Traces of am­phet­a­mines al­ter stream ecol­ogy, study shows

Baltimore Sun - - MARYLAND - By Scott Dance sdance@balt­

When sewage leaks, Bal­ti­more’s wa­ter­ways are not just fouled by the waste. They also be­come con­tam­i­nated with residues of phar­ma­ceu­ti­cals, per­sonal care prod­ucts and even il­licit drugs, re­searchers say.

Traces of am­phet­a­mines from pre­scrip­tion drugs and metham­phetamine make al­gae pro­duce less oxy­gen, speed the growth of midge flies and change the mix of bac­te­ria on stream bot­toms, ac­cord­ing to sci­en­tists who have been gath­er­ing data from the Gwynns Falls for nearly two decades.

While drugs have long been de­tected in ur­ban wa­ter­ways, the re­searchers have shown for the first time that the chem­i­cals can cause re­ac­tions up the food chain.

“We have not done this kind of re­search be­fore,” said Em­maRosi-Mar­shall, an aquatic ecol­o­gist at the Cary In­sti­tute of Ecosys­tem Stud­ies in New York and co-direc­tor of the Bal­ti­more Ecosys­tem Study. “We didn’t know this was the case.”

Sci­en­tists say that while they do not yet un­der­stand how the cock­tail of chem­i­cals car­ried in hu­man waste af­fects streams in com­bi­na­tion, they can in­fer that the drug residues are hav­ing an eco­log­i­cal im­pact.

Over the past 18 years, re­searchers have been study­ing the Gwynns Falls through the Bal­ti­more Ecosys­tem Study. The Na­tional Sci­ence Foun­da­tion-funded project has pro­duced sim­i­lar re­search pa­pers ex­plain­ing the ef­fects of an­tibi­otics, an­tibac­te­rial soaps and an­ti­his­tamines on aquatic ecosys­tems.

In this case, re­searchers built eight ar­ti­fi­cial streams in a lab at the Cary In­sti­tute. Half served as con­trol sub­jects, and the oth­ers were ex­posed to am­phet­a­mines at con­cen­tra­tions sim­i­lar to those found in the Gwynns Falls. The re­searchers found a clear dif­fer­ence from the pres­ence of am­phet­a­mines, a type of stim­u­lant. The re­sults were pub­lished this month in the jour­nal En­vi­ron­men­tal Sci­ence & Tech­nol­ogy.

In the layer of sin­gle-cell al­gae and bac­te­ria that makes stream beds so slick — known as biofilm — they found the drugs’ pres­ence stunted pho­to­syn­the­sis and changed the mix of or­gan­isms present. The biofilm is a key food source for in­sects that sus­tain fish, spi­ders, birds and bats. The am­phet­a­mines also af­fected the in­sects’ growth.

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