Impact of concrete on riparian ecosystems

Throughout the world, concrete is used extensively in urban development. Due to its convenience and durability, most paths, carparks, dams, and even drainage systems are constructed from concrete. However, recent studies indicate that concrete significantly affects water chemistry and that concrete infrastructure may have a major effect on the chemistry of nearby streams. This is particularly relevant for sensitive waterways such as those in the Blue Mountains region in Sydney, Australia. This study aimed to investigate the chemical changes associated with concrete exposure by conducting water recirculation experiments. Water collected from a pristine Blue Mountains Upland Swamp (BMUS) was mildly acidic (average pH of 4.65) with a low electrical conductivity (EC of 57.99μS/cm) before concrete exposure. After the water was continuously recirculated through a concrete pipe for 120 minutes, pH and EC increased significantly, to 7.87 and 137.72μS/cm respectively. Significant increases in concentrations of ions such as bicarbonate, calcium and sulphate were also observed. Results verify previous findings that concrete significantly and rapidly affects water chemistry and support the hypothesis that concrete plays a significant role in the chemical differences seen between urban and non-urban waterways. Results also indicate that concrete is a source of metals such as copper, chromium, strontium, titanium, and lithium. Furthermore, this study aimed to investigate whether these metals have the potential to affect ecosystems more broadly. Salix babylonica, a common invasive plant species in the Sydney region, was grown in pristine BMUS water and concrete-recirculated BMUS water. Plants grown in concrete-recirculated water had significantly greater new growth and the tissue of these plants was significantly higher in concentrations of barium, copper, lead, manganese, and strontium. As metals in the water appear to be moving into plant tissue, results suggest that these metals are bioavailable and thus have the potential to move into higher trophic levels and the ecosystem more generally. Further investigation is required to determine how far these metals may permeate the food chain

Places to Swim: Perspectives Report

People love to recreate around, on and in the water. As part of the Department of Planning and Open Spaces Program, Places to Swim provides an opportunity to improve access to natural waterways for recreation across NSW. This report investigates the issues, barriers and benefits associated with opening waterways for recreation. NSW is enriched with a range of beautiful and healthy waterways providing opportunities for people to swim and recreate safely, create places that people can visit, and help build better communities. A key attribute for all swimming sites is ensuring they are safe to use. Recreation involving waterways inherently involves risks, including exposure to waterborne contaminants and the risk of injury and drowning. As new swimming sites are opened the risks need to be identified, monitored, and managed

Geochemical impact of urban development on fragile freshwater wetlands

Urbanization is associated with increased cover of impervious surfaces, which poses significant challenges to freshwater ecosystems globally. Implications of catchment urbanization include altered natural hydrology, erosion, weed invasions and modified water chemistry. Blue Mountains Upland Swamps are sensitive freshwater ecosystems located in the Blue Mountains region in south-eastern Australia. They have high conservation value as they are located within a World Heritage Area, are a listed 'endangered ecological community' in Australia and contain endemic and endangered flora and fauna. Water chemistry was assessed in four naturally vegetated and four urban swamps. Urban swamps had higher impervious cover and modified water chemistry, with elevated pH, electrical conductivity and major ions compared to non-urban swamps. Water in urban swamps had elevated calcium, potassium and bicarbonate compared to non-urban catchments, by 19.8, 5.2 and 10.3 times respectively. Although further research is needed, we hypothesize that common concrete materials, particularly drainage infrastructure, strongly influenced differences between urban and nonurban catchments. This adds to growing international research highlighting the potential role of concrete in modifying urban water chemistry due to gradual dissolution and mobilization of ions. In an increasingly urban world, consideration of the ecological consequences of urbanization is required to guide future management approaches

Signatures of urbanization in Temperate Highland Peat Swamps on Sandstone (THPSS) of the Blue Mountains World Heritage Area

