The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n=16), pesticides (n=14) and pharmaceuticals, personal care and lifestyle products (n=12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings.

Factors governing spatial and temporal patterns of pesticide compounds (pesticides and metabolites) concentrations in chalk aquifers remain unclear due to complex flow processes and multiple sources. To uncover which factors govern pesticide compound concentrations in a chalk aquifer, we develop a methodology based on time series analyses, uni- and multivariate statistics accounting for concentrations below detection limits. The methodology is applied to long records (1996–2013) of a restricted compound (bentazone), three banned compounds (atrazine, diuron and simazine) and two metabolites (deethylatrazine (DEA) and 2,6–dichlorobenzamide (BAM)) sampled in the Hesbaye chalk aquifer in Belgium. In the confined area, all compounds had non-detects fractions >80%. By contrast, maximum concentrations exceeded EU's drinking-water standard (100 ng L−1) in the unconfined area. This contrast confirms that recent recharge and polluted water did not reach the confined area, yet. Multivariate analyses based on variables representative of the hydrogeological setting revealed higher diuron and simazine concentrations in the southeast of the unconfined area, where urban activities dominate land use and where the aquifer lacks protection from a less permeable layer of hardened chalk. At individual sites, positive correlations (up to τ=0.48 for bentazone) between pesticide compound concentrations and multi-annual groundwater level fluctuations confirm occurrences of remobilization. A downward temporal trend of atrazine concentrations likely reflects decreasing use of this compound over the last 28 years. However, the lack of a break in concentrations time series and maximum concentrations of atrazine, simazine, DEA and BAM exceeding EU's standard post-ban years provide evidence of persistence. Contrasting upward trends in bentazone concentrations show that a time lag is required for restriction measures to be efficient. These results shed light on factors governing pesticide compound concentrations in chalk aquifers. The developed methodology is not restricted to chalk aquifers, it could be transposed to study other pollutants with concentrations below detection limits.

Groundwater in the Chalk aquifer is an important water resource whose quality has degraded due to fertilizer and pesticide use. Atrazine, classified as a priority substance, has been one of the most applied pesticides and also one of the most frequently detected pesticides in groundwater. The present study investigated the transfer and degradation of atrazine in the unsaturated zone of the Chalk aquifer in Northern France. The study was conducted in an underground quarry (Saint-Martin-le-Noeud), which provides a direct access to the water table and intercepts the unsaturated zone at different depths. The lake and the ceiling percolation of 16 sites throughout the quarry were followed. For 16 sites, the percolating flow rate and lake level were measured and the lake water was sampled for nitrate, atrazine and deethylatrazine (DEA, main degradation product of atrazine) analysis over 2.5 years. High spatial variations in hydrodynamics (percolating flow rate and lake level) and in lake water quality (atrazine between 55±11 and 202±40 ng L−1 and DEA between 269±53 and 1727±345 ng L−1) indicate that the properties of the unsaturated zone influence the transfer and the degradation of atrazine. A counterclockwise hysteresis characterizes the relationship between the lake level and atrazine concentration. Temporal variation shows that the atrazine is transferred through the matrix and fractures with a delay caused by the sorption process that differs in atrazine and DEA. The layer of clay-with-flints is shown to favor the degradation of atrazine near the surface. Preferential pathways may be created below clay-with-flints, through which the transfer of atrazine is quicker.

Waste water treatment plants (WWTP) have attracted attention in numerous studies in their impact on receiving surface waters because of the presence of varied contaminants in their effluents. This study investigated the relevance of particle-bound contaminants using suspended particulate matter (SPM) to monitor the temporal variability of the impact of a WWTP discharge in a chalk stream (Loue River) in France. We performed five sampling campaigns of SPM and sediment during a year at different seasons and analyzed polycyclic aromatic hydrocarbons (PAHs) and phosphorus in both matrix. PAH contents in SPM ranged from 675 to 3709 μg kg⁻¹ dry weight (dw) and in sediment from 668 to 7712 μg kg⁻¹ dw. Levels of phosphorus ranged from 364 to 1380 mg kg⁻¹ dw in SPM and from 315 to 523 mg kg⁻¹ dw in sediment. The WWTP increased significantly PAH levels in SPM to the Loue River. However, our results did not allow to evidence significant differences on particulate phosphorus concentration in SPM. Nevertheless, we evidenced significant seasonal variations of PAH and phosphorus concentrations in SPM. Besides sediment sampling, the collection of SPM allowed to monitor changes in contamination from the WWTP and highlighted impact of WWTP on PAH concentrations and changes of PAH and phosphorus concentrations over time. Contamination of SPM of the Loue River was driven by mixed inputs from point source like WWTP and from diffuse sources in the catchment like runoff from impervious and pervious surfaces. Combining monitoring of SPM and sediment proved to be an improved approach to assess contamination of local and diffuse sources in chalk streams.

