SCIENTISTS ON WATER QUALITY CHALLENGES AND RESPONSES

Notwithstanding that over the past decade, the water quality of surface waters and ground waters has improved over many parts of the world, particularly in industrialized countries and in some parts of middle and lower income countries, reads the “Nairobi Scientific Communique (NSC) on Water Quality Challenges and Responses”.

Investing in waste water treatment, assuring access to safe water, preventing water pollution and restoring aquatic ecosystem are unfinished business that require the attention of policy makers and water experts, the scientific panel UN – Water and the Global Water System Project of the Earth Science Partnership (GWSPESP) at Unep says.

Prof. Joseph Alcamo, chief scientist, Unep, says that rivers and other fresh water systems are faced with new threats of their water quality. “In emerging and developing countries water quality is threatened by the increasing discharge of untreated or inadequately treated municipal waste-water as well as by diffuse sources of pollutants from agricultural, urban and other areas that degrade surface waters and groundwater.”

Alcamo adds that water quality degradation poses health risk to those who come in direct contact with it and undermines ecosystem services provided by surface and subsurface water. “Waste-water loadings also deplete dissolved oxygen, increase turbidity, and jeopardize the service they provide,” the statement says, adding that the “impact might include diminishing stocks of freshwater fish for food, declining aquatic biodiversity, deteriorating water quality, for industrial and agricultural use, and higher treatment costs for municipal water supply.”

Prof Shem Wandiga a don at the University of Nairobi who was part of the panel says that “people in developing countries are more susceptible to the impacts of water quality degradation than those in industrialized countries because the lower income trend put them at greater risk to disease, and their communities often do not have adequate funds for water treatment.”

In countries undergoing rapid economic development a new threat is caused by increasing discharge of toxic organic chemicals, heavy metal, and other substances to the surface waters. Some of these substances may accumulate in freshwater ecosystems or infiltrate to groundwater and thereby pose a long – term risk to human health and aquatic systems.

In industrialist countries, as well as in some developing ones, an increasing threat is the discharge to surface waters of unidentified and unmonitored residues from medicines and new chemical products. Since conventional waste-water treatment might not be able to remove some of the substances thus finding their way to freshwater systems.

Some of these substances might act as endocrine disruptors – harmful to the people and the environment, says the NSC , elaborating that another treat to industrialized countries, are the heavy metals and other toxins emptied into the rivers that become bound to the sediment of riverbeds which might be re-suspended in river water and have a negative impact on people and ecosystems.

CAUSES OF WATER QUALITY DEGRADATION

Expanding the coverage of water supply without providing adequate facilities to collect and treat its returning waste-water flows could result in degraded water quality, the panel articulates: “To avoid this problem, an integrated approach to water quantity and quality would be helpful, that is, the expansion of water supplies should always go hand in hand with the treatment and/or reuse of their waste-water return flows.”

Waste-waters are often discharged without adequate treatment directly or indirectly to different types of water bodies (rivers, groundwater, aquifers, wetlands, lakes, seas and oceans), these 11 scientist drawn from international water related institutions across the world says, explaining that, “these problems can be avoided by any number of available waste management techniques such as recycling or reusing waste streams within the manufacturing facility, or by on-site treatment of wastes.

In agricultural regions, a main source of water contamination is seasonal runoff of pesticides and fertilizers from cropland and pastureland, says the scientist among them Prof. Jamos Bogardi, executive officer, GWSPESP, Hungary, Prof. Xia Jun, president of the International Water Association, china, “other land – based water pollution are deforestation and intensive animal husbandry which often cause erosion and increased sediment loading to surface waters. Urban areas are also a major source of diffuse water pollutants. Beter land management and planning could help minimize these problems”.