Two decades of the EU Water Framework Directive: Evidence of success and failure from a lowland arable catchment (River Wensum, UK).

The EU Water Framework Directive (WFD) is widely regarded as a seminal piece of environmental legislation. However, two decades since its inception, many European waterbodies are failing to meet its ambitious goal to ensure 'good' quantitative and qualitative status. Here, we investigate the impact of the WFD upon the environmentally sensitive yet heavily impacted River Wensum, a lowland arable catchment in eastern England. Compiling a dataset of 10,950 water quality samples collected from 57 sites across the catchment at approximately monthly intervals during 2000-2022, we assess the spatio-temporal dynamics of 12 priority pollutants, identify the major drivers of water quality change, and evaluate current and future compliance with WFD goals. Our analysis reveals improvements in wastewater treatment initiated significant declines (11-50 %) in the concentration of key sewage pollution indicators (phosphorus, ammonium, biological oxygen demand (BOD)) during the early 2000s. Conversely, agricultural pollution indicators (nitrogen, suspended solids, pesticides) displayed either limited change or a deterioration in water quality, with oxidised nitrogen concentrations in particular having increased 23 % during 2015-2022. Concentration spikes of organic chemical contaminants in recent years (propyzamide, tetrachloroethylene) raise concerns about increased riverine pollution from hazardous substances. Similarly, changes in winter (+13 %) and summer (-7 %) discharge over the past two decades have increased the risk of diffuse pollution mobilisation and reduced the dilution of point source pollutants, respectively. By 2022, 'good' or 'high' water quality status for organic matter pollution indicators (dissolved oxygen, BOD, ammonium) was achieved for >98 % of samples, however WFD compliance fell to just 46 % for phosphorus and 1.8 % for nitrogen. Projections to the end of the third River Basin Management Plan cycle (2027) reveal that whilst phosphorus compliance is likely to improve, nitrogen compliance failure will persist due to the existence of catchment legacy stores and climate change induced impacts on nitrogen mobilisation.

Relationships between riverine and terrestrial dissolved organic carbon: Concentration, radiocarbon signature, specific UV absorbance.

The transfer of dissolved organic carbon (DOC) from land to watercourses plays a major role in the carbon cycle, and in the transport and fate of associated organic and inorganic contaminants. We investigated, at global scale, how the concentrations and properties of riverine DOC depend upon combinations of terrestrial source solutions. For topsoil, subsoil, groundwater and river solutions in different Köppen-Geiger climatic zones, we compiled published and new values of DOC concentration ([DOC]), radiocarbon signature (DO14C), and specific UV absorbance (SUVA). The average value of each DOC variable decreased significantly in magnitude from topsoil to subsoil to groundwater, permitting the terrestrial sources to be distinguished. We used the terrestrial data to simulate the riverine distributions of each variable, and also relationships between pairs of variables. To achieve good matches between observed and simulated data, it was necessary to optimise the distributions of water fractions contributed by each of the three terrestrial sources, and also to reduce the mean input terrestrial [DOC] values, to about 60% of the measured ones. One possible explanation for the required lowering of the modelled terrestrial [DOC] values might be unrepresentative sampling of terrestrial DOC, including dilution effects; another is the loss of DOC during riverine transport. High variations in simulated riverine DOC variables, which match observed data, are due predominantly to variations in source solution values, with a lesser contribution from the different combinations of source waters. On average, most DOC in rivers draining catchments with forest and/or grass-shrub land cover comes in similar amounts from topsoil and subsoil, with about 10% from groundwater. In rivers draining croplands, subsoil and groundwater solutions are the likely dominant DOC sources, while in wetland rivers most DOC is from topsoil.

Evaluating the impacts of contrasting sewage treatment methods on nutrient dynamics across the River Wensum catchment, UK.

