sentence: Long-term exposure resulting in U-Cd > 4 μ g / g creatinine ( cr ) and / or B-Cd > 4 μ g / L impairs renal tubular reabsorptive function , as shown by increased urinary excretion of low-molecular weight proteins ( LMWP ) such as β - microglobulin ( B2M ) , α - microglobulin ( A1M ) , and retinol-binding protein ( EFSA 2009a ; J ä rup and Å kesson 2009 ; Nordberg et al. 2007 ) .