Many human activities such as agriculture and mining are increasing water salinity in rivers and lakes and this has adverse effects on human health and ecosystem functioning. It can also have high economic costs due to loss of ecosystem services and direct costs related to water for human consumption. Our study also warns that in most cases preventive actions focus solely on human uses of water, ignoring the protection of aquatic biodiversity. Some countries have made progress in regulating salinity on the basis of ecological criteria. Even so, the degree of protection is insufficient. In most cases these are only recommendations based on the total quantity of salt, without taking into account the concentration of different ions that have different toxicity.
We call for global solutions and preventive policies based on the scientific consensus, taking into account social, economic and environmental issues in order to protect aquatic ecosystems from increasing salinity. We also predict that climate change will aggravate this situation because water evaporation will increase, diminishing the capacity of rivers and lakes to dilute salts, and sea level rise will cause intrusion in coastal freshwaters. We propose incentives for good practices and the use of technology that will reduce salt concentrations in freshwaters. We also recommend permits and controls for enterprises that discharge salt-rich effluents into freshwaters in order to control the concentration and timing depending on the dilution capacity of receiving waters.
Ecological disasters caused by increasing salinity, though few in number, have brought about large-scale loss of biodiversity and suffering for human inhabitants affected, as is the case of the fisheries collapse in the Aral Sea. We are still in time to prevent further disasters if appropriate prevention practices are put in place. Nonetheless, increasingly saline aquifers and arable land already make it impossible to cultivate certain crops (e.g. Ebro valley), rendering it harder to provide drinking water. The countries of southern Europe will suffer most from this situation and experience greatest difficulties in economic activities.
Cañedo-Argüelles M, Hawkins CP, Kefford BJ, Schafer RB, Dyack BJ, Brucet S, Buchwalter D, Dunlop J, Fror O, Lazorchak J, Coring E, Fernandez HR, Goodfellow W, Achem ALG, Hatfield-Dodds S, Karimov BK, Mensah P, Olson JR, Piscart C, Prat N, Ponsa S, Schulz CJ & Timpano AJ 2016, ‘Saving freshwater from salts’, Science, 351 (6276): 914.