Plants of the order Brassicaceae have evolved a chemical defence against herbivory: the glucosinolate-myrosinase system. Mechanical damage to plant tissues, such as grazing, initiates the production of phenethyl isothiocyanate (PEITC), a compound toxic to invertebrates. Mechanical damage caused during biofumigation and the harvesting and washing of watercress presents routes for PEITC release into waterbodies, such as the chalk stream spawning sites of brown trout (Salmo trutta). This laboratory study exposed developing S. trutta embryos to PEITC at concentrations of 0.01, 0.1 and 1 μg/L. S. trutta exposed to 1 μg/L PEITC during embryonic development resulted in 100% mortality after four dose days. Exposure to 0.1 μg/L PEITC resulted in an approximate fourfold increase in mortality relative to the controls, while exposure to 0.01 μg/L PEITC had a negligible effect on embryo mortality. Embryos exposed to 0.1 μg/L PEITC showed a significant delay in hatching and produced alevins with significantly shorter total lengths, lighter body weights and an approximate threefold increase in spinal deformities relative to those exposed to the controls and 0.01 μg/L PEITC. The results of a motor activity assay demonstrate that alevins exposed to PEITC showed a significant decrease in swimming activity compared with control animals during periods of illumination. The increased mortality, teratogenic effects and impaired behaviour in S. trutta following embryonic exposure to relatively low concentrations of PEITC highlight a need to accurately quantify and monitor environmental levels of PEITC.

This paper investigates the changes in bioavailable phosphorus (P) within the hyporheic zone of a groundwater-dominated chalk stream. In this study, tangential flow fractionation is used to investigate P associations with different size fractions in the hyporheic zone, groundwater and surface water. P speciation is similar for the river and the chalk aquifer beneath the hyporheic zone, with ‘dissolved’ P (<10 kDa) accounting for ~90% of the P in the river and >90% in the deep groundwaters. Within the hyporheic zone, the proportion of ‘colloidal’ (<0.45 μm and >10 kDa) and ‘particulate’ (>0.45 μm) P is higher than in either the groundwater or the surface water, accounting for ~30% of total P. Our results suggest that zones of interaction within the sand and gravel deposits directly beneath and adjacent to river systems generate colloidal and particulate forms of fulvic-like organic material and regulate bioavailable forms of P, perhaps through co-precipitation with CaCO3. While chalk aquifers provide some degree of protection to surface water ecosystems through physiochemical processes of P removal, where flow is maintained by groundwater, ecologically significant P concentrations (20–30 μg/L) are still present in the groundwater and are an important source of bioavailable P during baseflow conditions. The nutrient storage capacity of the hyporheic zone and the water residence times of this dynamic system are largely unknown and warrant further investigation.