Sewage effluent discharged from wastewater treatment plants (WWTPs) is a major driver of nitrogen (N) and phosphorus (P) enrichment, but tertiary treatment methods such as P-stripping have previously been shown to mitigate eutrophication risk. The aim of this study was to evaluate the impacts of sewage effluent discharged from WWTPs with contrasting classifications of tertiary treatment on nutrient dynamics across the River Wensum catchment, UK. River water samples were collected from 20 locations across the catchment at monthly intervals between October 2010 and September 2013, with 677 samples collected in total and analysed for a suite of hydrochemical parameters. The 20 sampling locations were divided into four classifications based on the type of upstream WWTP: (1) no WWTP; (2) WWTPs without P-stripping; (3) WWTPs with and without P-stripping; (4) WWTPs with P-stripping. Results revealed substantial overlaps in riverine nutrient composition making differentiation between classifications difficult. The majority of N (>97%) and P (~75%) was present in dissolved bioavailable forms across all sites and there was no significant difference in total N speciation between classifications. Total P (TP) speciation did, however, reveal higher proportions of particulate P at sites with no WWTP, indicating a greater P contribution of agricultural origin. Ratios of total dissolved to particulate P (TDP:TPP) and chloride concentrations proved effective discriminators of agricultural and sewage P, respectively, but phosphate­boron ratios (PO4:B) were ineffective discriminators in this catchment. Most importantly, there was no evidence that P-stripping reduced overall TP concentrations downstream of WWTPs, despite evidence of a per capita reduction, nor reduced the proportion of dissolved P released. These findings were attributed to P-stripping facilities serving larger populations and thus releasing greater effluent P load, thereby demonstrating that the presence of tertiary P-stripping alone is insufficient to overcome population pressures and ensure that rivers achieve good hydrochemical status.

Chronic pain and opioid analgesic use: A case report.

Relationship-based medical care is essential in the management of chronic pain. Opioids are often ineffective and can cause significant harm. However, there is significant time pressure, and there are insufficient resources and guidelines for GPs to be able to offer alternatives, putting the NHS at risk of a growing opioid epidemic.

Backbone-Degradable Vinyl Acetate Latex: Coatings for Single-Use Paper Products.

We report an approach to waterborne and degradable latex polymers. Emulsion polymerization of vinyl acetate (VA) with the cyclic ketene acetal 2-methylene-1,3-dioxepane (MDO) yields polymer particles and latex-based coatings that are hydrolytically degradable due to the presence of backbone ester groups. Polymerization under mildly basic conditions (pH 8) and at low temperature (40 °C) is critical: if the in-process pH is too acidic or the temperature too high, MDO is lost to hydrolysis, but when the media is too alkaline, VA monomer rapidly hydrolyzes. When coated onto commercial paper, films of these degradable particle dispersions show excellent oil and grease resistance as compared to non-degradable, VA-only compositions. This new class of latex is therefore well-suited for the design of next-generation, biodegradable and compostable single-use food service products, as well as for other applications where the erosion or degradation of polymer-based films and coatings is required.

Role of patients' organizations in Health Technology Assessment: a Habermasian system and lifeworld perspective.

Patient and public involvement in Health Technology Assessment (HTA) is gaining increased interest among research and policy communities. Patients' organizations represent an important link between individual patients and the health system. Social theories are increasingly being used to explain doctor-patient-system interactions, expanding understanding beyond the mere clinical perspective. In this sense, patient involvement in HTA can also be considered through the Habermas's theory of communicative action. From a Habermasian perspective, HTA as part of the instrumental rationality contributes to an increased efficiency of resource use within the system; however, such rationalization threatens to colonize the lifeworld by making it "increasingly state administered with attenuated possibilities for communicative action as a result of the commercialization and rationalization in terms of immediate returns." Using Habermasian system/lifeworld framework, this paper explores opportunities and obstacles to patient involvement in HTA, whereby trying to understand current and possible roles of patients' organizations as a mediating force between HTA as a function of the system and the lifeworld represented by patients.

Pharmacists' Prescribing in Saudi Arabia: Cross-Sectional Study Describing Current Practices and Future Perspectives.