Urban freshwater ecosystems exhibit distinct patterns of elevated major ions (calcium, potassium and bicarbonate) and metals, referred to as the ‘urban geochemical signature’. However, the implications of this urban fingerprint at the water-sediment interface within sensitive freshwater systems are not well-known. Temperate Highland Peat Swamps on Sandstone are unique freshwater wetlands found within and surrounding the high-conservation value Greater Blue Mountains World Heritage Area and are a listed ‘endangered ecological community’ in Australia. Water and sediment chemistry were assessed within four urban and four naturally vegetated swamp catchments, through field monitoring and novel laboratory techniques (including X-ray diffraction). Urban swamps had distinct elemental signatures compared to naturally vegetated swamps. Urban swamp water displayed increased pH, elevated ionic strength, major ions (calcium and bicarbonate) and metals (strontium, barium, manganese and iron). Urban swamp sediment had higher calcium, with calcium hydroxide detected at two urban sites. Urban development and concrete drainage infrastructure in swamp catchments modify natural hydrology and water chemistry. Findings suggest swamp sediments may act as sinks of metals and alkalinity, with urbanization remaining a potential source. However, the consequences for high-conservation value systems are not well understood. As urbanization continues to expand, this has implications for fragile freshwater environments worldwide

'Swimmability' : a key element for communities to safely engage with Australian urban rivers

Australia’s largest cities are growing, and this is placing increasing pressure on urban waterways. There is a growing awareness that the quality of life in Australian urban communities is enhanced through the engagement of people with healthy urban rivers. Swimming, boating, and fishing in many Australian urban waterways are popular recreational activities. Swimming and other activities associated with waterways contributes to quality of life in urban communities. Swimming in urban rivers can be risky. Hazards include dangerous currents, aquatic plants, submerged hazards, algal blooms, and unsuitable water quality. In Sydney, Australia’s largest City, swimming is popular in the Hawkesbury-Nepean River. Data from showed that E. coli levels in the river occasionally exceeded safe recreational guidelines for human health. The results are not reported to the public. We believe that it is more important than ever that government, industry and scientific bodies work to protect and improve the water quality of Australian urban rivers as our cities grow. Sharing this information with the community needs to consider education programs, public forums, and timely communication of the current state of local Australian urban rivers regarding their ‘swimmability’

Ecological and geochemical impact of an underground colliery waste discharge to a river

This study investigated the impact of mine wastewater disposal to a nearby river (the Bargo River). Mean electrical conductivity (EC) increased in surface waters below the mine discharge, rising more than six times from (219.5 μS/cm) upstream to 1551 μS/cm below the waste inflow. River pH increased from 7.12 (upstream) to 8.67 (downstream). The mine discharge strongly modified the ionic composition of the river. The mean concentration of several metals in the river were increased due to the mine wastewater. Nickel increased from 1.0 μg/L (upstream) to 32 μg/L (downstream). Zinc increased from 3.5 μg/L (upstream) to 23.5 μg/L (downstream). Our study also assessed the biological uptake of pollutants by growing weeping willow (Salix babylonica) cuttings in mine wastewater and contrasting to ‘control’ cuttings grown in river water from upstream of the mine. After growing in the laboratory for several weeks, the cuttings accumulated metals, dominated by barium, strontium and lithium. Results from the study constituted one of the most detailed geochemical and ecological studies investigating the impact of the coal mine waste discharge to an Australian river. Recommendations are suggested for improved regulation of the mine discharge to reduce its wastewater environmental impact

Elevated sodium concentrations in Australian drinking water supplies

Salt in the drinking water of many Australian water supplies could be adversely contributing to the ill-health of many people. Health care professionals often recommend low-sodium diets for patients with kidney disease, heart disease and cardiovascular disease. It is recommended that people on a low-sodium diet drink water with less than 20 mg/L of sodium. The sodium concentration of water supplies in many regional and remote regions of Australia often had water with elevated sodium (more than 20 mg/L) in their water supplies. In NSW 17 of the 21 regional water supplies tested had higher than 20 mg/L sodium. The issue of elevated sodium in many Australian drinking water supplies needs to be recognised more prominently. Sodium needs to be sampled more frequently and the results shared openly with consumers and health professionals. All water authorities that provide drinking water with sodium concentrations higher than 20 mg/L should be advising their customers of this fact as a high priority. People on low-sodium diets that have >20 mg/L sodium in their water supply should consider options to obtain low-sodium water

