Geology topics

Peter Van Metre

Publications and source records attributed to Peter Van Metre.

4 recordsLinked to original sources

USGS2024

Multiple lines of evidence point to pesticides as stressors affecting invertebrate communities in small streams in five United States regions

Multistressor studies were performed in five regions of the United States to assess the role of pesticides as stressors affecting invertebrate communities in wadable streams. Pesticides and other chemical and physical stressors were measured in 75 to 99 streams per region for 4 weeks, after which invertebrate communities were surveyed (435 total sites). Pesticides were sampled weekly in filtered water, and once in bed sediment. The role of pesticides as a stressor to invertebrate communities was assessed by evaluating multiple lines of evidence: toxicity predictions based on measured pesticide concentrations, multivariate models and other statistical analyses, and previously published mesocosm experiments. Toxicity predictions using benchmarks and species sensitivity distributions and statistical correlations suggested that pesticides were present at high enough concentrations to adversely affect invertebrate communities at the regional scale. Two undirected techniques—boosted regression tree models and distance-based linear models—identified which pesticides were predictors of (respectively) invertebrate metrics and community composition. To put insecticides in context with known, influential covariates of invertebrate response, generalized additive models were used to identify which individual pesticide(s) were important predictors of invertebrate community condition in each region, after accounting for natural covariates. Four insecticides were identified as stressors to invertebrate communities at the regional scale: bifenthrin, chlordane, fipronil and its degradates, and imidacloprid. Fipronil was particularly important in the Southeast region, and imidacloprid, bifenthrin, and chlordane were important in multiple regions. For imidacloprid, bifenthrin, and fipronil, toxicity predictions were supported by mesocosm experiments that demonstrated adverse effects on naïve aquatic communities when dosed under controlled conditions. These multiple lines of evidence do not prove causality—which is challenging in the field under multistressor conditions—but they make a strong case for the role of insecticides as stressors adversely affecting invertebrate communities in streams within the five sampled regions.

Science of the Total Environment↗

USGS2021

Inclusion of pesticide transformation products is key to estimating pesticide exposures and effects in small U.S. streams

Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosystems remains limited. We quantified 108 parent pesticides and 116 TPs in more than 3 700 samples from 442 small streams in mostly urban basins across five major regions of the United States. TPs were detected nearly as frequently as parents (90 and 95% of streams, respectively); 102 TPs were detected at least once and 28 were detected in >20% samples in at least one region—TPs of 9 herbicides, 2 fungicides (chlorothalonil and thiophanate-methyl), and 1 insecticide (fipronil) were the most frequently detected. TPs occurred commonly during baseflow conditions, indicating chronic environmental TP exposures to aquatic organisms and the likely importance of groundwater as a TP source. Hazard quotients based on acute aquatic-life benchmarks for invertebrates and nonvascular plants and vertebrate-centric molecular endpoints (sublethal effects) quantify the range of the potential contribution of TPs to environmental risk and highlight several TP exposure–response data gaps. A precautionary approach using equimolar substitution of parent benchmarks or endpoints for missing TP benchmarks indicates that potential aquatic effects of pesticide TPs could be underestimated by an order of magnitude or more.

Environmental Science and Technology↗

USGS2004

Collection, analysis, and age-dating of sediment cores from 56 U.S. lakes and reservoirs sampled by the U.S. Geological Survey, 1992-2001

The U.S. Geological Survey Reconstructed Trends National Synthesis study collected sediment cores from 56 lakes and reservoirs between 1992 and 2001 across the United States. Most of the sampling was conducted as part of the National Water-Quality Assessment (NAWQA) Program. The primary objective of the study was to determine trends in particle-associated contaminants in response to urbanization; 47 of the 56 lakes are in or near one of 20 U.S. cities. Sampling was done with gravity, piston, and box corers from boats and push cores from boats or by wading, depending on the depth of water and thickness of sediment being sampled. Chemical analyses included major and trace elements, organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, cesium-137, and lead-210. Age-dating of the cores was done on the basis of radionuclide analyses and the position of the pre-reservoir land surface in the reservoir and, in a few cases, other chemical or lithologic depth-date markers. Dates were assigned in many cores on the basis of assumed constant mass accumulation between known depth-date markers. Dates assigned were supported using a variety of other date markers including first occurrence and peak concentrations of DDT and polychlorinated biphenyls and peak concentration of lead. A qualitative rating was assigned to each core on the basis of professional judgment to indicate the reliability of age assignments. A total of 122 cores were collected from the 56 lakes and age dates were assigned to 113 of them, representing 54 of the 56 lakes. Seventy-four of the 122 cores (61 percent) received a good rating for the assigned age dates, 28 cores (23 percent) a fair rating, and 11 cores (9 percent) a poor rating; nine cores (7 percent) had no dates assigned. An analysis of the influence of environmental factors on the apparent quality of age-dating of the cores concluded that the most important factor was the mass accumulation rate (MAR) of sediment: the greater the MAR, the better the temporal discretization in the samples and the less important the effects of postdepositional sediment disturbance. These age-dated sediment cores provide the basis for local-, regional-, and national-scale interpretations of water-quality trends.

Alabama, Alaska, Arizona, California, Colorado, Fl↗

USGS2003

A chronicle of organochlorine contamination in Clear Creek, Galveston and Harris Counties, Texas, 1960-2002, as recorded in sediment cores

Clear Creek flows through the Texas Coastal Plain from its headwaters southeast of Houston, Texas, to Clear Lake, which empties into Galveston Bay. Segments of Clear Creek were on the State of Texas 303(d) list for 1998, 1999, and 2000 as a result of a fish consumption advisory issued by the Texas Department of Health. One of the contaminants for which the fish consumption advisory was issued is the organochlorine pesticide chlordane. Chlordane is a hydrophobic (“waterfearing”) contaminant; that is, it adsorbs to sediment at concentrations much greater than those found in water. The study described here sought to answer three questions: Does chlordane occur in Clear Creek sediments at present? Is there current loading of chlordane to Clear Creek? How has occurrence of chlordane in Clear Creek changed over time? To answer these questions, the U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA), collected and analyzed sediment cores from Clear Creek (fig. 1). Sediment cores sometimes can be used to reconstruct historical trends in concentrations of hydrophobic contaminants (Eisenreich and others, 1989; Van Metre and others, 1997). Cores were collected from five ponds connected to Clear Creek but out of the main channel (fig. 1). Cesium-137 ( 137 Cs) was analyzed in the cores to determine if the sediments in the cores were undisturbed and if the cores reached sediment predating 1964. The two cores that appeared most undisturbed on the basis of 137 Cs profiles (see sidebar, p. 2) were further subsampled and additional samples analyzed for 137 Cs, organic carbon, selected organochlorine pesticides (including chlordane), and total polychlorinated biphenyls (PCB).

Texas↗