Pharmacist prescribing is being increasingly undertaken to better use their skills and reduce the workload of existing prescribers such as doctors, often using formal processes to legitimate these activities. In developing countries like Saudi Arabia, however, pharmacists' prescribing remains informal with no legislation or formal training and there is a lack of research and understanding into such practices. Therefore, we aimed to describe current pharmacist prescribing practices in Saudi Arabia and explore pharmacists' views about pharmacists' prescribing. This is a cross-sectional survey study using an online questionnaire of hospital pharmacists in Saudi Arabia about pharmacists' prescribing, and associated views about prescribing legislation and barriers to implementing pharmacist prescribing. Over a quarter (28.5%) of pharmacists reported themselves as prescribers, 49% were following a collaborative prescribing model, 18% independent prescribing, and 33% were doing both. Ninety percent of prescribers reported confidence in prescribing the appropriate treatment and 92.3% perceived they will benefit from more prescribing training. Healthcare practice culture and pharmacist's competency were identified as barriers. There is an overall support for pharmacists' prescribing in Saudi Arabia among this sample of hospital pharmacists, with limitations in resources and the absence of standardized prescribing training being perceived as key barriers to pharmacists' prescribing.

Temporal hydrochemical dynamics of the River Wensum, UK: Observations from long-term high-resolution monitoring (2011-2018).

In 2010, the UK government established the Demonstration Test Catchment (DTC) initiative to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology whilst maintaining food production capacity. A central component of the DTC platform was the establishment of a comprehensive network of automated, web-based sensor technologies to generate high-temporal resolution (30 min) empirical datasets of surface water, groundwater and meteorological parameters over a long period (2011-2018). Utilising 8.9 million water quality measurements generated for the River Wensum, this paper demonstrates how long-term, high-resolution monitoring of hydrochemistry can improve our understanding of the complex temporal dynamics of riverine processes from 30 min to annual timescales. This paper explores the impact of groundwater-surface water interactions on instream pollutant concentrations (principally nitrogen, phosphorus and turbidity) and reveals how varying hydrochemical associations under contrasting flow regimes can elicit important information on the dominant pollution pathways. Furthermore, this paper examines the relationships between agricultural pollutants and precipitation events of varying magnitude, whilst demonstrating how high-resolution data can be utilised to develop conceptual models of hydrochemical processes for contrasting winter and summer seasons. Finally, this paper considers how high-resolution hydrochemical data can be used to increase land manager awareness of environmentally damaging farming operations and encourage the adoption of more water sensitive land management practices.

Staff perceptions of prescription and over-the-counter drug dependence services in England: a qualitative study.

BACKGROUND: Dependence to prescription and over-the-counter (OTC) drugs represents an increasing public health and clinical problem both in England and internationally. However, relatively little is known about those affected, particularly in relation to their management at drug dependence treatment centres. This study aimed to explore the views and experiences of health care professionals (HCPs) working in formal drug treatment services in relation to supporting clients with prescription and OTC drug dependence. METHODS: An exploratory, qualitative design was used involving semi-structured telephone interviews. 15 staff were recruited using purposive sampling to represent a variety of different professional roles, funding (NHS, charity and local government) and geographical locations across England. Transcribed interviews were analysed using Braun and Clarke's six stage thematic analysis. RESULTS: Current services were considered to be inappropriate for the treatment of OTC and prescription drug dependence, which was perceived to be a significantly under-recognised issue affecting a range of individuals but particularly those taking opioid analgesics. Negativity around current treatment services involved concerns that these were more suited for illicit drug users and this was exacerbated by a lack of specific resources, funding and commissioning. There was a perceived variation in service provision in different areas and a further concern about the lack of formal treatment guidelines and care pathways. Participants felt there to be stigma for affected clients in both the diagnosis of OTC or prescription drug dependence and also attendance at drug treatment centres which adversely impacted service engagement. Suggested service improvements included commissioning new specific services in general practices and pain management clinics, developing national guidelines and care pathways to ensure equal access to treatment and increasing awareness amongst the public and HCPs. CONCLUSIONS: This study reveals considerable negativity and concern about current treatment services for prescription and OTC drug dependence in England from the perspective of those working in such services. Policy and practice improvement are suggested to improve outcomes for this neglected group in relation to increasing funding, guidelines and awareness.

