Approximately 100 different human pharmaceuticals have been identified at low levels in wastewater treatment plant effluents, surface waters, seawaters, groundwater, and some drinking waters from around the world (Fent et al. 2006
; Hemminger 2005
; Kolpin et al. 2002
). Classes of drugs that have been detected include analgesics and anti-inflammatories, beta-blockers, lipid regulators, anti-epileptics, anti-depressants, oral contraceptives, and antibiotics. Intentional flushing of medications down the toilet, rinsing topically applied medications off in the tub or sink, and excretion of medications in urine or feces are the entry points for most pharmaceuticals into wastewater treatment systems. The federal government and a number of states have discouraged disposal of drugs by flushing them down the toilet, but this does not prevent contamination by rinsing or excretion. Although there are no documented health consequences from these exposures, there are concerns about the impact of long-term low-level exposures to medications, especially those that are environmentally persistent, and those that may bio-accumulate in the food chain. Impacts on ecologic systems are also of concern, especially in light of discovery of intersex fish in major waterways in the United States and their association with exposure to endocrine disruptors (Chambers and Leiker 2006
). Advanced water treatment technologies can remove many contaminants; however, this technology is expensive and may not be affordable for many municipalities. As communities look for alternative ways to manage pharmaceuticals and persistent chemicals in wastewater, the California ban on lindane deserves scrutiny as a potential approach to improve wastewater quality and limit global contamination with persistent organic pollutants (POPs).
Lindane, the gamma isomer of hexachlorocyclohexane (γ-HCH), is an environmentally persistent organochlorine insecticide manufactured since the 1940s for both agricultural and pharmaceutical purposes. In agriculture, lindane has been used as an insecticide to treat seeds, crops, and lumber/timber, and to treat cattle and other farm animals for ectoparasites. As a prescription medication, lindane is used as a topical treatment for human infestations of head lice and scabies.
Throughout the world, recognition of lindane’s toxicity and its environmental persistence has resulted in an overall decline in use. Lindane has not been produced in the United States for many decades and has undergone progressive limitations on agricultural use [Commission for Environmental Cooperation (CEC) 2006
]. In August 2006, the U.S. Environmental Protection Agency (EPA) cancelled all remaining registrations for agricultural uses of lindane (U.S. EPA 2006
When used as a pharmaceutical, acute exposure to lindane has been reported to cause skin irritation, dizziness, headaches, diarrhea, nausea, vomiting, and, in some instances, convulsions and death (Thomson Micromedex 2006
). There have been 3 confirmed deaths and 17 reported deaths associated with lindane use [Food and Drug Administration (FDA) 2003c
]. All of the deaths occurred when lindane was used in an off-label manner. Neurologic effects are commonly reported outcomes in the FDA adverse effects database (FDA 2003c
). Of the reported neurologic events, 70% included seizure, dizziness, headache, and paresthesias (FDA 2003c
). In some instances, lindane has caused seizures after one application given according to package directions (FDA 2003a
Lindane is the least effective common pharmaceutical treatment for head lice when compared in vitro
with other chemical alternatives including pyrethroids, malathion, or synergized pyrethrins (Meinking et al. 2002
). Because of toxicity concerns, in 1995 the FDA advised that lindane be labeled as second line therapy, only to be used after other treatments have failed (FDA 2003c
). In 2003, the FDA issued a “black box” public health warning for lindane treatments, reemphasizing that lindane should only be used as second line therapy and recommending use with caution in anyone weighing < 110 lb, the elderly, and those with seizure disorders (FDA 2003c
). Despite the cancellation for agricultural use, demonstrated toxicity in humans, and low efficacy in treating pediculosis (Meinking et al. 2002
), lindane continues to be available by prescription in the United States.
Lindane is a known contaminant in waste-water. Because head lice and scabies treatments are rinsed down the drain after use, lindane readily enters wastewater treatment plants. Wastewater treatment plants are not designed to remove lindane; therefore, much of the lindane passes through and enters downstream lakes, rivers, and the ocean (U.S. EPA 2002
). California has stringent water quality standards for lindane, including a criteria of 19 ppt for existing or potential drinking water sources (U.S. EPA 2000
). This standard is based on long-term human cancer risk from ingestion. Wastewater treatment engineers in Los Angeles, California, calculated that a single treatment for head lice or scabies contains enough lindane to bring 6 million gallons of water above this California water quality standard [County Sanitation Districts of Los Angeles County (CSDLAC) 2001
]. To address these concerns, the CSDLAC, the City of Los Angeles, and the National Pediculosis Association jointly conducted an outreach campaign in 1999 to provide information to clinicians on alternatives to lindane and to recommend limiting its use (CSDLAC 2000
). The outreach campaign consisted of three direct mailings to target audiences and mass-media exposure. Direct mailings included flyers (in seven languages), refrigerator magnets, and head lice combs. Presentations were made addressing the issues of the campaign. Mass media included newspaper, radio, and television coverage. The target audiences included doctors, hospitals, pharmacists, school nurses, and day care centers in Long Beach and Burbank, California. A relevant website and a toll-free hotline were also established.
In 2000, the California legislature passed, with no opposition on record, a ban on the sale of all pharmaceutical lindane products effective 1 January 2002 (State of California 2000
). To determine the potential impact of this ban on water quality, we obtained data from wastewater treatment plants on waste-water lindane concentrations. Also, to determine the number of acute poisonings due to lindane before and after the ban, we reviewed telephone calls to the California Poison Control System. To more systematically investigate the impact of the lindane ban on prescribing practices of health care providers’ in California, we surveyed pediatricians 3 years after the ban’s effective date.