Lenwood W. Hall

Evaluation of butyltin compounds in Maryland waters of Chesapeake Bay

A monthly sampling programme for dibutyltin (DBT), tributyltin (TBT) and tetrabutyltin (TTBT) was initiated for a period of one year (July 1985–June 1986) in the Maryland waters of Chesapeake Bay. Concentrations of the above butyltin species were evaluated in the microlayer and water column of eight sampling stations representing two small and two large marinas, a large harbour, two major river systems and a heavily used shipping channel. DBT concentrations in the microlayer were generally higher in the four marinas when compared with the other stations. The highest DBT concentration reported in the microlayer was 1156 ng l−1. Mean microlayer TBT concentrations ranged from 54–310 ng l−1 in the four marinas. Three TBT concentrations ranging from 1049–1171 ng l−1 were reported in the microlayer of the marinas. TBT concentrations of 41 and 29 mg l−1 were detected in the microlayer of a heavily used shipping channel (C & D Canal) during May and June. TTBT concentrations were not detected in the microlayer at most stations during the 12 month sampling period. n nMean DBT concentrations in the water column ranged from 23–145 ng l−1 in the four marinas. DBT concentrations in the water column of the other stations were < 35 ng l−1. Mean water column concentrations of TBT ranged from 51–408 ng l−1 in all four marinas. Peak concentrations of TBT were reported in May and June for the various marinas. The highest TBT concentration reported in the water column was 998 ng l−1. TBT concentrations of 20–24 ng l−1 were reported in one of the river systems (Potomac River). TTBT concentrations were not detected in the water column at most of the stations.

Acute toxicity of tributyltin to selected Chesapeake Bay fish and invertebrates

Abstract Acute tributyltin (TBT) toxicity experiments were conducted on selected Chesapeake Bay biota. Four invertebrate and five fish species were evaluated. Tests were conducted using continuous-flow conditions and TBT concentrations were measured every 24 h in test containers. Test solutions were generally within 10–15% of the predicted concentrations. Estuarine copepods were very sensitive to TBT. A 72-h LC 50 of 0.6 μg 1 −1 TBT was reported for Eurytemora affinis; Acartia tonsa had a 48-h LC 50 of 1.1 μg 1 −1 TBT. The most resistant invertebrate tested was the grass shrimp, Palaemonetes sp. (96-h LC 50 > 31 μg 1 −1 TBT). The most sensitive fish species tested were larval inland silversides ( Menidia beryllina ), (96-h LC 50 = 3.0 μg 1 −1 TBT) and juvenile Atlantic menhaden ( Brevoortia tyrannus ), (96-h LC 50 = 4.5 μg 1 −1 TBT). Mummichogs ( Fundulus heteroclitus ) and sheepshead minnow ( Cyprinodon variegatus ), (96-h LC 50 = 23.8 and 25.9 μg 1 −1 TBT, respectively) were the most resistant fish species tested. Concentrations of TBT exceeding the LC 50 values reported for both copepod species have been found in the water column from marinas in northern Chesapeake Bay. Acute TBT toxicity data and its application to environmental concentrations in Chesapeake Bay are discussed.

Mortality of Striped Bass Larvae in Relation to Contaminants and Water Quality in a Chesapeake Bay Tributary

Abstract Numerous factors have been implicated in the decline of striped bass Morone saxatilis along the east coast of the United States. This study was designed to evaluate the effects of contaminants and water quality on survival of striped bass larvae in a natural spawning habitat (Nanticoke River, Maryland). Larvae were tested in chambers submerged in the river. Organic and inorganic contaminants and water quality variables were monitored to correlate survival of larvae with habitat quality. In two 96-h experiments at three river stations, 90–99% of larvae died whereas control mortality was only 15–25%; the differences were significant. None of the 69 organic contaminants specifically analyzed were detected in river water and can be eliminated as causes of larval mortality. Of the eight metals analyzed, seven never exceeded 50 μg/L in river water, but total aluminum concentrations were 480–4,100 μg/L (39–181 μg/L filtered sample). Factors suspected as contributors to mortality were low pH (6.0–6.8), h...

