• How is water quality determined in general?

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    A number of criteria are used to assess water quality in general, such as mineral content, dissolved metals, and turbidity. In testing water quality, water is usually sampled and sent to chemical laboratories which measure the concentrations of potential contaminants. Guidelines for the different criteria have been developed by a number of governments and agencies worldwide to protect human health and the environment.


    Water quality is a measure of how suitable water is for a particular purpose. [1] The higher the water quality, the more applications it can be used for with minimal treatment. [1] For example, drinking water is of higher quality than seawater because seawater is unsuitable for drinking and irrigation. [2]

    Water quality is also important for the protection of aquatic ecosystems. High levels of contaminants such as phosphorous, dissolved metals, and sediment can have an adverse effect on the productivity of aquatic plants and the health of fish and other organisms. [2]

    Water quality characterization

    Any physical, chemical, or biological component which affects water quality is considered to be a water quality variable or parameter. [2] There are hundreds of water quality variables, but often only a few are relevant to a particular application. [2] Most of the parameters are measured as a concentration in milligrams (a thousandth of a gram) in one litre of water (mg/L). For instance, one packet of sugar (approximately 4 grams or 4,000 milligrams) would have a concentration of 20,000 mg/L in a 200mL (0.2 L) cup of coffee. For comparison, chloride can be tasted at about 200-300 mg/L, and the drinking water standard set by Health Canada for arsenic is set at 0.01 mg/L. Concentration can also be described in “parts per million” (ppm); in water, 1 ppm is equal to 1 mg/L.

    Characterization and sampling of water sources

    Whether fresh water is surface water or groundwater influences its chemistry, potential for contamination, management, and how it is monitored.

    Surface water is visible at ground level, and includes lakes, rivers, streams, wetlands, and ponds. It often provides habitat for aquatic organisms, a drinking water source for municipalities and wildlife, and a means to discharge waste water. As a result, surface water quality can be degraded by effluent discharge, contaminated runoff, and atmospheric pollutants, which can have far-reaching impacts on the health of aquatic organisms and ecosystems, and downstream water quality. [3] Surface water quality is measured by field equipment and/or sampled in containers and submitted for laboratory analysis.

    Groundwater is found below ground, contained in the spaces between sand grains or loose bedrock. Groundwater occurs most extensively in aquifers, which are important sources of well water in many areas. [4] Because groundwater is covered by a layer of soil and/or rock, it is generally considered to be less easily contaminated than surface water. [5] That said, groundwater is not completely isolated, and can be contaminated and contribute to the contamination of surface water where surface water bodies are fed from groundwater sources. [4]

    Groundwater can become contaminated where polluted runoff seeps through the ground to the water table or flows down fractures or cracks in bedrock. [5] In addition, groundwater often contains more dissolved minerals than surface water as a result of prolonged contact with rocks underground, which can reduce its quality. For example, a number of aquifers around the world naturally contain high levels of arsenic where the groundwater dissolves arsenic-containing bedrock. [6] Groundwater quality is measured using samples taken from monitoring wells at different depths, which are sent to a laboratory for analysis.

    Water quality guidelines

    Drinking water standards for different water quality parameters are set by Health Canada, most governments, and the World Health Organization. The guideline values are based on observed effects in people and animals from each chemical, and are set much lower than the concentration at which these effects are likely to occur. [7] This is designed to protect the most sensitive people in a population. [7]

    Water quality guidelines for the protection of aquatic life are published by the Canadian Council of Ministers for the Environment (CCME), and maximum allowable concentrations in industrial or municipal wastewater are designated by provincial and federal regulations in Canada. [8] Organizations such as the World Bank also have their own standards for wastewater quality in order to encourage good international industrial practice. [9]

    Water quality parameters

    The following table presents a summary of some of the more common water quality parameters that are used to assess the suitability of water for drinking, irrigation, industry, and aquatic life.

    Table 1: Water quality parameters, descriptions, and significance

    More information on drinking water criteria is available from Metro Vancouver, the British Columbia Ministry of Environment, Lands and Parks, and Health Canada.

    Measurement of water quality parameters

    Although some specialized equipment may be used to measure water quality in the field, most accurate measurements require the resources and expertise of a chemical laboratory. [23] Consequently, samples of water need to be taken, labeled, and transported to a laboratory for chemical analysis. [24] A description of the analytical procedures used to measure different water quality parameters is available from the British Columbia Ministry of the Environment.

