Best Practice Guide on the Management of Metals in Small Water Supplies

Sources of and Solutions to Toxic Metal and Metalloid Contamination in Small Rural Drinking Water Systems: A Rapid Review

“…Other factors that generally increase the rate of corrosion include low alkalinity and high temperature as well as higher concentrations of dissolved oxygen and natural organic matter. The impact of other water chemistry parameters including chloride, sulfate, salinity, and hardness on corrosion, while documented, is harder to define given their interactions with each other and with other water chemistry parameters [ 9 , 26 , 27 , 28 , 29 , 30 ]. Shifts in source water, which result in the introduction of water systems to novel water chemistries, can cause metal release from the water system [ 25 , 31 ].…”

“…Since all water systems, regardless of the material used, require periodic maintenance, it is important that proper maintenance procedures are followed [ 4 , 9 ]. As with installation, maintenance should only be carried out by trained personnel, which helps avoid the introduction of parts with unsafe TM levels and the application of modifications that do not meet system specifications [ 9 , 37 ]. To prevent excessive damage to and corrosion of water system parts, maintenance should be conducted on a consistent preventive schedule, instead of only in response to problems [ 37 , 49 ].…”

“…This can be achieved with methods such as pH modifications and the addition of corrosion inhibitors, the dosages of which must be adjusted based on water chemistry [ 35 ]. The International Water Association (IWA) cautions, however, that the process of handling and dosing chemicals is hazardous and may be difficult for non-professionals to manage [ 9 ].…”

“…Numerous methods for treatment were identified in the literature including physical filtration (loose media filters, cartridge filters), chemical filtration (activated carbon, manganese dioxide, activated alumina, granular ferric oxide/hydroxide, other locally produced options), aeration, ion exchange, coagulation, reverse osmosis, distillation, and magnetic purification [ 9 , 16 , 43 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ]. Each treatment method varies with regards to the TMs it treats, complexity of design, maintenance requirements, and costs.…”

“…In most cases where an extraction site is contaminated with TMs, it is simpler and less expensive to find an alternative source of water, especially for small rural drinking water systems that lack professional management [ 9 ]. Where there are no safer alternative sources of water, where remediation is required by law, or the contamination site is relatively small, it is possible to remediate contaminated soil and water.…”