Codeine Addiction and Internet Forum Use and Support: Qualitative Netnographic Study.

BACKGROUND: The use of codeine as an analgesic is well-recognized, but there are increasing concerns that for some individuals continued use may lead to misuse, dependence, and fatalities. Research suggests that those affected may represent a hard-to-reach group who do not engage with formal treatment services. OBJECTIVE: This study sought to explore the experiences of people with self-reported addiction to codeine and, specifically, how a social media forum is used to communicate with others about this issue. METHODS: Using a qualitative netnographic methodology, the social media forum Mumsnet was used, with permission, and searches were undertaken in 2016 of any posts that related to codeine and addiction. A total of 95 relevant posts were identified; a purposive sample of 25 posts was selected to undertake subsequent six-stage thematic analysis and development of emerging themes. These 25 posts were posted between 2003 and 2016 and comprised 757 individual posts. RESULTS: Individuals created posts to actively request help in relation to usually their own, but occasionally their partner's or relative's, problems relating to codeine use and self-reported "addiction." Varying levels of detail were provided in narratives of problematic codeine use. There were both positive and negative descriptions of side effects emerging, problems experiencing withdrawal, and failed attempts to discontinue codeine use. Mainly positive and supportive responses to posts were identified from those with either self-reported health profession experience or lay respondents, who often drew on their own experiences of similar problems. Treatment advice emerged in two main ways, either as signposting to formal health services or to informal approaches and often anecdotal advice about how to taper or use cold turkey techniques. Some posts were more critical of the original poster, and arguments and challenges to advice were not uncommon. Shame and stigma were often associated with users' posts and, while there was a desire to receive support and treatment advice in this forum, users often wanted to keep their codeine use hidden in other aspects of their lives. Distinctly different views emerged as to whether responsibility lay with prescribers or patients. Some users expressed anger toward doctors and their prescribing practices. CONCLUSIONS: This study provides a unique insight into how a public internet forum is used by individuals to confirm and seek support about problematic codeine use and of the ways others respond. The pseudonymous use of internet forums for such information and variation in treatment options suggested by often lay respondents suggest that increased formal support and awareness about codeine addiction are needed. There may be opportunities for providing further support directly on such online forums. Improvements in prescribing codeine and in the over-the-counter supply of codeine are required to prevent problematic use from occurring.

Mitigating river sediment enrichment through the construction of roadside wetlands.

Metalled roads have been shown to act as a major pathway for land-to-river sediment transfer, but there currently exists limited research into mitigation solutions to tackle this pollution source. The aim of this study was to assess the effectiveness of three roadside constructed wetlands, installed in September 2016, at reducing sediment enrichment in a tributary of the River Wensum, UK. Two wetland designs were trialled (linear and 'U-shaped'), both of which act as settling ponds to encourage entrained sediment to fall out of suspension and allow cleaner water to discharge into the river. Wetland efficiency was monitored through automated, high-resolution (30 min) turbidity probes installed upstream and downstream of the wetlands, providing a near-continuous record of river turbidity before (October 2011-August 2016) and after (November 2016-February 2018) installation. This was supplemented by lower resolution monitoring of the wetland inflows and outflows, as well as an assessment of sediment and nutrient accumulation rates within the linear wetland. Results revealed median river sediment concentrations decreased up to 14% after wetland construction and sediment load decreased by up to 82%, although this was largely driven by low river discharge post-installation. Median sediment concentrations discharging from the linear wetland (7.2 mg L-1) were higher than the U-shaped wetland (3.9 mg L-1), confirming that a longer flow pathway through wetlands can improve sediment retention efficiency. After 12 months of operation, the linear wetland had retained 7253 kg (305 kg ha-1 y-1) of sediment, 11.6 kg (0.5 kg ha-1 y-1) of total phosphorus, 29.7 kg (1.3 kg ha-1 y-1) of total nitrogen and 400 kg (17 kg ha-1 y-1) of organic carbon. This translates into mitigated pollutant damage costs of £392 for sediment, £148 for phosphorus and £13 for nitrogen, thus giving a combined total mitigated damage cost of £553 y-1. With the linear wetland costing £3411 to install and £145-182 y-1 to maintain, this roadside constructed wetland has an estimated payback time of 8 years, making it a cost-effective pollution mitigation measure for tackling sediment-enriched road runoff that could be widely adopted at the catchment-scale.

