectus) and black mangrove (Aviccenia germinans). In the Laguna “Salina” Tonameca, grows and develops the white, button, and black mangroves, whose spatial distribution decreases by deforestation, land use change, and increased saline substrate. Salinity of soil and waters, its concentration, and tipogenesis associated with the growth of mangrove trees were determined. Three saline gradients were identified in rainy season (gradient I: 2.18 dS m⁻¹; gradient II: 9.95 dS m⁻¹ and gradient III: 36.14 dS m⁻¹); while in drought season four gradients were detected (gradient I: 1.15 dS m⁻¹; II: 17.83 dS m⁻¹; III: 39.06 dS m⁻¹ and IV: 57.75 dS m⁻¹). The interannual saline variation is due to climatics, hydrologycal, and geomorpholigical conditions of the substrate. The lake salinity is hydrochloric, predominantly NaCl salt, of intense osmotic effect, which largely explains the mangrove halophytism. Moisture diluting brackish water, such that low salt conditions promotes growth and development of mangrove, but at concentrations > 35 g L⁻¹ limits their growth. In drought, hypersaline (>70 g L⁻¹) prevents the establishment and repopulation of this species.

Climate change is expected to affect the groundwater quality by altering recharge, water table elevation, groundwater flow, and land use. In fractured bedrock aquifers, the quality of groundwater is a sensitive issue, particularly in areas affected by geogenic arsenic contamination. Understanding how climate change will affect the geochemistry of naturally occurring arsenic in groundwater is crucial to ensure sustainable use of this resource, particularly as a source of drinking water. This paper presents a review of the potential impacts of climate change on arsenic concentration in bedrock aquifers and identifies issues that remain unresolved. During intense and prolonged low flow, the decline in the water table is expected to increase the oxidation of arsenic-bearing sulfides in the unsaturated zone. In addition, reduced groundwater flow may increase the occurrence of geochemically evolved arsenic-rich groundwater and enhance arsenic mobilization by reductive dissolution and alkali desorption. In contrast, the occurrence of extreme recharge events is expected to further decrease arsenic concentrations because of the greater dilution by oxygenated, low-pH water. In some cases, arsenic mobilization could be indirectly induced by climate change through changes in land use, particularly those causing increased groundwater withdrawals and pollution. The overall impact of climate change on dissolved arsenic will vary greatly according to the bedrock aquifer properties that influence the sensitivity of the groundwater system to climate change. To date, the scarcity of data related to the temporal variability of arsenic in fractured bedrock groundwater is a major obstacle in evaluating the future evolution of the resource quality.

Phosphorus (P) loss from diffuse sources remains as the main cause of freshwater eutrophication in agricultural regions. The amount of land used for different agricultural practices may be a strong explanatory factor for the P loading to runoff waters. A prerequisite is that the effect of changes in land use on P levels in surface waters needs to be ascertained and quantified. In this study, a comprehensive approach has been developed to explore the environmental consequences of P levels in receiving water with corresponding land use change in a heavily agriculturally influenced watershed. A coupled simulation using Dyna-CLUE model with grey relational analysis (GRA) and grey model GM (1,1) model was employed to stimulate spatial distribution and area demand. Besides, a comprehensive land use index with degree of P saturation (DPS%) as weight coefficient was developed to examine the statistical and spatial relationships of land use and P levels in receiving waters on regional watershed. Moreover, in order to evaluate the practical impact of land use change on water quality, a planned emigration and watershed ecological reconstruction planning were designed into the scenarios. The potential of changes in land use as an abatement action to curb eutrophication was evaluated by modelling the effect of issued emigration and ecological restoration programs in the local watershed of the Yuqiao water reservoir in northeastern China. Kappa indexes above 0.85 for the validation period verify that the coupled land use change model is able to simulate the effect of the abatement actions on land use. Scenario predictions reveals that local emigration and a comprehensive ecological restoration project as abatement actions could significantly decrease contents of P in receiving surface waters: Relative to year 2012, total P and orthophosphate could be reduced by 36 and 45 %, respectively, by the end of year 2018. This modelling approach can, with moderate modifications, also be adapted to other watersheds. The model developed in this study can thus be used by environmental managers as a tool to identify risk for P loss from diffuse sources within a watershed and assist policy makers to assess the effect on P losses by implementing abatement actions that changes land use.

China's Sloping Land Conversion Program (SLCP) was designed to restore perennial plant cover on sloping land in western China, in part to protect the Three Gorges Reservoir (TGR). In this study, we examined use of white mulberry (Morus alba L.) in the SLCP to protect water quality and conserve soil. We established nine runoff monitoring plots divided among three categories (vegetable farming, fallow control, and mulberry plantation) on a bank of the Liangtan River situated at the western margin of the TGR. The land had been used previously by farmers for growing vegetables. We found that soil loss and surface water runoff were lowest in the mulberry plots and highest in the vegetable plots. We used inductively coupled plasma atomic emission spectroscopy (ICP-AES) to assess the concentration of selected heavy metal pollution indicators (Zn, Hg, As, Ni, Pb, Cr, Cd, and Cu) in the monitoring plot soils at the beginning of the experiment in May 2009. The heavy metals were assessed again at the end of the experiment in October 2012, and we found that the concentrations of these pollutants had been reduced in all fallow and mulberry plots, and to the greatest extent in the mulberry plots. We found that levels of Hg, Pb, and Cu increased in the vegetable plots. For these reasons, we conclude that riparian mulberry plantations are useful for reducing rapid runoff of storm water, conserving soil, and sequestering heavy metal pollutants in the TGR region.