Tributyltin environmental studies in Chesapeake Bay

Abstract This paper presents and discusses all available data on tributyltin (TBT) monitoring and toxicity studies conducted in Chesapeake Bay. TBT evaluations in the water column were more numerous than microlayer, sediment or tissue assessments. Maximum TBT concentrations occurred in marina or harbour areas during the beginning of the boating season; significant reductions were reported during the summer and early fall. Significantly lower TBT concentrations generally occurred in non-marina areas. TBT toxicity data were available for various Chesapeake Bay invertebrates and fish. Few studies have been conducted with phytoplankton. Chesapeake Bay copepods were the most sensitive organism tested. Bivalve embryos were also sensitive to TBT. A comparison of TBT environmental concentrations with toxicity data was attempted. Maximum TBT concentrations reported in the water column of Chesapeake Bay marinas would likely be toxic to some copepods and early life stages of bivalves. Mean TBT values reported in some marinas would also be toxic to sensitive Chesapeake Bay copepods. If laboratory toxicity data are considered a realistic indicator of real world effects, then most of the Chesapeake Bay organisms tested to date would not be affected by TBT concentrations reported in non-marina areas. Full life-cycle toxicity tests are needed to evaluate chronic effects of environmentally realistic concentrations of TBT to Chesapeake Bay biota.

Spatial and temporal distribution of butyltin compounds in a Northern Chesapeake Bay Marina and river system.

This study was designed to: determine dibutyltin (DBT), tributyltin (TBT) and tetrabutyltin (TTBT) bi-weekly for a four month period (June-September 1986) in the Port Annapolis Marina, Mears Marina, Back Creek and Severn River area of Northern Chesapeake Bay; measure DBT, TBT and TTBT for five successive days (Thursday-Monday) to determine possible daily effects (weekday versus weekend) and determine DBT, TBT and TTBT every two hours for one full tidal cycle in the study area. Maximum concentrations of TBT were reported at both Port Annapolis Marina (1801 ng L−1) and Mears Marina (1171 ng L−1) during early June followed by significant reductions in TBT during late summer and early fall. All 4 Back Creek Stations also had highest concentrations of TBT in early June; significant reductions occurred during the next three months. The highest concentration of TBT reported in the Severn River (48 ng L−1) occurred in September. The lowest TBT value (5 ng L-1) at this station occurred in June. TTBT was not detected in any of the samples. The day of week sampled (Thursday-Monday) during the daily experiments was not found to significantly affect TBT concentrations. TBT evaluations every two hours during the tidal cycle demonstrated that values peaked at 1400 and 1600 hr time intervals. Peak concentrations of TBT occurred during a rising tide. The possible consequence of the measured TBT concentrations for aquatic biota are discussed.

MONITORING DISSOLVED COPPER CONCENTRATIONS IN CHESAPEAKE BAY, U.S.A.

Dissolved copper and selected water chemistry parameters were monitored for 11 months in Chesapeake Bay, U.S.A. Dissolved copper concentrations in four recreational marinas, a large harbor, two major river systems, and a heavily used shipping canal ranged from below detectable levels to 80 μg L-1 (-X=11.7 μg L-1). Dissolved copper was detected >91% of the time at five locations. Lowest copper concentrations were found in Potomac River, Baltimore Harbor, Pier One Marina, and C & D Canal (-X=6–10 μg L-1; slightly higher levels of dissolved copper were found in Choptank River (-X=12 μg L-1). Highest levels of copper were detected in Port Annapolis, Hartge, and Piney Narrows Marinas (-X=13–18 μg L-1), with the highest values observed in the study (70 and 80 μg L-1) found in two of these marinas. Copper in the three marinas with highest dissolved copper levels could have been toxic to some of the more sensitive aquatic species. Intensive study of one marina indicated that a likely source of dissolved copper was the recreational boats housed in the marina.

Acidification effects on larval striped bass, Morone saxatilis in Chesapeake Bay tributaries: a review

Reduced striped bass populations along the East Coast of the United States have prompted numerous studies to assess various factors contributing to the decline. Available data from in-situ, on-site and laboratory studies with striped bass in conjunction with water quality and contaminants data confirm that the eastern shore rivers of the Chesapeake Bay (Choptank, Nanticoke, and Pocomoke Rivers) are susceptible to acidic conditions. The Choptank and Nanticoke Rivers are significant striped bass spawning areas. Acidification conditions (low pH, Al, low hardness) were documented in these systems in 1984 at levels reported to cause high mortality to striped bass larvae. Striped bass populations in several western shore tributaries such as the Mattaponi, Pamunkey, Patuxent, and Rappahannock Rivers also appear to be vulnerable to acidic pH conditions. In-situ toxicity studies documenting actual striped bass larval mortality are lacking in these systems; however, based on laboratory data it appears that potentially toxic acidic conditions can exist. Although certain Chesapeake Bay spawning tributaries do exhibit acidic conditions during spawning periods, other systems are resistant to acidification. The Chesapeake and Delaware Canal (C & D Canal), Elk River and Susquehanna River of the Upper Chesapeake Bay and the Potomac River on the western shore appear to be resistant to reductions in pH. The upper Chesapeake Bay and Potomac River are major striped bass spawning areas. Therefore, reduced striped bass production in these systems may be related to factors other than acidification.