Structural and electrostatic effects at the surfaces of size- and charge-selected aqueous nanodrops.

The effects of ion charge, polarity and size on the surface morphology of size-selected aqueous nanodrops containing a single ion and up to 550 water molecules are investigated with infrared photodissociation (IRPD) spectroscopy and theory. IRPD spectra of M(H2O) n where M = La3+, Ca2+, Na+, Li+, I-, SO42- and supporting molecular dynamics simulations indicate that strong interactions between multiply charged ions and water molecules can disrupt optimal hydrogen bonding (H-bonding) at the nanodrop surface. The IRPD spectra also reveal that "free" OH stretching frequencies of surface-bound water molecules are highly sensitive to the ion's identity and the OH bond's local H-bond environment. The measured frequency shifts are qualitatively reproduced by a computationally inexpensive point-charge model that shows the frequency shifts are consistent with a Stark shift from the ion's electric field. For multiply charged cations, pronounced Stark shifting is observed for clusters containing ∼100 or fewer water molecules. This is attributed to ion-induced solvent patterning that extends to the nanodrop surface, and serves as a spectroscopic signature for a cation's ability to influence the H-bond network of water located remotely from the ion. The Stark shifts measured for the larger nanodrops are extrapolated to infinite dilution to obtain the free OH stretching frequency of a surface-bound water molecule at the bulk air-water interface (3696.5-3701.0 cm-1), well within the relatively wide range of values obtained from SFG measurements. These cluster measurements also indicate that surface curvature effects can influence the free OH stretching frequency, and that even nanodrops without an ion have a surface potential that depends on cluster size.

Hydrogeological Controls on Regional-Scale Indirect Nitrous Oxide Emission Factors for Rivers.

Indirect nitrous oxide (N2O) emissions from rivers are currently derived using poorly constrained default IPCC emission factors (EF5r) which yield unreliable flux estimates. Here, we demonstrate how hydrogeological conditions can be used to develop more refined regional-scale EF5r estimates required for compiling accurate national greenhouse gas inventories. Focusing on three UK river catchments with contrasting bedrock and superficial geologies, N2O and nitrate (NO3-) concentrations were analyzed in 651 river water samples collected from 2011 to 2013. Unconfined Cretaceous Chalk bedrock regions yielded the highest median N2O-N concentration (3.0 µg L-1), EF5r (0.00036), and N2O-N flux (10.8 kg ha-1 a-1). Conversely, regions of bedrock confined by glacial deposits yielded significantly lower median N2O-N concentration (0.8 µg L-1), EF5r (0.00016), and N2O-N flux (2.6 kg ha-1 a-1), regardless of bedrock type. Bedrock permeability is an important control in regions where groundwater is unconfined, with a high N2O yield from high permeability chalk contrasting with significantly lower median N2O-N concentration (0.7 µg L-1), EF5r (0.00020), and N2O-N flux (2.0 kg ha-1 a-1) on lower permeability unconfined Jurassic mudstone. The evidence presented here demonstrates EF5r can be differentiated by hydrogeological conditions and thus provide a valuable proxy for generating improved regional-scale N2O emission estimates.

Sequential water molecule binding enthalpies for aqueous nanodrops containing a mono-, di- or trivalent ion and between 20 and 500 water molecules.