The Mediterranean area is highly vulnerable to climate changes that combined with potential land use changes could influence its aquatic systems significantly. The Evros River is one of the most important surface water bodies in the Balkans with an ecologically significant delta that is protected by international legislation. The aim of this study is to analyze the impacts of climate and land use changes on Evros River water quality, for different climatic and socioeconomic scenarios. For this purpose, a hydrodynamic and advection-dispersion model was set up and calibrated, three IPCC climatic scenarios were applied, and the pollution loads of the catchment area were estimated. These scenarios involved river discharge decrease due to regional climate changes and socioeconomic and technological development that would lead to population growth and to the decrease of agricultural activities. The results indicated that in the case of discharge reduction only, the total nitrate and phosphate concentrations will be increased, while in case of combined land use and discharge changes, the concentration of nutrients will be decreased. Thus, a transboundary long-term management plan of the entire River is needed that would eliminate the pollution pressures and restore its good ecological status.

Due to the accelerated growth of society, the gaps between the capacity of ecosystems to provide services and human needs are steadily widening. Natural, semi-natural, or managed ecosystems had been able to provide ecosystem services to meet the needs of social development. Four agricultural ecosystem services (net primary production (NPP), carbon sequestration and oxygen production (CSOP), water interception, soil conservation and agriculture production) were quantified in Guanzhong-Tianshui economic region. Estimates of ecosystem services were obtained from the analysis of satellite imagery and the use of well-known models. Based on the ecological services in Guanzhong-Tianshui economic region, this study mainly analysed the driving mechanism of the changes from the two aspects of natural drivers and human drivers. Natural drivers (climate, soil, elevation, land cover) had incentive to the ecological services. Human activity was quantified by an integrated human activity index (HAI) based on population density, farmland ratio, and the influence of road networks and residential areas. We found relationships between ecosystem services, human activities and many natural factors, however these varied according to the service studied. Human activities were mostly negatively related to each ecosystem services, while population and residential land ware positively related to agricultural production. Land use change had made a contribution to ecosystem services. Based on the selected ecosystem services and HAI, we provided sustainable ecosystem management suggestions.

During the past decades, land use change has taken place around the Loess Plateau at unprecedented rates. Due to the impact of existing land use policy, great changes have taken place in the land use types in this ecologically vulnerable area. Taking eight counties in Yan’an, Shaanxi province, China, as the study area, this study analyzed the long-term (from 1997 to 2011) changes in land use and ecological vulnerability. Based on thematic mapper (TM) images of Yan’an in 1997, 2004, and 2011, the dynamic changes in land use are analyzed with the application software for remote sensing (RS) and geographic information system (GIS) since the implementation of the policy of returning farmland to forest. Combined with the land use data, the local socio-economic data, and natural resources condition, ecological vulnerability is evaluated using the spatial principal component analysis (SPCA) model in Yan’an region. Using the natural breaks classification (NBC), the evaluation results are divided into five categories: potential, slight, light, medium, and heavy. The results show that although the regional land use types changed markedly, the ecological vulnerability in the study shows greater than average optimism, and the ecological vulnerability index of the southern four counties is lower than that of the northern four counties. In 1997–2011, the eco-environmental quality gradually improved in most areas. However, it gradually deteriorated in some regions.

Potential detrimental impacts of neonicotinoids on non-target organisms, especially bees, have been subject to a wide debate and the subsequent ban of three neonicotinoids by the EU. While recent research has fortified concerns regarding the effects of neonicotinoids on ecosystem service (ES) providers, potential impacts have been considered negligible in systems with a relatively small proportion of arable land and thus lower the use of these pesticides. In this paper we argue that there is not sufficient information to assess magnitude and extent of neonicotinoid application, as well as potential non-target impacts on ES providers in grass-dominated systems with frequent land-use change. Using Ireland as an example, we show that the highly dynamic agricultural landscape, in conjunction with estimated persistence times of neonicotinoids in soils, may lead to a much larger area (18.6 ± 0.6 % of the Irish agricultural area) exposed to these pesticides than initially assumed. Furthermore we present a number of important gaps in current research regarding the impacts of neonicotinoids on ES providers in such systems.

The assessment of spatial and temporal variation of water quality influenced by land use is necessary to manage the environment sustainably in basin scales. Understanding the correlations between land use and different formats of nonpoint source nutrients pollutants is a priority in order to assess pollutants loading and predicting the impact on surface water quality. Forest, upland, paddy field, and pasture are the dominant land use in the study area, and their land use pattern status has direct connection with nonpoint source (NPS) pollutant loading. In this study, two land use scenarios (1995 and 2010) were used to evaluate the impact of land use changes on NPS pollutants loading in basins upstream of Three Gorges Reservoir (TGR), using a calibrated and validated version of the soil and water assessment tool (SWAT) model. The Pengxi River is one of the largest tributaries of the Yangtze River upstream of the TGR, and the study area included the basins of the Dong and Puli Rivers, two major tributaries of the Pengxi River. The results indicated that the calibrated SWAT model could successfully reproduce the loading of NPS pollutants in the basins of the Dong and Puli Rivers. During the 16-year study period, the land use changed markedly with obvious increase of water body and construction. Average distance was used to measure relative distribution patterns of land use types to basin outlets. Forest was mainly distributed in upstream areas whereas other land use types, in particular, water bodies and construction areas were mainly distributed in downstream areas. The precipitation showed a non-significant influence on NPS pollutants loading; to the contrary, interaction between precipitation and land use were significant sources of variation. The different types of land use change were sensitive to NPS pollutants as well as land use pattern. The influence of background value of soil nutrient on NPS pollutants loading was evaluated in upland and paddy field. It was found that total nitrogen (TN) and total phosphorous (TP) in upland were more sensitive to NPS pollutants loading than in paddy fields. The results of this study have implications for management of the TGR to reduce the loading of NPS pollutants into downstream water bodies.