Coal mine 'dewatering' of saline wastewater into NSW streams and rivers : a growing headache for water pollution regulators

Alteration to the ionic chemistry of a river or stream as a result of a land use activity, such as mining, would ordinarily be defined as pollution under most water protection legislation and therefore should be regulated. However, this is not always the case, particularly in NSW. This paper reports water chemistry in the vicinity of four coal mines in NSW. Each mine caused elevated pH and salinity and also modified the geochemistry of downstream waters. In all cases there was a change to the relative concentration of major anions and cations. In this study most reference (upstream) waterways had an ionic composition dominated by sodium and chloride ions while most coal mine drainage discharges caused increased concentrations (and often dominance) of sulfate and bicarbonate and other ions, in downstream waters. Results are compared to the Gibbs (1970) model for world geochemistry of surface waters. I discuss the implications of my findings to aquatic ecosystems and to the current regulatory approach controlling NSW mine wastewater discharges. I conclude that the levels and types of salts discharged to waterways from the coal mines are inadequately regulated and may represent an emerging environmental pollution dilemma

The potential and reality of the environment protection licensing system in New South Wales : the case of water pollution

The legislative basis and intent for pollution licensing in New South Wales is comprehensive and provides the Environment Protection Authority (EPA), as the regulatory authority for most pollution, with the ability to consider and protect a range of environmental values through the environment protection licensing system. Despite this ability, this is not occurring in New South Wales. The current regulation of pollution is far from achieving its aims to protect and enhance the quality of the environment, to maintain ecologically sustainable development and to prevent degradation of the environment. These aims are enshrined in the objects of the Protection of the Environment Operations Act 1997 (NSW) (POEO Act) and were widely proclaimed with the introduction of the Protection of the Environment Operations Bill in 1997. This article focuses on the current failures in the implementation of the pollution regulation framework, which have resulted in the degradation of many waterways as a direct result of industrial waste discharges, licensed under the POEO Act. It makes a number of key recommendations for reform of the pollution licensing system, including greater consideration of cumulative impacts of key pollutants, broader coverage of licences, expanded use of market-based approaches, independent monitoring and enforcement, continuous improvement and enhanced public participation. Although this article focuses on case studies involving water pollution, many points are applicable to the licensing and regulation of other types of pollution

Impact of mining and industrial pollution on stream macroinvertebrates : importance of taxonomic resolution, water geochemistry and EPT indices for impact detection

This study investigated freshwater macro invertebrate communities in waterways contaminated by active and abandoned mining and industrial activities in order to ascertain any impact on freshwater ecosystems. We compared macro invertebrate communities at the species, family and order levels of taxonomic resolution. We also collected water samples to compare ionic composition and metal concentrations from waste affected and reference (non-affected) sites. In addition to assessing ecological impairment, the study also sought to determine whether the degree of sensitivity in detecting any impairment varied according to the taxonomic level of identification used. We calculated the biotic indices of EPT richness and taxonomic richness at the species, family and order levels, and performed multivariate analyses to measure differences in community structure at all three levels. We found significant differences in both biotic indices and macro invertebrate community structure at each taxonomic level, indicating ecological impairment at waste affected sites. We also concluded that the most appropriate taxonomic level for evaluating macro invertebrates depends on the information required. In this study, the family level provided the clearest assessment of ecological impairment at waterways affected by mining and/or industrial wastes, and order-level data provided only a marginally less sensitive measure of this impairment