Sequential water molecule binding enthalpies, ΔHn,n-1, are important for a detailed understanding of competitive interactions between ions, water and solute molecules, and how these interactions affect physical properties of ion-containing nanodrops that are important in aerosol chemistry. Water molecule binding enthalpies have been measured for small clusters of many different ions, but these values for ion-containing nanodrops containing more than 20 water molecules are scarce. Here, ΔHn,n-1 values are deduced from high-precision ultraviolet photodissociation (UVPD) measurements as a function of ion identity, charge state and cluster size between 20-500 water molecules and for ions with +1, +2 and +3 charges. The ΔHn,n-1 values are obtained from the number of water molecules lost upon photoexcitation at a known wavelength, and modeling of the release of energy into the translational, rotational and vibrational motions of the products. The ΔHn,n-1 values range from 36.82 to 50.21 kJ mol-1. For clusters containing more than ∼250 water molecules, the binding enthalpies are between the bulk heat of vaporization (44.8 kJ mol-1) and the sublimation enthalpy of bulk ice (51.0 kJ mol-1). These values depend on ion charge state for clusters with fewer than 150 water molecules, but there is a negligible dependence at larger size. There is a minimum in the ΔHn,n-1 values that depends on the cluster size and ion charge state, which can be attributed to the competing effects of ion solvation and surface energy. The experimental ΔHn,n-1 values can be fit to the Thomson liquid drop model (TLDM) using bulk ice parameters. By optimizing the surface tension and temperature change of the logarithmic partial pressure for the TLDM, the experimental sequential water molecule binding enthalpies can be fit with an accuracy of ±3.3 kJ mol-1 over the entire range of cluster sizes.

Indirect Nitrous Oxide Emission Factors for Agricultural Field Drains and Headwater Streams.

Agriculture is a major source of nitrous oxide (N2O) emissions, a potent greenhouse gas. While direct N2O emissions from soils have been widely investigated, indirect N2O emissions from nitrogen (N) enriched surface water and groundwater bodies are poorly understood. In this contribution, indirect N2O emissions from subsurface agricultural field drains and headwater streams were monitored over a two-year period (2013-2015) in an intensive arable catchment in eastern England. Indirect N2O emission factors for groundwater (EF5g) and surface runoff (EF5r) were calculated for both field drain and streamwater samples, respectively, using two approaches: the N2O-N/NO3-N ratio and the IPCC (2006) methodology. Mean EF5g values derived from the N2O-N/NO3-N ratio were 0.0012 for field drains and 0.0003 for streamwater. Using the IPCC (2006) methodology, the mean EF5g values were 0.0011 for field drains and 0.0001 for streamwater. Thus, EF values derived from both methods were below the current IPCC (2006) default value of 0.0025 and a downward revision to 0.0012 for EF5g and 0.0002 for EF5r is recommended. Such revision would halve current estimates of N2O emissions associated with nitrogen leaching and runoff from agriculture for both the UK and globally.

Benefits and tensions in delivering public health in community pharmacies - a qualitative study of healthy living pharmacy staff champions.

OBJECTIVE: Healthy Living Pharmacies (HLP) were introduced in the United Kingdom (UK) in a further attempt to deliver public health benefits in community pharmacy settings. Central to the initiative are staff trained as Healthy Living Champions (HLC) and this study sought to explore HLC perceptions of positive and negative aspect of their work and the wider scheme. METHODS: A qualitative study was undertaken with a purposive sample of HLCs working in pathfinder HCPs in the Sheffield area in 2014. Participants were recruited by email to either a focus group (n = 7) held at a training event or later semi-structured one-to-one interviews in pharmacies (n = 6). Four stages of interpretative phenomenological analysis were used to code and identify themes. KEY FINDINGS: Four main themes emerged relating to the positive workforce development impact HLPs had upon HLCs themselves and on perceived customer and patient engagement and benefits. Tensions were identified with existing commercial business demands and negative views overall of the pharmacy setting with a perceived lack of not only integration with other services but also awareness among the public and health care staff. HLCs felt empowered and more confident in initiating conversation about health issues with patients, but identified barriers relating to workload, a lack of time to perform their role, isolation, tensions with non-HLC staff and logistical barriers such as poor Internet access. CONCLUSIONS: Delivering public health activities through the HLC role in UK pharmacies is associated with several perceived benefits for different stakeholders, but may be threatened by well recognised barriers in UK pharmacies related to the commercial setting.