Aqueous natural organic matter (NOM) impacted by two contrasting human impacts was analyzed using by multiresponse fluorescence, decoupled with the resolution routine PARAFAC. The first site is Chalk River, Ontario, Canada, near a pit formerly used to dispose low-level wastes. The second site is the Grand River in Cambridge, south-central Ontario, which is impacted by urban activities and agriculture. Our analysis included raw water, plus fractions from ultrafiltration and solid-phase extraction (SPE). The fluorescence spectra of the NOM, resolved with PARAFAC, showed three common features: humic-like components, at excitation/emission wavelengths 325-350/450-475 nm, fulvic-like components at 325/380-420 nm and protein-like components, at 275/300 nm. Ultrafiltration revealed that most of the NOM comprised fine material below 5,000 Da cut-off (<4% of the total) in the urban-impacted sites and the clean site at Chalk River, but the colloidal fraction (larger than 5,000 Da) was substantially higher in the contaminated water, with ∼18-26% of the total. The protein-like components in the contaminated Chalk River water were affected by ultrafiltration, but less so in the clean Chalk River sample and the urban-impacted waters. SPE preferentially removed the protein-like component in the contaminated Chalk River water (typically 89-95% signal decrease), but had a limited effect on humic- and fulvic-like components elsewhere. In conclusion, multiresponse fluorescence provided new information on the NOM quality from two contrasting sites, aided by ultrafiltration and SPE. These results are consistent with the in situ production of NOM in the Chalk River contaminated site, and natural production at the other sites.

This study investigated the causal linkage between environmental pollution by carbon dioxide (CO₂) emissions and net foreign direct investment (FDI), along with some other variables, namely economic growth by real per capita income and trade openness, using balanced annual data of 17 countries from Asia for the period from 1980 to 2014. Panel cointegration tests confirm the long-run association among the variables. After checking the panel data for stationarity properties, the method panel fully modified ordinary least squares (FMOLS) is implemented. The FMOLS estimates on CO₂ emission model reveal that inward FDI has a significantly positive impact on environmental pollution, supporting the pollution haven hypothesis (PHH). Likewise, FDI model results imply that CO₂ emissions represent environmental pollution; economic growth and trade openness are the pivotal determinants of FDI. Panel causality results suggest bidirectional linkages between CO₂ emissions and inward FDI. Empirical findings suggest that economic policy reforms are required to channelise foreign capital inflows to a more environmentally healthy direction. The governments of Asian countries should chalk out policies on FDI inflows and the environment in order to achieve sustainable economic growth and development.

The role of energy cannot be passed over in the process of economic growth and development in any economy. China consumes colossal quantity of energy; thus, the central objectives of this study is to empirically evaluate the linkages among energy use, environment by CO₂ emissions, human health by health expenditures, Foreign Direct Investment (FDI) inflows, and real GDP per capita used for economic growth over the period of 1995–2016 for China. The nature of the data directed to employ the Canonical cointegrating regression (CCR) method for unknown parameter estimation. Four equations have estimated namely for FDI, health, environment, and economic growth. The result for China during the period under the study reveals that energy consumption has significant positive impact on FDI, health, environment, and economic growth. The study results suggest that policy makers need to chalk out effective policy for effective utilization of energy so as to encourage permissible economic growth and development in China.

The occurrence of pharmaceuticals in freshwater ecosystems provokes increasing concern due to their potential risk to non-target organisms and to human health. Pharmaceuticals are used in both human and veterinary medicine and are essentially released into the environment via wastewater treatment plants (WWTPs) and from livestock. In this study, 31 pharmaceuticals were analyzed in effluent and surface water upstream and downstream of two WWTPs in the Loue–Doubs rural karstic catchment in Eastern France. Diclofenac (965 and 2476 ng L⁻¹), sulfamethoxazole (655 and 1380 ng L⁻¹) and carbamazepine (566 and 1007 ng L⁻¹) displayed the highest levels in the effluents of both WWTPs. Diclofenac levels were also high in surface water samples 300 and 166 ng L⁻¹ in the River Doubs and the River Loue, respectively, followed by paracetamol (273 and 158 ng L⁻¹) and sulfamethoxazole (126 and 73 ng L⁻¹). In both rivers, the most critical compounds were found to be the antibiotic sulfamethoxazole (risk quotient (RQ) from 23.7 to 51.1) and ofloxacine (RQ from 1.1 to 18.9), which reached levels inducing toxic effects in aquatic organisms. This study showed that WWTP effluents are the major sources of the pharmaceuticals, but raw discharges from human residences, pastures and livestock manure represent significant sources of contamination of surface water and groundwater. The aim of this study was to assist scientists and authorities in understanding occurrence and sources of pharmaceuticals in order to improve water quality management in chalk streams.