Richard A. Roline

Recovery of a stream macroinvertebrate community from mine drainage disturbance

Recovery of aquatic macroinvertebrates from the effects of mine drainage was documented using a ‘weight-of-evidence’ approach which included measures of physical, chemical, and biological data. Taxa richness; number of taxa in the orders Ephemeroptera, Plecoptera, and Trichoptera; and shredder taxa richness all increased downstream of the point source after water treatment was initiated. Cluster analysis of aquatic macroinvertebrate community data along with abundance of a metals sensitive mayfly (Rhithrogena hageni) also suggested recovery from metals effects. Response to decreased metal inputs was rapid and biological measurements of impacted sites attained levels comparable to upstream reference sites in two years. Our results suggest that aquatic communities impacted by metals, in the absence of degraded habitat and with nearby colonist pools, will recover quickly if low instream concentrations of toxicants are achieved.

The effects of heavy metals pollution of the upper Arkansas River on the distribution of aquatic macroinvertebrates

Water quality, types, and diversity of aquatic macroinvertebrates show that heavy metal pollution of the upper Arkansas River is presently moderately severe and conditions for aquatic life are generally poor, particularly in the Leadville area. A 2 year study was done on a 30 km section of the upper Arkansas River, Colorado, to determine the effects of heavy metals pollution on the distribution of the aquatic macroinvertebrates. Physical and chemical water parameters were measured, and aquatic macroinvertebrates were collected. The major sources of heavy metal-laden inflows are Leadville Drain, California Gulch, and a number of intermittent flows entering the Arkansas River between Lake Fork and Lake Creek. Important freshening flows are Tennessee Creek, Lake Fork (containing Halfmoon Creek), and Lake Creek.

INVERTEBRATE ASSEMBLAGES AND TRACE ELEMENT BIOACCUMULATION ASSOCIATED WITH CONSTRUCTED WETLANDS

Invertebrate assemblages were studied in eight monoculture wetland mesocosms constructed for wastewater treatment. Low concentrations of dissolved oxygen (D.O.) were measured in bulrush mesocosms while higher concentrations of D.O. were measured in open water mesocosms containing submerged pondweeds. Invertebrate taxa richness was positively related to D.O. concentrations that were, in turn, related to vegetation communities. Reference wetland sites contained a variety of plant species along with extensive open water areas. Invertebrate taxa richness was greater at reference sites than in any wastewater mesocosm. Invertebrate samples from the wastewater mesocosms and reference sites were analyzed for five trace elements. While the concentrations of aluminum, arsenic, mercury, and silver were below values harmful to wildlife, the concentrations of selenium reached levels of moderate concern on one occasion. Data from this study suggest that selenium bioaccumulation by invertebrates may be related to the type of vegetation community or detrital habitat type. Wetlands designed for invertebrate production for waterfowl should take into account the potential for low D.O. concentrations and trace element bioaccumulation associated with vegetation community types.

Relationships between metals and hyporheic invertebrate community structure in a river recovering from metals contamination

Biota and chemistry from hyporheic samplers were used to describe environmental changes, after treatment of mine drainage, in the shallow hyporheic zone in the upper Arkansas River, Colorado, U.S.A. Samples were collected (1992–1997) from above and below the mine drainage source, and further downstream where a historically cleaner tributary enters the system. Hyporheic metal concentrations were high during spring runoff at the impacted site even after initiation of treatment, but declined after several years. Correspondence analysis and increased invertebrate taxa richness suggested that hyporheic macroinvertebrates were recovering at the previously impacted site. Differences in substrate between sites and high water flows in 1995 also appeared to affect hyporheic communities. High taxa richness and abundance, taxa unique from those found at the surface, and high concentrations of metals found in the shallow hyporheic zone suggests that sampling this zone is important for monitoring recovery of polluted streams.

Selection of the Mayfly Rithrogena hageni as an Indicator of Metal Pollution in the Upper Arkansas River

ABSTRACT Macroinvertebrates from the upper Arkansas River were studied to identify taxa sensitive to heavy metal (zinc) impacts. Field collections and introduced substrates indicated that Rithrogena hageni was intolerant of conditions caused by mine drainage into the Arkansas River. Numbers of R. hageni at the impacted site increased significantly after treatment of mine drainage water was initiated. Data collected from this study suggest that the use of colonized substrates may be useful in studying metal impacts on macroinvertebrate communities.

Leaf Litter Breakdown in a Mountain Stream Impacted by a Hypolimnetic Release Reservoir

ABSTRACT The influence of a hypolimnetic reservoir discharge on breakdown of aspen (Populus tremuloides) leaves was investigated during the late summer and autumn at sites above and below a high mountain reservoir. During the two-year study, leaf packs (5-g envelopes) were secured to stream substrate in riffle/run areas. Leaves protected from invertebrates with fine mesh did not demonstrate differences in leaf loss between sites suggesting that microbial processing was equivalent. There were. however, significant differences in leaf loss in coarse mesh envelopes between sites, with losses higher at the site above the reservoir. Aquatic invertebrate communities colonizing the leaf packs also differed from above and below the reservoir suggesting that invertebrates played a role in the differing leaf loss. We hypothesize that during late summer and fall, leaf breakdown is slower below the reservoir because of the altered invertebrate community.

Use of Hyporheic Samplers in Assessing Mine Drainage Impacts

ABSTRACT Hyporheic pot samples and Surber samples were used to biologically assess an area recovering from the effects of mine drainage. Data indicate that hyporheic samplers are an important component in assessing macroinvertebrate communities impacted by heavy metals.

Changes in the Morphometry of Las Vegas Wash and the Impact on Water Quality

ABSTRACT Las Vegas Wash, a natural wash east of Las Vegas, Nevada, carries stormwater, groundwater drainage, and sewage effluent from two sewage treatment plants to Lake Mead. Over 80 percent of the normal discharge of approximately 3.4 m3/s (120 ft3/s) consists of effluent from the City of Las Vegas and Clark County sewage treatment plants. Beginning in the 1950s, a large wetland area developed along the wash that supported waterfowl populations and contributed to some water quality transformations. Heavy rains and subsequent flooding in the area in 1983 and 1984 resulted in erosion and channelization that greatly reduced the wetland area within Las Vegas Wash. The reduction in wetland area shortened water travel time in the wash and affected water quality. The primary impacts on the water entering Lake Mead have been an increase in temperature, a decrease in dissolved oxygen concentration, and an increase in ammonia levels. Other physical-chemical parameters and changes in nutrient transformations are a...