Assessing the effectiveness of a three-stage on-farm biobed in treating pesticide contaminated wastewater.

Agricultural point source pesticide pollution arising from contaminated machinery washings and accidental spillages pose a significant threat to river water and groundwater quality. In this study, we assess the effectiveness of a three-stage on-farm biobed for treating pesticide contaminated wastewater from a large (20 km(2)) commercial arable estate. The facility consisted of an enclosed machinery wash-down unit (stage 1), a 49 m(2) lined compost-straw-topsoil biobed (stage 2), and a 200 m(2) drainage field with a trickle irrigation system (stage 3). Pesticide concentrations were analysed in water samples collected fortnightly between November 2013 and November 2015 from the biobed input and output sumps and from 20 porous pots buried at 45 cm and 90 cm depth within the drainage field. The results revealed that the biobed removed 68-98% of individual pesticides within the contaminated washings, with mean total pesticide concentrations reducing by 91.6% between the biobed input and output sumps. Drainage field irrigation removed a further 68-99% of individual pesticides, with total mean pesticide concentrations reducing by 98.4% and 97.2% in the 45 cm and 90 cm depth porous pots, respectively. The average total pesticide concentration at 45 cm depth in the drainage field (57 µg L(-1)) was 760 times lower than the mean concentration recorded in the input sump (43,334 µg L(-1)). There was no evidence of seasonality in the efficiency of biobed pesticide removal, nor was there evidence of a decline in removal efficiency over the two-year monitoring period. However, higher mean total pesticide concentrations at 90 cm (102 µg L(-1)) relative to 45 cm (57 µg L(-1)) depth indicated an accumulation of pesticide residues deeper within the soil profile. Overall, the results presented here demonstrate that a three-stage biobed can successfully reduce pesticide pollution risk from contaminated machinery washings on a commercial farm.

Antecedent conditions, hydrological connectivity and anthropogenic inputs: Factors affecting nitrate and phosphorus transfers to agricultural headwater streams.

This paper examines relationships between rainfall-runoff, catchment connectivity, antecedent moisture conditions and fertiliser application with nitrate-N and total phosphorus (TP) fluxes in an arable headwater catchment over three hydrological years (2012-2014). Annual precipitation totals did not vary substantially between years, yet the timing of rainfall strongly influenced runoff generation and subsequent nitrate-N and TP fluxes. The greatest nitrate-N (>250 kg N day(-1)) and TP (>10 kg TP day(-1)) fluxes only occurred when shallow groundwater was within 0.6m of the ground surface and runoff coefficients were greater than 0.1. These thresholds were reached less frequently in 2012 due to drought recovery resulting in lower annual nitrate-N (7.4 kg N ha(-1)) and TP (0.12 kg P ha(-1)) fluxes in comparison with 2013 (15.1 kg N ha(-1); 0.21 kg P ha(-1)). The wet winter of 2013 with elevated shallow groundwater levels led to more frequent activation of sub-surface pathways and tile drain flow. Throughout the period, dry antecedent conditions had a temporary effect in elevating TP loads. Evidence of TP source exhaustion after consecutive storm events can be attributed to the repeated depletion of temporarily connected critical source areas to the river network via impermeable road surfaces. Fertiliser application varied considerably across three years due to differences in crop rotation between farms, with annual N and P fertiliser inputs varying by up to 21% and 41%, respectively. Proportional reductions in annual riverine nitrate-N and TP loadings were not observed at the sub-catchment outlet as loadings were largely influenced by annual runoff. Nitrate loadings were slightly higher during fertiliser application, but there was little relationship between P fertiliser application and riverine TP load. These data indicate that this intensive arable catchment may be in a state of biogeochemical stationarity, whereby legacy stores of nutrients buffer against changes in contemporary nutrient inputs.