Effects of acidification on metal accumulation by aquatic plants and invertebrates. 2. Wetlands, ponds and small lakes

Abstract

AbstractCompared were concentrations of Al, Cd, Ca, Cu, Fe, Pb, Mg, Mn, Hg, Ni, P, and Zn in water, plants, and aquatic invertebrates of wetlands, ponds, and small lakes in Maryland and Maine. The accumulation of metals by aquatic plants and insects and the concentration of metals in water were not greatly affected by pH. None of the metal concentrations in water significantly correlated with metals in insects. Plant metal concentrations poorly correlated with metal concentrations in water. Concentrations of metals exceeded acceptable dietary levels more frequently in plants than in invertebrates. Concerns about metal toxicity in birds that feed on invertebrates and plants from acidified waters seem to be unwarranted. Positive correlations among pH, Ca in water, Ca in insects, and Ca in plants imply that acidification can reduce the Ca content of aquatic biota. Aquatic insects were low in Ca, but crayfishes and snails, which are adversely affected by low pH, were very high. A concern for waterfowl is Ca deprivation from decreased Ca availability in low‐pH wetlands, ponds, and small lakes.