    Water sampling programs

    Water sampling programs are intended to establish an accurate and representative picture of the water quality of a particular water source. [23, 26] The water samples taken need to be suitable for chemical analysis, free from any external contamination, and of an appropriate number and frequency to capture the variation in water quality parameters over time and space. [23]

    Municipal water sources are sampled and tested to ensure the safety of drinking water. [13] Similarly, waste water is sampled and tested to protect the receiving water bodies and comply with regulations. [23] Metal mines and pulp mills in Canada are required to conduct environmental effects monitoring to ensure their waste water is not damaging the health of the aquatic ecosystems in the receiving waters. [27] Monitoring programs have also been established in natural water bodies such as the Great Lakes to measure trends in water quality and the aquatic environment, and how that environment is affected by human activities in general. [26]

    Data quality control

    Because of the low concentrations at which many of the water quality parameters are measured, it is very important to ensure that no external source of contamination is introduced into the samples. Sources of error can be minimized or eliminated by employing trained environmental technologists and developing standard operating procedures to ensure consistent sampling. [23] In addition, regulators in Canada require the use of a laboratory which has been certified under the Calibration Laboratory Assessment Service (CLAS). [23] Certified laboratories have met international standards for the accurate and consistent measurement of chemical substances. [28]


    Case Study: Community water quality monitoring at Marlin Mine, Guatemala

    The Marlin Mine in the western highlands of Guatemala is a gold and silver mine owned by Montana Explorada de Guatemala, S.A., a 100% subsidiary of Vancouver-based gold mining company Goldcorp. [29, 30] The Marlin mine has generated controversy as well as local opposition since its inception, in part based on allegations of water and environmental degradation. [31] It has also been recognized for its success in initiating and supporting a community environmental monitoring association known as the Asociación de Monitoreo Ambiental Comunitario (AMAC). [32-34]

    AMAC was established by community members from 7 surrounding communities in 2005, increasing to 10 communities in 2006, to conduct an independent, community-based environmental monitoring program in the area around Marlin Mine. [32, 33] Goldcorp provided training in field sampling to community members, which included instruction in the use and calibration of field equipment, chain of custody procedures, and sample bottle, preservation, and labeling requirements. [34] When AMAC realized a sampling field protocol was critical to the accuracy and integrity of the data, two professional advisors from the University of San Carlos were engaged to provide technical support. [33, 34]

    AMAC independently samples a number of surface water, groundwater, and effluent discharge monitoring stations. [33] Water quality parameters measured in the field include temperature, pH, specific conductivity, and dissolved oxygen. [30] Specific conductivity and pH are also measured by a commercial laboratory as are alkalinity, ammonia, chloride, fluoride, nitrogen, sulphate, suphide, phosphorous, cyanide, total dissolved and suspended solids, petroleum chemicals, oil and grease, dissolved metals, and total metals. [30] The samples are sent to ALS Laboratory, an internationally certified chemical laboratory in Vancouver, B.C. [30, 33]

    The results of the monitoring program are printed and distributed in bulletins, and are discussed in well-attended community meetings. [30, 33] The results of the AMAC monitoring program are comparable to those obtained by the internal Goldcorp and the Guatemala Ministry of Environment monitoring programs. [30] An independent report by E-Tech determined that AMAC has the technical capacity to conduct reliable environmental monitoring of the mine with the assistance of its technical team director and consultants. [30]

    Funding for AMAC is provided through La Fundación para la Superación de la Ingeniería (FUNSIN), a foundation at the University of San Carlos, which is supported financially by Goldcorp and the Canadian Embassy. [30, 33, 35] However, the continued reliance on Goldcorp for funding has undermined its credibility with some local people and organizations, and AMAC is continuing to seek independent funding. [33]

    The AMAC monitoring program has led to increased trust in the environmental performance of the mine. In the past, the contradictory information presented by different sources including Goldcorp, the Guatemalan government, religious institutions, and non-government organizations lead to disagreements among stakeholders about the perceived risk of the environmental impact, and left community members uncertain and fearful about whether they were at risk. [33] The establishment of the independent water quality monitoring program was found to build community trust, and the availability of certified data has helped to refute allegations and relieve community concerns about the mine. [34] In addition, the training of local representatives has allowed them to explain the sampling results in a way that could be understood by their peers, which has moderated fears and concerns about impacts on the quality of local rivers, wells, and the water supply. [32] In 2006, the Organismo Latioamericano de Mineria (Latin American Mining Industry Organization) awarded AMAC first prize for integrating mining and community in the most progressive way in Latin America. [34]

    Show References


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