Studies of striped bass in three Chesapeake Bay spawning habitats

Abstract Comparisons were made of in situ striped bass prolarval and yearling studies conducted in the Nanticoke River in 1984, Chesapeake and Delaware Canal (CD yearling experiments were conducted in 1985 and 1986. Water quality parameters, inorganic contaminants and organic contaminants were evaluated daily from 24 h composite samples taken during each study. Percent cumulative survival of striped bass prolarvae in the Nanticoke River was less than 10% after 96 h exposure at three field locations during two experiments. Acidic conditions, aluminium and soft freshwater (low buffering capacity) were suspected in causing the poor prolarval survival. Percent cumulative survival of striped bass prolarvae tested in the C&D Canal was 42–59.5% after 96 h of exposure at three field stations during two experiments. Mortality was not attributed to acute contaminant and water quality effects. All yearling striped bass exposed to habitat water for 10 d at the three field stations survived. However, histological effects (lamellar dilations) were reported. Percent cumulative survival of striped bass prolarvae exposed to Potomac River water ranged from 4.5–22.5% during three 96 h experiments at three field stations. Poor survival of prolarvae was attributed to various inorganic contaminants (monomeric aluminium, cadmium, and copper) and sudden decreases in water temperature. Yearling survival in the in situ Potomac River studies ranged from 0–77.5% at the three field locations during two 7 d experiments. High pH conditions and inorganic contaminants were suspected in causing mortality of this life stage. Histological changes in the kidney were also observed in yearlings exposed to Potomac River water. Striped bass prolarval and yearling survival from in situ tests was compared with a juvenile index used by the state of Maryland to assess striped bass production. Only at one site (Nanticoke River, 1984) did the prolarval survival data from the in situ tests predict the quality of Marylands junvenile index. Reasons why these two parameters do not and should not always correlate are discussed.

An evaluation of the potential toxicity of treated bleached kraft mill effluent to striped bass (Morone saxatilis walbaum) larvae exposed through metamorphosis to the juvenile stage

Abstract Twenty-day-old striped bass ( Morone saxatilis ) larvae were exposed to a range of treated bleached kraft mill effluent (BKME) concentrations from 0 to 20% effluent by volume (v/v) under continuous flow test conditins. The experimental test concentrations in the 2–20% BKME test aquaria had a BOD 5 which ranged from to 5 mg l −1 , TSS 12–17 mg l −1 , and true color 35–416 mg l −1 . Bleached kraft mill effluent did not kill larvae exposed to it for 20 days through metamorphosis to the juvenile stage. The BKME did not alter growth in length, weight or condition factor in larvae over the 20-day exposure period as determined by multiple regression analysis. A linear regression analysis on the dry weight data at Day 20 only, however, indicated a trend of decreasing weight with increasing BKME concentration. Effluent-exposed larvae also developed normally during the 20-day study. All individuals examined completed the transformation from postlarvae to juveniles by the age of 40 days.

The effect of acclimation temperature on the interactions of chlorine, ΔT and exposure duration to eggs, prolarvae and larvae of striped bass, Morone saxatilis☆

Abstract The effect of five acclimation temperatures on the interactions of total residual chlorine (TRC) (0.00, 0.15 and 0.30 mg l−1, ΔT (2, 6, 10°C above acclimation temperature) and exposure duration (0.08, 2.0, 4.0 h) conditions were evaluated for striped bass, Morone saxatilis, eggs, prolarvae and larvae. The range of acclimation temperatures (12.5, 15.0, 17.5, 20.0, 22.5°C for eggs and prolarvae; 15.0, 17.5, 20.0, 22.5 and 25.0°C for larvae) tested with each life stage included the lower, optimum and upper environmental temperatures that exist when these life stages may be subjected to power plant chlorination conditions. All organisms were tested using a fractional composite design in a 3 × 3 × 3 factorial matrix. Mortality of the eggs was highest at temperatures below 17.5°C; overall mortality decreased with increasing acclimation temperature. The factor causing the greatest effect with this developmental stage was ΔT, followed by TRC and exposure time. Mortality of striped bass prolarvae increased with acclimation temperature after exposure to interacting treatment factors. Interactions involving TRC were most important from 12.5 to 17.5°C; ΔT interactions were prominent at acclimation temperatures of 20.0 and 22.5°C. Larvae mortality was highest at 20°C with a gradual decrease at 25.0°C. Interactions involving ΔT, TRC and exposure time all contributed to the mortality of this life stage; TRC and ΔT caused the main effects. Striped bass eggs were the most resistant life stage; mean mortality averaged over all acclimation temperatures was approximately the same for prolarvae and larvae.