▁as ▁sur ma ▁are ▁recognized ▁as ▁one ▁of ▁the ▁important ▁sources ▁of ▁lead ▁expos ure ▁in ▁Pakistan . ▁As ▁ad verse ▁health ▁effects ▁of ▁heavy ▁met als ▁are ▁a ▁public ▁health ▁concern , ▁where ▁especially ▁lead ▁may ▁cause ▁negative ▁health ▁impact s ▁to ▁human ▁f etal ▁and ▁infant ile ▁development , ▁a ▁study ▁in ▁Pakistan ▁of ▁pre gn ant ▁women ' ▁n ails ▁in ▁ 2 0 1 6 , ▁showed ▁th ir teen ▁n ail ▁samples ▁out ▁of ▁ 8 4 ▁n ails ▁analyz ed , ▁contained ▁lead ▁higher ▁than ▁the ▁concentration ▁( 1 3 . 6 ▁ μ g / g ) ▁of ▁the ▁fatal ▁lead ▁poison ing ▁case , ▁with ▁the ▁possibility ▁of ▁an ▁external ▁cont am ination . ▁The ▁observations ▁showed ▁that ▁lead - cont aining ▁sur ma ▁consists ▁of ▁fine ▁particle ▁of ▁gal ena ▁( ore ▁of ▁lead ▁sul f ide ) ▁in ▁res pi rable ▁dust ▁range ▁( less ▁than ▁ 1 0 ▁ μ m ) ▁and ▁relative ▁in ▁vit ro ▁bio av ail ability ▁of ▁lead ▁in ▁the ▁sur ma ▁was ▁determined ▁as ▁ 5 . 2 %. ▁Thus , ▁lead - cont aining ▁sur ma ▁consists ▁of ▁in hal able ▁and ▁bio available ▁particles , ▁and ▁it ▁cont ributes ▁an ▁increased ▁risk ▁of ▁lead ▁expos ure . ▁ ▁" Blue " ▁K ohl ▁is ▁a ▁dark - bl u ish ▁black ▁p ig ment ▁composed ▁of ▁both ▁lead - based ▁comp ounds ▁as ▁well ▁as ▁a ▁comp ound ▁of ▁ant im ony . ▁The